This is a strange motherboard, runs for about two hours then locks up with video and audio random scrambles on the screen. When powered cycle it will run normally for another 1-2 hours.
I tried swapping out the OS card, RAM, and POKEY with known working chips.
The board was cleaned and so was the keyboard. Case was cleaned. A good candidate for retrobrite.
It might be one electrolytic cap on the middle left of the main board that needs replacement.
The keyboard port works, video port works, SIO port works, all the joystick ports work.
Includes keyboard, power socket works.
The electrolytc caps, and regulators on the power supply board were replaced and tested ok for voltages.
Shipping from 98686 17lbs.