Commodore VIC-20 upgrades

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): Use the five-pin composite cable or adapter, both of which explicitly list the VIC-20. The seller does not advertise the eight-pin S-Video branch for this computer.

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.

A current 1.5-meter five-pin DIN to SCART cable for several Commodore computer families.

For this system (exact model): The seller explicitly lists the VIC-20. Confirm the exact computer connector and the display's SCART composite-video support.

The product page exposed a current Add to Cart path on 2026-07-30. The cable is 1.5 meters long and terminates in a five-pin DIN plug, so it does not carry the separate luma and chroma signals used for S-Video. Confirm that the intended display accepts composite video through SCART and that its regional video standard matches the computer.

Uses one microSD cartridge and interchangeable adapters to load software and provide selected storage, cartridge, memory, and diagnostic functions on many vintage computers.

For this system (exact model): Use the VIC-20 adapter. BackBit supports cartridge, program, tape-container, and disk-image files plus selectable 3 KB through 35 KB RAM expansions.

The current store listed the assembled BackBit Pro for $129 on 2026-07-27 with one assembled adapter choice included. A microSD card is not included. Additional adapters are sold separately and require through-hole soldering. Firmware updates use the microSD card. An original C64 Assy 326298 needs the documented reset fix, and the SX-64 needs the straight C64/128 adapter.

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

For this system (exact model): The maker lists VIC-20 among the preconfigured PS/2-to-Commodore and Commodore-to-PS/2 options. Match the VIC-20 keyboard connector orientation and selected firmware mapping before installation.

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.

Adds SD-card PRG and TAP loading, a fast loader, Wi-Fi file transfer, and cross-development tools through the cassette port of several Commodore 8-bit families.

For this system (exact model): The maker reports successful VIC-20 testing. Some programs that overwrite the cassette buffer may need the standard slow PRG loader instead of Cassiopei's fast loader. Disable JiffyDOS and avoid other cassette-port hardware.

The maker states that Cassiopei v2.0 is not available. The hardware is described as functionally complete, while firmware, software, manuals, and downloadable updates remain published.

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

For this system (exact model): individual Computers documents the VIC-20 user-port registers and lists the machine as compatible. Software must be written for the adapter; the current assembled seller pages focus on C64 and C128 use.

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.

External displays for checking the 5 VDC and 9 VAC outputs of Commodore power supplies, with the MkII adding current measurement under load.

For this system (exact model): The reviewer used the MkII continuously between a later VIC-20 and its supply. The supplied seven-pin inline cable does not establish compatibility with an early two-pin VIC-20. Confirm the exact connector and do not assume that user-port reset or current measurement works in every physical configuration.

The exact review was published in March 2020 and a February 2023 comment says the seller was still making the monitors. The review describes an unofficial Commodore-styled product made by an unnamed Australian builder, not a verified Commodore-manufactured accessory. A current-looking Pocket 1501 eBay route failed exact Tavily extraction and failed again after the required 60-second retry under WF-068, so its maker, stock, price, package, and relationship to MkI and MkII remain unverified. The separate FDD II drive-supply monitor is not folded into this host-monitor family. This device displays readings; no automatic cutoff, regulation, over-voltage clamp, fuse, or other protective action was verified.

6522 VIA interposer that changes a Commodore 1541 drive between device IDs 8 through 11 without cutting its original jumpers.

For this system (bus/interface): Use through a compatible 1541 drive. The drive must have, or be modified to have, a socketed 6522 VIA at the documented board position.

TheRetroChannel listed five boards in stock on Lectronz on 2026-07-27. External wiring and DIP switches are not included. A drive with a soldered 6522 first needs the chip desoldered and a socket installed; an external switch may require case cutting.

Replaces a missing or failed Commodore power indicator with a prewired round or rectangular LED assembly selected for the case and motherboard layout.

For this system (exact model): Retroleum explicitly says its original round breadbin-style C64 LED assembly was also used in the VIC-20. Confirm the LED mount, cable length, connector, motherboard revision, and polarity before installation.

AMI64 listed its red breadbin and C64C choices for GBP 4.95 on 2026-07-30. Poly.play also maintained separate current short and long C64C and breadbin product routes. Retroleum listed original and new round and rectangular assemblies but was temporarily closed until approximately the beginning of August 2026. Color is cosmetic, but LED shape and cable length are not: choose them for the exact case and board position. Confirm current stock before ordering.

