[Jim - G4MEZ]

I'm fixing one of the above - the later silicon version with the daughter boards - for a friend of mine...

The original fault was a blown (gently) 1.6A DC fuse... Basic checks showed no really obvious issues and I powered up with a 500mA fuse and ammeters monitoring the output stage quiescent currents...

Basically, they were a bit high but not outrageously so. The amp works fine...

I set the quiescent currents as per the manual (30mA with no signal) and kept an eye on it, rechecking when the amp was nice and warm and had been playing at moderate volume for a while.

The right channel set fine with plenty of reserve travel on the setting pot (P5) but the left channel will only just set to 30mA with the pot on the end-stop...

I'm not happy with this and given the original fault was a popped fuse - perhaps from a bit of a runaway - and would like to see P5 set more or less mid-travel like the other channel.

Any suggestions for the most likely cause of this given that the amp works well and is clean with no distortion or any other obvious issues?

Thanks, any thoughts much appreciated...