[sdiy] strange analog problem (mixer console)

[Ingo Debus]

Nils Pipenbrinck wrote:
> However, I can "activate" the right channel again by running a hot signal
> into it (9V battery does this job). It makes "plopp" and then the right
> channel comes to life again. It'll also stay alive as long as some signal is
> present (usual audio, not the 9V). I'm still happy with the mixer. After
> resurection it sounds as it always did. Just the "kick in the butt"
> procedure is anoying.
> 
> Btw, if I stop using it for a while (no signal at the inputs, but chords
> connected) the right channel will go dead again.

I had a similar problem with my old stereo amp. This was a kit I had 
assembled when I had been quite young and not good at all at 
soldering. Usually I had just to turn up the volume for a moment to 
fix the problem. One day I got tired of this and I resoldered 
everything. The amp was full of bad solder joints. Since then it 
worked fine. AFAIR I didn't replace any component.

I have no idea why a bad solder joint can be made conductive again for 
a while with a higher voltage or current. Anyone?

Ingo