Easiest Commodore 64 Char ROM adapter



This is a tested and working project.

No waste of big EPROMs, no jumpers, no configurations, no SMD.

It uses a cheap 2732 EPROM that can be easily found on Aliexpress, eBay, etc.

What you need:

1) The PCB from PCBway, of course;

2) a 2732 EPROM programmed with the characters ROM (get the zip file from this page);

3) 1x 24 pin wide socket [1];

4) 2x 12Pin Connector Header Round pins [2] Male pitch 2.54mm

(get something like this one: https://www.aliexpress.com/item/4000341349347.html and cut in two pieces of 12 pins each)

[1] You will need two sockets if the Commodore 64 ROM isn't on socket yet (unless you decide to solder the adapter directly on the C=64 board - not recommended);

[2] I strongly suggest to use the thin, round pins type, because the square, thick ones tend to damage the socket.

How to proceed:

1) solder the 2x connector headers on the "C=64" side, as marked on the PCB (the 1st and the 3rd rows looking at the board with the notch oriented upside). To keep the headers in the right alignment while you're soldering them, I suggest you to put headers into a socket to keep them in the right position.

2) Solder the socket on the "EPROM" side (on the right side, as marked on the PCB);

3) Program the EPROM with the image from the ZIP files I provided;

4) Put the adapter with the EPROM installed into the C=64 character ROM socket.

Note: If the Character ROM isn't on socket, you will need to remove it and put a socket. If the chip is broken and ready for the junk bin, it can be easily removed simply cutting all the pins from the chip, removing the chip and then un-solder every pin, once at a time. Take your time, because the Commodore boards are known to be weak and it's easy to damage them if you don't take care.

NOTE:

Inside the Zip file I provided the VIC-20 characters ROM image too. The VIC-20 and C=64 images are fully compatible, so you can use any of them in a C=64 or VIC-20. The VIC-20 will produce a thinner font.

(BEWARE: ONLY THE FIRMWARE IMAGES ARE INTERCHANGEABLE, NOT THE ADAPTERS! This adapter is intended for the C=64 only and will not work in the Commodore VIC-20)

If you need a Char ROM adapter for the Commodore VIC-20, click on this link:

https://www.pcbway.com/project/shareproject/Easiest_Commodore_VIC_20_Char_ROM_adapter_using_2732_EPROM_064be19d.html