[sdiy] strange PCB faults, was:OTA question

[Ingo Debus]

Am 17.09.2010 um 14:51 schrieb Harry Bissell:

> seriously, was it a copper clad perfboard ?  Sometimes there are  
> faults in copper-clad
> where there are subterranian short circuits (contamination in the  
> laminate that can
> join unknown circuit points).

Recently I tried (in vain) to fix a stereo amp, whose PCB in some  
places obviously was soaked with something conductive. The stains  
were visible, and when I placed the test leads of my ohmmeter on the  
PCB it showed a few megohms. Cleaning didn't help much.
Could this come from a leaking electrolytic? Do lytics leak that much?

This amp was oscillating, and I couldn't fix it. Probably unwanted  
feedback paths all over the place.

Ingo