Current C64 and C128 user- and cartridge-port boards that expose labeled pins for prototyping and hardware development.

For this system (exact model): Only the retired Syzygy Systems V0.9 user-port variant explicitly supports the VIC-20. Its manual says to follow the This Side Up silkscreen, press evenly on the connector tabs, and solder the supplied two 12-pin male or female header rows. The current Commodore4ever pages do not claim VIC-20 support.

Commodore4ever exposes current priced product variants for separate C64/128 user-port and cartridge or expansion-port boards. The user-port page documents its labeled male header and intended test uses. The expansion-board title and board label say EPB and cartridge or expansion port, but its body mistakenly describes access to the User Port and does not enumerate its signals. Human inspection found these guide breakouts to be basic passive pin extenders with no visible active components. No buffering, isolation, fusing, or current limiting is documented; exposed computer pins should not be treated as protected. Syzygy's C64 user-port version is retired and needs its selected header rows soldered.

Period cartridge interfaces connect a C64 or VIC-20 to PET-style parallel disk drives, printers, modems, and other IEEE-488 equipment.

For this system (exact model): The archive identifies a distinct original Commodore IEEE-488 interface for the VIC-20 with preserved schematic and ROM. Do not substitute the C64 cartridge.

These are original period interfaces to find used or reconstruct from archives, not current products. Match the cartridge to the exact computer and verify its ROM. The original C64 software occupies part of the $C000 area and disables serial IEC; Andre Fachat's separate modified C64 KERNAL can retain both buses, but it is not part of the cartridge.

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

For this system (exact model): The board is designed for the VIC-20, but the author says revision 1.0A had so far been tested only with a PET. Treat VIC-20 use as an unverified design target and check user-port, cassette-port, power, and driver requirements.

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.

Host-specific passive A/V adapters for the VIC-20, C128 family, Plus/4, and Ultimate64 replacement mainboards.

For this system (exact model): The VIC-20 variant provides composite video plus the same mono audio signal on both left and right outputs. The seller does not advertise separated luma and chroma or S-Video for this version.

Commodore4ever exposed active Add to cart controls for all four variants on 2026-07-30. The Ultimate64 board uses a different A/V pinout from an original C64; do not use that adapter on a stock C64 or assume compatibility with the newer Commodore 64 Ultimate. The C128 variant handles the 40-column analog output, not the separate 80-column RGBI port.

Protected switched-mode replacement supplies for the C64 and round-connector VIC-20CR, with separate adapters for the C128 and Plus/4.

For this system (exact model): Direct compatibility is limited to the later VIC-20CR with the round power connector. These pages do not support the early VIC-20 two-pin power input. Match the connector and mains version before ordering.

On 2026-07-30, Commodore4ever listed the original ATOM and ATOM v2.5 at USD 59.99 and ATOM RETRO at USD 69.99; all three were sold out. The official Plus/4 adapter was also sold out at USD 24.99. A separate live 90-degree adapter page listed a 64-to-128 option at USD 14.99, but did not expose unambiguous variant stock or identify every supported ATOM revision. The original ATOM page lists separate North American 120 VAC and European 230 VAC configurations, ATOM v2.5 lists only the North American input, and ATOM RETRO says its European version is currently unavailable. Surviving pages provide too little detail to establish exact specifications or final availability for the older PS-64 with LED and PS-64/128. Do not assume that ATOM specifications apply to those predecessor models.

User-port Wi-Fi modem for reaching Telnet BBS services from several Commodore 8-bit computers.

For this system (exact model): The seller documents VIC-20 user-port operation at up to 1200 baud.

The seller's collection listed the modem as sold out on 2026-07-30. An optional case is an accessory for the same modem family. The product page does not provide a public firmware or complete hardware build package.

Historical breadboard adapters for prototyping through a Commodore control port or the VIC-20 expansion port.

For this system (exact model): The joystick adapter explicitly supports the VIC-20. The separate VIC-20 expansion-port board exposes every expansion line, aligns +5 VDC and ground with breadboard rails, and provides a reset-to-ground button. Insert the expansion board with the reset switch facing upward, work only with power off, and follow the feature page's experienced-builder warning.

