Hi,
Quoted from smailskid:... Would be possible/likely that I would have a corrupted ROM? I have checked many other things but nothing yet. I do not have a eprom reader at this time.
Thanks
No, probably not. Usually after high voltage injected on board, the EPROM is burn and don't work anymore. Corrupted/partially erased is less probable, because the CPU start and look to run normal (attract mode is working, test mode is available).
So, you have several lamps activated at same time, and Q/T relays during attract mode (that are driven like lamps L0 and L1), the culprit should be in the lamp matrix. As you individually test the transistors on the driver board, the issue is not here, but on the CPU board.
You say that you have also a sound problem, so the issue source look to be definitely in the U6 area on the CPU board.
During the attract mode, the lamps are lighted on/off quite randomly, but the first group (including L0/L1 Q and T relays) is normally, never activated. The strobe line DS1 is thus, never driven. But, as you notice it is, this means that there is a problem either at Z34 (less probably) or at the 74154 decoder (Z33), or even at the U6 port B.
For sounds, this may be one of the IC burned, Z31 or Z27 or even at U6 port A.
2017-12-20_11h21_25 (resized).png
Without a bench test fixture, difficult to identify the culprit, but... as you have already replaced U4 and U6, I suppose they are now mounted on sockets ?
Try to interchange U4 and U6 to see if the problem could be a defective U6.
May be, the problem is only U6 that is not well plugged in his socket. Check the pins states.
Even if your U6 is NOS, it can be defective (or partially defective, like some ports but not the ram/timers). This sometimes happen, so try to interchange U4 and U6 to see if the problem persist.
If this change nothing, then may be a short-circuit on the A/B ports or some burned IC.