5.1 surround system always at max volume.

[ACEFIGHTER8]

My teacher has a Genius SW HF5.1 6000 surround system that has been dead for 4 years. I took it to repair, put new capacitors but when I turn it on and put it on DVD, TV or AUX, the speakers start making sound at max volume. I have no ideea what to do. I have the diagram of the circuits but don't have the expertise to diagnose that level of electronics. If any of you can help, it would be awesome.

 

P.S. The first photo has the Subwoofer pcb, the second the amps for the rest and the third has a general view. Also to note: there is a control interface on the front with a spinning dial for volume that is not firmly fixed. You have to press it to change the volume easily. The pcb with the front commands has a chip that I think is a preamp so maybe that can be the issue?

[VoidX]

Genius has a long history of easily breaking potentiometers, which is usually fixed by (at least I fix them by) bypassing them entirely, killing volume control in the process. I just stopped caring and put it on shift + mouse scroll.

[ACEFIGHTER8]

And how do I do that? There is a volume control wheel on the front and an IC above. Maybe that is the problem?