I was recently troubleshooting some sound issues on my Embryon game (Bally '81), and unfortunately in doing so I have made things worse. Or maybe it's fortunate, since now I get to learn what I did wrong

In either case, here is a brief history...

I obtained this game about two months ago. It is my first pin, and I really don't have any experience or knowledge when it comes to maintaining one. I am an experienced solderer, but that's about the extent of my relevant skill set.

The game was working pretty well when I received it. It had some cabinet damage, so I disassembled it to repair and repaint the cabinet/backbox.

The biggest updates/changes I made to the machine were:

1) Replaced the original speaker (which I stuck my thumb through) with the appropriate Pinball Pro speaker. Also added a Molex connector to the speaker wires.

2) Replaced the ground braid throughout the cabinet/backbox. I removed the original ground braid as I went along installing the new one, to make sure I replaced it in the same spot.

3) Replaced the original damaged power cord as well as the line filter/varistor.

4) Replaced the Power Module with a new one.

I have many pictures, if needed.

The machine also came with a replacement MPU from nvram.weebly.com

So all that being said...

After I got the game reassembled, everything was working normally. With one exception: the Speech volume was very very quiet, even with the volume turned all the way up on the speech pot and on the main coin door. The game Sound volume was normal volume, and showed no issues. Only the Speech volume was quiet. This was not happening before I took the machine apart.

I tried turning the two pots back and forth a few times on the S&T (AS-2518-61A), but no change. Shortly after that, I noticed the underlying "heartbeat" sound effect in the game went missing. The other game sounds were still playing normally, but the heartbeat sound was gone. And the Speech was still very very quiet.

In a moment of genius, I decided to swap the two pots on the S&T and see if that would give any clues. Nope. No change.

Then, I went and made things worse. I was trying to get some readings off of the amp, and managed to touch a lead of my DMM to something bad and heard a nice -POP-, and now...no sounds at all, whatsoever.

To the best of my recollection, I must have touched a lead of my DMM to the heatsink shroud around the amp? But there wasn't another lead attached to anything at that point, so I'm not really sure what I did. But the only thing I was nosing around in with the DMM was the amp.

Upon turning the machine power on now, the S&T shows me 4 (out of the normal 5) LED flashes.

Might I have blown the amp? I didn't notice any fuses or anything blown.

I'm a total novice, so not really sure where else to start. Thanks for your help!

Thanks for the feedback. I apologize I didn't fully explain in my original post...but the S&T was updated previously (before I bought it). I will include some images here, but it looks like the caps were replaced, and has replacement volume pots as well.

Front
Back

Appreciate the input. I did check voltages, and they seemed in line. TP3 was little high. The readings I took were:

TP2 = (-)5 VDC (I'm not sure why this showed negative, seems my DMM displays opposite what it should be. Perhaps I have it set wrong.)
TP3 = (-)14.2 VDC
TP4 = (+)5 VDC

I can replace those caps and the 6821 PIA. I would assume I need to keep the same jumper to that chip that is on the back?

Right on.

I think my plan will be to replace the PIA, the caps noted, and the amp, since I think I may have fried it. That's within my skill set. If none of those help...I will have to call in a pro Any other tips or suggestions welcomed.