Nomad Repair Question

This is from new member Atlantawiseguy:

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Hello all, I have a nomad that was working but suddenly stopped and has no power. In attempting to find the fault I currently I have 10 to 14 volts at the input pin on the power jack but nothing going into the power switch. So something along the circuit is preventing voltage going to the power switch itself. If I had some Nomad schematics then I would of already had this fixed but since none exist, I'm out of luck atm. I just have power at the input pin of the power jack, no power anywhere else on the board.

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Thanks Melf, I appreciate it! :) If anyone could give me some advice on where to test next I would be grateful. Like I stated above, there is no power anywhere else on the board including the input pin on the voltage regulator. I'm not very good at tracing circuits blindly without schematics. Thanks all!

I don't have any sort of schematic to reference, and am not super familiar with the nomad, but I would just try to follow the voltage line until you find a fault. You say there is power at the input, but none by the time it hits the power switch. If you can, follow the trace from the input through each component until you find one where power does not flow. I understand that this might be easier said than done though, but you might be able to find a fault.

I keep a collection of high res circuit board images from all my consoles. I have 3 nomad photos, maybe they can help you.

https://imgur.com/a/2HDXShT

What's usually the case is that the power input jack has broken free from the board, or broken the solder connection at least. Continuity is confirmed from the points on the plug, to the next accessible spot they're electrically connected to on the board?

Power jack is fine, I had just replaced it. Took me awhile but eventually found the broken trace. Simple fix, now it's back to working. Only thing left to fix is the player two port. When a controller is plugged in all directions and buttons work except right. Been following the traces for awhile with no luck.

Okay, so I've been working on tracing the player 2 port issue. According to the genesis controller pinout, pin 4 is Right. On the nomad I have continuity from pin 4 on the port all the way to pin 96 on IC3 (315-5700). Pretty much stuck for the moment on where to go next. Console5 is my go to source for chip datasheets and that chip doesn't seem to have any info. Any suggestions?

A controller issue isn't too bad. There is a custom Sega chip near the center of the LCD and power board that has a demultiplexer plus some other stuff. It's used in all 6 button Genesis controllers. I would just find a 6 button controller to hack apart and take out that chip and replace it. After you do that everything should work.

EDIT: I see now this was a player 2 controller Port issue. Whoops. That's much more problematic and will require some soldering skills replacing the giant 315 - 5700. Unlike player one those pins go directly to that chip. If you can find a late model Genesis 2 you'll have a donor chip. I might have one around myself, but this repair is not for the faint of heart.