Playchoice-10 - Single Monitor - Bad sound (very low volume)

[ebo0763]

I have this single monitor Playchoice-10 pcb with a very weak sound output. All contacts are tested good and my other pcbs work well on the cab. So I thought I could check the sound section. Pins 1 and 2 of the CPU outputs the sound and pin 20 on the main pcb edge connector outputs sound, I'm trying to figure out what's the the sound circuit by checking what's between CPU pins 1+2 and the edge connector pin 20. Trying to find which part is bad...

What I did:
- Replaced the CPU and tested each pin connection
- Replaced capacitors C37, C24 and C30

Next, I plan to:
- Replace capacitor C32
- Replace chip LM3900N
- Replace chip TC4066BP

Any suggestions? Am I on the right track?

[ebo0763]

Here's a video update:

[mgb]

I may be off or missed something but why do you suspect the low audio issue in the main game board and not the audio board by the monitor?

[SlammedNiss]

I may be off or missed something but why do you suspect the low audio issue in the main game board and not the audio board by the monitor?

he mentioned other pcb's worked fine in the cab.

[mgb]

Oops. I guess I missed that