Interest for a C64c (250469) PLA replacement?
Posted: Wed Nov 15, 2017 7:55 am
As some of you may have noticed, over the last 2 years, I have invested time and energy developing replacements for a few custom chips used in Commodore 8 bit computers.
These include:
- PLAnkton which replaces the C64/SX-64 programmable logic array 906114-01 or 251064-01
- TOLB which replaces the 7701/8701 clock generator used on later C64 boards, the C64c and the C128
- GandALF which replaces the 1541 custom controller and array 325572-01
I am presently considering the possibility of making PLA replacements for the C64c board 250469, specifically part no. 251715-01. Board 250469 can use 2 different types of PLA which incorporates most of the glue logic ICs used in the original C64 and they are part no. 251715-01 and 252535-01. Making PLA 252535-01 may prove too difficult because it incorporates the 512x4 bits color RAM and this type of chip is no longer in production.
So far, I did not make this substitute strictly because there doesn't seem to be much interest, not because there are any technical hurdles I can't overcome. This variant of the PLA is based on more modern technology than the one employed on 28 pin PLAs and it doesn't produce any discernable heat so it fails far less frequently.
I would like the people of Denial to indicate if there is, in fact, sufficient interest to make a substitute for PLA 251715-01 used on board 250469 and how much people would expect to pay for this replacement.
Thank you all for your feedback.
- Francois
These include:
- PLAnkton which replaces the C64/SX-64 programmable logic array 906114-01 or 251064-01
- TOLB which replaces the 7701/8701 clock generator used on later C64 boards, the C64c and the C128
- GandALF which replaces the 1541 custom controller and array 325572-01
I am presently considering the possibility of making PLA replacements for the C64c board 250469, specifically part no. 251715-01. Board 250469 can use 2 different types of PLA which incorporates most of the glue logic ICs used in the original C64 and they are part no. 251715-01 and 252535-01. Making PLA 252535-01 may prove too difficult because it incorporates the 512x4 bits color RAM and this type of chip is no longer in production.
So far, I did not make this substitute strictly because there doesn't seem to be much interest, not because there are any technical hurdles I can't overcome. This variant of the PLA is based on more modern technology than the one employed on 28 pin PLAs and it doesn't produce any discernable heat so it fails far less frequently.
I would like the people of Denial to indicate if there is, in fact, sufficient interest to make a substitute for PLA 251715-01 used on board 250469 and how much people would expect to pay for this replacement.
Thank you all for your feedback.
- Francois