Nicolas Welte's Hardware Projects

Welcome to my hardware projects page. I hope you will find something useful here, I'm sure you will like the stuff if you're into Commodore computers.

Looking for recent updates? Then have a look at the history and news page!


Universal 6502 RAM and ROM expansion

Upgrades/replaces RAM and ROM with a 32kB SRAM and 128kB FlashROM chip. By the use of a personality chip the same hardware can work in a lot of different 6502 based computers and peripherals. So far I made personality chips for the Commodore CBM and PET computers, the Commodore VIC-20 computer, and the Commodore 1541/1571 disk drives and compatibles.

main page: general information, parts list, downloads

construction page: instructions for assembling the device.

configuration guide: all DIP switch settings are explained here

disk drive flash software: driver software for the 6502 expansion when used in Commodore disk drives.

1541-II notes: in this drive there isn't enough space for the standard board. Look here how you can make it fit.

prototype pictures page: shows early versions and applications examples.

Universal Flash/EPROM adaptor

A small adaptor board that allows you to use large Flash-ROMs or EPROMs (2764 up to 29C010) in the ROM sockets (2364, 23128, 23256) of Commodore computers. Depending on the size of the original ROM and the Flash or EPROM that is used to replace it, up to 16 ROM sets can be selected with an optional switch.

main page: general information and configuration overview

construction page: instructions for assembling the adaptor.

PET2001 RAM/ROM adaptors

Very small adaptors to replace the custom 6540 and 6550 display RAM/ROM chips in the original PET with easily available replacement chips. Great as an addition to the RAM/ROM expansion, but they also work without it.

main page: contains all information about the project

PET/CBM Video Adaptor

A convenient way to connect an external monitor to Commodore's first professional series of computers. I mostly use it during repairs so I can put the internal monitor out of the way.

main page: contains all information about the project

A570 2MB RAM expansion

The Commodore A570 is a CD-ROM drive that plugs into the A500 and A500+ to make it compatible with the Commodore CDTV. The 2MB expansion plugs into the internal memory slot and adds 2MB autoconfigure fast RAM.

main page: currently only a short description and a prototype picture is available


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