retronynjah / dela-eprommer-ii-27512-extension Goto Github PK

Hi,
not an issue, actually...
I translated the software (both original and 512k versions) from german to english (at least I did my best), using Google and an hex editor. I wish to release it, are you interested to put it here?

Hello,
I've built your adapter. But I have an issue with the eprommer that prevent me to use both the eprommer and the eprommer with the 512k extension.

I know that you have nothing to do with the eprommer design, but you're the only one person I could ask some help...

I built the https://github.com/Commodore-Bench/DELA-EPROMMER-II project, but I'm getting corrupted / scrambled data when I try to read an EPROM. Unfortunately this project doesn't allow issues, so I have no way to contact the owner.

I got the following issue:

I read an EPROM (I tested it from 2716 to 27256.... I did a quick test with 2716 and 2732 and they seem to be ok, while I have the problem with 2764 to 27256) addressing it to $1000 as suggested in the original manual.

If I then compare the EPROM I've just read with the memory content at $1000, most time it seems to be the same (but sometimes it reported corrupted data);

I extracted the saved PRG from the disk, using DIRMASTER on my Windows PC;
I opened it with an hex editor and I removed the two first bytes (loading address);
I compared it with the original BIN: the content is scrambled: it is saved in blocks that are in different location respect the original BIN file (i.e. $0800-$0FFF is saved at $1800-$1FFF, etc.). Sometimes the content is different (corrupted).

I've built three different DELA eprommers (just to be sure it wasn't my issue in the assembling process);

I tried to replace all the ICs using another from other sellers (the only parts from the same seller are the zener diodes and the transistors);

I tested it with three different Commodore 64;

I tried to read a 27256 EPROM many times and saving it to disk, using both SD2IEC and real 1541 drive;

Honestly I ran out of ideas; I can only imagine there's a flaw in the project or some of the components I'm using are wrong/fail/fake/etc.

I know that you didn't design the above project, but have you any clue about what's going on and what could cause this kind of problem? I supposed the CD4040 would be the potential culprit, for that reason I bought new ICs from a totally different seller, but the behavior is exactly the same... also the other ICs come from different sellers / lots / brands;

Have you any way to know if the project I used (link above), is the same of the (no more available)https://github.com/DL2DW/DELA-EPROMMER-II project you cited in your page and / or if it's know to be a working project?

Any kind of help you can give me will be highly appreciated!