I work on a number of these early Williams boards and use @pincoder test ROMs to troubleshoot and test the boards on the bench, but swapping eproms in and out for each test has been a pain. I have seen all sorts of discussions about building an adaptor board to have all the files in one eprom but have never seen anyone produce one except for a couple bread boarded ones.

In discussions with @barakandl he pointed me to a Gerber file he created, but never had made, for a 4 dip switch 27256 eprom. So I went ahead and had some made. The pcb house I used makes these on a minimum sized board so I got 10 of them and I really only need 1, lol. I went ahead and built up all of these so I have a few extras, like 7 of them. If anyone wants one for $15 shipped (that’s want I have in it) in the US pm me and I’ll get it sent. It will not include the 27256, you will need to program that as suits your needs.

Here is a picture of them. The one on the bottom with the eprom is the one I use, I just put it in the picture so you know what a complete one looks like. I also made up a chart of the files I put in my eprom and the associated switch settings so I can quickly jump from test to test without having to remember what is where on the chip.

This is only for 2K test files since it is a 27256 with a 4 position dip switch. You can fit 16 files in one 27256 eprom. Pretty basic but works well for my needs. Just offering in case someone else has similar needs. Hopefully @pincoder or someone else will come out with a more robust adaptor soon, but for now this serves me well.

You certainly need to download the documentation @pincoder has on his website to understand how to use the tests and what they do. He has lots of good troubleshooting tips there also. I can’t say enough about what he has done here to help the hobby, Thanks @pincoder !!

20FD6E4E-57FE-4053-AB93-DB9B4CD10D05 (resized).jpeg

58B9C2C9-9EF1-45E7-9051-04ECB1FEC399 (resized).jpeg