Gallien Krueger MB 150S-112 Cutting Out

[cudabake]

I have a GK MB150S combo amp that has been stored for a while. When I tried using it recently, the speaker has no sound after I turn the power on. I confirmed it powers up as the green light is on. After maybe 20 times of turning it off and on, it sometimes works and has sound.

Anyone know what the problem is? I am trying to avoid going to the repair shop if I can fix it myself. Thanks.

 

[B-string]

Corroded effects return jack is first thing that comes to mind. Run a loop cable from effects send to return, if it now works, clean the effects return jack (and all others).