Atari 800XL upgrades

Upgrades an Atari 1050 disk drive for divisor-6 high speed, 180 KB per side, and flashable firmware slots.

For this system (bus/interface): This modifies an external Atari 1050 SIO drive rather than the computer. Confirm normal drive and SIO operation before installation and use host software that supports the selected high-speed and density modes.

Lotharek marks 1050E discontinued. The seller calls installation solderless, but it still requires opening the drive, removing three chips, moving the 6507 CPU, and preserving socket orientation. Confirm that a used kit is complete, that all original chips and sockets are healthy, and that suitable 1050E firmware and host software are available.

Provides 64 KB of main RAM and 256 KB of RAMBO-compatible extended memory through a 1090XL-family expansion slot.

For this system (bus/interface): Use through a compatible 1090XL-family expansion system. The card adds 256 KB of RAMBO-compatible extended memory to the 800XL's 64 KB main configuration; check its PBI-memory jumper against any VBXE or Ultimate 1MB installation.

The page reported three cards in stock on 2026-07-27. A 1090XL or 1091XL base system is required and is not included. The PBI-memory option must remain off when the host has VBXE or Ultimate 1MB. The RAM-disable option is recommended for modern reproduction systems so other cards can map their own memory.

Provides 80-column text over HDMI from a Raspberry Pi Pico card installed in a 1090XL-family expansion system.

For this system (bus/interface): Use through a compatible 1090XL-family expansion system. The card replaces normal video while enabled and is limited to text software using Atari operating-system input and output.

The page reported three cards in stock on 2026-07-27. A 1090XL or 1091XL base system and a separate HDMI display are required. Enabling the card disables normal video output; holding Shift while booting disables the card. Each installed expansion card needs its own jumper-selected device ID.

Connects an Atari CX-85 numeric keypad through a 1090XL-family expansion slot with an onboard input handler.

For this system (bus/interface): Use through a compatible 1090XL-family expansion system with a separate CX-85 keypad. The onboard handler is documented only for software using Atari operating-system input and output.

The page reported two cards in stock on 2026-07-27. A 1090XL or 1091XL base system and an Atari CX-85 keypad are required. Current compatibility is limited to software that obtains input through the Atari operating system.

Adds five 1090XL-family expansion slots to an Atari 600XL or 800XL through the rear parallel bus.

For this system (exact model): The seller explicitly supports the 800XL through its rear parallel bus. Use the supplied 50-pin cable and provide the separate 9 VAC Atari power supply.

The page reported one system in stock on 2026-07-27. The 50-pin parallel cable is included, but a compatible 9 VAC Atari power supply is not. Expansion cards and the optional 12 V supply configuration cost extra; the seller says no currently available card needs that optional 12 V rail. Systems are assembled on demand and may take several days to ship.

Adds Hias high-speed SIO and Fast Math F+ through a 1090XL-family expansion card.

For this system (bus/interface): Use through a compatible 1090XL-family expansion system. High-speed SIO still requires a compatible peripheral such as a suitably upgraded 1050 drive.

The page reported two cards in stock on 2026-07-27. The sale includes only this card; the 1090XL-family base system and the separately pictured CP/M card are not included.

Adds an 8 MHz-or-faster Z80, 64 KB of onboard memory, and a beta CP/M environment through a 1090XL expansion slot.

For this system (bus/interface): Use through a compatible 1090XL-family expansion system. The Z80 card supplies its own 64 KB, but the host still needs the base system, storage, and beta CP/M software.

The page reported one card in stock on 2026-07-27. CP/M customization and utilities remain late beta. The card is sold with or without a Z80; a user-supplied CPU must be rated for at least 8 MHz. The pictured 80-column RPP card is optional and not included. Double-density disk use also requires supporting drive hardware. The exact page names only the 1090XL, so confirm 1091XL compatibility before using it in that implementation.

Expands an Atari 600XL or 800XL to 320 KB through the rear parallel bus without opening the computer.

For this system (exact model): The seller explicitly supports the 800XL but warns that most units do not power the module through the parallel bus. Select the external-power jumper position and provide 5 V through USB-C or the documented wired input when required.

The Tindie page reported one unit in stock on 2026-07-27. A 600XL supplies power through its parallel bus. Most 800XL computers do not, so the board provides a jumper-selectable USB-C or wired 5 V input. Follow the seller's internal-versus-external power procedure and jumper setting for the exact computer.

Rebuilds an Atari 800XL around a newly manufactured Revision 1.2 motherboard with bare, programmed-chip, and assembled options.

For this system (exact model): The Revision 1.2 PCB is explicitly a remake of the Atari 800XL C061851 Revision D system board. Bare and mostly bare options require advanced assembly; the completed option requires a working donor board.

The main board page reported two units in stock on 2026-07-27. A completed board requires the buyer to send a functional, non-returnable donor board because original Atari chips and some connectors are no longer made; the seller estimates about two weeks for completion and testing after receiving it. The separately orderable programmed-chip page reported four sets in stock. Its EMMU must match the intended memory configuration and is optional for a 64 KB-only build.

Current composite and S-Video cable options for compatible Commodore computers, with a five-pin composite branch that also serves selected Atari systems.

For this system (exact model): The five-pin composite cable and adapter explicitly list the Atari 800XL. This relationship covers composite video and audio only; the Commodore eight-pin S-Video branch does not apply.

