I've got a soft-modded machine, and I've noticed when I play things in my Genesis or SNES emulator, the left audio channel sounds a little scratchy once in a blue moon, and rather frequently it will just cut out entirely. Earthworm Jim 2 for Genesis for example, when a homing missile explodes and makes its loud bang noise, half the time the left channel will just drop entirely.
If I go back to the dashboard, the left channel is still dead.
If I unplug the AV cable (using 1st party component leads) and plug it back in a couple times, I'll hear a "pop" from the left speaker and then the channel works alright again for a given length of time but will usually drop out again at some point
Is this common to any degree? Is there anything specific I should be looking for on the board to fix/replace? I'm kinda bummed 'cause I'm in college and this machine functions as a brief retreat, so I'd kinda like it to not me failing

Any help would be appreciated; I do have most of my tools up here too, along with a soldering iron.