Bish500
Experienced Member
I have a non-functional 8296. The PLA at U5 is super hot as soon as it’s powered up. I’m assuming it’s bad. Does anyone know of a replacement PLA for this machine?
Thanks!
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8296 bad PLA
- Thread starter Bish500
- Start date
RobertB
Veteran Member
On my 8296-D, out of the 2 PLA's, one was bad, and it was replaced by an EPROM on an adapter.
Truly,
Robert Bernardo
Fresno Commodore User Group - http://www.dickestel.com/fcug.htm
Southern California Commodore & Amiga Network - http://www.portcommodore.com/sccan
Truly,
Robert Bernardo
Fresno Commodore User Group - http://www.dickestel.com/fcug.htm
Southern California Commodore & Amiga Network - http://www.portcommodore.com/sccan
Bish500
Experienced Member
I’ve been looking at doing that. There’s an article called “How to replace the PLA UE5 in a CBM8296 with a GAL 20V8” written in 2005 by Nicolas Welte that looks promising, but the adapter would be difficult to make. The article is here: http://x1541.de/
I was hoping someone had come across a more ready-made solution. I looked into something called the PLAdvanced which could be used to replace PLAs in the following devices: Commodore 64 (and SX64), 1551 floppy drives, the CBM 6×0, CBM7xo, Commodore 16 (and C116 & plus/4), the CBM 8296 UE5, the CBM 8296 UE6, the P500 U78 and the P500 U88 (and U78).
It looks like it stopped being available in 2018 though.
I was hoping someone had come across a more ready-made solution. I looked into something called the PLAdvanced which could be used to replace PLAs in the following devices: Commodore 64 (and SX64), 1551 floppy drives, the CBM 6×0, CBM7xo, Commodore 16 (and C116 & plus/4), the CBM 8296 UE5, the CBM 8296 UE6, the P500 U78 and the P500 U88 (and U78).
It looks like it stopped being available in 2018 though.
Last edited:
retrobecanes
Experienced Member
Roberto, how did you determine that one was bad. Did you perform a test of some sort?
RobertB
Veteran Member
I didn't test it, but my friend who knows PETs determined that one PLA was bad.
Truly,
Robert Bernardo
Fresno Commodore User Group - http://www.dickestel.com/fcug.htm
Southern California Commodore & Amiga Network - http://www.portcommodore.com/sccan
Truly,
Robert Bernardo
Fresno Commodore User Group - http://www.dickestel.com/fcug.htm
Southern California Commodore & Amiga Network - http://www.portcommodore.com/sccan
snuci
Veteran Member
Does anyone have the JEDEC files for the two 8296 PLAs? I can program them if I had the JEDEC files and it would be a single chip replacement.
Same here, I can program them too. Also, I can re-compile the equation to make a valid jedec file if the equations are available, or I can reverse engineer the equations if someone has a binary (ROM-like)
dump.
I haven't looked too hard to find these files since so far I haven't made any 8296 repair anyway.
Frank
snuci
Veteran Member
Here are the two BIN files if you can work with these: http://vintagecomputer.ca/files/Commodore/8296/8296-PLA-BIN.zip
https://drive.google.com/file/d/10RqxCNOR9oaRIGEmVC70-qaPI0ojySh-/view?usp=sharing
since I don't have any 8296 to test these maps, use at your own risk
Frank
since I don't have any 8296 to test these maps, use at your own risk
Frank
mister-freeze
Member
@iz8dwf
Frank,
I would like to use the .jed to burn 8296 PLAs with 82S100/PLS100 Chips. But before I brick them I wanted to ask you the following:
The .bin files from above are exactly the files to create an EPROM PLA Replacement. The pin order of the input and output pins does not correspond to the PLS100-PLD. pin numbering. The PINS were used in a way that the physical position of the Eprom pins fits best.
Did you consider this when creating the .jed's ?
If it helps I can do a bin-dump of the 8296 PLA's with the "correct" pinout.
(And thanks for the video regarding the C64 PLA and the Soviet chip !! I puzzled around for ages but your tip with the 2 missing lines in the DATAIO-Jedec was the solution.The information for the 2 missing lines could well be taken from the jumbled Jedec file).
Many greetings,
Chris