The two five-pin products exposed Add to cart controls, while the eight-pin product exposed current priced options on 2026-07-30. The five-pin cable and adapter carry composite video and two audio connectors; those connectors do not create an independent stereo source in a stock mono computer. The eight-pin S-Video branch requires a host that supplies separate luma and chroma. Its stereo option requires a compatible second audio source on the designated extra pin. Match the connector, resistor, audio wiring, display input, and regional video standard before ordering.

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

For this system (exact model): The current seller explicitly lists the Atari 800XL, and the project documents and photographs cased 800XL use. Never connect USB while the cartridge is inserted in the Atari. DIY builds require the specified purple USB-C Pico clone; the official green Raspberry Pi Pico has different pin functions and may damage both devices.

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.

Retains the original POKEY while adding FPGA stereo POKEYs, Covox channels, digital mixing, and a high-rate stereo DAC.

For this system (exact model): The page gives an 800XL example for the full mixing stage, including removal of C19, C22, and R8 and connections for PBI, SIO, bell, and mono audio. Use the staged installation guide and keep pin 31 isolated.

The product exposed a login-or-register-to-buy path on 2026-07-27. It requires a working original POKEY and can be installed in stages: basic stereo output, a second POKEY through an A4 connection, Covox through D6xx or D7xx decoding, and full internal-audio mixing. The approximately 1 mm PCB intentionally leaves pin 31 unconnected; verify that it remains isolated from the motherboard. Only the basic stage uses a single address jumper, while the expanded functions require additional signal and audio wiring.

Replaces the Atari XL or XE operating-system ROM with a switchless 32-image OS selector and high-speed SIO features.

For this system (exact model): Atarimax provides an 800XL installation path for the generic kit. Confirm socket orientation and follow the exact model guide; backwards insertion or excessive force can damage the module.

The official page showed self-installation and professional-installation options in stock on 2026-07-25. The generic kit is for XL and XE computers except XEGS; the special 1200XL kit includes an XE MMU and internal BASIC upgrade. The 1200XL procedure is an advanced modification that can require desoldering and replacing ROM sockets, moving jumpers, adding wires and a resistor, and modifying or omitting the RF shield.

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

For this system (exact model): The project is titled for the Atari 800XL and shows a tested prototype. Although the underlying Pixels Past cartridge supports the broader 400, 800, XL, and XE family, no other host was verified for this exact eight-way modification.

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.

Breaks compatible Atari and Commodore monitor-port signals out to S-video, composite video, and bridged mono audio connectors.

For this system (exact model): The seller says an 800XL provides composite through the breakout without modification. S-video requires chroma to be connected, so verify whether the computer already has the needed chroma wiring.

The current product data and catalog reported the assembled breakout in stock on 2026-07-27. Cables and any required computer modification are not documented as included.

Selects between two programmed Atari operating-system ROM banks according to the Reset key state at power-on.

For this system (exact model): The seller's installation material explicitly identifies the Atari 800XL motherboard. Follow the exact installation procedure for the board revision and do not combine the switcher with Ultimate 1MB.

Lotharek's version 2 page exposed a login-or-register-to-buy path on 2026-07-27. It arrives flashed with Atari OS and QMEG 4.04, and a small onboard switch selects the default bank. A socketed OS ROM makes installation simple; otherwise the original ROM must be desoldered and a socket should be fitted. The page markets the device for Atari 8-bit computers but illustrates only an 800XL connection, so broader target relationships remain withheld. Do not use it with Ultimate 1MB.

Adds a battery-backed real-time clock to Atari XL and XE computers as an internal module, pass-through cartridge, or circuit inside another cartridge.

For this system (stated family): The project is designed for Atari XL and XE computers. Choose the internal, pass-through cartridge, or inside-another-cartridge form before laying out the circuit and backup supply.

The project page publishes a parts list, clock and address-decoder schematics, battery and rechargeable-cell backup circuits, and an ARC handler archive. It recommends internal installation because the pass-through and inside-another-cartridge forms may cause more problems. The page does not provide a step-by-step bus-wiring guide: an internal build must source D0-D3, A0-A7, R/W, phase 2, power, and D5xx cartridge-control signals, while a cartridge build uses the cartridge connector. No explicit project license or current assembled seller was verified.

Period SIO floppy drive adds double-sided, double-density 5.25-inch storage and faster double-density transfers to Atari 8-bit computers.

For this system (exact model): Atari's manual explicitly covers the 800XL and its built-in BASIC behavior. Full double-sided, double-density use requires software beyond the bundled DOS 2.5.

Find a complete used drive with the correct AC adapter and SIO cable. The bundled DOS 2.5 supports single and enhanced density but not the XF551's full double-sided, double-density capacity; use DOS XE or compatible third-party software for that mode. Most drives use a Mitsumi mechanism with a rectangular activity LED, while later Chinon examples have a round LED and stricter flippy-disk limitations. The 300 RPM mechanism can also conflict with a small amount of speed-sensitive copy protection.

Provides blank flash cartridges and a USB programmer for building reusable Atari 8-bit multicarts.

For this system (stated family): Atarimax explicitly describes the Maxflash system for Atari 400, 800, XL, and XE computers. The cartridge is used in the Atari while the separate USB programmer and Maxflash Studio prepare its contents on a modern computer.

