Yamaha RX-V650 AV Amp No Output From Front Right Speaker

[grannysmith]

Hi, I have a Yamaha RX-V650 amp with no output from the front right speaker. All other speakers are fine.

I have swapped the speaker and the cable.

I have also moved both front speakers from the "A" output to the "B" output, with the same results.

Can anyone point me in the right direction please?

I have searched for schematics online but cannot find any.

Thanks.

[Fidelity Audio]

I would check the muting relay , they have been known to carbon up on the contacts.
The left and right channel will share the same relay, so at least you know its switching.

Also check for dry joints on the output binding posts, these may have dry jointed on the pcb.

[XEAGLEKEEPER]

I have a service manual for a RX-V630/730. Does your unit have a test function on the remote? If so , connect all speakers ,power up unit and press the test button you should get a test tone from each speaker one at a time LF,RF,LR,RR,CTR AND SUB ( not necessarily in that order) .. If there is no test feature check to see if you dont just have a dirty source input connection or possibly dirty selector switch,or volume control.

[grannysmith]

Originally posted by rowemeister
I would check the muting relay , they have been known to carbon up on the contacts.
The left and right channel will share the same relay, so at least you know its switching.

Also check for dry joints on the output binding posts, these may have dry jointed on the pcb.

I've had it apart today, resoldered the joints on the output binding posts.

How do I check the relay? I was going to replace it but can't locate where to buy one from.

Couldn't see anything obviously faulty (burnt etc.)

[grannysmith]

Originally posted by XEAGLEKEEPER
I have a service manual for a RX-V630/730. Does your unit have a test function on the remote? If so , connect all speakers ,power up unit and press the test button you should get a test tone from each speaker one at a time LF,RF,LR,RR,CTR AND SUB ( not necessarily in that order) .. If there is no test feature check to see if you dont just have a dirty source input connection or possibly dirty selector switch,or volume control.

Yes, there is a test function, there's no test tone from the front right, a test tone is audible on all of the others.

The auto setup also fails saying no front right speaker.

Are there any specific parts in your service manual that you think I should check please? I'm hoping the rx-v650 is quite similar!

[XEAGLEKEEPER]

o.k. on the v730/630 Q7-Q10 should have around +/- 44-45 vdc on the collectors these are the amp output transisters for right front . should be 1.0vdc or less on the emitters and bases. also relay 102 is for left&right front ( RLY102).

[XEAGLEKEEPER]

I purchased my service manual at Yamaha.com.
Cheers Dave

[grannysmith]

Originally posted by XEAGLEKEEPER
o.k. on the v730/630 Q7-Q10 should have around +/- 44-45 vdc on the collectors these are the amp output transisters for right front . should be 1.0vdc or less on the emitters and bases. also relay 102 is for left&right front ( RLY102).

Thanks very much, I'll take a look.

Thanks for the service manual info too.

[mastertech]

"The auto setup also fails saying no front right speaker."


sounds like syscon fault is this a receiver?

[grannysmith]

Thanks for everybody's help, I've finally got around to taking it apart again and think I've found the problem by measuring the voltages on each component in the circuit (working back from the posts) and comparing to the equivalent component on the front left circuit with the help of the circuit diagram. I used a mono sound source.

There seems to be a faulty transistor (hugely different readings), the problem is I cannot find an equivalent anywhere.

The original transistor is a 2N5551C-AT but I can only find a 2N5551. The supplier that sells it (www.maplins.co.uk part no. UL36P) cannot find any spec sheets for the original either.

Can anybody help with regard to the suitability please?

Many thanks,

Alan.