Tag: open hardware

Recreates an Atari 8-bit computer on a Mini-ITX motherboard with integrated memory, input, mouse, and video upgrades.

The maker publishes schematics, a BOM, production Gerbers, firmware, and PCB source files. The page points to The Brewing Academy for boards and systems, but current assembled stock was not checked in this pass.

Selects which 1088XEL joystick port receives input from its PS/2 mouse.

The maker publishes a schematic and Gerbers and links to both bare-PCB layouts at OSH Park. This is a self-built selector rather than a current assembled product; the generic layout requires suitable LED and switch openings in the chosen case.

Recreates an Atari 8-bit computer for an Atari 1050 case with integrated IDE storage, expanded memory, PS/2 input, video, stereo audio, MIDI, and expansion.

The maker publishes schematics, a BOM, firmware, panel files, and production Gerbers. The project page links to The Brewing Academy for boards and assembled systems; verify current stock on the seller page.

Replaces the Atari 1200XL memory subsystem with 1088 KB of SRAM.

The maker publishes a schematic, Gerbers, and the programmed-logic JED file but no bill of materials. The installation removes twelve socketed chips from the motherboard and transfers four original chips to the upgrade. The RF choke may need to be bent or removed for clearance. Install the 1 mm board only with the motherboard out of its case and supported on a solid surface because the stacked machine-pin sockets require substantial insertion force.

Recreates an Atari 8-bit computer on a compact 4.5-inch motherboard with 576 KB of RAM, PS/2 input, selectable ROMs, and modern daughterboard expansion.

The maker publishes Gerbers, schematics, a BOM, firmware, and case files, and points to The Brewing Academy for assembled systems and boards. The current project page requires a documented oscillator video fix on existing builds.

Adds wired 10 Mbit Ethernet and RR-Net-compatible networking to C64-family computers, with an optional multi-ROM socket.

The current RETRO Innovations store exposed the 64NIC+ category and a Choose Options purchase path on 2026-07-30. The product comes in four case and ROM-selector configurations. Network software, an Ethernet cable, and a 10 Mbit-capable network connection are required separately.

Generates digital video from Apple II display memory through an HDMI-compatible connector.

JCM showed 22 v2.0 cards and 20 v4.4 cards in stock on 2026-07-24. On an Apple IIgs, A2DVI displays only legacy Apple II modes; 320- and 640-pixel Super Hi-Res applications do not appear on its output. A v4.4 card runs only one selected firmware function at a time.

Open hardware and software platform for building Raspberry Pi Pico-based Apple II peripheral cards.

JCM showed 36 assembled A2Pico cards in stock with selectable preinstalled firmware on 2026-07-24. Choose the board and firmware together. The simpler A2Pico2Lite design uses a Pico 2 and omits the original A2Pico microSD slot. Unpowered USB OTG hubs can cause device problems, especially with mice.

Open 68060 processor card for Amiga 3000 and 4000 computers.

AMIGAstore warned that only the last assembled units remained on 2026-07-24. Rabbit Hole Computing's bare PCB listing was sold out. Building from the GPL-licensed project files is an advanced assembly requiring the processor, programmed logic, connectors, and the rest of the bill of materials.

Adds 8 MB of Fast RAM and a bootable 44-pin IDE controller at the Amiga 500 CPU socket.

The assembled Lotharek revision exposed a login-or-register-to-buy path on 2026-07-27; the original Oleg Mishin design files, ROM, firmware, software, and four-layer PCB are public. The box contains only the board. Kickstart and Workbench 1.3 or newer can autoboot without a patched scsi.device. A socketed CPU makes installation simple, but an unsocketed CPU must be desoldered. Pin 1 must be observed when attaching CF or SD hardware because a reversed adapter can destroy the CPLD. The open repository documents the original A500 design, while the current seller alone claims A500 Plus support for its revised hardware.

Loads cartridge images and XEX files from USB-managed flash storage through an inexpensive RP2040-based Atari XL/XE cartridge.

A8Renegade's live Shopify product data and collection reported the assembled cartridge orderable on 2026-07-27, despite a contradictory sold-out label in the rendered product page. The complete open design also remains buildable.

Uses an STM32 and SD media as a mature open Atari ST hard-drive emulator with ACSI, disk-image, and GemDrive modes.

The upstream project describes hardware and software version 5.00 as finished and mature. Its release package contains files for ordering a compact board with assembly, but the builder must flash it initially with a 3.3 V-compatible USB-to-UART adapter and supply 5 V USB-C power, media, and an optional CR2032. Firmware 1.x, 2.x, and 3.0-or-later boards have different compatibility paths; the current compact design should use the matching current firmware. Lotharek's separate four-slot ACSI2STM Redux case design remained not yet available on 2026-07-27 and is not represented as a current assembled seller.

Recreates the circa-1990 AdLib OPL2 FM-synthesis sound card as a buildable open hardware project.

This is a self-assembly reproduction rather than a currently sold assembled card. The repository has no packaged release; use the project files and parts list directly.

Replaces the Amiga 3000's ZIP-package Fast RAM with standard 72-pin SIMMs.

Rabbit Hole Computing marked the bare PCB sold out on 2026-07-24. The PCB did not include SIMM sockets, adapter pins, capacitors, resistor, LED, or SIMMs. Its linked project page now returns 404, so verify that a used board includes the build information and all required parts.

Recreates the Comspec SA-1000 sidecar to add a SCSI bus and real-time clock to an Amiga 1000.

This is a self-assembly project with a schematic, bill of materials, and fabrication package. It requires programmed GALs and ROMs plus careful alignment of the 86-pin edge connector. The alternate RTC-72421 clock chip is suggested but untested.

Generates crisp 640 by 480 VGA from Apple II video memory using a Raspberry Pi Pico bus-snooping card.

JCM showed 36 assembled A2 VidGA cards in stock on 2026-07-24, with firmware choices for Apple II and II Plus or Apple IIe. RetroFletch's A2 Analog seller was taking a break on 2026-07-27; its published board has a critical VGA IDC footprint error, so the cable's red wire must face the motherboard. A2 Analog can also conflict with some accelerators, card autodetection, CFFA3000, and ROMX configurations. Infinity Products' SMC A][ VGA Mini was out of stock, and Laser's assembled Mark Aikens variant showed zero stock. Choose the exact hardware and firmware branch rather than treating every variant as interchangeable.

Lets a 1088XLD emulate a joystick with its PS/2 keyboard arrow and trigger keys.

The project publishes schematics, Gerbers for both required boards, a bill of materials, and TK-II 2.7J firmware. A complete installation needs the piggyback board, interface board, ribbon cable, and programmed keyboard-controller firmware. The three auxiliary outputs are momentary open-collector signals and may need latches for some uses.

Adapts the Pixels Past 8K or 16K EPROM cartridge into an eight-selection homebrew multicart for the Atari 800XL.

Human review found the combined visual material sufficient for a skilled builder. It remains an adaptation rather than a revised fabrication package: the linked Gerbers and assembly material are for the unmodified Pixels Past single-cartridge PCB, while the eight-way changes appear only in an inline diagram with no separate revised Gerbers, bill of materials, ROM-preparation guide, or textual selection instructions. Pixels Past licenses its base files under CC BY 4.0, but no license for the eight-way modification was verified.

Recreates the Gravis Ultrasound PnP ISA sound card around an AMD InterWave chip, with an optional IDE CD-ROM interface.

The maker has not fabricated or tested this board and has not generated a fabrication package. It also requires an AMD AM78C201 InterWave chip. Treat it as an experimental design and build at your own risk.

Open hardware SCSI emulator with SD-backed storage, optional Wi-Fi networking, and host-side management tools.

Current seller checks on 2026-07-27 found a $39 internal 50-pin Pico 2 W kit, a $49 assembled external DB-25 model, a $49 PowerBook model, and a $59 assembled Ultra Narrow 50-pin model at authorized seller ToTs RETRO. JCM also carried assembled Ultra hardware and model-specific Macintosh adapters. Prices, stock, included media, and support differ by seller. Ultra models require Berg or Molex power and cannot run from SCSI termination power. The initial Ultra hardware release is not yet open hardware, although its firmware remains GPL; the project says hardware licensing will open later.

Provides a daisy-chainable SmartPort hard disk backed by one to four ProDOS images on microSD.

Joe's Computer Museum showed 33 assembled DominoDisk units in stock on 2026-07-24. The Mini BurgerDisk page also exposes an assembled selector, while the public project supplies firmware, PCB, schematic, and enclosure files for a DIY build. Follow Apple's device-order rules in a daisy chain; a Liron card cannot drive a 5.25-inch drive.

Uses a PS/2 keyboard on supported Commodore computers or converts their original keyboards and optional joysticks for a PS/2-equipped host.

The RETRO Innovations store exposed a configuration selector and Add to Cart path on 2026-07-30, with the bare PCB listed at USD 6 and configured kits priced separately. Kits and assembled units are made after ordering and normally take four to five weeks. The maker explicitly treats C=Key as a project rather than a fully supported product because its firmware is not extensively tested or easily upgraded; an AVR programmer is strongly recommended. Use a true PS/2 keyboard because passive USB adapters may not work.

Generates configurable YPbPr or RGB from VIC-II bus activity with an FPGA while retaining improved composite and S-Video output.

