CBM 4040 drive with a VERRY STUBBORN 5 flash error!

[DistantStar001]

I've posted about this before, but recently figured out how to use my Promenade C1 to program replacement EPROMS. Long story, won't go into it, but apparently it didn't like my C64c but it does like my bread-bins.

In any case, I've replaced all the 2114 RAM, the 6532s, the 6530 (with the recommended MonoTech board), and the 6504. Heck! On a total "couldn't hurt" I replaced the 6502 as well... And nothing!

For a while, I thought maybe I requested the wrong ROM image from MonoTech, or maybe it was programed wrong? (That's where the Promenade came in.) But i just finished programming every available ROM image for the drive and none of them worked.

The Rom images in question are from here: https://www.zimmers.net/anonftp/pub/cbm/firmware/drives/old/index.html
Recommended on this thread: https://forum.vcfed.org/index.php?t...ive-and-6510-kernal-for-a-ted-system.1247252/

Note in case this is my issue: MonoTech used a 2764A EPROM, where I only have regular 2764s. I don't think that's the problem since they should be pin compatible, but I'm very new to programing EPROMs.

Also, I tried verifying the EPROM provided by MonoTech to the ROM images I have, and it failed each time. So odds are whatever it is... It's not one of the images on the site above.

Last Note: The original thread is here: https://forum.vcfed.org/index.php?threads/cbm-4040-5-flash-failure-need-parts.1243391/#post-1320700
I would have continued on that thread, but I might be asking very different questions, and sometimes it's just easer to sum up what I've done. But I linked it anyway in case there's something I missed.

 

[miata]

Hi, I got a similar journey when trying to fix my 4040 two years ago. I also got 5 flashes and I nearly replaced all chips on the logic board. Then I learned that you cannot simply replace the ROMs by 2532 or 2732 type EPROMS. These are “dual/triple CS mask roms” as I was told by another nice member (Frank) of the vcfed forum, „iz8dwf”.

To use EPROMS you need an adapter board between the socket and the chip. Back in the day we figured UL1 as the possible culprit in my machine but I remember also UK6 was in question. Frank was very nice and sent me an adapter board he built for me for the UL1 (901468-12) and after installing it my 4040 came back to life

Maybe you drop him a PN and he can also help you? Say hello from Denis

 

[DistantStar001]

Hi, I got a similar journey when trying to fix my 4040 two years ago. I also got 5 flashes and I nearly replaced all chips on the logic board. Then I learned that you cannot simply replace the ROMs by 2532 or 2732 type EPROMS. These are “dual/triple CS mask roms” as I was told by another nice member (Frank) of the vcfed forum, „iz8dwf”.

To use EPROMS you need an adapter board between the socket and the chip. Back in the day we figured UL1 as the possible culprit in my machine but I remember also UK6 was in question. Frank was very nice and sent me an adapter board he built for me for the UL1 (901468-12) and after installing it my 4040 came back to life

Maybe you drop him a PN and he can also help you? Say hello from Denis

Thanks for this! And will do. At the moment, the only EPROM on the board is the 2764 on the MonoTech replacement or the 6530. I had thought about replacing the mask-ROMs before. Not that I thought the ROMs were necessarily bad, but that they may not be a true match for the available 6530 images. I was thinking of simply replacing them, but as you pointed out, I don't know the pin-outs for the mask-ROMs.