First post and a recent hobbyist of tinkering and repairing amps. please bear with me through any dumb questions.

I have a Crate DX-112 amp that has intermittent loud crackling.
this is a digital amp and the chasis has been inspected with no obvious bad caps. I suspected it could be a dirty pot and used deox it on the pots and inputs which I thought had fixed it but it hasn't.

What else could cause this? Could this be a sign of a speaker going bad?