VideoGamePerfection's EUR 60.00 kit was out of stock on 2026-07-27, but the complete open design remains buildable and upstream firmware 2.12 was released on 2026-07-03. This is a substantial soldering installation, and the original RF output is removed.

Open, through-hole RF-modulator replacement with adjustable C64 luma and chroma output levels.

The repository supplies KiCad sources, Gerbers, a schematic, a BOM, and assembly and adjustment instructions. Components were estimated at about $12 when documented, excluding PCBs and shipping. Building the board requires through-hole assembly; installing it requires safely desoldering the original RF can and selecting the correct jumper configuration. Using the shortboard setting on a longboard can feed the wrong voltage and damage the VIC-II.

Provides an open build for selecting either Commodore 64 control port from one Atari-style joystick, with optional second-fire and autofire circuits.

The repository supplies KiCad files, Gerbers, a schematic, bill of materials, and assembly guidance. Inspect the completed board for solder bridges and support it while pressing its buttons. Never move jumpers while powered or map two physical inputs to the same function. Do not connect a Sega Genesis or Mega Drive controller; the maker warns that it may damage the C64 and directs those controllers to the separate Mega Switcher.

Turns as many as two Atari-style digital joysticks or four paddles into USB input devices for a modern computer.

The repository supplies board fabrication files, a schematic, Arduino firmware, a bill of materials, and assembly guidance. A build needs an Arduino Pro Micro and the components selected for either the Atari-style or Sega configuration. Paddle mode is a JoyConverter firmware option selected while powering the adapter.

Replaces the paired 41464 or 4464 DRAMs on later two-chip C64 boards with a modern SRAM module.

Jaystonian showed nine assembled modules in stock at USD 14.99 on 2026-07-29, and Retro Lemon exposed a GBP 17.50 product page without an out-of-stock marker. Assy 250469 is the well-tested target. Jaystonian reports mixed results on 250466, and the open project's author had only tested 250469. Original soldered DRAMs require careful desoldering and sockets before this becomes a plug-in repair.

Adds a Yamaha V9958 or V9938 video processor, 128 KB of dedicated VRAM, RGB output, sprites, and enhanced graphics modes through the expansion port.

The project publishes the final 1.0 PCB, schematic, Gerbers, GAL files, documentation, and demonstration software, but no current assembled seller was verified. A build requires a V9958 or modified V9938 configuration, two compatible DRAM devices for 128 KB of interleaved VRAM, programmable logic, an EPROM or EEPROM if desired, and substantial surface-mount assembly.

Open RF-modulator replacement that improves the C64's original luma, chroma, and composite video signals.

Retro Electronics listed one board in stock on 2026-07-25. Installation is an irreversible soldering job that removes the original RF modulator, adds two headers, and solders a ground wire.

Adds the loopback modules needed for complete 586220 C64 or 785260 C128 port and interface diagnostics.

Current routes on 2026-07-30 included Retro-Updates' EUR 17.95 harness with an Add to Cart path, Retro Rewind's CAD 75 harness with a one- to two-week lead time, Retro Rewind's separate CAD 22 C128 keyboard dongle in stock, and AMI64's GBP 49 complete eight-ROM kit. Retro Electronics had one complete kit on 2026-07-25 but documented only one tested PAL C64 board revision. Confirm the exact harness revision, cartridge, keyboard dongle, cable lengths, model settings, and included manuals before ordering. Human review found no evidence that the current retail dongle solves the documented C128DCR keyboard-jack power conflict.

Packages 586220, 785260, and related service ROMs as current single-ROM and switchable multi-ROM diagnostic cartridges.

Current choices on 2026-07-30 included Retro Rewind's in-stock CAD 22 C64 586220++ and C128 785260 cartridges, its CAD 40 four-ROM C64 cartridge with a two- to three-day lead time, AMI64's GBP 19 eight-ROM C64 cartridge with an approximately seven-day lead time, ogHugo's USD 26.99 before-tax two-sided C64 cartridge with an Add to Cart path, Retro-Updates' EUR 17.99 two-sided C64 cartridge, and C64iSTANBUL's orderable two-ROM PCB with current fabrication files. DIY8BIT's USD 22.95 781220/586220 cartridge was unavailable while its Etsy shop was on break. Retro Rewind's older Dual Diag route now displays the store's not-found page. ROM sets and model support differ by variant; a full port test requires a separately bought or built harness.

Adds two joystick ports to a compatible Commodore user port for four-player games that support the CGA adapter protocol.

Protovision showed 17 individual Computers adapters in stock at EUR 25 with a one- to two-week shipping estimate on 2026-07-30. CBMretro also exposed an add-to-cart route for Pasi Lassila's enhanced Neat design at EUR 26.90, and ZGCS showed two assembled compatible boards at USD 22 on Tindie. Install or remove the adapter only with power off and observe connector orientation. Do not connect it to a Plus/4: individual Computers warns that doing so risks damage. The PET 2001 user ports lack the required power connection, and the maker discourages modifying a historic machine to add it.

Connects one CS/A65 expansion card to a Commodore 64 expansion port or beneath a PET's socketed 6502.

The C64 revision 1.0C is marked okay and publishes Eagle files, but it works only with the C64, not the C128, and a fitted CS/A card can conflict with long video or IEC plugs. For PETs, revision 1.1A was tested only in a CBM 8296 and had power and clearance problems. Later 1.2A and 1.2B layouts add 3.3 V power and more mounting options but are explicitly untested. A working 8296 Ethernet stack is documented. usb65 later lists PET plus adapter plus NetUSB 1.x as tested, although the older NetUSB page says its single PET-adapter test was not fully working and suspected a supply problem. Treat that USB path as experimental. No current assembled seller was verified.

Adds experimental USB host and device hardware through Commodore user and cassette ports.

Revision 1.0A is marked okay but was tested only on a PET. Revision 1.1A adds separately regulated, switchable USB host power but is explicitly untested. The interface uses both the user port and cassette port; PET ROM interrupt handling can switch cassette-motor-controlled USB power off unless software works around it. usb65 describes preliminary keyboard mapping, limited features, broken MAX3421 hub enumeration, and only partly working device mode. USB mass storage and networking are future plans, not supported features.

Open replacement battery module for the Compaq Portable III using a CR2477N coin cell.

This is a self-assembly project rather than a retail product. Follow the documented cell polarity and solder the pin headers in the specified upside-down orientation.

Builds a PET 4032-compatible mainboard from modular CS/A65 processor, PET I/O, and video cards.

No assembled seller or current PCB supplier was verified. A build needs three or four CS/A65 cards, a backplane, components, a programmed ROM, a case, a display or video-interface circuit, and a power supply. PETCPU revision 1.1B publishes board files but its layout is marked untested; the current VDC and PETIO pages publish later revisions marked okay, while the replica instructions date from 2010.

Builds a Commodore 1581-compatible IEC disk drive from CS/A65 processor and floppy-interface cards.

No assembled seller or current PCB supplier was verified. A build needs PETCPU and DRVIO cards, a backplane, components, a suitable 720 KB drive mechanism, a legal 1581 ROM image, power, cabling, and an enclosure. DRVIO revision 1.1A is marked okay and was tested with double-density PC drives; PETCPU revision 1.1B publishes board files but its layout is marked untested. High-density operation can overclock the WD1772 and is not the documented 1581 configuration.

Switches an Apple II F8 ROM socket between its normal Auto-Start Monitor and a licensed RAM diagnostic ROM.

The current Infinity Products page listed an assembled product without an out-of-stock marker on 2026-07-24. Personal-use fabrication files remain available under a noncommercial license; the Dead Test ROM has separate licensing terms.

Open 1 MB C64 flash-cartridge family that can be reprogrammed directly by the computer without an EPROM programmer.

The EasyFlash and EasyFlash 1CR designs remain buildable. Poly.play's assembled original-style EasyFlash was out of stock on 2026-07-30.

Open C64 flash cartridge with seven EasyFlash slots, eight external KERNAL slots, freezer-cartridge support, and USB transfer.

AMI64 described its assembled EasyFlash 3 as newly available on 2026-07-30. The package includes the cartridge and a printed quick-start guide; a USB cable and any separate C64 storage device are not listed as included.

Expands eMate 300 system RAM and internal flash storage while widening both buses to 32 bits.

JCM showed 54 assembled DRAM-plus-flash modules in stock on 2026-07-24. Installing or removing this version causes a full factory reset and erases internal storage, so back up first. The developer also reports that repeated module swaps on a tester preceded lost calibration data and disabled battery charging.

Adds a two-drive floppy controller and DS1302 real-time clock to RC2014 and RCBus systems.

Tindie listed the complete Flock V2 kit without an out-of-stock notice on 2026-07-25, and open build files remain available. The CR2032 battery and optional 300 Kbit/s parts are not included. The drive-power output is unfused; avoid overloading or shorting it.

A DIY USB floppy interface and cross-platform toolkit for reading and writing unusual disk formats with a conventional PC floppy drive.

Building the original interface requires a compatible PSoC 5 development board, a floppy connector, soldering, a conventional PC floppy drive, cabling, and drive power. The project warns that not every listed format has been tested on physical disks; its dinosaur markers identify encoders or decoders based only on captured data. Copy-protection schemes are not a core focus.

Adds Wi-Fi networking and platform-specific peripheral emulation to several vintage computer families.

