One of my stereo out channels is stuck ridiculouly loud

Hi all, I've had my 60 for a few years now but it had this issue when I bought it. One side of my stereo output is crazy loud (way higher than the other side on max volume) and it doesn't change volume when I turn the volume knob. So basically the stereo out is unusable. Other outputs are all good.
Has anyone encountered this? I opened it up but dunno wtf I'm doing so put it back together again.

Hi mate, how are you.
Do you know the technical history of the machine?
If anything already has been fixed or changed to it? If it’s only the L or R channel that’s doing this in playback mode and not the rest of the channels an technician could be able to adres this quite well, but it does sound like u need some help from an technician , if so and you don’t know the technical history, a recap would be a good starting point as wel. The machines are getting older. Be gentle on them

Greets
Danny