The official page showed the cartridges and USB programmer in stock on 2026-07-25. These are blank programmable products and do not include commercial ROM images. Unplug the programmer before attaching a cartridge, verify label-side-up orientation, and connect directly to the PC rather than through a USB hub for first-time use. Backwards insertion can damage both the cartridge and programmer.

Adds CompactFlash storage, cartridge-image loading, and onboard flash and SRAM to Atari XL and XE computers.

For this system (stated family): Atarimax describes MyIDE-II for the Atari XL and XE family through the cartridge port. Confirm CompactFlash preparation and software requirements before use.

The official page showed MyIDE-II cartridges and accessories available on 2026-07-25. A prepared CompactFlash card is offered separately, so confirm the selected package contents. No ROM images are included; users must supply legal images and software.

Connects Atari 8-bit SIO computers and disk drives to a modern host for peripheral emulation and disk transfer.

For this system (bus/interface): The interface works with Atari 8-bit computers through SIO. USB versions are intended for Atarimax APE on Windows, while the RS-232 version is compatible with SIO2PC software available for several host operating systems. Confirm the required SIO cable and chain position.

The official page showed USB and RS-232 ordering options on 2026-07-25. Select the interface and connector arrangement for the intended host software and SIO chain. An Atari SIO cable and the computer or disk-drive hardware needed by the chosen workflow are not included. The USB setup documentation is dated and lists Windows 95 through Windows 7, so confirm current host support rather than assuming modern Windows compatibility.

Adds a two-port USB host interface for supported keyboards, controllers, mice, and other driver-backed devices.

For this system (stated family): Atarimax explicitly describes the cartridge for all Atari 8-bit computers. Confirm that a MicroUSB driver exists for the exact USB device and Atari software workflow you intend to use.

Atarimax marked the cartridge in stock and ready for shipment on 2026-07-25, although the same page called the current price a preorder promotion through 2026-07-31. This is not a generic plug-and-play USB port: support depends on Atari-side drivers. Atarimax still describes the software as early beta, and the MicroUSB project's substantive status notes are historical, so check the device matrix and exact driver before buying hardware for a particular peripheral.

A family of SD multicarts for Atari 8-bit computers, ranging from cartridge loading to disk, tape, memory, clock, and audio expansion.

For this system (exact model): AVGCART explicitly supports the 800XL and XE family. Cartridge-only functions use the cartridge port; fuller disk, tape, memory, clock, or audio workflows require the appropriate variant and optional SIO, ECI, PBI, or DAC cable.

All three product pages showed In stock and Add to cart on 2026-07-24. Optional SIO, ECI, PBI, and DAC cables are separate. SUBCART's extra functions need ECI or PBI, and the maker does not recommend them on a machine with U1MB or another third-party internal memory expansion.

Adds 1 MB of banked RAM to an Atari 1200XL or 800XL with a 30-pin SIMM and custom refresh and bank-selection logic.

For this system (exact model): The archive explicitly indexes this as an 800XL and 1200XL upgrade, but the article publishes 1200XL connection locations and says only that similar 800XL points should work. Derive and verify the 800XL wiring before construction.

The archived article provides the circuit discussion, 1200XL connection table, SIMM pinout, and software notes but describes the 800XL only as having similar connection points. It is an advanced historical wire-and-perfboard build. The author reports that the SpartaDOS cartridge does not function with this configuration and that ordinary SpartaDOS and much commercial software see only a 320XE-style subset; MYDOS 4.5.1M or newer needs the documented page sequence.

Replaces the Atari FREDDIE memory-management chip with a CPLD module.

For this system (stated family): The seller says XL systems have no general height problem, but not every 800XL board uses FREDDIE. Open the machine and identify the motherboard and original chip before buying or installing this replacement.

Lotharek marks FreddieCPLD discontinued. It is a full replacement for a computer already fitted with a FREDDIE chip, unlike the current Freddy Module v2 companion clock board. Installation requires safe removal of the original chip and correct orientation. The supplied bottom socket can make the module too tall in XE cases; the seller recommends removing it after testing and soldering the module into place. Confirm that the exact motherboard actually uses FREDDIE.

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

For this system (stated family): The official project supports the Atari 8-bit family with a platform-specific FujiNet. It emulates several peripherals, including disk drives, printers, cassette, modem, and the FujiNet network device.

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.

Adds digital RGB, optional 31 kHz scandoubling, display corrections, and an 80-column overlay while retaining the original GTIA.

For this system (stated family): The draft manual supports the entire PAL and NTSC XL/XE family and says its palettes were measured on 600XL and 800XL hardware. Not every model and region combination was tested. Confirm GTIA socket height, update firmware, and use the documented output mode and cable pinout.

The product exposed a login-or-register-to-buy path on 2026-07-27. Update its initial firmware before installation. A socketed GTIA may still require careful removal of the adapter's bottom socket for height; a soldered GTIA must be desoldered. The May 2026 hardware manual is explicitly a draft. The product page publishes a complete VGA pinout but leaves the 15 kHz connection diagram unfinished, so do not improvise a SCART or RGB-monitor cable from that page. SECAM computers use an incompatible FGTIA pinout and are not supported.

Upgrades an Atari 1050 disk drive with true double density, faster backup operations, and protected-disk support.

For this system (bus/interface): This upgrades an external Atari 1050 SIO disk drive rather than the computer itself. The guide covers all Atari 1050 drives and explicitly excludes other drive models; verify that the 1050 and the rest of the SIO chain work normally before installation.

