I'm trying to revive a Bally 35 that had moderate acid damage. It's currently on the bench with a PC PSU 12v hooked to TP2, and 5v hooked to TP5. I'm trying to get the board to boot barebones, so only U6, U11, and U9 are installed.

I've stripped the components that we're corroded, sanded, neutralized, and replaced them with components from a big daddy's electronics kit, I've repaired all broken traces I could find and verified connectivity of each pin to it's uncorroded destination on each of the following sockets I replaced: U6, U7, U11, and U8.

I'm following the troubleshooting guide on pinrepair.com (or its foreign mirror) and it says I should have 5v on pin 40 of the U9 CPU. I have 2.13v which is definitely wrong. Additionally, I have 4.1v at U9 pin 5, which according to that guide should be 2.8v

Any Bally repair gurus out there? Posting pics just in case

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No, this board has never booted in my presence. I have several chips for U6 and U 11, but only one 6800 CPU. All are unknown however.

I'm double checking everything. I still get ~2v with U9 removed.

I'm all set. Turns out I had switched the Q1 and Q5 transistors. I reversed them, which fixed the voltage, I installed U9, 11, and 6 still had a solid LED, I switched the chip I had in U6 for another I had in better shape, and success! I have a flicker in my LED. now to continue through the troubleshooting steps. I'll be back if I get stuck again. Thanks!