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Denon DRA-335R receiver - Left speaker channel not working on speakers A/B.

Pepi9

Nov 3, 2017
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I just bought a used Denon DRA-335R receiver. The left speaker channel not working on speakers A/B. The right speaker channel is fine on both A/B. Any ideas? I am also trying to find a User Manual for this receiver. Thx
 

Pepi9

Nov 3, 2017
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Hi: Thank-you for the links to the manuals. Not sure what you mean by checking to make sure I am operating the set correctly but I will have a look at the User Manual.
 

shrtrnd

Jan 15, 2010
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I'll just start out of the gate with what I usually find wrong when this happens:
The speaker selection switch needs to be cleaned or replaced.
That may not be your problem and you may have to troubleshoot to find the electronics failure, ....
but I'd check my suggestion first.
(And don't forget to follow kellys_eye's suggestion that you have all the cables hooked-up correctly and that your receiver operator's manual set-up is correctly)
 

kellys_eye

Jun 25, 2010
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Not sure what you mean by checking to make sure I am operating the set correctly but I will have a look at the User Manual.
...as per @shrtrnd (above) the fault may be very easily rectified however there is always the possibility that a 'finger fault' may be the cause.

Whilst my first instinct is that the fault is 'genuine' there are protocols to follow in any fault finding process and the basics, that may sound 'teaching granny to suck eggs', is still valid!
 

Pepi9

Nov 3, 2017
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Hi:

Let me try this again as I appreciate the advice being provided and as such am confirming the steps I have taken below.

I am currently just trying to get the receiver to work in Tuner mode. Having said that, the only connections I have made are:

1. Speakers "A" - connected both left and right speaker, ensuring polarity is correct for both. (Tested Speakers "B" in same way.) I did confirm via another receiver that both speakers are in working condition.
2. FM Antenna connected.
3. Power cord plugged in.

Turning on the power and ensuring that I selected the "Tuner" mode, I located a stereo signal. Upon turning up the volume, I am only getting sound from my right speaker. I have ensured that the balance knob is in the centre position.

I have tried this with both "A" and "B" speaker buttons engaged and get sound from the right speaker only in both cases.

Is there an easy way to clean the speaker selection switches?

Thanks for your assistance.
 

kellys_eye

Jun 25, 2010
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Do both channels work in any other mode?

We need to isolate whether the fault is in one channel of the (stereo) FM receiver or in the amplifier itself. Do you have headphones (and a socket to use them in)? Try them if you have.

It is quite likely that one channel is defective - a common problem with 'second hand' equipment.

As with many electronic items like yours, repair is always possible but the final decision may be based on either your skill sets in managing the repair yourself (with our full assistance of course) or handing it over to a 'paid' repair service where the costs exceed the value.
 

duke37

Jan 9, 2011
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If you have a mono switch, then switching to mono will provide the same signal to both audio amplifiers.
If sound comes out of both sides, then the tuner (switch?) is faulty, the amplifiers,cables and speakers are OK.

If one side is still faulty, I would compare the amplifier voltages with the good side but this may be getting a bit deep for you.

Crossed with kellys_eye.
 

Pepi9

Nov 3, 2017
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Do both channels work in any other mode?

We need to isolate whether the fault is in one channel of the (stereo) FM receiver or in the amplifier itself. Do you have headphones (and a socket to use them in)? Try them if you have.

It is quite likely that one channel is defective - a common problem with 'second hand' equipment.

As with many electronic items like yours, repair is always possible but the final decision may be based on either your skill sets in managing the repair yourself (with our full assistance of course) or handing it over to a 'paid' repair service where the costs exceed the value.

Hi:

Plugging headphones into the headphone jack and I get the same result. Sound in the right ear, nothing in the left.

I would love to be able to fix this on my own, but not sure I own the proper tools to do so...suggestions on what I may need to do and what is required?
 

kellys_eye

Jun 25, 2010
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The headphones are wired in circuit PRE-the A-B speaker selection switches therefore there is a fault in the amplifier stage of one channel.

Page 14 of the technical manual shows how and where to measure the amplifier bias current and by following those instructions you may be able to isolate WHICH channel the fault is in.

Sadly, there are no independent fuses PER CHANNEL so repair is likely to be down to replacement of something in the output stage of one channel - the main power transistor(s) are the usual suspects. On a more positive note, these are widely available as replacements so fixing the unit seems more than probable.

The simplest test is to measure the DC value at the junction of the emitter resistors in the output stages (TR321/323 and TR322/324 - page 29). Given that the other channel works we can take it for granted that the DC positive and negative rails are ok.

If you are ok with basic multimeter operation and use and reasonably skilled with a soldering iron I see no reason why you cannot successfully fix the unit.
 

Pepi9

Nov 3, 2017
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Hi: Just wanted to follow up and thank you for the responses and suggestions for the non working left channel on the second hand Denon receiver I bought. Fortunately for me, I was able to return the receiver to the seller as I did not have any more time to spend on trying to repair it. I appreciate the time and support provided. Thank-You.
 
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