JCM showed 16 Apple II base units in stock on 2026-07-24. On 2026-07-27 Lotharek offered its assembled Atari Professional version both alone and with a dedicated SIO cable. It normally takes operating power from Atari SIO and uses USB-C for firmware flashing, although the page separately calls USB-C an optional power source for the 1200XL. The project also lists other small-batch vendors and open design files. Stock, enclosure, connection, power, and required interface hardware vary by computer.

Connects one six-button Sega Mega Drive or Genesis controller to both C64 or C128 control ports with port switching and extra button mappings.

BackBit says it no longer has capacity to build this former product and has released the design under GPL-3.0. The repository supplies KiCad board and schematic files, CUPL source, printable case files, and a bill of materials; a build also needs the listed ATF1502 CPLD and an ATDH1150USB programmer. The former store URL returned 404 twice, including after the required 60-second retry.

Open ISA controller that connects ATA or IDE drives to an XT-class computer.

Retro Electronics listed the bare Revision 4 PCB in stock on 2026-07-25. The builder must source the components, assemble the card, and follow the project instructions; no current kit or assembled-board availability was verified.

Provides selectable Apple Slinky or RAMFactor-compatible memory using modern low-power SDRAM.

The assembled Tindie card was out of stock on 2026-07-24 and had been sold out since January 23, 2025. Schematics, board files, CPLD firmware, utility software, and fabrication files remain available under the project's dual-license terms.

Provides MDA and CGA-compatible display modes with 31 kHz VGA output for modern monitors and capture devices.

This is a self-assembly project. The maker advises checking for shorts between each power rail and ground before installation; the oscillator configuration also affects CGA composite color accuracy.

Adds the SoftSP ROM path needed to use a Disk II controller and SPIISD V2 in SmartPort mode.

The current store listed bare PCB, kit, and assembled configurations without an out-of-stock marker on 2026-07-24.

Connects a modern computer over USB to a separate floppy drive for reading, analyzing, and writing disks at the raw flux level.

An assembled board still needs a compatible Shugart-interface floppy drive, ribbon cable, USB cable, and suitable drive power. Older 5.25-inch and 3-inch drives often need 12V or a separate supply. Remove the write-enable jumper while preserving originals. Apple II, Macintosh, and Commodore 64 GCR disks can require trial and error with drive choice.

Open four-layer 30-pin FPM memory family with 4 MB, parity, 16 MB, and early-Macintosh PAL SIMM variants.

The assembled GW4192A kit was out of stock on 2026-07-24 and had been sold out since October 26, 2022. GW4194A had been sold out since January 19, 2023. Open schematics and layouts remain available. These modules support FPM, not EDO, even when an EDO chip is wired to operate in FPM mode. Check refresh type, parity, capacity, bank population, and physical clearance against the exact computer before building or installing a variant.

Open low-power 2 MB geoRAM-compatible expansion cartridge for the Commodore 64.

The assembled Tindie cartridge was out of stock on 2026-07-24 and had been sold out since June 10, 2024. The open design remains buildable. This is geoRAM memory, not an REU: software must explicitly support geoRAM. Most C64 programs use neither expansion-memory type, and GEOS needs an added geoRAM driver on its boot disk.

Open 64-pin ROM SIMM with selectable 32-bit-clean System 6 and System 7.1 ROM disks for six 68030 Macintosh models.

The assembled Tindie module was out of stock on 2026-07-24 and had been sold out since May 7, 2025. Hardware, software, and fabrication files remain public. Most tested 68030 accelerators work, but some 68040 accelerators do not; select the stock IIsi or IIx ROM when the custom image is incompatible. Only 8 MB of the 16 MB flash can be selected at once, with the computer powered off before changing the switch.

Open 512 KB 68-pin Macintosh VRAM SIMM built with new 80 ns or faster memory.

The assembled Tindie module was out of stock on 2026-07-24 and had been sold out since May 5, 2024. Schematics and board files remain available for commercial and noncommercial use. A 512 KB module can replace a 256 KB module where the connector is compatible, but that machine will use only 256 KB; never mix capacities within one VRAM bank.

Open low-profile card that adds 3 MB to a Macintosh Classic using two modern DRAM chips.

The assembled Tindie card remained out of stock on 2026-07-27 and had been sold out since August 13, 2025. The schematics and board layouts remain available for commercial and noncommercial use.

Convert the unusual HDI-45 video port on first-generation Power Macintosh systems to Macintosh DA-15 or VGA-style HD-15 output.

JCM showed five DA-15 adapters and seven HD-15 adapters in stock on 2026-07-24. The open designs remain buildable under a CC BY-NC 4.0 license. The HDI-45 pins are unusually thin and flexible, and the project strongly recommends its printed case for pin alignment and stability.

Streams read-only floppy images from a modern USB host to compatible 34-pin drives or an Amiga external-floppy adapter.

The standalone unit, cable set, and Ami2PC bundle exposed current login-or-register-to-buy paths on 2026-07-27. The official HxC home page and release notes show that the software project remains active in 2026. The unit needs a modern computer running the HxC host software and emulates disks read-only. The standalone set includes a 40 cm floppy ribbon and USB A-to-B cable; Ami2PC instead adds the Amiga external-floppy adapter. Never connect or disconnect the 34-pin or Amiga-side cable while USB is attached; disconnect USB first. Ami2PC can use Amiga disk-copy software to write a real disk in DF0 from an emulated DF1. Its early-boot workflow needs Kickstart 2.0 or newer. The seller still does not identify which oldest Amigas need its unspecified modification, so do not rely on early-model boot support without separate instructions.

Open hardware reproductions of the two interface cards used to connect an IBM PC or XT to a 5161 Expansion Unit.

Adds LocalTalk networking to an Apple ImageWriter II or ImageWriter LQ printer.

JCM's current page offered fully assembled and board-only choices on 2026-07-24. A DIY build needs correctly selected jumpers, a programmed EEPROM and NVSRAM, suitable board clearance, and several vintage chips. The project recommends installing the original-style grounding wire.

Replaces the power light with a two-color indicator that shows the computer's IRQ-line state.

Shareware Plus said the C64 breadbin, C64C slimline, and VIC-20 versions were in stock at GBP 9 each plus postage on 2026-01-25 and accepts email orders. The tebl C64 design is buildable under CERN OHL v1.2. This is an IRQ-line indicator, not a complete CPU-usage or disk-activity meter. Installation opens the computer and places clips on cartridge-port ground, +5 V, and IRQ contacts; verify every connection with power off.

Arduino-based C64 cartridge family for fast PRG loading from SD storage or a serial connection.

Gotek Retro lists IRQHack II at EUR 25 including its housing and provides a current order-interest form. The form offers an IRQHack II package with a populated SD card but explicitly has no stock management or availability guarantee and ships only within Europe, with non-EU European destinations handled case by case. Confirm stock and included media before ordering.

Open RTL8019 Ethernet card that brings NE2000-compatible networking to 8-bit ISA computers.

The fully assembled card was out of stock on Tindie on 2026-07-25 and had been sold out since December 15, 2025. Open KiCad files, Gerbers, software, and a separate bare-PCB path remain available. A DIY build needs a unique valid MAC address and surface-mount RTL8019 assembly.

Implements an experimental STM32-based USB host for operating ISA cards on an external backplane.

Treat this as an unfinished development platform, not a turnkey USB-to-ISA product. The repositories provide Revision A fabrication files and early STM32 firmware but no documented host application, VM integration, release, or end-user procedure. A linked 2020 development thread demonstrates predecessor Arduino Mega experiments with serial ISA reads and writes, isapnptools, an Aztech sound card, and PCem, but does not establish that those workflows were implemented for ISASTM. Revision A has signal-integrity and reset-pull-up errata, and USB High-Speed is untested and may not work. The required ISA backplane supplies power.

Programs supported PIC microcontrollers from an Atari 8-bit computer through a joystick port.

Schematics, Gerbers, parts information, Atari software, and bare-PCB order links are public. A build still requires assembly and careful device orientation. Confirm that the exact PIC is supported before programming it; the STIK socket does not support every PIC package or family.

Intercepts the C64 keyboard matrix to add programmable shortcuts, macros, remapping, remote control, and sixteen hardware-control lines.

The maker currently offers revision 4 assembly kits with a PCB, preprogrammed ATmega, and components except connection cables for EUR 30 by email. Kits are made in small spare-time batches and may require prepaid backordering. Version 1.6 firmware, configuration tools, Gerbers, KiCad design files, schematics, and source remain downloadable.

Open microSD cartridge that emulates many C64 and C128 cartridge formats and loads programs and disk images.

Retro Electronics listed one assembled cartridge in stock on 2026-07-25 without a microSD card. Lotharek also exposed a current order path on 2026-07-27 for a redesigned board in a transparent case. Retro Electronics installs Version 1.35 by default and treats its NTSC build as work in progress; check the current Codeberg releases before use.

Open SwiftLink-compatible expansion-port UART design for connecting supported Commodore computers to DB9 RS-232 equipment.

RETRO Innovations does not sell assembled Link232 cartridges. The maker publishes EAGLE schematic and PCB files for builders. A separately mentioned future Turbo232-compatible revision has no documented release and is not part of this record.

Combines a SwiftLink-compatible high-speed serial cartridge with an ESP8266 Wi-Fi modem for Commodore 64 and 128 systems.