The 5cfab stand-alone Happy Warp 1050 v7.1 reproduction reported two boards in stock on 2026-07-27; Atarimax still provided a conditional add-on route on 2026-07-25. The 5cfab board includes its CPU and needs no soldering, but installation still requires opening the drive and carefully replacing internal hardware. Align the board's crystal with its clearance hole. The Atarimax guide also warns about static, alignment, and orientation.

Adds an SIO-connected General MIDI file synthesizer with external stereo output and Atari audio mixing.

For this system (bus/interface): The device connects through SIO and supplies separate stereo output. Confirm the required Atari player software, supported MIDI workflow, and monitor-audio behavior for the 800XL.

The product exposed a login-or-register-to-buy path on 2026-07-27. It is a MIDI-file synthesizer, not the MyTek MIDI input/output interface already in the catalog. The public page and human review provide no written player-software, file-workflow, or model-specific SIO-audio instructions. Treat the external stereo output as the documented playback path and confirm software availability before purchase.

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

For this system (stated family): The project uses an Atari 8-bit joystick port and Atari flashing software. Build the programmer, provide the required firmware file, and verify the target PIC and orientation.

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.

Replaces a failed or missing Atari POKEY with an updateable FPGA module in the original DIP-40 socket.

For this system (exact model): The seller explicitly names the Atari 800XL. Installation is a direct swap only when the existing POKEY is socketed; firmware can be updated through the module's built-in USB interface.

The product exposed a login-or-register-to-buy path on 2026-07-27. Installation is solderless only when the computer already has a compatible DIP-40 POKEY socket. This is a functional FPGA replacement, not a transistor-level NMOS clone; the seller warns that software depending on undocumented analog behavior or exact electrical characteristics may behave differently. The built-in USB port allows future firmware updates.

Adds an internal PS/2 or USB keyboard interface to supported Atari 8-bit computers by interposing at the POKEY socket.

For this system (exact model): The PS/2 page explicitly names the 800XL in its original-keyboard troubleshooting note. Installation interposes at POKEY, adds four control wires, and requires the supplied external keyboard connector; remove R2 and R3 if the original keyboard stops working.

Both variants exposed login-or-register-to-buy paths on 2026-07-27. A non-socketed POKEY must be desoldered, four control wires are required, and installation calls for a new case opening for the supplied keyboard socket or cable. The PS/2 page says an original keyboard that stops working on a 600XL or 800XL requires removal of R2 and R3; XE and XEGS machines leave those resistors intact.

Breaks a compatible Atari five-pin monitor output into S-Video, composite video, and audio connections.

For this system (bus/interface): Human review confirms a stock five-pin DIN monitor connector. The direct-plug variant can attenuate chroma for displays that need a lower level; jumper on is the direct signal.

All three variants exposed login-or-register-to-buy paths on 2026-07-28. Human review established that the Atari 800, 800XL, and 1200XL have the required stock five-pin DIN connector. The Atari 400 and 600XL do not, so they are deliberately excluded. Atari 65XE and 130XE support is banked until those targets enter the catalog. Confirm that the exact regional motherboard exposes the desired luma and chroma signals before buying for S-Video use.

Connects Atari SIO computers to a modern USB host, with 10502PC variants that can also image disks through a physical Atari drive.

For this system (bus/interface): All variants connect through a free SIO port. Select DSR or CTS handshaking for the exact adapter and configure the host software before booting; use a 10502PC variant when imaging disks through a physical Atari drive.

The basic SIO2PC USB, 10502PC Revision 2, and USB-C Revision 3 pages all exposed login-or-register-to-buy paths on 2026-07-27. Host emulation requires a modern computer, FTDI serial drivers where needed, and software such as RespeQt or AspeQt. The basic interface's manual uses DSR handshaking, while the 10502PC pages specify CTS for SIO2PC mode. Physical-drive imaging requires a 10502PC variant, ALibPC, and the documented FTDI setup; launching ALibPC changes the adapter to 10502PC mode, and unplugging and reconnecting USB restores its default SIO2PC mode.

Replaces Atari 8-bit dynamic RAM with modern SRAM or configurable FPGA-managed PSRAM in three current versions.

For this system (exact model): The pages provide an 800XL memory-replacement diagram and signal references. The basic version replaces 64 KB and delay-line logic, Lite offers common configurations through 320 KB, and Professional adds larger menu-selected modes and requires current firmware.

All three memory variants exposed login-or-register-to-buy paths on 2026-07-27. Installation goes under the CPU and may require removal or isolation of the original DRAM, desoldering, new sockets, and EXT_SEL or CAS_INHIBIT connections. The Professional version also uses an MMU adapter and its page says to install the latest firmware before use. The optional Freddy Module v2 cannot operate alone: the seller requires the basic SRAM module first and says VBXE owners do not need the Freddy replacement.

Converts composite, S-Video, RGB, RGBI, and VGA-family retro signals to simultaneous digital and analog DVI-I output.

For this system (stated family): The current mode list covers Atari XL/XE VBXE RGB, and generic composite or S-Video can use the analog decoder. Supply a correctly wired SCART or VGA input cable for the installed video hardware and confirm the destination display accepts the output refresh rate.

