Transistor Hi-Fi amp - fixed... but how?

[Buddha's Guitar Tech]

i know little of transistors.

Poking around a friend's amp for a bit of a challenge, i noticed what i thought might be an odd voltage. i figured the two trimmers should be on the same voltage, as i was going on the theory that somewhere, a transistor (in the left channel) was out of bias.

All i did was touch one leg of Q603 with my DMM probe and AC/DC resumed in stereo. After a wiggle, nothing else to report. It's like electron magic.

Can anyone tell me what i did? More importantly, what i might do next?

[img:431:640]https://lh3.googleusercontent.com/-FegX ... G_1860.JPG[/img]

[passfan]

double post

[passfan]

Cold solder joint on bottom of board ? More than likely will happen again, especially after continual use for extended periods of time. Access the solder side and reflow the connection.

[Structo]

You probably know this but be careful of applying too much heat to the transistors if you touch them up.
If there is room, use a heat sink clip on each lead before soldering.

[Buddha's Guitar Tech]

You probably know this but be careful of applying too much heat to the transistors if you touch them up.
If there is room, use a heat sink clip on each lead before soldering.

i do know this, but thanks for reminding me. There are a million things we know - sometimes we just forget!

[Aurora]

Had a voltage reg in a fixed base VHF transceiver doing just that. After a power break, it had to be "kick started" with the DVM probes.
Very certain it was the transistor itself, - problem disappeared when I changed the bugger...( resoldering was the first thing I tried..)

[Buddha's Guitar Tech]

Ah, yes, sounds like my thing. I only touched it - very very gently. Maybe it just needed a little electron arrangement?