I need help! I swapped my DE JP MPU into my DE SW for a diagnostic verification. I swapped ROMs to get the right game software loaded and confirmed my issue. I put the JP MPU back into JP and fired it up. The game went into normal start mode with trex moving around, chomping, etc and then the sound went out. I checked fuses and found F7 on the power supply blown (0.5 amp). I checked all my MPU cable connections and added another 0.5 amp fuse and now it blows immediately on start up. I pulled the MPU and found I had bent a leg on the JP ROM chip (ack!!). I straightened it and reassembled everything but the fuse still blows immediately on startup. Did I screw up the ROM or something else? Any ideas?
Thanks
Dan

LTG - can I put the SW ROM in JP on the JP MPU? Will it try to boot it? Is that insane to try?

Since it failed in the Trex startup diagnostic, I'll pull Trex apart to look for cut wires.

I did recheck all my connectors - they are well organized in the backbox so it's very difficult to get them mixed up. I got the ribbons on correctly.
Thanks
Dan

I have some new info.

Today I verified that with the MPU power disconnected, the fuse still
blows. The fuse is wired to the transformer directly so I check
voltages - supposed to by 90v ac per the manual going into that fuse. I get around 120v ac
off the transformer connector. I checked the transformer in SW (same part
number), it's reading 90v ac at that connector (in SW). I swapped the
transformer over into JP and checked it's output at that location and it's
around 120v ac! Not sure what's going on there.

Since the problem seems isolated between the transformer and the power
supply board, I started checking components on the power supply
board. 3 diodes are shorted. I can't try the SW power supply - it's
a different revision and not compatible.

Still not exactly sure what's going on. If I replace the various
shorted diodes, they may short again on the next startup.
Dan

Ok - last week I found a few shorted diodes on the power supply board so it appears the high voltage circuit 'blew'. I replaced the transistors and diodes (resistors seemed fine, no burning on the board or hot spots). I had to use a different diode for a 1n5379 (110 v) since those are not available. I used a 1n4764 (100v). The game booted fine, but with the lower diode threshold I expected the DMD do be less bright but in fact there is more background on the DMD and it appears brighter and more flicky. I reseated the ribbons with no change. Any idea why it appears this way?