The assembled Tindie listing was retired by 2026-07-30. The project repository retains Eagle design files, case files, firmware, software patches, and setup documents. The maker says prebuilt units sometimes appear through the linked eBay seller page, but no specific current listing was verified.

Reimplements the Lisa 1 and Lisa 2/5 as an open FPGA system with HDMI, USB input, and SD-backed ProFile storage.

The complete JCM first production run was out of stock on 2026-07-24, with a notification form for a planned second run. The project provides source code and PCB files for DIY builds. A complete setup also needs suitable USB-C power, a microSD card, a 1080p HDMI display, and a supported keyboard and mouse. Onboard floppy emulation does not yet work. Optional original Twiggy-drive support requires the separate breakout and remains untested; JCM showed three breakout boards in stock.

Exposes the Apple IIgs Ensoniq chip's native stereo channels through a rear-panel audio output.

The JCM-1 page showed an in-stock Add to cart path on 2026-07-24. The project reports a harmless shutdown chirp with the ReActiveMicro power supply and says other aftermarket supplies may behave similarly.

Adds a hardware azimuth indicator to a Commodore 1530 Datasette so its tape head can be aligned without running a program.

The GPLv3 reverse-engineering files remain available. Shareware Plus described a small reproduction batch at GBP 16, with an optional GBP 6 brass adjustment rod and GBP 5 printed support, but that page was last updated on 2025-01-01 and uses email ordering. Confirm present stock and exactly which parts are included. Installation modifies a Datasette and requires soldering to points that can differ between PCB revisions.

Current and buildable replacement ROMs for early compact Macs with a customizable bootable ROM disk and HD20 support.

On 2026-07-24 JCM showed eleven 128K/512K modules and nine Plus modules in stock. Infinity Products also listed standard and spare-ROM kits without an out-of-stock marker. Installation requires opening the Macintosh, removing its ROMs, and soldering three or four address and write lines to the mainboard. BMOW provides the original parts list, Gerbers, assembly instructions, Flash Tool, and ROM data.

Open replacement RAM expansion board for an original or Reloaded Macintosh Classic logic board.

The public repository supplies Gerbers, BOM, and pick-and-place data under a noncommercial Creative Commons license. The Classic BBU limits total memory to 4 MB; larger SIMMs do not raise that limit. Builders must source 256x4 SOJ RAM, SIMM sockets, and the listed parts.

Recreates the Macintosh IIfx logic board with new board files, schematics, a parts list, and rewritten PAL logic.

This is an advanced noncommercial board-build project, not an assembled product. The recreated PALs need suitable 16V8 or 20V8 devices. Low-power ATF16V8B parts do not work, and ATF16V8C parts may be problematic.

Recreates the Macintosh LC 475 and Performa 475 logic board as a buildable replacement PCB.

This is an advanced noncommercial board-build project with no assembled purchase path. The repository warns that fabrication data was generated for JLCPCB and may need changes for other manufacturers.

Recreates the Macintosh Quadra 950 logic board with new fabrication and assembly data.

This is an advanced noncommercial board-build project with no assembled purchase path. Its Gerbers and placement data target JLCPCB and may need changes for another fabricator.

Redesigns the SE/30 logic board as a buildable replacement with Gerbers, placement data, a BOM, and recreated programmable logic.

This is a fabrication package, not an assembled order path. The published Gerbers were generated for JLCPCB and may need adjustment for another fabricator. Low-power ATF16V8B programmable-logic parts do not work, and ATF16V8C parts may also cause problems. The build still depends on Apple custom ICs sourced from donor hardware.

Adapts selected simple C64 or C128 I/O cartridges to the VIC-20 expansion port.

RETRO Innovations retains a USD 11 product page and publishes the schematic and PCB artwork under CC BY-SA 4.0, but the extracted store page did not expose an unambiguous stock or Add to Cart state on 2026-07-30. Confirm assembled availability before ordering or build from the project files. The repository README's first paragraph mistakenly says the target is a C64, SX-64, or C128; its title, About text, usage section, official product page, and store page all establish that the adapter is for a VIC-20.

Adds flash-backed ProDOS volumes, a RAM disk, recovery ROM, clock, network transfer, and Applesoft enhancements inside an Apple IIc or IIc Plus.

JCM showed assembled 128 MB Apple IIc units in stock on 2026-07-24, while human review found the separate assembled IIc Plus package out of stock. The family remains available through the IIc version. A system-ROM replacement is required. Early ROM 255 IIc boards may need W1 and W2 modification, and early spring-clip keyboards may need the low-profile stiffener for clearance.

Builds a compact modular IBM PC/XT-compatible computer with an 8088 or NEC V20, up to 640 KB of base RAM, optional upper memory, and 8-bit ISA expansion.

The GPL-3.0 project provides KiCad files, Gerbers, a bill of materials, BIOS, programmable-logic files, and build instructions. Retro Electronics had six bare ENIG PCBs in stock on 2026-07-27; every component and all assembly are excluded. Weird Electronics' board and complete-kit listings were temporarily unavailable while the seller takes a break through August 20, 2026. A separate assembled-board listing had been sold out since May 11, 2026. Weird Electronics sells a Version 1.4 PCB with larger Flash-ROM support, while the repository README documents layouts through Version 1.3; follow the documentation for the board actually supplied.

Recreates several Commodore PET models on a modern single board with a faster 65816, expanded memory, color VGA graphics, USB input, and SD storage.

No current assembled seller was verified. Revision 3.0A has public GPL-3.0 hardware files, but it is an advanced build with fine-pitch surface-mount parts, separately programmed FPGA and boot firmware, and dependencies across several repositories. The family documentation warns that boards, bills of materials, and firmware are moving to newer video timing and says to contact the maker before building.

Upgrades compact Macintosh computers with a 16 MHz 68030 and optional 68882 FPU through original vintage cards or modern recreations.

The open clone remains buildable, but MacEffects' assembled Macintosh SE variant was sold out on 2026-07-27. The original MicroMac page was last modified in 1998, so its order form and prices are archival rather than a current purchase path. Modern-clone operation has been tested in the Macintosh Plus and SE, but not in the Classic; no secure socket has been found for the Classic's PLCC CPU. Host-specific U7 and SJ2 settings are mandatory. GAL16V8-15 and PALCE16V8-15 parts are tested, while ATF16V8 and other speeds are not.

Open dual-SID board with mixed 6581 and 8580 support, runtime address selection, channel mixing, paddle compatibility, and stereo output.

The complete GPL-2.0 hardware, GAL, Gerber, and build documentation remains available. A Tindie assembled listing reported out of stock since 2020 but says the seller may assemble a unit on demand; treat that as a contact route rather than stocked availability. SID chips are excluded.

Open ISA controller with two floppy controllers for up to eight drives, plus optional serial and BIOS hardware.

The assembled and tested card was out of stock on Tindie on 2026-07-25 and had been sold out since January 31, 2026. Open KiCad files, Gerbers, a bill of materials, and a manual remain available. Optional 5 V-on-pin-3 jumpers are only for compatible PS/2-style floppy drives and can damage standard drives if installed incorrectly.

Replaces the circuit board in an original or reproduction NES controller so it works as a Commodore 64 gamepad.

AutumnHippo exposed an add-to-cart route with a USD 8 base price on 2026-07-30. The page offers a bare PCB, a kit with a reproduction case, and a fully assembled controller, but it does not expose every option price in extracted text. A bare-board build needs a case, a correctly traced cable, a switch or solder bridge, and basic soldering. The maker also states generic Amiga and Atari computer compatibility, but exact model relationships are not attached without model-specific evidence.

Expands a 576NUC+ to 1088 KB and adds a real-time clock, A8PicoCart, SDrive-ng, and optional FujiNet networking and MIDI synthesis.

Revised Gerbers, schematics, BOM, datasheet, firmware, and case files were published in March and April 2025. The maker says The Brewing Academy will offer assembled and DIY parts, but current seller stock was not verified in this pass.

Converts two Wii Nunchuk or NES and SNES Classic Mini controllers into the two Commodore 64 control-port inputs.

Sordan exposed a current Buy route at EUR 30.99 excluding VAT on 2026-07-30. The maker also publishes KiCad files, Gerbers, firmware, assembly instructions, printable cases, and a GPL-3.0 license, and invites direct contact for DIY kits. Controllers and wireless receivers are separate. The guide's acrylic-case tile is an enclosure accessory and is folded into this hardware family.

Replaces many 24-, 28-, 32-, and 40-pin EPROMs and mask ROMs with a configurable RP2350 board programmed over USB.

OneROM boards do not include ROM contents. Supply legally obtained images, choose the correct 24-, 28-, 32-, or 40-pin hardware, configure the exact ROM type and chip-select behavior, and confirm socket clearance and orientation. The open project provides a fabrication path. On 2026-07-24 JCM listed Fire 24, Fire 28, Fire 32, and Fire 40 as kit or assembled options, but its extracted page still called the 32- and 40-pin versions coming soon and did not establish which options could actually be ordered.

Replaces a 24-pin 2364 ROM with a programmable 27xxx-family EPROM or EEPROM and optionally switches among several ROM images.