The European SCART and Japanese JP21 Revision B pages exposed login-or-register-to-buy paths on 2026-07-27. Never connect an EU SCART cable to the JP21 version: the seller says the different pinout can damage the device. The newest dated hardware announcement says units made since June 2025 have a larger OLED and USB-C power, but an older section still says Micro-USB. Human review found no package clarification, so confirm the connector, power requirement, and included USB items with the seller. A DVI-to-HDMI cable and source-system cables are sold separately. Medusa line-doubles when needed but does not change vertical refresh rate, so the destination display must accept the resulting 50 or 60 Hz signal and may blank briefly when the source changes resolution. Install only firmware matching the hardware revision.

Connects a PS/2 mouse to Commodore, Amiga, Atari ST, and Atari 8-bit computers with host-specific mouse, joystick, paddle, and tablet modes.

For this system (stated family): The Atari 8-bit mode defaults to the Atari ST mouse protocol and also offers CX22 trackball, Amiga mouse, joystick, paddle, and Koala Pad modes. Software must support the selected protocol.

The official shop listed immediate delivery from EUR 34.07 on 2026-07-30. Protovision listed five units from EUR 38, with the slim connector costing EUR 3 more. The slim version fits every supported computer; the wider screw-in version has documented clearance exclusions including the Amiga 600 and Atari 1200XL. A USB mouse works only if the mouse itself supports the PS/2 protocol through a passive adapter.

Converts a PS/2 mouse into Atari 8-bit or Atari ST quadrature mouse signals.

For this system (stated family): The project explicitly supports Atari XL computers. An external build can use a joystick-port plug; an internal build requires protected wiring behind the motherboard's in-line resistors.

The maker publishes beta firmware, source, a pinout, and programming files but not a finished adapter PCB on this page. A build requires a programmed PIC16F1847 and suitable wiring or an enclosure. For an internal installation, connect behind the computer's in-line joystick resistors so a plugged-in joystick cannot directly short the PIC outputs. USB mice work only when they also implement the PS/2 protocol.

Adds IDE hard-disk storage through cartridge, internal flash-OS, and original Atari 800 DIY implementations that predate MyIDE-II.

For this system (exact model): The cartridge version works without internal modification. The documented internal kit replaces the OS ROM with its flash module, requires three soldered signal connections, and may require RF-shield removal or modification.

The official Atarimax page said the interfaces were in stock and extended its sale through 2026-07-31 when checked on 2026-07-27; verify that short-lived offer before ordering. The family has been superseded by MyIDE-II but remains functionally distinct because it accepts IDE devices rather than providing MyIDE-II's onboard CompactFlash and FAT32 loader. The cartridge requires a 64 KB XL or XE. Internal installation ranges from an OS-ROM socket plus three signal wires in an 800XL to extensive socket, jumper, MMU, BASIC, and wiring changes in a 1200XL. Mr. Atari's original 800 version is an advanced personal-use DIY design with schematic and firmware files but no complete build instructions or bill of materials.

Connects MIDI instruments or an optional DreamBlaster wavetable module to an Atari 8-bit computer through SIO.

For this system (stated family): The product page explicitly covers Atari 400, 800, XL, XE, XEL, and XLD systems. On an 800XL, use the SIO2MIDI or SIO2MIDI-S2 variant and provide the required SIO cable and compatible MIDI hardware or software.

The storefront family was sold out on 2026-07-24, but MyTek publishes schematics, Gerbers, firmware, and bare-PCB order links for SIO2MIDI and SIO2MIDI-S2. SIO2MIDI-S2 does not route its synthesized sound through the Atari; use its headphone or speaker jack. The maker page also includes 1088XEL-only MIDI-XEL variants, which are not attached to factory-computer entries.

Sharpens video on some PAL or NTSC Atari 600XL and 800XL boards by disconnecting one filter capacitor.

For this system (exact model): The exact 800XL instruction is to disconnect C56, but some later Revision D boards reportedly omit that component or differ from the pictured board. Confirm the schematic and silkscreen first.

The recovered 2017 discussion says to lift or cut one capacitor leg, making later restoration possible, and the author tested PAL and NTSC machines only. SECAM compatibility is unresolved. Several commenters report that later Revision D 800XL boards omit C56 or use a different layout, so identify the exact board revision and component before changing anything. The quoted 80 percent improvement is the author's subjective estimate, not a measured specification; more complete video upgrades may produce better output.

Adds a vintage 1 MB banked-memory board to an Atari 800XL or 1200XL with several selectable PIA banking configurations.

For this system (exact model): The archived manual supplies exact 800XL chip locations, ribbon connections, banking choices, test software, and troubleshooting guidance.

Only archived installation instructions and the used market were verified. Installation requires the original Newell board or a faithful equivalent, memory devices, extensive motherboard wiring, isolated IC pins, and model-specific changes; a 1200XL also needs three address-trace changes. The recommended banking method preserves OS control and ANTIC banking but repurposes other PIA bits and may require BASIC and diagnostic switches. The top RF shield may no longer fit.

Replaces the 74LS08 clock logic in Atari XL and XE computers with four separately buffered O2 outputs.

For this system (exact model): The page gives pin 12 for a usual 800XL and pin 2 for an 800XLF, but requires continuity testing from CPU pin 39. Use the uncapped top output for Ultimate 1MB.

The product exposed a login-or-register-to-buy path on 2026-07-27. Installation replaces a 74LS08; a non-socketed chip must be desoldered and the required 14-pin socket is not supplied. The installer must identify the motherboard's actual CPU O2 connection by continuity rather than relying blindly on a model example. Three outputs carry 680 pF capacitors, while the uncapped top output is intended for Ultimate 1MB; remove a corresponding capacitor if a capped output causes instability.

