Stereo Receiver Right Channel Distortion.

[Rick79]

OK, so you could replace the resistor, but it will most likely get hot and burn out again. (or there may have been a short with Q210R, and it has magically survived).

If it does, then we can search nearby for the faulty component.

Did anyone short the speaker terminals by accident? Or play something extremely loud? If we know what happened just before you noticed the fault, it could be useful in figuring out what went wrong.

My aunt was using it at the time and I believe the speaker wires probably touched because I had seen them barely hanging on the terminals behind the speakers.
So does the resistor have to be a specific 82 ohm resistor?

 

[(*steve*)]

Well, it is an indication of the sort of overload that could cause an output transistor to fail. They normally fail short circuit, and that may have lead to the failure of this resistor.

I also didn't notice a discoloration of the board that might indicate the resistor was running very hot for a long period of time.

Possibly (probably?) that resistor suddenly let out a small puff of smoke a fraction of a second after the transistor failed.

We need to check the output transistor first to find the failure point.

Also, you mentioned that the sound is fine using headphones. Headphones typically take a signal from before the main output stage.

Try to trace the wires from the failed channel's output connectors back to a transistor on a heatsink. It may not be direct, so you may need to follow stuff on the PCB too.

 

[(*steve*)]

It probably should be an 82Ω resistor, don't worry that is a common value. I'm not sure what power rating you should use. Try to get a metal film resistor of the similar (or larger) dimensions.

Also, follow the recommendations you've received earlier in this thread about things to do.

 

[tt1987]

Have you measured the dc output voltage of the channel in question with respect to 0V assuming it has a split supply.

I have tested and repaired successfully

 

[Martaine2005]

Would you kindly explain what the prroblem was and how you came to that conclusion before successfully repairing it?.
Trying to help in ‘text’ version over the internet is hard enough, we don’t have the unit in front of us.
It would be appreciated and could help somebody else in future with the same unit.

Martin

 

[WHONOES]

Well done. As requested by Martin, could you tell us what the fault was and how you fixed it as it may help others.

 

[Rick79]

Would you kindly explain what the prroblem was and how you came to that conclusion before successfully repairing it?.
Trying to help in ‘text’ version over the internet is hard enough, we don’t have the unit in front of us.
It would be appreciated and could help somebody else in future with the same unit.

Martin

I don't know who that is that replied saying "I have tested and repaired successfully" they probably commented on the wrong thread. But today I have replaced the burnt open resistor with a new one and now it's fixed.

 

[Rick79]

Well done. As requested by Martin, could you tell us what the fault was and how you fixed it as it may help others.

R223R was burnt and I replaced it with a new one and that fixed the distortion problem. Thank all of you guys for your help. Next time I will first inspect all the components more closely.

 

[rdimmmell]

Sorry to pick up on this thread so late. I have a AVR20ii with the same problem would the fix for the AVR 10 be similar for mine?