The Atari-specific Brewing Academy page exposed an Add to Cart path on 2026-07-24, and the open design includes fabrication files. The assembled adapter is configured for a 2764; other capacities need the documented resistor configuration and optional switches. The open project says only the W27C512 configuration was thoroughly tested. Supply legally obtained, exactly sized ROM images and verify socket orientation.

Open PCB that exposes every Commodore 1530 Datassette connector line for Tapuino builds and cassette-port adapters.

The repository provides the KiCad board, schematic, footprint, and documentation files and invites builders to fabricate the open hardware. PCBWay currently offers the 26.92 by 26.03 mm V2 design as a 1.6 mm, two-layer bare PCB and labels that shared project CC BY-SA 3.0. No connector, Mini-DIN lead, enclosure, Tapuino electronics, buffering, isolation, fusing, or current limiting is included or documented. Review the manufacturing files and wiring before ordering and connect hardware only with power off.

Open internal video-overlay module that displays expansion status and other configured messages over C64 composite or S-Video output.

The maker offered assembly kits by email for 25 EUR including regular worldwide mail on 2026-07-30, with a limit of two per person. Stock is kept when practical, but prepaid production batches can take several weeks. The kit includes the PCB, a preprogrammed ATmega, and board components, but not the computer-specific wiring. C64 installation is an advanced internal modification: use amplified luma from A/V pin 1 for S-Video or composite from pin 4, never the unamplified VIC-II luma signal. Driving both outputs requires an expert RF-modulator connection, and excessive overlay brightness can disrupt sync.

Replaces all eight kilobytes of hot-running 6550 system RAM in an original PET 2001-8 with one open modern board.

The assembled Tindie board has been out of stock since 2025-08-04, but source, documentation, and design files remain linked from the product page. This is specifically for 6550-based PET 2001-8 system RAM and should not be treated as a generic replacement for later PET memory organizations.

Replaces a socketed 6502 with a W65816 running at up to 10 MHz, backed by fast RAM and programmable flash ROM.

The project publishes Eagle board and schematic files, VHDL and CPLD binaries, test software, and GPLv2-licensed documentation, but no current assembled seller was verified. Revision 1.2b is marked 'ok'; older revisions are prototypes. Building it depends on older Xilinx ISE-era tooling or a compatible programming path, two programmed flash devices, and a socketed host CPU. The author's 10 MHz timing uses 55 ns SRAM outside its rated access time; his burn-in test passed, but builders should not treat that result as a component guarantee.

An 8-bit ISA card with switchable classic sound-card modes plus MIDI, USB game-controller, and CD-ROM emulation.

Joe's Computer Museum showed the assembled PicoGUS 2.0 in stock on 2026-07-24. The official site also listed stocked UK and EU sellers. Open design files and build guidance remain available for people who want a DIY board.

Emulates IDE hard disks and ATAPI CD-ROM drives from image files on a microSD card, with optional front-panel and Wi-Fi controls.

Crowd Supply was accepting orders from limited campaign inventory on 2026-07-24, but production was still underway and the original June 2026 shipment had slipped. A June update says production firmware will support two simultaneous devices; the current setup guide still labels the two-device jumper mode as future. The project describes the hardware and firmware as open source, but this pass did not verify a complete public fabrication package.

Current multifunction 8-bit ISA card that adds emulated storage, memory, networking, and USB or SD-connected devices to PC/XT-class computers.

Open, reversible Pico ATX power-adapter family for the Macintosh 128K, 512K, Plus, SE, and SE/30.

On 2026-07-27, the 128K/512K/Plus listing showed order controls at $29.99 and the SE/SE30 listing showed order controls at $34.99. Both offered kit and assembled choices. Their United States shipping sections simultaneously displayed rates and a does-not-ship warning, so confirm destination availability at checkout. A suitable PicoPSU and adequately rated 12 V center-positive power brick are separate parts.

Adds a 16 MHz 68030 to a Macintosh Plus with a compact hobbyist-buildable board derived from the MicroMac Performer.

This build requires a PGA 68030, five programmed 16V8 devices, and soldering a socket on top of the Macintosh Plus 68000. The maker does not recommend the System 7.0 GemStart driver, reports garbled or intermittent audio, and warns builders to watch the first SIMM's clearance.

Converts compatible PS/2 or AT keyboards for IBM PC and XT keyboard ports.

Retro Electronics listed one assembled converter in stock on 2026-07-25, and the open version remains available as build files. A USB keyboard works only if it implements the PS/2 or AT protocol and can use a passive USB-to-PS/2 adapter.

Open four-port Commodore IEC hub with a switch that can hide each attached branch from bus attention.

Retro 8bit Shop showed one new unit in stock on 2026-07-27, while the Eagle design remains open for DIY builds. This original design switches only ATN, not every IEC signal; disabled devices remain electrically connected to CLK, DATA, and RESET and can still load or disturb the bus. The acrylic case is an accessory folded into this hardware family.

Adds an Apple II-compatible environment to an IBM PC through an ISA expansion card.

The author provides complete design and fabrication files but does not sell the board. This is a large full-length card with programmed logic, RAM and ROM parts, and several required cable assemblies. It also needs the original Quadlink software disk images and DOS. The clone has been tested only in an IBM 5150; the 5160 is expected to work but remains untested by the author, and faster ISA systems may fail because the software may contain CPU-dependent timing loops.

Connects modern USB HID keyboards and mice to Macintosh computers through Apple Desktop Bus.

HIDHopper Base, Base with USB Hub Hat, and Hub Hat-only selections could be added to the JCM cart on 2026-07-24. The assembled QuokkADB Rev. 2022g remained sold out, while its Raspberry Pi Pico Community Edition remained buildable. HIDHopper's Hub Hat requires external USB-C power, must be power-cycled between Macintosh starts, and can otherwise exceed the host's ADB power budget.

Uses a Raspberry Pi cartridge to emulate up to 16 MB of REU memory or up to 4 MB of GeoRAM-compatible memory on a C64 or C128.

Retrobit listed five assembled cartridge boards with cases at PLN 93.50 on 2026-07-27. A Raspberry Pi Zero 2 W and microSD card are not included. The upstream project describes RAD as a playground for new features and documents machine-dependent timing and power limitations.

Recreates the 1986 Soviet Radio-86RK home computer on one board with an Intel 8080A, 32 KB of SRAM, integrated keyboard, monochrome composite video, cassette, serial, and parallel interfaces.

The GPL-3.0 repository provides Version 1.4 KiCad files, Gerbers, a bill of materials, monitor and font ROM images, project notes, and archived original magazine material. Weird Electronics' bare-PCB listing was temporarily unavailable while the seller takes a break through August 20, 2026; when active, it includes only the main PCB and two ROM-cartridge PCBs. This is a large through-hole build requiring several vintage Intel 8xxx or compatible chips, 67 key switches, programmed ROMs, and regulated power. The Tindie heading incorrectly calls it an Intel 8088 computer; its own detailed specifications and the project repository correctly identify an Intel 8080A.

Open ATmega328P bench tester that automatically identifies and checks a broad range of vintage DRAM and 2114 SRAM.

The repository was active on 2026-07-20 and documents firmware 5.0.7. It links ready-made routes at AmiBay, Lectronz, eBay, and Tindie plus a PCBWay through-hole board, but those sellers were not independently checked for stock in this pass. Hardware is CERN-OHL-S v2 and firmware is GPLv3. Builders may use through-hole or surface-mount files and must select or build any required adapter for the exact package.

Adds 128 KB of low-power Saturn-compatible bank-switched RAM to slot-based Apple II systems.

The assembled Tindie card was out of stock on 2026-07-24 and had been sold out since March 14, 2025. The open repository provides schematics, KiCad files, Gerbers, and documentation. In an Apple IIe or IIgs this is not normal auxiliary or fast memory; only software that understands a Saturn-type card in a peripheral slot can use it.

Adds low-profile, adjustable RAMWorks-compatible auxiliary memory to an Apple IIe.

The assembled Tindie card was out of stock on 2026-07-24 and had been sold out since December 1, 2025. The open repository remains buildable. A Revision A IIe needs the card's DHGR jumper resistor or trace removed and then loses double-high-resolution graphics support. An A2Heaven VGA Scaler's long 14 MHz clock lead can cause RAM errors unless its clock connection is buffered or otherwise corrected as documented.

Adds selectable 4 MB or 8 MB of low-profile SDRAM fast memory to an Apple IIgs.

The assembled Tindie card was out of stock on 2026-07-24 and had been sold out since June 17, 2025. The repository retains hardware, programmable-logic, documentation, and fabrication sources. Select 4 MB when every byte must be DMA-accessible; at 8 MB, only the first 4 MB is DMA-compatible.

Recreates the RAMBO 256 KB memory upgrade for Atari 800XL and 1200XL computers.

The maker publishes a schematic and Gerbers but no bill of materials, and recommends the 74LS logic shown in the schematic over the HCT parts pictured on one build. Installation is model-specific. A 1200XL also requires replacing its original 64K DRAM devices with 256K versions.

Adds 4 MB of auxiliary-slot RAM to an Apple IIe in assembled or through-hole kit form.

The current page offered assembled and kit selectors with an Add to cart path on 2026-07-24. This is a complete 4 MB card, distinct from A2Heaven's 64K RamWorks III clone kit.

Recreates an expandable Apple-1-compatible computer as either a compact single board or a set of functional cards on a backplane.

