Orion HP 4800 help

Hi everyone


Trying to troubleshoot my Orion HP 4800. It powers on and works however the rear ch3/4 speaker output is very low. Gain has to be turned up almost all the way and even then it is very hushed. I assume it is some sort of fault.

When connecting the 3/4 channel to 1/2 channel speakers play nice and loud.

ESP light is constantly on.