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Hello. I'm trying to repair / troubleshoot an Armor Attack sound board without the monitor or CCPU or original wire harness(es), and could use some pointers.
I currently have it wired up to a refurbished Condor power supply (on which I've confirmed the expected output voltages at the correct pins).
Happy to provide more detail if someone would like, but at this point I'm basically wondering if this kind of test bench setup is even possible.
(Outerworldarcade has a few videos showing an arduino-based bench test setup, with a custom chip standing in for the data stream from the CCPU, so I think it is possible).

How I have it wired up:
Wall outlet 120VAC 2-wire <--> PS J2 pins 1 & 2

PS J1 pin <--> Sound board J1 pin
. . . . . . . 7 <--> 4 (+25v)
. . . . . . . 8 <--> 6 (-25v)
. . . . . . . 9 <--> 9 (+5v)
. . . . . . 11 <--> 7 (+5v return GND)

Sound board J1 pin
1, 3, 8 <--> 10K pot (1 on middle spade)
. . 2, 5 <--> 8-ohm speaker

Two dumb questions:
1) Does the power supply need ground from the wall? (GND-HOT-NEU instead of just HOT-NEU)
2) Does the +/-25v that goes to the sound board need a way to reference +/-25v return on the power supply? (PS J1 pin 12)


Further testing / symptoms info about the repair for context:
I found the 2N6107 transistor had failed closed, and one of the 22uF 50v capacitors nearby had failed open; replaced both adjacent capacitors and 2N6107.
Both before and after these faulty components were discovered and replaced, I was able to successfully complete the test procedure on 6-10 of the manual.
Also confirmed the various GND and +5v are reaching the correct chip legs as described on page A16-1.

Symptom before the faulty components were replaced was a loud buzzing in the speaker (like an open ground buzzing, I believe, like the buzzing in an amp when you unplug the lead from your guitar).
Symptom after the faulty components were replaced is a looping, sputtering clicking pattern repeating in the speaker ... until the final part of the initial test procedure (load all highs onto IC1-13 ... tap IC3-11 with ground lead), at which point the speaker goes quiet.
Some of the sounds seem like they're "trying" to work when grounding test points in Table 1 on page 6-10, in that each test point now produces distinct, repeatable but weak little gurgles.

Tools I'm using are a multimeter and a component tester. I have access to an oscilloscope at my library, but basically zero experience using one (though I'm willing to learn).

My next step was going to be replacing the 2N6292, 7815 and 7915, even though they seem to be testing fine out of circuit.
Failing that, replace all the electrolytic capacitors on the board, even though none look particularly bloated (it's probably been a good 20 years since any were changed, if at all).

Links for reference:
PS pinout
AA Manual
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