Big Bang Piggy Bankin - Boot Problem

[jtampa22]

Need some help from those more knowledgeable than me. Picked up a non-working Big Bang Piggy Bankin machine. When I got it, F2 (3A SB fuse) in the PDU was blown with black marks telling me that it was a short that took it out. Traced it out and found a pinched with in the upper cabinet florescent fixture. Fixed the and replaced F2. Machine booted and was playable for about 5 minutes. Shut down for the night and came back to it the next day.

The internal switching power supply has been removed and bypassed with an ATX power supply providing +5, +12 & -12V DC directly to J1 inside the PDU. Have verified that the voltages are all present to J1.

Now when power is turned on, get a normal, single "bong" and then a "buzz" about 2 seconds later. Tilt is illuminated, but no tilt codes on the displays. Checking the IO Board, all 5 leds on the right are lit and have a illuminated DS1 LED.

Not sure where to check from here, so any suggestions or pointers would be welcomed.

[jtampa22]

Follow Up

Checked the voltages at the J12 output (cable that goes to the backplane). All the voltages are there except for +5VDC on pin 13. The comes from the output of the HCPL-3700 optocoupler on the PDU board. Does any know if there is any problem if this were to be connected to the +5VDC that is available on pins 20-22 ?