Hi Mooger5, how are you? I've read your threads. Inspiring.
Good news, I've desoldered the slave D7811G CPU and I there are no shorts on the above-mentioned pins. Cleaned up the IC29 socket and going to be installing 4 single-row IC mounts for a new CPU. As I don't have a proper Mask ROM 102 CPU, I've prepared the programmed EPROM with a wide DIP-28 socket for IC37 with the B2 dump and a TC40H373P flip-flop for retrofitting.
I will probably need to remove the J1 resistor and put a jumper on J2 to enable external ROM. Can anyone confirm that?
Unfortunately, I ran out of single-row 2.5mm IC panel sockets and isopropyl alcohol. Got 3, need 1 more for the CPU and 6 more for the 80017A chips. My local electronics store doesn't carry 2.0mm pitch sockets for the 5534 chips, which is a shame as I won't be able to test.
I still need to replace R30, R66 and R100 with proper resistors. The ones the previous owner has fitted are wrong size and wrong value. My store also doesn't carry those. Can anyone recommend a replacement?
Getting a bit ahead here, but I also found a few components missing on the Jack board and I am having a bit of trouble finding suitable replacements. It's C3, C53, C57. They look like polyesther and two foil capacitors, not something my local shop has. Here are the reference photos of my first unit which has a working and fully-populated jack board.
