MCR power chassis/brick and supply overview

Made adjustments to the A082-90412-D000's 5v pot and saw that translate to pin 3 on the CPU. Good on 5v.

Adjustments to the 12v were unsuccessful. With the harness attached, it doesn't budge from a 6.17v reading at cap 102. With the harness removed, cap 102 measures between 12v and 13.3v rotating its pot. Noted R110 almost too hot to touch in the process of testing with the harness attached. With it removed, the ceramic resistors cooled down.

Still with harness removed, checked my unregulated 12v at cap 101, and from the collector side of the transistors—everything matching Jacklick's test results on the 5v and 12v unregulated sides.

@TRON Guy—saw that you have a -D000 board for sale recently. Do you feel it's appropriate to try another P/S board, or should I focus on testing the harness's J4 and J5 bundles? This seems to point towards the harness/pcb side. Next thoughts were to unplug all pcb, remeasure, and start adding them one at a time.

Appreciate everyone's input.
 
I need to go read up again, but it seems like your power board has an issue on the 12v rail/section. It's dropping voltage under a load.
 
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Unplugged all pcb except connections to the CPU and sound board. Now reading good 12v at c102 and at CPU.

Will chase this down and get back to you. Thx!
 
Something on your power board is failing. Jacklick has a nice colored breakdown in this thread of the parts you should look at.
 
Shorted tantalum cap on the 12v rail on the ssio. edit - or R110 is bad.
 
Okay, I'll swivel to these. Thanks fellas.

FYI, I started adding back pcb and measuring 12v after each was added. 12v held for adding the relay control boards (2), Squawk and Talk, -5v aux, dual power amps (2), speakers, lamp sequencer pcb and lamp assemblies. When I added the flashing fluorescent pcb, it dropped into mid 7v, and the coin door took it lower into 6v.
 
The Flashing fluorescent pcb shouldn't have 12v to it at all.
 
try unplugging the relay pcbs, but leave the flashing fluorescent and see what it does.
 
11.99v with flashing fluorescent pcb attached but relays disconnected. On the cable going to J2 of the relay, I checked pin 1's voltage and had 11.99v there. Attaching the relays (click heard on both) dropped voltage to 7.8v.
 
Try the relays one at a time and see if one of them might be causing more voltage drop than the other. Did you rebuild the power supply? Sometimes, when removing the bottlecap transistor, the via gets pulled out, and it'll show voltage until its under a load, then it drops out. I would check continuity between the 2 pins on the 12v bottlecap (2n3772 or 5304 or whatever they used) and the other end of the trace and make sure that isn't the issue.
 
I did rebuild it. I do not have continuity between E and B on the marked 2n3772 and to the trace B connects to. Missed this. Sigh. Fetching the pyropen.

Thanks Cdjump!IMG_5672.jpeg

IMG_5673.jpeg
 
Fixed the continuity to the trace and upon reinstalling, had full 12v…for about a minute. Heard the relays click and the saw the coin door go dark and stay dark. 12v reg side is at .7v. 😕

Have another board on its way. Will update when installed.
 
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Another question for the subject matter experts here. AC Sync.

In the EDOT schematics, this is output on the power supply's J4 connector, pin 14. What exactly is it (a particular voltage?) and purpose? It's marked with a 'S' that runs to the AC Sync input of the Flasher Control pcb, J1, pin 10.

I've read elsewhere that it's possibly used to control the timing of the pulse to the fluorescent lamps so that it's in sync with the AC phase?

Thank you!!

76592087196__B88BE9BB-3E70-4705-8063-7CF5849BA303.jpeg

IMG_5958.jpeg
 
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Just a follow-up on the AC Sync circuit. With my logic probe attached to 5v reg, I have a very rapid pulse from the 90412-D000 pin 14, which heads to pin 10 of the Flashing Fluorescent pcb.
 
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