C64 OS preserves the former $13 joystick and $19 VIC-20 listings, but no current product was exposed on Dorktronic's eBay profile in July 2026. The joystick item URL also failed two Tavily extractions after the required 60-second retry and is logged as WF-062. Treat both boards as used-market finds. Documentation was not included. Both designs expose computer power and signal lines directly; the VIC-20 feature explicitly warns that improper prototyping can damage the computer.

Current protected replacement supplies with separate direct-connect C64/VIC-20 and C128 versions.

For this system (exact model): The C64 version explicitly names the VIC-20 but uses a round seven-pin output. This supports later round-connector systems, not the early two-pin VIC-20.

On 2026-07-30, Electroware listed the eleventh-revision C64 version at EUR 46.99 and the twelfth-revision C128 version at EUR 52.99, both with dispatch in three to five days. Each has regional mains choices and an optional Adjust and Protect trim of roughly 4.9 to 5.3 V. Buy the direct version for the computer; the C64 model reaches a C128 only through a separate adapter.

A single replacement supply that powers a C64 or later VIC-20 together with a 1541-II or 1581 floppy drive.

For this system (exact model): The seller names the VIC-20, but the supplied computer lead is the round seven-pin C64-style connector. This supports later round-connector systems, not an early two-pin VIC-20.

Electroware listed the twelfth-revision supply at EUR 68.99 with dispatch in three to five days on 2026-07-30. Regional mains configurations and an optional Adjust and Protect 5 V trim are offered. C128 use requires a separate C64-to-C128 adapter; choose and verify that adapter rather than connecting the C64 lead directly.

A calibrated cassette-port display that measures the computer's live 5 V rail while preserving the Datasette connection.

For this system (exact model): The seller explicitly supports the VIC-20 through its cassette port. The page does not distinguish early and later motherboard revisions, but this relationship does not depend on the computer's external power connector. Attach or remove the meter only with power off.

Electroware listed the factory-calibrated meter at EUR 18.99 with dispatch in three to five days on 2026-07-30. It measures the live 5 VDC rail only. It does not display 9 VAC, apply a test load, regulate voltage, or automatically disconnect a failing supply.

Modern VIC-1011-style user-port RS-232 adapter with status lights, reset, and a software-dependent 9600-baud mode.

For this system (exact model): The seller explicitly lists the VIC-20, but does not provide a model-specific speed or software procedure.

Tindie marked the adapter out of stock on 2026-07-30 and says it has been sold out since 2026-01-05. A DB25-to-DB9 adapter is an optional passive accessory, not a separate catalog product.

User-port USB serial adapter for linking supported Commodore 8-bit computers to a modern host's virtual COM port.

For this system (exact model): The seller explicitly lists the VIC-20. Match terminal software and serial settings to the host and intended service.

The Tindie seller was taking a break on 2026-07-30 and did not expose an ordering path. GGLABS publishes a schematic, but the page does not present a complete fabrication and assembly package.

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

For this system (exact model): Shareware Plus explicitly sells a VIC-20 variant. The hands-on installation connects its clips to cartridge-port pin 22 for ground, pin 21 for +5 V, and pin 19 for IRQ. Remove the original power LED and install the replacement only with the computer disconnected from power.

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.

Licensed replacement computer and disk-drive ROM system that accelerates Commodore serial storage and adds DOS commands.

For this system (exact model): The official site identifies the VIC-20 as a supported computer family. Obtain a licensed, machine-specific offering from an authorized seller and verify board revision and installation method.

The official licensing site listed five authorized sales channels on 2026-07-27. Offerings include licensed ROM images, replacement ROM overlays, and switchless overlays; stock and the exact supported machine or drive vary by seller.

Adds about 1.7 meters of reach between a compatible nine-pin controller and its vintage computer.

For this system (exact model): AutumnHippo explicitly lists the VIC-20. Extend only a controller already verified for the computer.

AutumnHippo exposed an add-to-cart route at USD 7 on 2026-07-30. Protovision separately showed ten joystick extension cables in stock at EUR 10 with a one- to two-week shipping estimate. The exact long and short products pictured by the C64 OS guide are not identified, so the catalog keeps current length and seller variants together.

