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PostPosted: Thu Feb 02, 2017 3:08 pm 
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Joined: Mon Oct 05, 2009 6:17 pm
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Location: Bowmanville, ON, CA
RX-V1 YAMAHA Receiver; No Front Center Channel, No Rear Center Channel:

Shop Diagnosis at Yamaha Head Office at Markham, Ontario:
The problem of NO center and NO rear center channels are because of the circuit inside the DSP Board. Highly unlikely the problem resides in the DAC IC PCM 1704 or OP amp ICs because there is no sound at all on both channels. DACs usually if faulty pass but pass noisy or distorting bits and then also both the Rear Centre and Centre are not passing signals . The Centre and rear center amplifiers and volume ICs pass if signal fed through the 6 CH input direct or through the pre/in jacks. See section of the DSP block diagram attached.

Any Comments on this problem will be greatly appreciated. If anyone knows a good shop that can repair this unit, please let me know.

nabo@rogers.com


Last edited by nabo on Thu Feb 02, 2017 6:18 pm, edited 2 times in total.

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PostPosted: Thu Feb 02, 2017 3:52 pm 
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Joined: Tue Sep 15, 2009 4:04 pm
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Location: Vancouver, BC, CA
Pre-outs prone to oxidation and it will have no sound.. Try inserting RCA in and out of the pre section and see if it restores...

If it does, best to buy RCA covers to cover all the preouts!

Have V1 in the staple and still going strong..


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PostPosted: Thu Feb 02, 2017 5:43 pm 
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The rear center channel and the Center channel amplifiers on a Yamaha RX-V1 ...both share relay part #RY503 in the schematic.

Having both fail at the same time as the only failure, means the only component they share or only condition they share, is probably to blame.

If the POWER AMPLIFIER aspect is what we are talking about, ie to power speakers directly, is the failure point ....then it is probably relay #RY503.

One has to be explicit, correct and detailed when explaining the problem.

To check on this, one has to try using the preamp outputs for these two channels, while feeding the unit proper signals. If the preamp outs for both work, then it is probably the mentioned shared amplifier/speaker relay.

Should be less than $100 to repair, if this is the correct diagnosis. The relay is less than $20, the rest is for getting in there, doing the replacement....getting back together again..and testing it. Time and labour over a smaller parts cost.

Of course, this is counting on things going correctly, and according to this diagnosis. Which they may not.

If the listed info is Yamaha's official report, it sounds like no-one even bothered to crack open the tech manual.... as I found the common connection between the two channels... in about 4 minutes or less.

It's taken me 5-6x more effort to type this up.

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PostPosted: Thu Feb 02, 2017 6:45 pm 
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Location: Bowmanville, ON, CA
Teo Audio, Thank you very much for your reply. I really appreciate it. I am an industrial electronics tech; I do not have the tech manual. So, I first replaced all the surround channels' pre-out jacks following Yamaha tech's phone support. Than I decided to replace all the relays blindly since I've found a bad one after finding a suspect relay. I ordered 5 from Yamaha but they had only 4 in stock and I replaced 4 relays. That did not make a difference. I took the RX-V1 to a shop owned by a 55 years old RCC graduate electronics technician, after checking it he said it would be really involved and recommended to take it to Yamaha, so did I. When I apply RCA for input signal to the front center pre-in from a source, front center channel works and if I insert the RCA partially to the rear centre pre-in it works but if I push it all the way in, it cuts out. Please see his report and mine and let me know if you still think it is #RY503 causing this problem. Not sure if the relay I did not replace is #RY503. If you think it is, I will replace that as well.
The below report was typed by the technician at YAMAHA. I spoke to him on the phone and he says amplification stage on all channels are good.
Thank you in advance, sir...

RX-V1 YAMAHA Receiver; No Front Center Channel, No Rear Center Channel:

Shop Diagnosis report at Yamaha Head Office at Markham, Ontario:
The problem of NO center and NO rear center channels are because of the circuit inside the DSP Board. Highly unlikely the problem resides in the DAC IC PCM 1704 or OP amp ICs because there is no sound at all on both channels. DACs usually if faulty pass but pass noisy or distorting bits and then also both the Rear Centre and Centre are not passing signals . The Centre and rear center amplifiers and volume ICs pass if signal fed through the 6 CH input direct or through the pre/in jacks. See section of the DSP block diagram attached.

-- 03 Feb 2017 02:53 --

Teo Audio,
Sorry, I've read your comment second time and I noticed that I missed it out totally. I understand that it is not the #RY503 since with proper signal front and rear channels they both work. Also when I run the test function rear center gives the test sound but not the front center channel.
Your comments will be greatly appreciated.


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PostPosted: Thu Feb 02, 2017 8:55 pm 
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you can go here to get the tech manual for free, just register, you will get an automated reply, and then once in their system, you can get the tech manual. takes no more than 10 minutes. they do not share your info, and any old email address will do.

https://www.hifiengine.com/manual_libra ... x-v1.shtml

with the tech manual, you can see how the preamp level signal is routed, it may be that the rca jacks, if the solder breaks free, may cause a discontinuity in the signal flow..as it goes onward to the given channel of the power amp proper -for that given channel..

In this case, trace backward from the speaker outs, into the power amplifer's input system. Due to the unit's complexity, that is probably the quickest bit of tracing to reach the source of the issue.

These big complex beasts are really a bear to work with. Reading the comments on the unit at the given reference page for the manual, it seems this is a common problem area for this particular unit.

This means there will be more of this issue covered in other places on the internet. Someone might hit the nail on the head, but it may take some searching and reading.

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(Ken Hotte, of) Teo Audio


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