The GPL-3.0 repository supplies KiCad design files, fabrication exports, schematics, bills of materials, firmware, and assembly guidance. Builders must fabricate boards, source components, solder the computer, program its EEPROM, and load the Arduino Nano interface software. Retro Electronics had one bare backplane PCB, three bare VDU PCBs, and five bare VDU color-amplifier PCBs in stock on 2026-07-27; these are parts of the RC6502 build and do not constitute a complete kit. Early SBC revisions D and E need the documented CPU-power patch wire; the repository's current bill of materials names Revision H.

Open FPGA hardware and gateware platform in a DIP-28 package for emulating 6581 and 8580 SID chips.

The official repository provides hardware and gateware, but this bounded pass did not verify a current assembled-product seller.

Standalone testers for checking vintage nine-pin joysticks and controllers without relying on a working retro computer.

AMI64 listed its encased tester at GBP 15 with a battery included on 2026-07-30. Commodore4ever listed its tester at a USD 9.99 sale price; a Micro-USB Type-B cable is not included. PCBWay retains the 2021 schematic, layout, bill of materials, and PCB ordering route under CC BY-NC-SA 4.0. These are related tester variants, not electrically identical revisions. Confirm connector gender, supported controls, and power source for the chosen unit.

Open 90-degree cartridge adapter that brings a C64 cartridge upright and can include a reset button.

Sordan exposed an assembled C64 unit with a printed case and stand for dispatch in one to three working days on 2026-07-27. The open repository also provides fabrication files and a printable-enclosure link. A completed 2024-2025 seller run offered bare, kit, and assembled versions tested on C64 or C128 systems.

Converts Sophia or VBXE RGB video to VGA inside a 1088XLD.

The project publishes schematics, Gerbers, source, and PIC12F1572 firmware, but requires a separate GBS-8200 board and mechanical installation. Firmware 1.2 is beta, high-resolution modes are untested, and its rudimentary presets do not work with every monitor. The maker notes that Sophia2 is generally the better universal VGA and DVI solution.

Open PET repair board replacing 32 KB of system RAM and selectable ROMs while adding built-in diagnostics.

The assembled Tindie board has been out of stock since 2025-08-04, but GPL-2.0 design files remain public. The maker pages repeatedly label the $0000-$7FFF replacement as 32MB; that address range is 32 KB, and independent technical coverage also identifies 32 KB, so this catalog records the functional capacity rather than the apparent unit typo.

Open 8-bit ISA real-time clock card for PC/XT systems without a built-in battery-backed clock.

Weird Electronics' assembled, complete-kit, and PCB-plus-programmed-SPLD options were temporarily unavailable while the seller takes a break through August 20, 2026. Aitor Gomez Garcia's low-profile version showed three units in stock on 2026-07-27 but currently ships only within Spain. A CR2032 battery is not included.

Combines a working Z80 or Z180 computer with RC2014-compatible expansion sockets on one buildable motherboard.

The official pages listed complete-kit and bare-PCB suppliers on 2026-07-27, but no assembled and tested option. Exact inventory varies by model and supplier; the Tindie seller was temporarily on a break when checked. Each board still needs assembly plus the documented power, terminal, and storage accessories.

Adds CompactFlash storage to an RC2014 through a simple 8-bit IDE interface.

The project supplies a schematic, Gerbers, and build documentation, and lists kit and bare-PCB suppliers; an assembled version is not offered. The unbuffered IDE connection must remain short, not every CompactFlash card is compatible, and the maker says older cards tend to work better. Power the CompactFlash adapter directly from SC145 as documented.

Adds four switchable 32K banks of Flash ROM to an RC2014 system.

The project page provides firmware, a schematic, PCB files, Gerbers, and supplier links. CP/M use requires the separate SC150 Paged RAM Module. Leave the Flash write-protect jumper in its normal read-only position unless deliberately programming the ROM.

Combines 128K of Flash ROM and 128K of paged RAM for RC2014 systems, including CP/M configurations.

The project page provides firmware, a schematic, PCB files, Gerbers, and supplier links. A later SC707 design also exists, but SC152 remains documented and buildable. Keep the Flash write-protect jumper in its normal read-only position except when programming it.

Builds complete RomWBW and CP/M computers from matched 40-pin or 80-pin RCBus backplanes and modules.

The official pages listed complete-kit and bare-PCB suppliers on 2026-07-27, but no assembled and tested option. Exact inventory varies by model and supplier. A suitable power supply, storage card, USB serial adapter, terminal computer, and assembly tools may be required as specified for each model.

Add supervised 5 V power, manual reset, and power-on reset to an RCBus system.

The projects provide schematics, Gerbers, PCB design files, and kit or bare-PCB suppliers; assembled versions are not offered. SC712 requires a regulated 4.75 V to 5.25 V input. SC703's linear regulator can run hot at higher input voltages and loads. Enable only one voltage supervisor in a system.

Adds a software-driven I2C master interface to RC2014 and RCBus systems.

The project supplies a schematic, Gerbers, PCB design files, and links for kits and bare PCBs; an assembled version is not offered. On PCB v1.0.0, the example I2C read and write address labels are reversed: read starts at 0xA1 and write starts at 0xA0.

Adds a clock-stable 68B50 serial port with TTL-level flow control.

The project provides a schematic, Gerbers, PCB design files, and kit or bare-PCB suppliers; an assembled version is not offered. The serial-header power jumper must not connect two competing 5 V sources. Multiple SC705 modules require distinct I/O addresses.

Provides a modular Z80 processor with flexible clock and reset options.

The project provides a schematic, Gerbers, PCB design files, and kit or bare-PCB suppliers; an assembled version is not offered. PCB v1.0.0 needs a wire link across C7 when X2 is not populated. Enable only one voltage supervisor in a system.

Adds 128K of Flash ROM and 128K of paged RAM for a CP/M-capable Z80 system.

The project provides Small Computer Monitor S8 firmware, a schematic, Gerbers, PCB design files, and kit or bare-PCB suppliers; an assembled version is not offered. Observe the Flash write-protect jumper and avoid function conflicts with other system memory modules.

Combines a Z80, paged RAM and Flash, clock, reset, and serial terminal on one RCBus module.

The project provides firmware, a schematic, Gerbers, PCB design files, and kit or bare-PCB suppliers; an assembled version is not offered. SC708 has no automatic power-on reset, so press its reset button after applying power. Avoid duplicate CPU, memory, clock, reset, or serial functions when adding it to a modular system.

Adds 512K of Flash ROM and 512K of banked RAM for RomWBW and CP/M.

The project supplies RomWBW and Small Computer Monitor firmware, a schematic, Gerbers, PCB design files, and links for kits and bare PCBs; an assembled version is not offered. It is intended for the SC706 Z80 CPU module and is not compatible with the SC730 CPU plus MMU module. JP1 controls Flash write protection.

Adds CompactFlash storage to RC2014 and RCBus systems at I/O ports 0x10 through 0x17.

Both designs have schematics, Gerbers, PCB files, and kit or bare-PCB paths; assembled versions are not offered. Plain CP/M 2.2 can address the first 128MB and RomWBW up to 2GB. The maker recommends avoiding high-capacity, high-speed cards and documents a critical 5 V power issue with some visually identical CompactFlash adapters.

Adds two clock-stable serial ports using a Z80 SIO/2.

The project supplies a schematic, Gerbers, PCB design files, and links for kits and bare PCBs; an assembled version is not offered. The full interrupt daisy chain and optional bus signals require the 80-pin RCBus or additional wiring as documented.

Adds 16 programmable parallel I/O lines and four handshake lines through a Z80 PIO.

The project supplies a schematic, Gerbers, PCB design files, and kit or bare-PCB paths. On PCB v1.0.0, JP2 and JP3 are tight against the P2 box header; the assembly guide recommends filing a little plastic from those headers before soldering.

Adds four programmable counter and timer channels with frequency and interrupt generation.

The project supplies a schematic, Gerbers, PCB design files, and kit or bare-PCB paths. The optional onboard oscillator is not included in the kit. Mode 2 interrupt chaining needs suitable backplane support or flying leads.

Adds eight 5 V TTL inputs and eight 5 V TTL outputs with state LEDs.

The project supplies a schematic, Gerbers, PCB design files, and kit or bare-PCB paths. PCB v1.0.0 leaves insufficient space for C5 to sit tight against the board; this is fixed in PCB v1.0.1.

Adds 512K of RAM and selectable 512K Flash ROM to a 20-bit-address RCBus system.

The project provides Z80 and Z180 firmware, a schematic, Gerbers, PCB design files, and kit or bare-PCB suppliers; an assembled version is not offered. Observe the Flash write-protect jumper and select the ROM/RAM arrangement required by the processor and firmware.

Adds an 18.432 MHz Z180 processor, dual serial ports, and a microSD interface.

The project provides firmware, a schematic, Gerbers, PCB design files, and kit or bare-PCB suppliers; an assembled version is not offered. RomWBW supports the microSD interface, while the documented Small Computer Monitor configuration does not. On PCB v1.0.0 the JP2 RX2 and TX2 labels are swapped; v1.0.1 corrects them.

Combines two Z80 SIO/2 serial ports with four programmable Z80 CTC channels.