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

For this system (exact model): The official project explicitly lists the Atari 800XL as supported and tested. Select and configure the correct OneROM pin-count variant for the ROM being replaced.

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.

For this system (stated family): The Atari storefront variant is intended to replace the BASIC ROM in Atari XL computers, including use of Revision C BASIC. Confirm that the 24-pin BASIC ROM is socketed; otherwise installation requires desoldering and fitting a socket.

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.

Emulates writable Atari XL and XE floppy drives from SD storage using the original ATmega8 SDrive design or the NUXX packaging variant.

For this system (stated family): The original project explicitly supports Atari XL and XE computers through SIO. SDrive NUXX was developed for use with an 800XL and retains the original firmware behavior in a redesigned external enclosure.

The original GPL-3.0 hardware, firmware, Atari-side software, documentation, and source remain public. Its 2009 documentation specifies cards up to 2 GB with FAT16, while the repository also contains a later 2012 SDHC-supporting source revision; match the firmware, media setup, and documentation deliberately. The NUXX archive is frozen as of 2020 and says its function is identical to original SDrive, but adds a different PCB, enclosure, connector options, and optional STK200-style parallel-port programmer. No current assembled seller was verified.

Adds a four-channel discrete DAC beneath the PIA chip for higher-quality Atari 8-bit sample and module playback.

For this system (exact model): The seller's demonstration shows the board operating in an 800XL. Installation interposes beneath PIA and needs at least one address-select wire; a second wire may be needed for direct CPU PHI2. Confirm the motherboard revision, PIA orientation, O2 selection, address decode, and audio-mixer wiring before installation.

The product exposed a login-or-register-to-buy path on 2026-07-28. The seller's demonstration shows an Atari 800XL, which is the only exact model established by human review. The published address table assigns both LS138 pin 9 and pin 10 to $D600, so verify the desired address against reliable board documentation rather than relying on that table. A non-socketed PIA must be desoldered and socketed.

Uses a 1 MB 30-pin SIMM and GAL controller to add switchable Compy Shop or Newell/RAMBO banked memory to Atari XL and XE computers.

For this system (exact model): The page provides separate detailed procedures for original delay-line 800XL and Freddie-equipped 800XLF boards, including wiring, timing changes, first power-up, and memory tests.

The Polish project page publishes a schematic, GAL JEDEC file, utilities, parts list, full 800XL and Freddie-equipped 800XLF instructions, startup tests, and timing troubleshooting. Installation is highly invasive and may require trace cuts, lifted or bent IC pins, motherboard timing changes, and RAS-delay tuning for a particular machine. The page groups the 600XL and 1200XL with older 800XL memory-control hardware but does not provide separate step-by-step guides for those models. No explicit project license was verified.

Provides a modern regulated 5 V, 3 A power supply for explicitly supported Atari XL and XE computers.

For this system (exact model): The seller explicitly names the 800XL. Supply the separate country-appropriate mains lead and verify the seven-pin DIN connector is undamaged and correctly oriented before use.

The product exposed a login-or-register-to-buy path on 2026-07-27. It includes the power supply but not the country-specific mains lead. Use only with one of the seller's explicitly named computers and verify connector orientation and mains-cord type before powering the machine.

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

For this system (exact model): The project explicitly recreates the RAMBO 256 KB upgrade for the 800XL. Follow the project schematic and original RAMBO installation manual, and verify the wiring against the exact motherboard revision.

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.

Replaces the Atari 8-bit CPU with a 20 MHz WDC 65C816 accelerator backed by fast SRAM, SDRAM, flash, and software-selectable modes.

For this system (exact model): The XL package and Adaptus instructions are specifically for the Atari 800XL. Identify whether the motherboard has Freddie, replace the original DRAM with the required SRAM module, and follow the corresponding signal connections. Professional installation is prudent.

Both Lotharek hardware packages are discontinued. The 800XL package includes two Adaptus boards and requires CPU and OS ROM removal, socket work, a correctly oriented ribbon cable, and EXTSEL, MPD, and ground connections that differ between Freddie and non-Freddie boards. Its page says replacing DRAM with the separate SRAM module is mandatory and records additional O2 timing workarounds for Ultimate 1MB. The XE package may need four or five precision sockets to clear the cartridge slot. The official Rapidus PDF remains unavailable to automated extraction under WF-001, so obtain complete documentation before installing a used board.

Reimplements SDrive around a 48 MHz Cypress PSoC ARM controller with microSD, capacitive controls, eight drives, and cassette emulation.

For this system (exact model): The project explicitly lists the Atari 800XL. Match the version 1.1 hardware, update firmware, controller programmer, and SD-card setup before building.

The repository publishes Eagle hardware files, PSoC firmware, update binaries, documentation, and enclosure models. Initial controller programming requires a Cypress KitProg-compatible programmer and the source expects the older PSoC Creator 4.0 toolchain. The latest tagged update is from 2018 and fixes FAT16, large ATR and 256-byte-sector handling, applies Hias patches, and improves SD-card compatibility; the last repository change shown is from 2022. No current assembled seller or explicit repository license was verified.

Emulates Atari SIO disk and cassette drives from microSD storage with an Arduino and touchscreen.

