Finally sat down and looked at the dead sound board I got with my previous MK1 main board. Out of the gate, it had no signs of life at all. All the boards I got out of this lot had a lot of corrosion and rust, so I expected the same here.
Visual inspection showed that the GAL on the board was sitting in a corroded socket. Pulled and replaced that, but no luck. Broke out the logic probe and found that all address and data lines on the ROMS were not pulsing. Checked at the CPU and found the same. Pulled the CPU to find a couple of pins with corrosion deeper in the socket. Replaced the socket and started to get activity on the bus, but still no sound.
Ran through a cap kit and found 3 caps that had leaked quite a bit and a few others that were starting to leak. Replaced all electrolytics, axial and radial, and had sound again!
Still need to replace the thermal grease on the amp, but I'll mark this one as successfully done!
Visual inspection showed that the GAL on the board was sitting in a corroded socket. Pulled and replaced that, but no luck. Broke out the logic probe and found that all address and data lines on the ROMS were not pulsing. Checked at the CPU and found the same. Pulled the CPU to find a couple of pins with corrosion deeper in the socket. Replaced the socket and started to get activity on the bus, but still no sound.
Ran through a cap kit and found 3 caps that had leaked quite a bit and a few others that were starting to leak. Replaced all electrolytics, axial and radial, and had sound again!
Still need to replace the thermal grease on the amp, but I'll mark this one as successfully done!
