Juno 106 - suddenly no sound on any output

Hey people! New here and really glad I found this place. Maybe someone can help me out.

I have a Juno 106 which had a faulty voice chip. I removed the chip and installed a DIL32 socket in its place. Used an acetone bath to remove the coating from the chip and put it back. In voice test mode it worked correctly. However, I noticed after playing for a few minutes, that the sound suddenly drops out, and the synth is mute from that moment on.

Now, just to be safe, I removed the problematic voice chip and tried to start the synth without it. Everything worked correctly, and the sound dropping out wasn’t happening any more.

At that point I decided to leave it like that for now, and went to close the top cover and screw everything in place. From that moment on, there was no sound coming out.

I read online that sometimes giving the HML switch on the back a wiggle could solve that issue, and I tried that, and wouldn’t you know it, the sound was back.

But, some moments later, it was gone again, and this time I can’t get it back whatever I do.

I’ve checked all the caps visually, on all the boards, none seem blown, ICs don’t look fried, and all the cables are seated properly and tightly. I have no idea what this might be, and how to solve it, so any help would be greatly appreciated.

Cheers!

[EDIT] Forgot to add, besides no audio output, the display, LEDs, selecting patches and all, look like they work properly.