API 550b

[Siegfried Meier]

Hey guys!

I have a 550b EQ here that has no effect in the top end last 2 boost positions - so the +9 and the +12 positions do nothing. Does anyone know what might cause something like this?

Any advice much appreciated!
Thanks,
Sig

 

[john12ax7]

Sounds like the switching contract not making connection. Could be the switch itself or poor solder joint on the switch or adjoining parts.

 

[pucho812]

test continuity on the switch and adjoining circuitry.