Provides a new 1.7-meter nine-conductor lead for repairing compatible vintage joysticks and controllers.

For this system (exact model): The seller explicitly lists VIC-20 controllers. Shared connector shape does not establish that a controller wired for another named system is VIC-20 compatible.

AutumnHippo exposed an add-to-cart route at USD 7 on 2026-07-30. Basic soldering is required. Trace the existing cable or controller circuit before removal: the seller explicitly warns that wire colors can differ and that systems sharing a nine-pin plug do not necessarily share controller wiring.

Protected regional replacement supplies for the C64, later VIC-20, and C128 in Classic, Modern, and current RetroPower enclosures.

For this system (exact model): Keelog's C64 branch names the VIC-20 and uses the round seven-pin C64 pinout. This relationship is limited to later round-connector systems, not the early two-pin VIC-20.

Keelog's current family pages listed regional C64 and C128 supplies on 2026-07-30. Representative EU Classic or Modern products were USD 65.99 or EUR 57.99. Classic measures 86 by 70 by 48 mm; Modern measures 125 by 59 by 42 mm, with black and gray choices. Keelog also identifies RetroPower as the successor enclosure. Match the computer branch, connector, mains voltage, and regional plug rather than selecting by case style alone.

Protected dual-output supplies for a C64 or later VIC-20 and a 1541-II, 1571-II, or 1581 floppy drive.

For this system (exact model): The seller explicitly names the VIC-20, but the computer cable uses the round seven-pin C64 pinout. This relationship is limited to later round-connector systems and does not include the early two-pin VIC-20.

Keelog listed current regional RetroPower, Classic, and Modern configurations on 2026-07-30. The representative RetroPower US model was USD 89.99 or EUR 78.99 and included its device cable. Select the correct 120 V or 230 V version and regional plug. The current RetroPower page calls that enclosure the successor to the earlier Classic and Modern styles.

A repairable metal-cased C64 replacement supply with fused 5 VDC and 9 VAC sections, a power switch, and optional C128 or Plus/4 adapters.

For this system (exact model): The earlier maker announcement explicitly limits VIC-20 support to late models. This is the later round-connector revision, not the early two-pin VIC-20. Confirm that the current build still includes the required lead.

The newest readable announcement was published on April 18, 2022 and listed the Nu-Brick 64 at USD 65 plus USD 15 shipping, with C128 and Plus/4 pigtail adapters at USD 15 each. It directs buyers to message Kevin Ottum on Facebook. No current stock or price page was verified on 2026-07-30, so confirm that he is still accepting orders and specify the required computer and connector.

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

For this system (exact model): The adapter plugs into a VIC-20 and accepts selected C64 or C128 cartridges. It does not translate software, reproduce missing hardware, or make arbitrary game, freezer, accelerator, DMA, or system-specific cartridges work. The maker identifies simple single-purpose I/O devices, including some Ethernet or RS-232 cartridges, as the intended class. Establish the exact cartridge's address, electrical, and VIC-20 software requirements before use.

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.

Emulates Commodore IEC devices and loads files from local flash, an SD card, or network servers over Wi-Fi.

For this system (exact model): The project repository explicitly names the VIC-20. Select a documented hardware profile and verify the intended virtual-device workflow and firmware before connection.

The project provides source, several ESP32 hardware profiles, build instructions, and a browser-based firmware flasher. No direct retail source was verified, so builders must select matching hardware and firmware before connecting it to a computer.

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 (exact model): The VIC-20 has adjusted 1351 and NEOS modes plus digital joystick, Amiga mouse, paddle, and Koala Pad modes. Confirm that the selected software supports the chosen emulation.

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.

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 VIC-20 as supported and tested. Verify the original ROM package, chip-select configuration, board orientation, and physical clearance.

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 (exact model): The open project tested the adapter in VIC-20 KERNAL and BASIC sockets on Assy 250403. Confirm the motherboard and ROM socket, program 8 KB images at the documented offsets, and wire any bank-select switches correctly.

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.

Combines configurable VIC-20 RAM, a large built-in software library, diagnostics, fast loading, and optional SD2IEC storage.

For this system (exact model): The maker explicitly supports PAL and NTSC VIC-20 systems. Select the memory layout required by each program; the built-in browser can choose layouts for supported files. TurboLoad works with compatible disk drives and SD2IEC but not Pi1541 or 1581.

