Absolutely, I had set out to improve my soldering skills by making C64 cartridges. The 8kB multi cartridge from Sukko Perra.
https://www.pcbway.com/project/sharepro ... __8K_.html
Go there you'll see me banging on about the cartridges. I also made up some Multi kernal replacement ROM PCB's.
https://www.pcbway.com/project/sharepro ... er_V2.html
I muffed that one up as you'll see in the photos. I fixed the other 3 up with the suitable precision turned socket pins. NOTE never use pin headers for inserting into the socket receptacles .... big no no....oops.
I fixed the first 2 up with a file!!!
His stuff is actually very good and his documentation is excellent.
These cartridges and the ROM adapters holds 8 x 8kB ROM images. That is to say a 64kB EPROM . One needs to concatenate the 8 x 8kB files into 1 x 64kB file image to then be burnt on to the EPROM.
At that point I had absolutely no idea what that meant or how do it.
Some how I stumbled on to people talking about using EEPROM's as PLA's. I kept seeing 64kB file size and the chip I had.
In fact there was quite a deal of documentation and it just so happened that they had the same EPROM burner I had.
Then I thought it would be much easier to lay down one whole 64kB file with the burner.
I was using Winbond electrically erasable to start with. There were others were in the mail (cheap M27C512-90B6's - the picture on the web site was actually no reflection of what came).
Have a look!
https://www.aliexpress.com/item/3296631 ... 4c4dGIvYof
I had a go at it and I seemed to create the chip image successfully. That's what the mini pro TL866 EPROM burner informed me.
I made the harness up. It wasn't a very good job.
Tested it and it worked....sort of...
I stumbled upon this site
https://www.hackup.net/2018/04/retro-repair-addendum-i/
I saw a comment from Mindflare Retro regarding his video. I went looking for it.
Mindflare Retro put me on to your site. I saw his video of your test circuit in operation.
I saw your posts about the ST M27C512-90B6 I had some of those. You may remember that this site had taken down the pic's of your original ST M27C512-90B6 PROMS down (as Luck would have it). I had some like yours or so I thought.
I gave one a go (not realizing they are OTP and not like yours). This one worked much better by a long shot..
An amazing story....But true!!
Oh ... I finally worked out how to concatenate multiple 8kB files - use HJSplit for Windows . It makes life very easy.....and be sure to print off Sukko Perra's ROM table for jumper settings for easy manipulation of the multi cartridge. Also make sure that each game image is exactly 8kB in size when joining.
Your PLA test circuit diagram is very unique. I have never come across anything even closely like it. I am sure many others haven't as well. That's most likely why I pursued it. I wondered what it could be...
I can only find that circuit diagram reference in the video. You will probably see that I just screen captured it of Mindflare Retro's video from my tablet. (Thank you Mindflare Retro
).
