So here are some photos. I'll post more in a few minutes...
So here where things are at after some initial testing...
I replaced the 3A 250V fuse on the bottom right of the fuse holder. It looks like this fuse / circuit sends transformer power to the APU.
I hooked up to my spare p/s , made sure everything was connected. I started it up and the same fuse above was blown. It also sent the power supply into shut down mode. Obviously there is a short somewhere.
I suspected the APU so I disconnected the red and brown wires that come from the power switcher that sends +5 power to the APU board. I replaced the blown fuse and I left every thing else hooked up, basically ONLY isolating the switching +5 power from going to the ACU. This said, the APU is still getting some power from the transformer itself.
Started it up, fuse did not blow, switcher did not shut down, here is what I have:
Main PCB boards are up: all lights on, EXCEPT for CR1, CR2 on the large board closest to the Seat, should be good, as they are the test LED's I think...
Main PCB: CR3 on the center board is not on, area for concern?
Motor AMP: LED ON
Shifter board: NO LED. The current PTC .9A, 50V fuse is blown (see photo, what is the best place to get one of this rating)? I also tested the incoming power to the Shifter board, no power to the Shifter board. I assume that is because the APU is not being fully powered as I removed the +5 in from the switcher to the APU? Perhaps the fuse was blown as there is an issue with the APU?
SGB Board: LED ON
I did one more thing. I hooked up the +5 power to the APU from the switcher, but before I turned things back on, I unhooked ALL cables going into the APU (except for +5 power from the switcher) and started things up. No issues. I then hooked up one cable at a time back to the APU. All of them don't cause a shut down except for the top middle connector and the bottom left connector.
Oh, I also unhooked the shifter board and the motor amp connectors, to make sure those were not causing a fault/short. With those unhooked, I still could not hook up either connector mentioned above to the APU without causing a shut down. Not sure what other PCB's may be hidden that could be causing a fault?
In the end, do I have a bad APU or what else should I look at isolating from the APU to see if something else is causing a short?
Also, I need to get a fuse for the shifter board, ideas on what I can do there?
Can't thank you guys enough for all your help. My plans are to restore this to as near new condition AFTER I get it functional.