Sega Genesis audio crackle

[bmoc]

Sounds like you're describing "dirty power sound" which is an issue I run into during mobile DJing sometimes. I can usually trace it to a grounding issue. If the power supply is not grounded properly, it can cause a "dirty" sound in the speakers. High power speakers are more susceptible to this than low power speakers.

I'm thinking this as well. An easy test would be to get or borrow a ground loop isolator. They aren't very expensive. If a ground loop isolator gets rid of the noise then it is very likely the power supply or power outlet.

[Sarge]

I'll give that a go, then. I've also uploaded a video, to give an idea what it sounds like. The crackle is right at the beginning, but you can hear the low-level audio hiss throughout. (There's a little from my phone, but it's mostly from the TV speaker.)

https://www.youtube.com/watch?v=ZNide4z0EQE

[Sarge]

Well, quick update: definitely not a ground loop. The isolator did nothing. It's either right from the chip, or perhaps a sketchy surface-mount cap on that path. Reckon I'll be performing the S-Video mod on a different Genesis in that case. Too bad, too, given that I recapped this one.

[strangenova]

I know you said you recapped this one, but I had a genesis with the same bad audio problems and I got it recapped and it solved my problem. Maybe check the recap job you did.

[Sarge]

I just find it odd that, despite swapping every electrolytic cap, the behavior is identical to how it started. This indicates to me that it's not those caps that were the problem. I'll do some checking, but I'm pretty sure I've isolated it to one section of the board, so I'll debug that when I get a chance.