The project supplies a schematic, Gerbers, PCB design files, and kit or bare-PCB paths. The optional oscillator is not included in the kit. Standard RomWBW does not enable CTC support, so its documented jumper setup bypasses the CTC and assumes a 7.3728 MHz CPU clock.

Generates three independently selected clock outputs for RCBus processor and peripheral timing.

The project provides a schematic, Gerbers, PCB design files, and kit or bare-PCB suppliers; an assembled version is not offered. Check every destination jumper to avoid driving a bus clock signal from more than one source.

Adds a battery-backed DS1302 real-time clock and several spare I/O bits.

The project supplies a schematic, Gerbers, PCB design files, and kit or bare-PCB paths. The clock is supported by RomWBW but not by plain CP/M 2.2 or Small Computer Monitor. Writes to spare output bits require care because the port is shared with the RTC control bits.

Combines a Z80 processor with a 20-bit MMU for SC721's 1 MB linear memory.

The project provides firmware, a schematic, Gerbers, PCB design files, and kit or bare-PCB suppliers; an assembled version is not offered. Pair it with SC721 linear memory and do not combine it with the bank-switching SC707 or SC714 memory modules.

Adds two independently writable pulse-width modulation outputs.

The project supplies a schematic, Gerbers, PCB design files, and kit or bare-PCB paths. The base address must be even; 0x04 is the documented example. Pulse frequency is the selected clock divided by 128.

Controls two hobby servos through two tightly decoded output ports.

The project supplies a schematic, Gerbers, PCB design files, and kit or bare-PCB paths. Although the servos can use the computer's 5 V rail, the maker strongly recommends an external supply because of loading and electrical-noise concerns.

Adds simple bit-banged microSD storage with RomWBW support.

The project supplies a schematic, Gerbers, PCB design files, and kit or bare-PCB paths. Support is included in RomWBW v3.5; RomWBW v3.4 needs SDENABLE enabled in the RCBus_std configuration. Small Computer Monitor does not support it.

Adds a software-enabled 50 Hz system tick interrupt.

The project supplies a schematic, Gerbers, PCB design files, and kit or bare-PCB paths. Interrupt generation is disabled at reset. A jumper routes the signal to /INT, /INT1, or /INT2 where the chosen bus exposes it.

Adds supervised power-on reset, a debounced reset button, and software-triggered reset.

The project provides a schematic, Gerbers, PCB design files, and kit or bare-PCB suppliers; an assembled version is not offered. Enable only one voltage supervisor in a system and choose an I/O address that does not conflict with another module.

Mounts a BlueSCSI or another 50-pin SCSI device directly above a Macintosh internal SCSI connector.

The current store page listed partly assembled and complete options without an out-of-stock marker on 2026-07-24. The maker repository also provides assembly material and Gerbers.

Connects a 50-pin SCSI device such as BlueSCSI V2 directly to an external Macintosh DB-25 SCSI port.

The store page explicitly said Out of Stock on 2026-07-24, but the maker repository includes assembly instructions and Gerbers for noncommercial DIY fabrication.

Adds SCSI disk hardware to a Commodore 64 through a CS/A adapter, with experimental external IEC-drive variants.

Only the modular C64 CS/A adapter plus CS/A SCSI card combination is reported tested and working. The simplified combined C64 board was not fully checked. VC-SCSI 1.0's component boards were tested separately but not as a complete drive, VC-SCSI 1.x remained an idea, and VC-SCSI 2.x was preliminary and untested. The published FAT12/FAT16 filesystem software is explicitly early beta and may corrupt a disk; never test it with valuable media. No current kit or assembled seller was verified.

Provides open internal and currently assembled external SD-based SIO disk-emulator variants for Atari 8-bit computers.

Lotharek exposed a login-or-register-to-buy path for SD Drive Mini on 2026-07-27, and Retro Lemon also listed it with pricing. It plugs directly into SIO, uses a FAT32 microSD card and SDRIVE.ATR, and provides two buttons plus LEDs for selecting four drive slots. The separate open SDrive-Simple-II build still requires PCB assembly, ATmega328P programming, and an internal SIO connection. Its documented firmware supports cards up to 32 GB and ATR and XEX files, but not CAR, ROM, ATX, XFD, or CAS files, and it has no control for swapping disks in a multi-disk title. The former SDriveXEL assembled source and exact public build package remain unavailable.

Safely connects a Sega Mega Drive or Genesis controller to a Commodore 64, Commodore 128, or Amiga with configurable fire and jump mappings.

The open CERN OHL 1.2 project supplies design and fabrication files plus a bare-PCB ordering route. On 2026-07-30, Gotek Retro listed its assembled C64/128 and Amiga adapter at EUR 15 and AMI64 listed its assembled C64 and Amiga adapter at GBP 20. Turn the computer off before changing selectors, choose the correct computer mode, and assign each function only once. The open and AMI64 versions may need a joystick extension cable at an Amiga 600.

Open ISA card combining a two-drive floppy controller, RS-232 serial port, and optional BIOS ROM.

The repository supplies KiCad files, Gerbers, a bill of materials, and assembly documentation rather than a retail order path. Install the 5 V-on-pin-3 jumper only for a compatible PS/2-style drive; using it with a standard drive causes a short. Version 1.0 also has a documented option-ROM switch-table error.

Open ISA sound-card design using Yamaha OPL2 hardware for AdLib-compatible FM synthesis.

Retro Electronics listed the Version 1.2 bare PCB in stock on 2026-07-25. No components or assembly are included; the obsolete Yamaha sound chips can be harder to source than the common logic and passive parts.

Open Trident TVGA9000i VGA card for 8-bit ISA computers, including the original IBM PC and XT.

Use PCB version 1.1 for an original IBM PC or XT; version 1.0 needs the documented ALE rework. On version 1.1, the C17 silkscreen incorrectly says 1 uF instead of 1 nF. The project also documents a color-monitor detection workaround for newer DDC displays.

Combines a Z80 CPU, 512 KiB Flash, 512 KiB SRAM, clock, reset, and RomWBW paging on one modular card.

Tindie listed the complete Z80-512K kit without an out-of-stock notice on 2026-07-25; complete open files also remain available for both designs. The Z80-CPM store page failed extraction, so no stock claim is made for that variant. Z80-512K builders using its supervisor without a backup battery must short the battery connector as documented.

Open hardware 10/100 Ethernet card designed around a modern controller for the Macintosh SE/30 PDS.

Uses a Raspberry Pi cartridge to emulate memory, sound, cartridges, ROMs, and file-loading functions across several Commodore 8-bit systems.

The open project publishes Gerbers, BOMs, software, and case files for full-size and Zero boards. Retro-Updates' assembled Sidekick64 Zero was out of stock on 2026-07-27 and excludes the Raspberry Pi Zero 2. The maker calls the project a personal playground and warns that unsupported images, timing glitches, and unsafe cartridge combinations remain possible.

DIY RP2040- or RP235x-based replacement for one or two 6581 or 8580 SID chips, with optional FM emulation and paddle or mouse input support.

Choose the hardware design and matching firmware together. The official project documents different DAC, PWM, connector, line-output, and host-interface arrangements plus a list of preassembled sellers. Multi-SID or FM modes need the documented address-signal wires. Never power the module from USB and the Commodore computer at the same time.

Emulates Atari 8-bit disk drives from SD or MMC cards through the SIO port.

Lotharek offered the Biggus Dickus, metal-cased XL and XE, and color variants through login-to-buy paths on 2026-07-27. The metal-cased versions include an SIO cable, while the base Biggus Dickus listing includes neither cable nor SD card; other listings bundle those accessories with the same hardware. The official project also publishes Eagle schematics and boards plus firmware, making a DIY path possible. Upstream firmware reached 3.3 in 2023, while Lotharek says its assembled versions use customized 3.1 RC2 firmware, so do not assume identical features without checking the installed version.

Open ROM adapter that selects alternate C64 KERNALs through the RESTORE key and indicates the active bank with an LED.

The open project provides Gerbers, firmware, and programming guidance. Retro Electronics lists an assembled board, cables, LED, and blank 27C256 or W27C512, but its page did not expose a current stock or ordering state on 2026-07-25. Users must program legally obtained ROM images; the seller specifically notes that JiffyDOS and JaffyDOS require licenses.

Recreates the 1989 Sound Blaster 1.0 with digital playback and recording, AdLib-compatible synthesis, CMS audio, and a joystick/MIDI port.

This is a self-assembly project. Follow the documented bodge resistor, MIDI jumper-wire, firmware, DMA, IRQ, joystick, and I/O-address instructions before use.

Implements Sound Blaster-compatible audio for Micro Channel systems with OPL2 synthesis and CPLD-managed bus, interrupt, and DMA logic.

Installation requires the supplied ADF and the host reference-disk configuration program. The maker warns against LS or HCT logic because it may not meet Micro Channel timing margins.

Open five-board set for bringing Commodore cassette, user-port, and PET IEEE-488 connections to headers and ribbon cables.

The public repository provides revisioned PCB project files, pictures, and a GPLv3 license, but no current assembled seller is documented. Builders must fabricate the required board pair, fit connectors, and make the matching ribbon cable. The concise README does not document buffering, isolation, fusing, current limits, or a safe live-connection procedure; verify orientation and wiring and make every connection with the computer powered off.

Adds an internal SwiftLink-compatible ESP8266 Wi-Fi modem to the flat-model Commodore 128 while leaving its cartridge port available.

