Blast city speaker and potentiometer problem

[Hilight]

Hi everyone !

I have a problem with my Blast City,
My left speaker and the sound potentiometer dosen't work.
I thought it was a capkit problem so yesterday I've made the entier PSU + Sound amp capkit.
Yesterday night after the capkit, still no sound on the left (tested both on mono and stereo) but the potentiometer worked.
This morning I wanted to test if it had changed or see where my speaker problem was coming from, but the potentiometer is already not working and there's still no sound on the left.
(I've plugged and unplugged the connector on the IO Board, maybe it was a bad connection but it wasn't. And good to know, both speakers are brand new.)

Have you ever had this problem?
Do you have any idea where it might be coming from?

Thank you,
Hilight

 

[Hilight]

Okay so I tested the continuity of the two wires from the two speakers, the right one perfect (since it's the one that works) but I only have continuity on one of the two pins on the right one so I'll have to follow the wire.

(I tested the continuity between pins L-10 of the JAMMA to the red and black AMP UP of the speakers).

The potentiometer still doesn't work though, so I'm going to try spraying the power supply connector with contact spray.

 

[Zepherino]

I recently had an issue with my volume control potentiometer in a NVS-4000 PSU that I picked up. What I ended up doing is throwing the potentiometer into a zip lock bag full of IPA, and putting that bag into my ultrasonic cleaner for about 10 mins (which was full of water, I normally do that to save on IPA... Also filling a ultrasonic cleaner with flammable liquid probably isn't a good idea anyways). I was afraid that the IPA might eat away the carbon conductor inside (I've seen this happen before ein other situations), but this has fixed my issues so far.