Game has been working great for years.
Now tonight when I power it up I can hear the power up sound but the game will not go into game mode.
Sometimes it does, but only for a few seconds then it shuts itself back off again.
What should I look at first here?

Looks like LED's 2 and 3 are not lighting up on the Power Driver board and D20 on the CPU board will go on and off.

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Thanks. I will check all TP tabs tomorrow night.

I suspect the same.
Have been to busy with other things to really check yet.
I will report back here when I get the test done.
This board had the dreaded Check F115 and 116 fuse problem many years ago.
Turned out the C2 has leaked underneath and eaten the traces.
Had it professionally fixed.
Been very stable till now.

Ok here are my test point readings.

TP1 = 17.68
TP2 = 4.95(rock solid even during resets)
TP3 = 11.98
TP4 = .387
TP6 = 86.0
TP7 = 26.1

Thanks.
Will do

I think you just solved the issue.
Somehow the little jumper ribbon cable had worked its way loose on the right side in this photo.
Game back on and stable

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