For this system (stated family): The project is an Atari 8-bit SIO peripheral. A build needs compatible Arduino and display hardware, a microSD card, firmware programming, an SIO connection, and a safe power arrangement.

The Brewing Academy kit was sold out on 2026-07-24, but the firmware and build files remain public. Its kit still requires assembly and part of an SIO cable. The official project strongly recommends external power because the approximately 150 mA load exceeds the Atari SIO specification; follow its wiring instructions carefully to avoid back-powering the computer or device.

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

For this system (stated family): The maker describes SDrive-Simple-II as fitting virtually any factory Atari 8-bit computer above its SIO connector. Confirm internal clearance, SIO wiring, SD access, and firmware programming before assembly.

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.

Expands one Atari SIO connection into four peripheral ports with optional external power and bus-activity indicators.

For this system (bus/interface): The seller specifies Atari 8-bit computers and a standard SIO input. Supply the separate computer-to-hub SIO cable and avoid exceeding the available SIO power budget when attaching several peripherals.

Retro Lemon marked the assembled hub in stock and Lotharek exposed a login-or-register-to-buy path on 2026-07-27. Both pages describe the same one-input, four-output design with command, read, and write activity LEDs and a 4 mm acrylic top cover. An Atari SIO cable is required but not included. External power is normally unnecessary; when needed, use a 5 V center-positive supply for the 2.1/5 mm DC jack, which is also not included.

Turns supported Arduino hardware and a microSD reader into a single Atari 1050-compatible SIO disk emulator.

For this system (stated family): The maker explicitly supports Atari XL computers through SIO. Optional LCD and button controls can select images, or a reset button can mount renamed SDrive control software from the microSD card.

The maker says SIO2Arduino has been superseded by SDrive-MAX and is no longer actively developed, but its GPL source and detailed wiring instructions remain online. It currently emulates only one D1: drive. A build needs a supported Arduino Uno, Mega 2560/ADK, or Teensy 2.0, a compatible SD reader, the specified SdFat library, an Atari SIO connection, and configuration matched to the chosen hardware. LCD and physical controls are optional.

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

For this system (bus/interface): The official project describes SIO2SD for Atari 8-bit computers through SIO, and the assembled seller calls its cable compatible with all Atari 8-bit models. Prepare a FAT-formatted card with an ATARI directory and confirm firmware-specific format, drive-count, and high-speed behavior.

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.

Replaces an Atari 8-bit computer's GTIA with a modern video board offering DVI output and selectable color palettes.

For this system (exact model): The seller offers an 800XL PBI replacement cover and a double-length cable option. Confirm the selected cable length and GTIA socket before ordering.

The Atari 8-bit collection did not mark Sophia 3 sold out on 2026-07-24. A non-socketed computer requires desoldering the GTIA and fitting a 40-pin socket. Regular installations otherwise need a case opening or an exposed connector; the 600XL and 800XL can instead use model-specific PBI covers.

Replaces the 4050 video buffer and routes configurable conditioned video signals to the Atari's output connector.

For this system (stated family): The seller explicitly supports all Atari XL computers. Installation replaces the 4050 and requires GTIA color and video-output wiring; confirm the board revision and desired jumper settings.

The product exposed a login-or-register-to-buy path on 2026-07-27. Installation replaces the 4050, connects GTIA pin 21 to the board's color input, and rewires output signals at the computer's video connector. A non-socketed 4050 and the output modification require desoldering and model-specific board work.

Publishes an experimental 1024 KB plus 64 KB SRAM expansion board for the Atari 600XL and 800XL.

For this system (exact model): The project title explicitly names the 800XL and shows board-placement material, but remains under development without a complete build or validation report.

The author labels the April 2025 post UNDER WORK and calls it a placeholder. A KiCad archive containing the stated schematic and Gerbers is downloadable, but the page provides no bill of materials, assembly guide, firmware, electrical test results, completed installation report, or explicit license. Treat it as an unfinished engineering project for experienced builders, not a validated kit.

Connects a PS/2-compatible mouse to an Atari 8-bit or Atari ST-family computer.

For this system (stated family): The 8-bit adapter page explicitly supports Atari XL systems. Its described uses are FlashJazzCat's Graphical Operating System and the Diamond GOS cartridge.

Both storefront collections marked their matching adapter sold out on 2026-07-24. A USB mouse works only if it also supports the PS/2 protocol and is used with a suitable passive USB-to-PS/2 adapter.

Replaces aging Atari XL and XE power bricks with a regulated supply or a USB-powered DIN-7 cable.

For this system (stated family): The 800XL is part of the supported XL/XE family and is not among the three explicit exclusions. The USB cable needs a separate 2 A or stronger charger; USB 1.0 500 mA power is insufficient.

Human review found both current variants sold out on 2026-07-24. Neither variant supports the 1200XL, 1400XL, or 1450XLD. Confirm connector, polarity, voltage, and current before powering a computer.

Adds a battery-backed real-time clock and calendar to Atari 8-bit computers through the cartridge port.

For this system (stated family): The product supports Atari XL systems through the cartridge port. It works with multiple Atari DOS versions but is described as most useful with SpartaDOS.

The collection marked both versions sold out on 2026-07-24. The stand-alone version is no longer supplied with a case. The drop-in version is an assembled board intended for an original R-Time 8 shell. The seller estimates three to five years of battery life.