TFW8B listed the PenUltimate+3dcr as shipping on 2026-07-29. The older PenUltimate+, +2, and microSD-based +3 are end-of-life variants. Product-page option text mixes retired and current generations, so confirm that an order is for the +3dcr and whether any optional media are included.

Cycle-exact Commodore 1541 disk-drive emulation using a Raspberry Pi and SD-card disk images.

For this system (exact model): The official project explicitly supports the VIC-20 through its IEC serial bus. Use the matching CBM file browser when selecting images from the vintage computer.

Retro Electronics listed one assembled Option B Pi1541 Hat in stock on 2026-07-25. The Hat is the only supplied part; add a supported Raspberry Pi, SD card, serial cable, legal drive ROM, quality USB cable, and at least a 2.5 A power supply. The official project does not support Raspberry Pi 4 or 5.

A compact semiconductor protector for the 5 VDC and 9 VAC rails of compatible Commodore power supplies.

For this system (exact model): The seller names the VIC-20, but the standard product is built into a seven-pin male DIN connector. Treat the relationship as limited to later VIC-20CR hardware using the compatible C64-style power connection; it does not establish support for an early two-pin VIC-20.

CMD Marketplace listed four units at USD 40 on 2026-07-30. The page claims a 20 microsecond semiconductor response versus 200 milliseconds for a relay design. After a 5 V trip, its 1.25 A SMD fuse must be replaced with a soldering iron; one spare is supposed to be included. The page simultaneously displayed a USD 9 United States rate and a notice that the item does not ship to the United States, so confirm destination availability before ordering.

Custom replacement supplies ranging from simple C64 units to multi-connector systems for several Commodore computers and drives.

For this system (exact model): The feature explicitly lists VIC-20 compatibility, but the public page does not distinguish early two-pin and later round-connector revisions. Because these were custom supplies, order or verify the exact connector and electrical configuration rather than assuming that a C64 lead fits every VIC-20.

The readable C64 OS feature was last modified in September 2022 and gave a USD 35-100 range for standard examples, with more elaborate custom builds possible. It directed orders and inquiries to Ray Carlsen by email. Both linked maker pages failed Tavily extraction and failed again after the required 60-second retry under WF-066 and WF-067, so current ordering, prices, model names, electrical ratings, protection, and mains options must be confirmed directly. Do not transfer the specifications or simultaneous-device behavior of one custom build to another.

Current handmade composite, S-Video, SCART, and luma/chroma cable choices for compatible Commodore computers.

For this system (exact model): The seller explicitly lists the VIC-20 for the five-pin composite RCA and SCART leads. The separate eight-pin S-Video and luma/chroma branches are not advertised for this computer.

AMI64 exposed current priced choices on 2026-07-30. The eight-pin S-Video branch includes a 300-ohm chroma resistor. Connector, signal, and display requirements differ between variants: select a five-pin composite lead for an early C64 or VIC-20, and use the eight-pin luma/chroma branches only with a computer and display that expose those separate signals. The seller describes PAL and NTSC use, but the connected display must still accept the computer's regional video standard.

A historical relay protector with alternate DC and AC inputs for several Commodore power configurations.

For this system (exact model): The maker explicitly limits VIC-20 support to the later VIC-20CR. This does not support the early two-pin VIC-20. Confirm connector wiring and the selected trip threshold before using a vintage unit.

The surviving Round 4 sale thread is explicitly titled SOLD and dates to 2017. It offered complete kits at USD 45 and assembled units at USD 85. C64 OS repeated those prices in 2022, but that does not establish later production. The former hookturn.com user-guide URL now resolves to a parked domain. Use the preserved feature and forum specifications for identification, and search the used market rather than contacting the old seller as though stock were current.

Family of IEC storage devices that lets supported Commodore computers access files and disk images on SD or other removable media.

For this system (exact model): Endresz, PolyPlay, and the open SD2IEC LP documentation explicitly list the VIC-20. Verify the selected variant's physical connection, power path, and firmware configuration.

