Quad 34 no output on left channel

After doing some research, it's probably one of the opamps that's faulty. Questions:

- Is IC7 or IC27 the most likely culprit ?

- Does it make sense just to replace 1 IC with e.g. OPA134 or OPA2134 resulting in differences in sound between the left and right channel or should I than just replace all Opamps in both channels ?

The 34 was revised by Quad Revisie in 2014 where they replaced all caps and fixed the balance pot meter.

Thx for your comments. I started to do some measuring. All voltages are just fine. I couldn't see a bad joint. If it was a bad joint, than I should at least hear some sound on the channel I guess, be it a bad or noisy sound. Now it looks like the channel is dead.

Measuring the caps on the board is difficult. All elcaps have been replaced a few years ago. Shoudl I check all other caps ? It's not likely they would die.

According to a document in the download section it refers to IC17 as a possible cause.

It could be IC17 or anything to the left of IC22, the common point where the M (mono) logic level is applied between the channels If it was IC17 it might also affect the F1/F2/Slope operation: worth checking if they are out.

My money is still on a dry joint ;-) Have a good look at the six terminals of the volume control, looking for little rings around the centre terminal. If found, remove all solder and redo completely. Ditto the balance control. In fact it mightbe the balance control, in which case you could be in for a bit of fun disassembly.