Connects an Atari 8-bit computer to a modern Mac or Windows computer for disk, cassette, modem, printer, and file-transfer emulation.

For this system (stated family): The product explicitly supports Atari XL systems through SIO. Use a modern Mac or Windows computer, a suitable Micro-USB cable, and compatible host software configured for the adapter's DSR connection.

The Atari 8-bit collection marked all versions sold out on 2026-07-24. Dual-SIO versions can sit within an SIO chain; single-SIO versions must be at the end or on a splitter. All listed versions include a printed case and an 8 GB microSD card, but need a separate Micro-USB host cable and a Mac or Windows computer. Windows may also need a UART driver.

Reprogrammable multi-mode cartridge for Atari XL and XE computers, prepared with modern-host and Atari-side tools.

For this system (stated family): The maker explicitly identifies The!Cart as an Atari XL/XE module. Prepare content with The!Cart Studio and the Atari-side flasher; verify cartridge fit and the desired emulation mode before use.

The maker's linked ABBUC product URL returned 404 on 2026-07-28, and human review found that ABBUC no longer appears to operate a store. No current direct order path is known, so treat the cartridge as a used-market find unless the maker announces another batch. The maker page, Studio, and Atari-side flasher remain available; its separate WUDSN hardware-details link is also dead.

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

For this system (exact model): The vendor selector explicitly assigns the TK-II-PB-R version to the 800XL. Choose the single- or dual-jack interface, confirm the POKEY socket, and plan the external PS/2 connector mounting.

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.

Adds configurable expanded memory, flashable operating-system slots, SpartaDOS X, and a battery-backed clock to Atari XL and XE computers.

For this system (stated family): The product supports all XL and XE machines. Socketed MMU and OS ROM chips simplify installation, but the supplied four-wire CPU connection still requires careful fitting and may require soldering.

The Brewing Academy collection marked its 2026-version package sold out on 2026-07-24. Lotharek still exposed a login-to-buy path for a closely related regular-firmware version. The TBA package includes the board, MMU and OS ROM adapters, a four-wire cable, and mounting parts, but no printed manual. A board without socketed MMU and OS ROM chips needs desoldering and new sockets; those sockets are not supplied.

Adds clean composite and S-Video output circuitry to supported Atari 8-bit computers.

For this system (stated family): The product explicitly supports Atari XL computers, including the 800XL family. Check the model-specific manual section, CD4050 socket, board orientation, video jack wiring, and whether the original circuit will remain connected.

The Atari 8-bit Rev. D page said Now shipping on 2026-07-24 and offered plug-in, basic, kit, and 1088 variants. Installation still requires soldering, output jacks, and the ability to follow a schematic. The vendor calls its large manual a starting collection and warns that not every machine has explicit or fully current instructions. The separate 600XL monitor port and BOBby audio/video breakout are installation accessories, not standalone upgrades.

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

For this system (exact model): MyTek explicitly describes 800XL installation as very easy and nearly solderless. Confirm GTIA clearance, output routing, optional interface-board parts, and any motherboard solder points before assembly.

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.

For this system (exact model): The active 800XL layout is tailored for the Atari 600XL and 800XL. It supports the project's Atari extra-button protocol and fits the two control ports directly.

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.

Adds RGB output, enhanced graphics modes, a blitter, and true 80-column text to supported Atari 8-bit computers.

For this system (exact model): The installation manual provides separate procedures for the original delay-line 800XL and the Freddie-based 800XLF. Select the XL hardware, verify which motherboard type is present, use its exact clock and memory signals, and perform the documented EXTSEL resistance check before fitting the board.

The XL and XE product pages both exposed login-or-register-to-buy paths on 2026-07-27. Choose the machine variant deliberately: both storefront descriptions say an XE adapter is included, but the installation manual explicitly says the XL and XE ANTIC adapters differ. Installation requires ANTIC removal, an adapter soldered to the motherboard, several model-specific signal connections, and an EXTSEL safety check that may require modifying a Freddie pin. The current manual documents 800XL, 800XLF, XE, and XEGS paths, not 600XL or 1200XL.

Connects supported vintage computers to Wi-Fi BBSes through an RS-232 serial port.

For this system (exact model): The vendor explicitly lists the Atari 800XL among tested computers. It does not plug directly into SIO; a suitable RS-232 interface and correctly wired cable are required, along with external 5 V power.

The current Pro V2 model was in stock on 2026-07-30. It has a female DB25 connector, a color TFT screen, a printed case, faster interface buffers, and signal-state LEDs. It needs an external 5 V micro-USB supply, and the host may also need a gender changer, DB9 adapter, or correctly wired computer-specific serial cable. The older display-free and OLED WiModem232 models are discontinued and replaced by this version.

Adds an 80-column text display to Atari 8-bit computers, with composite output and an optional HDMI conversion path.

For this system (stated family): The device communicates through one Atari 8-bit joystick port, which also supplies 5 V to the main board. The optional HDMI converter separately needs Micro-USB power and a suitable cable from the Atari's normal video output if 40-column switching is wanted.

The Brewing Academy collection marked XEP80-II sold out on 2026-07-24 even though its product description still called the units build-to-order. The listed DIY option supplies a bare main board with a tested NS405; assembled and cased options were also described. A separate listing offers programmed OS and character EEPROMs for DIY builders. The HDMI converter needs separate Micro-USB power. Unlike Atari's original XEP80, XEP80-II has no parallel printer port.