I had a member approach me as his SAD4069 chip on the Bally "Say It Again" board in a Centaur had carked it - a very common problem as it turns out.
These chips are LONG obsolete and rumour has it they were all faulty from new and some say they disintergrate from the inside??
I trolled the web looking for ideas and found a couple of people had come up with some clever fixes for the problem but again, all using either obsolete parts or very complex methods.
I enquired of a semiconductor factory I do some business with in PRC and they are sending me some samples of a product they make that is CURRENT production - so that's a good start.
My fix (if it works
) will be a small plug in PCB and NO soldering or modifications. The old adjustments on the main board will become unused and the new adjustments are on the daughter board.
I have made up a prototype (looks horrible as the finished board will be double sided and therefore won't have jumper wires everywhere like the proto) and here it is - waiting for the sample chips to arrive.....
If all goes well I will put it into production even though there is probably a pretty limited market even worldwide??
