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Post by 24century on Jan 30, 2018 15:49:37 GMT -5
Bought an used Yamaha receiver after my son break my previous Pioneer AVR about a year old, stayed with an Onlyo via optical SP-DIF but not work for my needs.
It has almost all features besides Atoms & DTS-X which I am not crazy about it since it still works not the same as theater processing, just 2 layers of audio plus less speakers supported.
Set everything up and it goes smoothly, Blu-Ray works and ARC works with TV as indented, however the sound has been cutting in and out every 2 mins then back on in 30 secs, that is crazy.
Double checked all connection which is all proper set, upgrade to the latest firmware, problem stays, did a system factory reset, cut-off won't go!! also tried straight mode doesn't make any different.
Called Yamaha who doesn't provide much help at all.
Research shows multiple users are experiencing similar problem, even after send in to Yamaha repair center
Get lost, need help
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Post by mastertech on Jan 30, 2018 16:28:33 GMT -5
Model number?
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Post by 24century on Jan 30, 2018 17:20:19 GMT -5
Yamaha RX-V675
Will test on Coax connection and analog input as well late today
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Post by mastertech on Jan 30, 2018 17:55:48 GMT -5
That would of been my next question. What inputs have you tested?
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Post by 24century on Jan 30, 2018 23:54:30 GMT -5
It happens on all sources on the main zone, seller intend to lie abt the problem.
Before system reset, display will say “decorder off” then resume, now speaker icons disappear when sound got cut off then both resumed (sound and icons) after 15-20 sec
Did get it solved after turning, drc (dynamic range control) & enhancer options off, worked well for the entire hour, after getting back from store, problem back.
Tried to pull the power cord out for the cold reset, same thing, the flu resist.
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Post by mastertech on Jan 31, 2018 20:30:50 GMT -5
This sounds a lot like the same problem many Onkyos are having with the DSP chip.
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Post by 24century on Jan 31, 2018 23:23:08 GMT -5
Could be, spent another 2 hours double check connection cable, tried page 28 self-diagnostic from service manual didn't report any problem back, tried low-volume it behave the same, sometime the receiver just cutoff after a noise produced, malfunctioning, have to turn it off and turn it back on, video always works with no problem.
Dolby/DTS/LPCM all same, zone-2 works beautifully.
Did read the spec and service manual prior to purchase, it use 4 of TI PCM5101 SMD DAC chip, plan to replace the stereo one IC481 with a PCM5102a chip that I had to get 6Db gain, now it looks like no point to do that.
Any input is appreciated, thx
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Post by 24century on Feb 1, 2018 15:52:01 GMT -5
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Post by mastertech on Feb 1, 2018 17:41:52 GMT -5
I know you have some wishful thinking on this but these links do not help.
Your first link is a different model and it was not determined the HDMI board was not the problem. The replacement board was bad and no further information given. So no conclusion. Not even to remove the HDMI board as to be the problem.
In you video link, again it is a different model and the problem is NOT the same as yours. Center channel still works on it, the speaker icons do not disappear and I do not think your model even has that same side board.
Have you identified this same side board and op-amp locations?
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Post by 24century on Feb 1, 2018 20:35:30 GMT -5
The HDMI board was being switched to a different one but doesn't solve the problem, then they talked about order a new HDMI board from there, no further info since from the 1st forum.
Need to spend more time with the machine and service manual, too early to get a conclusion, digital or analog part, probably digital
Will disassemble it this weekend and go from there, thx
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Post by mastertech on Feb 1, 2018 20:56:19 GMT -5
Quote from other forum:
"The technician came out on Sunday.
After listening to the problem, he figured the HDMI board needed replacing. He said that even though the problem persisted without the use of HDMI, most of the circuits and chips are on the same board. He brought a new one, however, the new one didn't seem to work either. It didn't play sound at all, and wouldn't take an update.
He put the old board back in, and the sound worked again, but still had the same problem cutting out. He said he'd have to order another board."
This does not mean it did not fix the problem. It means there was something wrong with that new board. It does not indicate what so ever that the problem was somewhere else in the unit and not on the HDMI board. Plus, it is a different model receiver then yours.
You cannot use these links as a guide for your unit.
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Post by mastertech on Feb 1, 2018 21:00:43 GMT -5
Will disassemble it this weekend and go from there, thx Look for loose or bad connection cables, or bad solder joints. A loss of a voltage on the DSP ic or related ic could cause an intermittent issue. |
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Post by 24century on Feb 3, 2018 13:45:50 GMT -5
1st dis-assembly done, didn't get much result, I know it is not Op-Amp for sure, they are located on the main board same with AMPs to answer your last question.
No sign of previous open, normal dust due to 2-3 years of use, gentle cleanup, no bad or un-reliable cable connection found, neither bad solder joints, SBL & SBR speaker terminals are losing position, feels previous owner was experiencing the problem tried some wire adjustment cause then give up after that, did reset and self-diagnostic again, problem stays the same as previous.
5 DAC chips (BB PCM5101) are lined by right side from the top digital board, forget to do noise test from DAC outputs, clean-up the dust between DSP and other bigger chips pins, no luck on locating and testing from the regulator ICs, that will be for the 2nd disassemble round
IC6&8, IC421, IC91/92, IC926/927 are regulators (standard or linear), IC 4 is a 1-channel step-down DC-DC converter from the schematic, can you spend a little time to see which IC(s) are the most important test point? Your theory is the most sense making so far
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Post by dobrykamil on Feb 4, 2018 20:20:31 GMT -5
Do you get the same symptoms in Direct mode?
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Post by dobrykamil on Feb 4, 2018 20:40:39 GMT -5
I reckon, the problem is with DAC's VCC or more likely with IC153 (R2A15220FP) I've had at least 3 or 4 Sony av receivers with dodgy +7V or -7V,causing similar symptoms. Use any of the analog inputs, and switch on Direct mode.
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