Before I throw in the towel and buy an after market Sys 1 power supply board, I thought I'd throw this out to the Great Pinball Gurus!

After I spent 6+/- hrs testing and replacing components I took my 2 boards w/ same problem to my board guy and we spent another 4 plus hrs duplicating some of my previous efforts, retesting and replacing more components. All to no avail, still 2.4v - 2.6v at the 5V pin(A2P2.) All input voltages(A2P1) are correct. Let's see if I can remember all replacements;

7 pin Connector(A2P1), CR1 & 2, CR 3 & 4, Q1, IC1, CR5, CR101 & 201, Pot R4, CR21, R21,LIC1, additionally C1 w/ supplemental grounding line added.

Additional info...., -12v good, 60v and 42v good on A2P3 , as expected 4v & 8v virtually nil.(can't remember exact)
My board guy has a good board/working machine(Joker Poker). Oddly and likely meaningless, both bad boards are off Genie.

Thoughts, suggestions, directions(even toward the fridge) are welcomed.

Thanks for the Reply, I'm fairly certain there's no bridge rectifier on the power board, and voltages to board measure out correctly. Somewhere in the convoluted mess of them tweaking the incoming 11.5 VAC it doesn't quite make the 5DVC outgoing to the MPU.

See attached.Gottlieb Sys 1 Power Supply Schm 07292015_0001.pdf

Our initial test on CR1 & 2 tested good, however because of the disassembly of the board and backing plate every time a component is replaced(because of Q1 mounted from behind plate and then soldered to board), we began to replace multiple components. Some I had replaced and/or were thought good or new, including CR1 & 2.

I lik might be very tight working those tests on the front, but there's no getting to the back once assembled.

Thx for the input!

backing plate w Q1.JPG
Sys 1 power board on plate.JPG

@ barakandl

Make sure Q1 is connected. If you have an open circuit on one of the legs you get a 2.5v on the 5v rail (dont ask me how i know this *grumble*).
It is really easy to bust the through hole as you have to pull that transistor off to even get at the solder side of the board.

Forgive my less than perfect reply technique, but this is fairly new to me.
The Q1 was actually replaced(in our process) a couple of times, the insulator is good(even for thru holes) mica and heat sink goop good. Are you maybe speaking of the thru holes on board that have the metal circles that the solder joins the board to pins?

Thanks, I will share that info with my board guy/friend in possession of both boards. Did I mention, both boards have same issue, he's never seen this.