Behringer. No sane person repairs these. At about $200 brand new and $40-50 used, why would you?
Oh why not. Let’s open it up.
This one has a bad hum. To get to the circuit boards and internal power supply, you have to disassemble everything. And they mean everything. Every single knob and screw has to come out.
This one left scorch marks on the inside of the cabinet.
And here’s the culprit. One bad capacitor in the -15V supply. That failure took out the 7915 -15V regulator, both in spectacular fashion. Cheap no-name capacitor, probably from a third-tier Chinese supplier. You get what you pay for.
As long as the thing is open, we’ll change all the power supply caps. These mixers are peppered with polarized electrolytic caps in the signal path. Again- you get what you pay for.
About an hour to disassemble and reassemble. Another half hour to clean all the switches and pots, as they all have audio passing through them. You get what you…well you know. Less than $5 in parts. Back to the owner it goes!