Mackie Big Knob Repair

[Siegfried Meier]

Hey guys,

So a client gave me his big knob for free as it had a damaged Speaker B switch.  I thought, hey I'll repair this easily enough...

Well, I get in there, and it appears he's already attempted to remove the switch...badly.  So I cleaned it all up and installed the new switch.  Now, I get both left and rights from Speaker A...but both Speaker B and Speaker C outs have no right side...just left...

I've tried to trace what I can without a schematic, but I can't for the life of me figure out or see what's different  about A vs B and C...

Any thoughts much appreciated.
Thanks!
Sig

 

[scott2000]

I found this....haven't looked at it though......

 

[scott2000]

I guess the power supply here

 

[Siegfried Meier]

Very much appreciated.  A trace has been damaged on the top of the board, and it's some sort of complex routing that I can't figure out...now that the new switch has been soldered over top, I can't even see where it was supposed to go. 

I even opened up a 2nd fully working unit, but I can't understand how those switches route audio at all so it makes no sense to me...

I think she's ready for the e-waste bin...