Behringer DDX3216 Repair Help

[Fugue]

Hi - glad I found this forum! I have a 14 yr old DDX3216 that needs help. With no inputs/outputs connected, ALL meters are maxed out with an accompanying screaming noise coming through every output line. No change whatever the faders do. Any advice appreciated...

[S2udio]

Start with recapping the PSU, its a simple must do for these mixers before going any further, sounds like a +/- 17v rail low opr missing.
Check out all the other DDX threads here, you will learn a lot.