Retro Lemon listed its user-port-powered C64, C128, VIC-20, and SX-64 variant in stock at GBP 34.17 on 2026-07-27, and Sordan exposed a current Buy now path for its combined SD2IEC and Tapecart variant. PolyPlay's plain external Sordan Micro device and Retro Electronics' internal board were out of stock, while the RetroFletch backplane seller was on a break. A complete open C64 SD2IEC LP hardware build is also available. Variant power, connectors, controls, and firmware configuration differ. The official firmware site says 0.x firmware is obsolete and warns that newer-dated bootloaders are not necessarily safer or better.

Assembly kit that adds a numeric track or sector display to supported Commodore floppy drives.

For this system (bus/interface): Use the display through a supported 1541-family drive. Confirm the exact drive board, available internal clearance, and display mounting before installation.

Commodore4ever and Protovision both exposed current-priced product pages on 2026-07-27, but neither extraction exposed an unambiguous Add to Cart control. Confirm availability before ordering. The kit requires through-hole assembly, display wiring, and internal drive installation; stacked boards or sockets can create clearance problems.

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

For this system (exact model): Sidekick20 requires one of the published passive adapters. Raspberry Pi Zero 2 operation needs overclocking; 3A+ and 3B+ are also supported. VIC emulation and HDMI output additionally require the A15 signal wired from CPU pin 25.

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.

Connects a Super Nintendo controller to the user port of supported Commodore computers for software written to read its serial protocol.

For this system (exact model): The seller explicitly names the VIC-20. Ordinary joystick software cannot read this user-port serial adapter without support.

TexElec listed the adapter at USD 14.99 and in stock with backordering enabled on 2026-07-30. Most supported machines use the supplied power jumper. Some PET systems do not provide user-port power and need 5 V from the cassette port or an external source; high-current third-party controllers should also use external power because the user port is rated for 100 mA.

Adds a live track, density, write-protect, motor, and sync display to supported Commodore floppy drives.

For this system (bus/interface): The tracker modifies a supported 1540 or 1541-family disk drive rather than the VIC-20. Confirm the exact drive and whether its VIA is socketed before installation.

The standard and 6522-included variants were both out of stock on 2026-07-24. The 1541-II and 1571 require the special version with a 6522 VIA soldered to the tracker board; the standard version will not work in those drives. Installation can require desoldering the original VIA, fitting a socket, and mounting the display and button externally.

Installs inside supported Commodore floppy drives to duplicate protected disks and add disk utilities.

For this system (bus/interface): Use through a supported 1541-family serial disk drive. The board modifies the drive rather than the VIC-20, and some drive revisions require 6502 desoldering and a socket.

Both assembled variants were out of stock on 2026-07-24. Each listing includes a 40-pin socket and version 6.0 software on two 5.25-inch disks. Some drives require desoldering the 6502 and installing a socket, so identify the drive model and board revision before ordering or installing.

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

For this system (exact model): The repository explicitly names the VIC-20 for the cassette breakout and user-port output. Use only the matching port board and ribbon cable, and do not infer that the PET IEEE-488 arrangement applies to the VIC-20.

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.

Arduino-based SD-card datasette emulator family for Commodore cassette ports, with TAP writing on the Mini variant.

For this system (exact model): Both seller variants explicitly support the VIC-20 through its cassette port. The Mini reads and writes TAP files; both variants require a user-supplied SD card.

Retro Electronics listed one full-size Tapuino and two Tapuino Mini units in stock on 2026-07-27. An SD card is not included, and the required C16/Plus/4 cassette-port adapter is excluded.

Cassette-port interfaces that load tape audio from a phone, tablet, or other player into supported Commodore computers.

For this system (exact model): The current uCassette page explicitly lists the VIC-20. Supply an external audio player and compatible tape audio.

AMI64 exposed an active Add to Cart listing on 2026-07-27. The page documents audio playback into the computer but does not claim that this interface can record or save tape output.

Adds banked programmable flash and configurable RAM for storing and launching VIC-20 software.

For this system (exact model): UltiMem is a VIC-20 cartridge. Its menu can select unexpanded, 3 KB, and 24 KB-compatible layouts, and each expansion block can be configured separately. Some protected or unusually mapped images may need manual settings or hidden configuration registers.

The official project page preserves GPL-licensed menu and programming software plus detailed operation notes, but its RETRO Innovations product link is no longer a verified order path and no complete open hardware fabrication package was confirmed. Search for a used cartridge or choose a current UltiMem-compatible device such as VIC-MIDI.

