Rotel RA-930AX One channel out No sound

mrfix90 · 31st August 2009, 09:03 AM

One channel perfectly working. Another channel I can hear sound very faint only if I tunr the volume really high. Do I have some kind of bad transistor or bad capacitor?

I am sure the pots are perfect.

Please help me if anybody has any idea.

Mooly · 31st August 2009, 10:33 AM

Cracked print somewhere ? might be favourite, or cracked track on a pot.
More info needed.
Are all inputs affected ?
A quick test is to (very carefully) buzz the inputs to the power amp if you have no test equipment.

mrfix90 · 2nd September 2009, 05:44 AM

Quote:

Originally Posted by Mooly

Cracked print somewhere ? might be favourite, or cracked track on a pot.
More info needed.
Are all inputs affected ?
A quick test is to (very carefully) buzz the inputs to the power amp if you have no test equipment.

mrfix90 · 2nd September 2009, 05:45 AM

I have digital multimeter. I tried to buzz but no luck. I can hear very faint sound from one channel if I turn the volume very high. Only problem with one channel.

Mooly · 2nd September 2009, 05:49 AM

Are you "buzzing" the inputs to the power amp on the PCB itself ?

mrfix90 · 2nd September 2009, 05:51 AM

yes buzzed the PCB ..no luck..

Mooly · 2nd September 2009, 05:58 AM

Does sound like a "fault" as such then on that channel.
Withhout knowing how experienced you are it's difficult to suggest anything.
If you have only a multimeter I would compare the DC output voltages of the amp with no signal. Should be zero. And then measure the quiescent current of each channel (volt drop over emmiter resistors) and compare good and bad channels. If that shows nothing then it sounds like an "AC" fault... a cap, broken print etc.

31st August 2009, 09:03 AM	#1
mrfix90 diyAudio Member Join Date: Mar 2009	Rotel RA-930AX One channel out No sound One channel perfectly working. Another channel I can hear sound very faint only if I tunr the volume really high. Do I have some kind of bad transistor or bad capacitor? I am sure the pots are perfect. Please help me if anybody has any idea.

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31st August 2009, 10:33 AM	#2
Mooly diyAudio Moderator Join Date: Sep 2007	Cracked print somewhere ? might be favourite, or cracked track on a pot. More info needed. Are all inputs affected ? A quick test is to (very carefully) buzz the inputs to the power amp if you have no test equipment.

2nd September 2009, 05:45 AM	#4
mrfix90 diyAudio Member Join Date: Mar 2009	I have digital multimeter. I tried to buzz but no luck. I can hear very faint sound from one channel if I turn the volume very high. Only problem with one channel.

2nd September 2009, 05:49 AM	#5
Mooly diyAudio Moderator Join Date: Sep 2007	Are you "buzzing" the inputs to the power amp on the PCB itself ?

2nd September 2009, 05:51 AM	#6
mrfix90 diyAudio Member Join Date: Mar 2009	yes buzzed the PCB ..no luck..

2nd September 2009, 05:58 AM	#7
Mooly diyAudio Moderator Join Date: Sep 2007	Does sound like a "fault" as such then on that channel. Withhout knowing how experienced you are it's difficult to suggest anything. If you have only a multimeter I would compare the DC output voltages of the amp with no signal. Should be zero. And then measure the quiescent current of each channel (volt drop over emmiter resistors) and compare good and bad channels. If that shows nothing then it sounds like an "AC" fault... a cap, broken print etc.