This brings back a memory from the TRW days. A guy got a replacement board that supposedly worked but didn’t on arrival at the shop and they couldn't figure out why. I was one of the younger techs and not even trained on it but took a look. I noticed a component on the board was bent over touching another and pointed it out and separated them. They tested it again and it worked. Maybe tangentially related.
Any transistors or resistors on the mb bent out of shape that can be manipulated back into shape? If things were bouncing around it had to bounce off quite a few things.