| 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. |
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| 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. |
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| 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.
:smash: |
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| grannysmith |
| quote: | 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.) |
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| grannysmith |
| quote: | 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.
:smash: |
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! |
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| 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).:) |
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| XEAGLEKEEPER |
I purchased my service manual at Yamaha.com.
Cheers Dave |
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| grannysmith |
| quote: | 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. |
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| mastertech |
"The auto setup also fails saying no front right speaker."
sounds like syscon fault is this a receiver? |
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| 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. |
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| XEAGLEKEEPER |
Hello Granny
The transistor in question should do fine provided it is a TO-92 package. If you still need further assurance go to www.mouser.com and search for 2N5551 there are several choices with techdata. |
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| grannysmith |
| quote: | Originally posted by XEAGLEKEEPER
Hello Granny
The transistor in question should do fine provided it is a TO-92 package. If you still need further assurance go to www.mouser.com and search for 2N5551 there are several choices with techdata. |
Thank you very much for the info and taking the time to help me out. I will post an update when I have replaced the transistor.
Many thanks. |
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| XEAGLEKEEPER |
| I looked up a specsheet at www.mouser.com for the 2n5551 they have 3 or 4 different mouser part #'s but all have the same specs. A TO-92 case style 160v. I would have no problem subbing the 2N5551. |
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| mrshow4u |
| Yamaha+2N****??:bigeyes: Does it really call for that in the service manual?? That's a bit unusual for Yamaha. They usually stuck with Japanese numbered (2S, 2SB, 2SC, 2SD, 2SJ, 2SK, etc) parts. I'm not trying to cause a problem, but it looks like things have changed for Yamaha. |
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| grannysmith |
| quote: | Originally posted by mrshow4u
Yamaha+2N****??:bigeyes: Does it really call for that in the service manual?? That's a bit unusual for Yamaha. They usually stuck with Japanese numbered (2S, 2SB, 2SC, 2SD, 2SJ, 2SK, etc) parts. I'm not trying to cause a problem, but it looks like things have changed for Yamaha. |
Yes, that's what's listed in the service manual. |
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| clem_o |
A glowing example of globalization. China-made 2N5551 cheaper than almost anything else you can find... except maybe a china-made 2N2222...
:-)
Cheers! |
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| Leolabs |
| quote: | Originally posted by grannysmith
The original transistor is a 2N5551C-AT but I can only find a 2N5551.
Can anybody help with regard to the suitability please?
Many thanks,
Alan. |
If the transistor is operated as differential amp,then replace both. |
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| grannysmith |
OK, replacing the transistor didn't make any difference, so I need to supply a few more details:
The speakers that are normally connected are 6 ohm.
The speakers that I have been using for testing it are 8 ohm.
When the 8ohm speakers are connected there is sound from both channels but the faulty channel is distorted.
If the original speakers are connected then there is only the occasional noise from the faulty channel.
Does this help at all?
Thanks. |
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| XEAGLEKEEPER |
Hello Granny
On the rear of my HTR 5560 there is a switch that must be in the 8 ohm or 6ohm position (depending on speakers used )and should not be changed from 6or8 with power applied.This may not be your problem but It won't cost anything to investigate. |
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| grannysmith |
| quote: | Originally posted by XEAGLEKEEPER
Hello Granny
On the rear of my HTR 5560 there is a switch that must be in the 8 ohm or 6ohm position (depending on speakers used )and should not be changed from 6or8 with power applied.This may not be your problem but It won't cost anything to investigate. |
There's a switch on my amp also. I can confirm that it was set correctly (with the power off) for each set of speakers. |
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| mrshow4u |
I beleive all that switch is a secondary winding voltage selector. They give it a little less rail, for the low impedance setting. I can't say for sure on this particular Yamaha. I think that impedance switch will affect all channels wired on that power transformer.
Do you lose the right channel when the surround DSP is off? in "Direct" or "Stereo" mode? In other words, is the problem nailed down to a line stage or power amp stage problem? |
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| grannysmith |
| quote: | Originally posted by mrshow4u
Do you lose the right channel when the surround DSP is off? in "Direct" or "Stereo" mode? In other words, is the problem nailed down to a line stage or power amp stage problem? |
Just to clarify the situation so far, with my original surround speakers (6ohm) there was no output from the front right channel apart from the occasional sizzle. (Hence the title of the thread - No output).
However, when I connected some 8ohm speakers for testing purposes I found that I have normal sound from the left front channel and *distorted* sound from the right front channel.
This distortion occurs even when the DSP surround is off and the direct 2 ch stereo setting is used.
With regard to the voltages on the schematics, are these steady voltages that should be present with no signal going through the amp? i.e. No input present?
I look forward to any help anyone can give me. |
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| mrshow4u |
| This is sounding more and more like a "dirty" speaker relay. Has that possibility been looked at? |
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| grannysmith |
| quote: | Originally posted by mrshow4u
This is sounding more and more like a "dirty" speaker relay. Has that possibility been looked at? |
I'm going to look at the relays at the weekend, I'll do a swap with the other channel.
Thanks. |
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| grannysmith |
| quote: | Originally posted by grannysmith
I'm going to look at the relays at the weekend, I'll do a swap with the other channel.
Thanks. |
OK, so I swapped over the left and right relays and the problem remains on the right.
But now there is no sound from the right speaker for a few seconds after the left speaker comes on. The right speaker fades in and is then distorted.
Any more ideas please? |
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| mrshow4u |
| This is sounding not like right and left relays, but more like "Speaker A" and "Speaker B" relay's. .......AND that the right channel is bad on both. Try this: when the Right speaker is distorting, tap the top of the relay and see if the sound improves. If it does, the relay sounds "crusty". |
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| grannysmith |
| quote: | Originally posted by mrshow4u
This is sounding not like right and left relays, but more like "Speaker A" and "Speaker B" relay's. .......AND that the right channel is bad on both. Try this: when the Right speaker is distorting, tap the top of the relay and see if the sound improves. If it does, the relay sounds "crusty". |
But the problem exists on both A and B, could this still be the problem? |
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| mrshow4u |
Grannysmith wrote:| quote: | | But the problem exists on both A and B, could this still be the problem? |
It could be the problem, It could be something different too. So the problem is common to speaker A or B. The Right channel is bad. It could be both relays are bad in the Right channel. Speaker relays are often DPDT (double pole, double throw). Left is on one set of contacts, right is on the other set. The volume getting reduced with a distorted sound is the dead on description for an amp with "dirty" relay contacts. It definitely sounds like a poor connection. A poor contact that is current hungry will definitely cause distortion. So, where to look? If there's a headphone jack on the amp, the headphone signal might be pre-relay and run right off of the amp's output points. Listen to headphones phones pre-relay (even while the speakers are playing) Anyway, check solder connections up to the speaker relays. Check solder from the relays to the output terminals. See if tapping the speaker relay (at low or moderate volumes) induces or reduces the distortion heard of the speaker. Make sure the B+/B- (+ and - voltages sometimes called "rails")exist. These voltages should be on the Collectors of the output transistors. Look for +/- 25V~90V somewhere in there. See if tapping stuff can pinpoint the location of the failure. I know there is no wagering allowed, but I'm still thinking relay. |
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