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

For this system (exact model): These are VIC-20 expansion-port cartridges. Enable only the RAM and ROM blocks required by the program being used, and avoid mapping RAM, flash, and EPROMs into the same block. Power off before inserting, removing, or changing hardware that is not explicitly documented as hot-switchable.

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.

For this system (exact model): The open design and both current kits explicitly support PAL VIC-20 and PAL VC-20 systems as well as NTSC VIC-20 systems. The diagnostic test needs the complete feedback harness and a correctly configured cartridge. JiffyDOS fails the expected KERNAL checksum, and an absent keyboard dongle can be reported as OK, so interpret results with the manual. Attach or remove every cartridge and dongle only with power off.

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.

Vintage VIC-20 multifunction cartridge combining configurable RAM, flash storage, SD2IEC storage, a real-time clock, and a launcher menu.

For this system (exact model): Final Expansion 3 is a VIC-20 expansion-port cartridge. Its menu can configure several common memory layouts, but software still needs the layout it expects. Review the manual before changing flash contents or attaching optional hardware.

Historic Revision 11 production batches sold out. No current primary order path or complete, current fabrication package was verified on 2026-07-27, so look for a used unit and confirm its revision and condition.

Combines switch-selectable 35 KB VIC-20 RAM expansion with a battery-backed real-time clock and 115 bytes of persistent user memory.

For this system (exact model): The seller designed the cartridge for the VIC-20. Configure only the RAM blocks a program expects. The clock can be disabled while installed in an expansion chassis if another device needs its I/O area.

Tindie showed eight cartridges in stock at USD 49.99 on 2026-07-29. A CR2032 is expected to last about two years and is replaceable. The alarm interrupt and square-wave outputs are exposed only as through-holes, not as finished external connections.

Adds MIDI In, Out, and Thru, RS-232 communications, programmable flash, and UltiMem-compatible RAM expansion to a VIC-20.

For this system (exact model): VIC-MIDI is designed specifically for the VIC-20 cartridge port. The current assembled unit is preloaded with a MIDI controller application, while the downloadable program can be loaded from drive 8. MIDI and RS-232 share the UART and are selected through the documented control bit.

The RETRO Innovations store exposed an Add to Cart path at USD 65 on 2026-07-28, although its current-stock field was blank. No enclosure is included. Supply a 5-pin DIN MIDI cable and use the downloadable VIC-MIDI software; the project page also publishes EAGLE 6 design files and a bill of materials.

Bare replica of the later seven-pin-power VIC-20 Assembly 250403 motherboard.

For this system (exact model): This is specifically the later Assembly 250403 layout with the round seven-pin C64-style power input. It does not replace an early two-pin 9 VAC VIC-20 board. A complete build requires advanced soldering, the exact BOM, and correctly matched original or validated replacement parts.

Bob's Bits listed the bare Vicky Twenty PCB at USD 35 on 2026-07-30 with a live color selector and optional resistor, capacitor, and power-switch controls. The page exposed no destination-specific shipping decision until a country is selected. The base product is an unpopulated board; none of the optional packs supplies every component or custom chip required for a working VIC-20.

Adds Wi-Fi BBS and Hayes-modem access through the user port of supported Commodore computers.

For this system (exact model): The official manual names the VIC-20 and installs the standard WiModem in its user port with the computer powered off.

The standard display-free version and both PET versions were out of stock on 2026-07-30. The standard OLED page still said a new design was pending and did not offer ordering. Check the direct pages for a restock or revised design.

Bridges a modern computer over USB serial to Commodore IEEE-488 and IEC equipment, or supplies host-backed storage to a Commodore computer.

For this system (exact model): The project explicitly includes the VIC-20 among serial-IEC computers that can use PC-backed storage. Confirm the cable and host software, and correct the documented board-connector footprint problem.

The maintainer explicitly calls XS1541 orphaned and reconstructed its documentation from an archived build guide. The surviving page provides a schematic, firmware, and detailed assembly and flashing steps, but not a turnkey current kit. The original board connector footprints are buggy: the narrow connector can short contacts unless the coding gap is physically corrected. A build also requires fine-pitch FT232RL soldering, ATmega programming, fuse setup, cables, and suitable host software.