The assembled Tindie listing was retired by 2026-07-30, while the open project retains hardware and firmware material. The archived Tindie instructions specify socket U4, but the maker's merged README says U2, and human review found no surviving material that resolves the conflict. Do not install from the catalog summary; inspect the project files and verify the correct CIA socket against the exact board.

Adds an internal SwiftLink-compatible ESP8266 Wi-Fi modem to supported Commodore 64 longboards and Commodore 128DCR systems.

The assembled Tindie listing was retired by 2026-07-30. The open project retains Eagle design files, firmware, patches, and installation material. This is a board-specific internal installation that requires removing and reusing a 6526 CIA plus routing flying leads; verify the motherboard revision and instructions before fitting it.

Adds a DE10-Nano Linux coprocessor, 1080p HDMI video, DMA, storage, networking, and a framebuffer overlay to a Commodore 64.

The project remains under construction and its current releases are alpha previews. Carrier Gerbers, a BOM, placement data, and preview releases are available, but a DE10-Nano or compatible MisterPi board and the supplied SD image are also required. Change the default Debian root password before connecting it to a network.

Connects a modern Mac or Linux computer directly to vintage LocalTalk computers and peripherals over USB.

JCM showed 181 assembled units in stock on 2026-07-24. A standard Macintosh crossover serial cable or a LocalTalk dongle is still required; a straight-through serial cable will not work. TailTalk describes itself as a work-in-progress prototype and currently expects a routerless AppleTalk setup.

Adds SD mass storage to Commodore 264-series computers and can replace the paddle cartridge in a real 1551 drive.

The repository provides Gerbers, firmware, hardware instructions, and release files sufficient for a DIY build. The maker invites requests for a completed unit but does not advertise standing stock. Disk images are read-only, and the device does not reproduce a 1551 exactly. When a TCBM cable is fitted, both specified ground pins must be connected as documented.

Combines ROM and program loading, MIDI, Ethernet, NFC launching, remote control, a real-time clock, and REU functions in a Teensy 4.1 cartridge.

The maker's Lectronz store showed six fully assembled revision 0.4 units at USD 64.00 on 2026-07-27. The programmed Teensy 4.1 and case are included. A CR1225 battery is included only with United States shipments, and an SD card or USB drive is needed for content beyond the built-in files.

Open 1 MB battery-backed RAMFactor-compatible memory card with a NoSlotClock-compatible clock and ProDOS restore image.

No current assembled seller was verified on 2026-07-24, but the GW4206B hardware, CPLD, firmware, documentation, and fabrication files remain public. A CR2032 is required for clock operation, retained RAM, and the restore partition. Replacing it erases RAM and resets the clock. Disable TimeDisk's clock when another NoSlotClock-compatible device is present. The USB updater requires 64-bit Windows 10 or later, including supported Boot Camp or Parallels configurations.

Business-card-sized RC2014-compatible Z80 computer with 1 MiB of memory and integrated serial and parallel I/O.

This is a surface-mount self-assembly project with KiCad, Gerber, CPLD, and firmware documentation. Programming its MAX7000AE CPLD requires the older Quartus II 13.0sp1 toolchain because newer Quartus versions do not support the device.

Lets Atari 8-bit computers use an external PS/2 keyboard through a POKEY-based internal adapter.

The Brewing Academy versions were sold out on 2026-07-24, while MyTek publishes schematics, board files, firmware, parts information, and bare-PCB order links. A 600XL or 800XL uses the TK-II-PB-R installation. Expect soldering and possible case modification; an unsocketed POKEY must be desoldered and fitted with a 40-pin socket. The Stereo version needs a second genuine POKEY and external amplification for its line-level output.

Recreates a 25 MHz 68040 accelerator for the Macintosh LC, LC II, and Color Classic.

This is a noncommercial self-build project with no assembled purchase path. The XC1736 configuration PROM at U15 must be programmed with reset polarity set high, and the complete build requires an XC3030 FPGA plus the listed 68040 and support parts.

Builds an integrated modern PET-compatible computer with selectable PET models, accelerated operation, enhanced color video, storage, audio, and current input.

No current assembled seller was verified. Revision 1.3A has public GPL-3.0 hardware files, but a build requires fine-pitch surface-mount assembly, separate FPGA and ROM projects, and programmed devices. The family documentation warns that boards, bills of materials, and firmware are moving to newer video timing and says to contact the maker before building.

Improves Atari 8-bit analog video and corrects overscan for modern displays.

The Brewing Academy configurations were sold out on 2026-07-24. MyTek publishes the current UGV-II schematic, bill of materials, PIC firmware, and Gerbers. The 0.8 mm main board requires assembly and PIC programming. A normal installation is nearly solderless at the GTIA, but routing video to the stock DIN connector can require a few motherboard solder points.

Connects modern Bluetooth gamepads and, on selected models, mice to Commodore, Amiga, and Atari computers.

The official C64, A500, and 800XL Tindie pages were out of stock on 2026-07-30, although the project marks those models active and supported. CBMretro had equivalent cased C64/C128 and A500/A1200 hardware available at EUR 41.90; the original designer does not support third-party builds. Open hardware, firmware, and documentation remain available. The guide's original Unijoysticle tile is folded here as the retired WiFi predecessor: it needed a separately powered ESP8266 receiver and phone or desktop client, unlike the Bluetooth successor.

Open EPROM cartridge board for making single-ROM, switchable multi-ROM, and diagnostic cartridges for the C64 and C128.

The repository provides board revisions, fabrication files, and documentation. A working cartridge still requires a PCB, components, a correctly programmed EPROM, and configuration appropriate to the selected ROM images.

Provides switch-selectable VIC-20 memory layouts with current assembled 35 KB and 37 KB cartridges plus an open 32 KB design.

Jaystonian showed eight HyperExpander SMD cartridges in stock at USD 29.99 on 2026-07-29. Retro Lemon exposed a GBP 20 product page without an out-of-stock marker. The open 32 KB project remains buildable. The guide's old fixed 24 KB eBay listing is retained only as an archive because its current order path was not verified.

Tests a VIC-20's keyboard, IEC, user, cassette, and joystick interfaces with a machine-specific cartridge and loopback harness.

AMI64 listed its GBP 47 complete cartridge-and-harness kit as available in around ten days on 2026-07-30. CMD Marketplace listed three USD 59.90 PAL/NTSC kits, but its Tindie page exposed conflicting United States shipping text and no usable US rate. Sven Petersen publishes the GPLv3 hardware and firmware project.

Open internal C64 modification that switches between installed PAL and NTSC VIC-II chips and includes LumaFix64 video cleanup.

The current project page provides build files, component links, PCB ordering routes, and a video guide under CC BY-NC-SA 4.0. This is not a plug-and-play board: installation removes the RF shielding, desolders motherboard parts and jumpers, adds pins, and requires both a 6567 and 6569 VIC-II. The connected display must accept both PAL and NTSC or one switch position may produce monochrome video or no usable picture. The authors provide no warranty or installation support.

Shares one basic ADB keyboard and mouse among as many as four retro-computer hosts.

The current product page offered build-it-yourself and fully assembled selections on 2026-07-24. Only basic ADB keyboards and mice are supported. The firmware remains under active development and the maker warns that bugs remain.

Open cartridge-port expander with three independently controlled positions, configurable bus signals, and a reset switch.

The official store exposed an active $30 listing on 2026-07-27, and the open Eagle files remain available. Cartridge combinations are not guaranteed, the two connectors at the third position share one set of switches, and the passive bus can worsen marginal signal integrity. Insert, remove, and configure hardware only with the computer powered off.

Adds an internal CompactFlash hard drive to the 1088XEL through its MPBI expansion interface.

Both variants have public fabrication material, and the Rapidus board adds KiCad source. Use only the specified Texas Instruments 74F-series logic. The interface needs flashjazzcat's special 1088XEL Ultimate 1MB BIOS, replacing the original SIDE PBI and loader. Keep the IDE cable under 10 inches when practical. The maker does not guarantee every CompactFlash card and reports the best results with genuine SanDisk cards rated at 30 MB/s or less.

USB interfaces that connect Commodore IEC disk drives to a modern computer for disk transfer and archival.

Retro Electronics listed two assembled USB-C compatible boards in stock on 2026-07-25. The reference ZoomFloppy hardware files are openly published. Required USB and Commodore drive cables are not supplied with either documented route, and parallel-transfer features need additional drive-side hardware.

Open-firmware SCSI emulators in DB-25, internal 50-pin, laptop, and Wide SCSI form factors.

Rabbit Hole Computing offered current Compact RP2040, Blaster, and Wide variants on 2026-07-24. A 2026-07-27 follow-up found its mostly assembled $25 Pico Slim V1.3 PCB kit sold out, while SamplerZone exposed an Add to Cart path for a $79.95 assembled and cased Pico Slim with configured microSD media. Rabbit Hole's direct Pico2 Slim and Laptop Blaster pages were also sold out. TinySCSI was archived in January 2025, but its V1.0 and V2.0 KiCad files remain available for personal builds. A project discussion documents Wi-Fi DaynaPORT operation on a Pico Slim under System 7.5.5 with the DaynaPORT SCSI-port driver, but does not establish a minimum System version or equivalent networking support for every family variant. Connector, termination, power, speed, and initiator support vary by hardware.