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Marantz 2216 troubleshooting RH Channel INOP

These are the components i have change up to now:

R716
R734
C704
C706
C708
C710
C722
C724
M702
H704
H706
H708
H712
H714

Could resistors R736/R738 be the guilty of the trouble? i see that in LH CH both have been changed. The measures with the DMM are ok, but i don't know where to continue.

I'm lost, really lost...
 
Those are the emitter resistors. They can cause all kinds of trouble. But if they measure close to spec, I doubt if they are the problem. How do your DC measurements around the transistors compare to the hi-res schematic?
 
Steven Tate said:
Those are the emitter resistors. They can cause all kinds of trouble. But if they measure close to spec, I doubt if they are the problem. How do your DC measurements around the transistors compare to the hi-res schematic?
Click to expand...
I just measured DC on all transistors and all of them are ok. Also compared with the transistors of LH CH i have the same measures.

It's crazy!
 
Sorry, I’m hoping someone else will look at this with new eyes. At this point, the problem is distorted right channel and bias won’t set to spec. Is that right?
 
Steven Tate said:
Sorry, I’m hoping someone else will look at this with new eyes. At this point, the problem is distorted right channel and bias won’t set to spec. Is that right?
Click to expand...
Exactly Steven. I recovered the sound on RH CH, but it sounds distorded and not able to regulate the BIAS (0mV).
 
You have changed so many potential culprits, it hard to know where to turn. You probably have already checked most of them, but I would be testing every resistor, diode and transistor. Usually there is one bad hidden component somewhere wreaking havoc with the circuit. Of course, triple check for cold solder joints, solder bridges, etc. Freeze spray on transistors or tapping on components, listening for a change in sound are also worth doing.
 
Steven Tate said:
You have changed so many potential culprits, it hard to know where to turn. You probably have already checked most of them, but I would be testing every resistor, diode and transistor. Usually there is one bad hidden component somewhere wreaking havoc with the circuit. Of course, triple check for cold solder joints, solder bridges, etc. Freeze spray on transistors or tapping on components, listening for a change in sound are also worth doing.
Click to expand...
R736 and R738 replaced. Also C720 replaced and no changes. Cold solder joints checked, freeze spray used on transistors and tapped all of them. Distorded sound on RH CH continues. Here you can see components replaced highlited.

upload_2020-12-17_14-17-25.png
 
Hmmm. I would say try swapping the inputs from the preamp to see if the distortion swaps sides. But since you can’t set bias on the right side, it’s bound to be the amp. I wonder about M702 - mainly because I don’t know much about those in-circuit lamps. But I wonder if it could have different resistance characteristics from the original. Maybe you could switch M701 and M702 to rule that out? Hoping for some others to chime in with ideas.
 
Steven Tate said:
Hmmm. I would say try swapping the inputs from the preamp to see if the distortion swaps sides. But since you can’t set bias on the right side, it’s bound to be the amp. I wonder about M702 - mainly because I don’t know much about those in-circuit lamps. But I wonder if it could have different resistance characteristics from the original. Maybe you could switch M701 and M702 to rule that out? Hoping for some others to chime in with ideas.
Click to expand...
I installed the new lamps on both CH and LH CH sounds fine. Lamps discarded.
 
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