I’m stumped on this board I was trying to rebuild. Here’s the problem
I turn the machine on, I get the 5sec delay, then it boots. All 4 displays come on. When it flashes to high score it’s blank.
The match is on 70 but the credits are blank. It will not coin up and the test button does not work. I thought the spider chip was toast, ( I luckily had a spare board with bad traces that had known good spider chips) I changed the U4 and U5 with the same type of chips (so I know their compatible). No change, it seems the problem lays with the coin door not getting the communication from the MPU. any help with this will be much appreciated...

Thanks for your reply, I should mention a good board plays flawless in this machine, so I know it’s isolated to the MPU,
The edge connectors look bright, I may repin just to get a nice tight fit, but as I stated, another board works in this machine. Do you know if a chip on the MPU communicates with the coin door? I was hoping that it would be as simple as changing out a chip... thanks again...

I didn’t. I do have a 5011 I guess it won’t hurt, Thanks for the suggestion, my nerves are shot from unsoldering the 4 spider chips. Then soldering 2 back in. Do you think it could be a memory problem??

I’ll replace the ram chip tomorrow, but I’m not confident that’s the problem, I wouldn’t think the test button would have anything to do with the memory, but what do I have to lose...

This is a system 1 board the spider chips are U1 U2 U3 U4 U5 and U6
I changed out U4 and U5
I changed out Z9 Z8 Z28 Z6 and Z7
I don’t know what more to do on this board...