Sound Crackles

Hi, my MV-1FZS is having some sound issues. It makes seemingly random crackling sounds (in the audio channel, not physical crackling) while running. Sometimes they go away, sometimes they are quite bad. This is not cartridge related as far as I can tell because all my carts and the slot are very clean and it never happened before. Is it is also possible this is some kind of harness wiring problem? Because I did wire the harness myself. Any suggestions, etc would be helpful. Thanks!

bump. Anyone know what's going on?

Tried another speaker?

Does moving the speaker wires seem to have any effect on the static?

Dirty volume control, bad speaker, problems with the 12v line, dirty carts, dirty slot, bad caps...

Well, I ruled out the speaker, and also the slot and carts. How would I test the 12 volt line, or the volume control or locate bad caps? Thanks!

It's unlikely to be a cap problem.

Most likely a boogered trace or slot problem. If one of the data lines is messed up going to the YM2610 from the slot then it'll sound like that. Caps usually don't make staticky sounds.

I tested the 12v line, seems clean. I still don't understand how it would be a slot problem, the thing is very clean. I guess I'll check it out again and make sure. If I were to look for trace damage where would I want to look? And you're probably right about the YM2610 being the issue here, because all the other sounds work, and it's the FM channel that sounds crackly.

If you had a high impedance audio probe then you could check the audio signals right of the Yamaha DAC chip and immediately isolate the noise to either the digital section or the amplifier section of the sound subsystem.

RJ

So I poked around a bit more closely this time. I actually removed the board all the way from the cab and did some close inspection. I saw one little tiny spot of corrosion near the YM chip on the backside of the board which was touching a couple of pins. I cleaned that up, and then decided to do one last inspection of the harness. Seemed to be OK, and the ohmmeter said it was all OK, but after hooking up it didn't fix the problem. So I looked around one more time to see if I had missed anything obvious and noticed a spot where the harness had gotten pinched- the 12v line to be precise. After replacing the wire it just started working again. Now I am just wondering what was wrong with my ohmmeter to say the wire was OK.