Tag: eprom

Modifies an Amiga 1000 to boot Kickstart from four EPROMs while retaining access to its 256 KB daughterboard RAM.

This is an advanced board-level modification, not a plug-in board. It requires a GAL16V8A, four 27C512 EPROMs, a legally obtained Kickstart image, device programming, desoldering, jumper installation, and PCB trace cuts.

Published twelve-chip Motorola 6800 teaching coprocessor that takes control of the Apple II bus.

This is a published construction project, not a current kit or finished product. The paper supplies a circuit diagram and tested monitor listing but no PCB layout, Gerbers, bill of materials, or explicit reuse license. A builder must recreate the board, source period logic, program a 2716 EPROM, and validate timing and bus loading.

Published 1985 Apple II coprocessor prototype with a 68020, optional 68881, 32K SRAM, and boot EPROM.

Treat this as a historical experimental build, not a safe drop-in design. The creators used custom wire-wrapped and insulation-displacement construction rather than a published PCB. Later design notes estimate roughly 1 A typical and as much as 1.5 A from +5 V even though the Apple II specifies 500 mA shared by all peripheral cards, and they identify excessive data-bus loading. A faithful build needs its own engineering review and likely a redesigned power and bus interface.

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

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

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

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

Vintage and DIY C64 freezer cartridge that saves restartable memory snapshots to disk, tape, or EPROM-oriented cartridge files.

DDI's Re-Capture page still exposes Gerbers, a parts list, a Capture ROM archive, and a manual link. The parts list specifies the EPROM, SRAM, logic, passives, and switch choices, but ReplayResources says the schematic is still missing and no complete assembly or test guide was found. Neither page supplies a clear license for the reproduction files or Capture software. ReplayResources quotes permission relating to Jason-Ranheim's separate Promenade materials but explicitly says its own Capture permission requests went unanswered, so the catalog does not treat the Capture ROM as open or freely licensed. Original cartridges remain worth searching for used.

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

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

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

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

Adds flexible ROM sizing and the ability to page ROM out for a full 64K of RAM.

Current options include a standard or ZIF socket and optional blank or programmed PROMs. The base kit excludes a ROM. A ZIF release bar can foul a nearby logic chip unless the chip is lowered, the socket is reversed, or the bar is shortened. 28C EEPROM support is described as untested.

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

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

MSX cartridge kit for 8 KB through 64 KB DIP28 EPROMs, including a switchable dual-32 KB mode.

The current storefront listed bare-board and kit configurations without an out-of-stock marker on 2026-07-24. Neither the IC socket nor EPROM is included.

Provides a programmable 2 MB Macintosh ROM SIMM using four socketed PLCC32 flash chips.

The current page offered populated and chipless versions in multiple PCB colors on 2026-07-24. Its dated notice says the red PCB alone was out of stock on 2026-04-26, with black and purple also listed.

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

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.

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

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

Provides a menu-driven utility cartridge or a bare board for building a custom multi-EPROM C64 cartridge.

The complete new-old-stock cartridge was out of stock, but bare genuine boards were in stock on 2026-07-24. A bare board includes no case or EPROMs. Building a custom cartridge also requires legally sourced Promos or Promenade Menu Maker software, which CBMSTUFF cannot distribute, plus EPROM programming and assembly.

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

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