Apple III Plus upgrades

Adapts a modern PicoPSU and external power brick to the Apple III and Apple III Plus.

For this system (exact model): The maker explicitly supports the Apple III Plus. Select all required components and verify the power connections before installation.

The build-a-kit page showed the core, switch, PicoPSU kit, and non-destructive power lead in stock on 2026-07-24. Buyers must select the complete set of required components rather than treating an inexpensive switch or lead as a full replacement.

Supplies replacement capacitors for the Astec AA11190 and AA11190-B Apple III power supplies.

For this system (exact model): The current store classifies the kit for both Apple III models, but the installed power supply must be an Astec AA11190 or AA11190-B.

JCM showed 151 kits in stock on 2026-07-24. This kit is only for Astec AA11190 or AA11190-B supplies and requires safe mains-side power-supply repair skills.

Provides an RCA color-composite output from the Apple III family's 15-pin color-video connector.

For this system (exact model): The current store classifies Colorizer 3 for both the Apple III and Apple III Plus. PAL systems produce monochrome output.

JCM showed 14 units in stock on 2026-07-24. A PAL Apple III still produces monochrome video through this adapter; Colorizer 3 does not convert PAL timing to NTSC color. JCM recommends the separate Phase 3 modification for more accurate NTSC color.

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

For this system (bus/interface): JCM lists the Apple II base unit in its Apple III Plus category, but the official project page names only the Apple III. Treat this as a seller-supported interface relationship: a compatible SmartPort card and custom cable are still required, and no separate Plus test is documented.

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.

Replaces Apple III boot, synchronization, video, and bipolar state-machine ROMs with modern EEPROM carrier boards.

For this system (exact model): JCM's Apple III Plus category lists the 342-0145-A Plus SyncROM plus the shared boot, video, and selected bipolar replacements. It does not list 342-0042 or 342-0044 for the Plus. Do not substitute a similarly positioned ROM without confirming its exact part number and function.

JCM's current Apple III categories listed all fourteen variants on 2026-07-24. Representative boot, sync, video, and bipolar pages showed stock, but availability can differ by part number. These adapters are position-specific replacements, not interchangeable upgrades.

Converts Apple III or compatible Apple IIe TTL RGB to CGA-style and Apple IIgs-monitor outputs.

For this system (exact model): The maker explicitly supports the Apple III Plus. Use a compatible CGA monitor, AppleColor RGB A2M6014 monitor, or the computer's composite output path.

The current page offered a fully assembled option on 2026-07-24. It does not work with the Apple IIc. An Apple IIe Extended 80-Column RGB Card needs the documented jumper installed near its video header.

Replaces the General Instrument AY-5-3600-PRO keyboard encoder in several Apple computers.

For this system (exact model): The encoder includes the Apple III Plus factory mapping and has passed Apple III Plus Dealer Diagnostics.

The current page offered jumper and socket selections on 2026-07-24. Original Apple II and II Plus support applies to non-Datanetics keyboards; Datanetics keyboards use the separate MM5740AAE replacement.

Corrects the color-phase error in the Apple III family's NTSC composite-video signal.

For this system (exact model): The current store classifies Phase 3 for both the Apple III and Apple III Plus. It applies only to the NTSC color-composite path.

JCM showed 75 units in stock on 2026-07-24. Phase 3 affects only the NTSC-compatible color-composite signal on the 15-pin video connector. It does not add color to the rear black-and-white jack, alter RGB output, or work on PAL-coded systems.

Adds a Z80 processor and Microsoft SoftCard III compatibility for running CP/M on the Apple III family.

For this system (exact model): The current store explicitly classifies the reproduction for the Apple III Plus as well as the Apple III.

The current page offered assembled, kit, and PCB-only choices through its product selector on 2026-07-24. The PCB-only option does not include the ROM adapter or programmed ROM, and no option includes a rear-panel bracket. JCM tested assembled units booting Apple III CP/M from both wDrive and an original floppy.

Replaces the Apple III boot ROM so SOS can boot directly from compatible ProDOS block storage.

For this system (exact model): JCM explicitly classifies its ready-made B9 replacement for the Apple III Plus. Use only with the project's compatible boot images and storage setup.

JCM showed eight programmed replacements in stock on 2026-07-24. Existing boot images are not automatically compatible: users must install the project's modified boot loader, SOS.KERNEL, and drivers or use a prepared image. The ROM normally searches slots 4 through 1 for a ProDOS block card and falls back to the internal floppy.

Adds an Apple IIe-compatible mode with 128K RAM and Double Hi-Res graphics to the Apple III family.

For this system (exact model): The current store explicitly classifies the reproduced set for the Apple III Plus as well as the Apple III.

JCM showed one fully assembled set in stock on 2026-07-24 and also listed kit and boards-only choices. No option includes rear-panel brackets. The card set requires the documented startup software and installation procedure, and the reproduced III+II board cannot be used by itself because original conversion changes are built into the other boards.