Need Help regarding Yamaha RXV371. No Sound Output

[kellys_eye]

Are those voltage measurements with the connectors fitted or removed? Measure using a proper, designated, 0V point and NOT the chassis (which may well be isolated/earthed)

 

[Hemant Choudhary]

The connector we fit. Do I need to check the voltages with -ve to MG and connectors removed.

Also is the measurements be done by repeatedly turning the receiver on..or just press the power switch and take the measurement?

Regards,

 

[kellys_eye]

Connector OUT. Measure the supplies with respect to 0V (analogue ground where the supplies are stated to be for the analogue circuitry and digital ground where they are otherwise noted)

 

[73's de Edd]

Sir Hemant Choudhary . . . . .

Oh-tay y y y y y . . . in now starting with YOUR unit of the two YAMAHAULER units at hand.

Here, you have both power supply sections . . . . .which I have now unitized upon one close up page.
The top SBY PS is being continually on . . . 48 hours a day .

INITIAL ANALYSIS . . .of these two supplies . . . .

AC power . . . in at right top corner area and flows to primary of T1501 and it rectifies, regulates and creates the ~10VDC at the ORANGE arrow of CB1151. . . . at far left.

Should you now power on the unit with its switch, the LIME GREEN arrow path should send drive voltage to the base of the Q1501 relay driver transistor to activate the DLS901 power relay, then its switching contacts at the end of the fine PINK line should close and apply AC power to the BLUE arrow line . . .IF PURPLE F1501 fuse is not blown.
The transformers secondary AC windings come into CB135 at the bottom of the BLUE arrow line.
Then the different PINK sections create the + and -12VDC and +9, 7 and +5 VDC supplies, that you see exiting at connectors CB134 and CB135.

The GREEN arrow path is the AC supply for the separate , QUITE hefy, + and - ~30VDC supplies for the POWER amplifier section .

You now want to check all of those voltages to see if they hold on , considering that the DLS901 holds closed.
If so . . . . . that would suggest that the POWER amp section is at fault and going into protection mode and opening the different set of relays, that otherwise, would connect output audio into the speakers.

Sooooooo . . .lets see if this section, and its 2 power supplies are good.

***** Initial observations of your voltage readings at the SBY power output connector, and IF CB132 is being plugged in, is suggesting that pin S9 is unloaded and being high. FIO . . The MG is being a valid ground for metering referencing. Your other AC voltage det voltage is an AC voltage.
Considering that CB132 is plugged in, the relay driver base voltage initially should be there
at power up . . . . . but may drop off . . . which is what we are wanting to find out initially.

UNITIZED SCHEMATIC REFERENCING . . . . .

73's de Edd
.....

 

[Hemant Choudhary]

Thank You Sir Edd,

As posted earlier, below the the reading on CB151, with all the connectors fit,

MG= 0v
ACDET = 9.8v
PRY = 0v
S9 = 14.6v

When the power switch is pressed, there is a change in the voltage at PRY upto 2.5v but it does not hold long and the goes to 0v as soon as the relay is opened for the second click. ( 1st click for close),

I truly appreciate your effort in making the diagram so easy for me to understand.

Regards,

 

[Hemant Choudhary]

Also, the power supply section is "OK" as there are approximate voltages present when the receiver is turned on for the brief moment ( i think so ) but in case, if they are to be tested again, if you guide me i am ready.

Let me know

Thanks,

 

[73's de Edd]

OK let's take one quantum jump ahead by seeing that there is being CB3, (Reference page 83) connector, at the main amplifier cable run from the power transformer secondary.
We want to unplug that connector to see if disconnecting that MAIN raw power to the AUDIO amplifiers will result in the standby supply now staying on.

 

[Hemant Choudhary]

With all connectors inserted and CB3 removed the standby supply does not turn on. ON and then OFF.

 

[Hemant Choudhary]

Is a measured value of 42 -48 milivolts of DC voltage OK at the middle pin of the emittor resistor.

Kindly advice.

Regards,
Hemant.

 

[Hemant Choudhary]

Hi Moderator,

Please close this thread , i was able to complete the repairs..there was a supply voltage problem of the many aupplied that were being fed to the amp and digital ckt.

Regards,
Hemanr.

 

[73's de Edd]

If it was the loss of the +7 VDC supply it must have been the R1326 fusible resistor, D1309 FWB rectifier pack or the C1320 electrolytic storage capacitor.

 

[MarkHu]

Hi Moderator,

Please close this thread , i was able to complete the repairs..there was a supply voltage problem of the many aupplied that were being fed to the amp and digital ckt.

Regards,
Hemanr.

Hi Hemant,
How did you fix it? My rx v371 have the same problem, I checked the +7VDC supply, around 9VDC.

 

[Hemant Choudhary]

Hi,

As per sir Edd notes,

My bridge diode D1309 was heating up and el cap C1320 was shorted.

Regards,

 

[73's de Edd]

Sir MarkHu . . . . .

Seems like he didn't come back and elaborate, my end comment was relevant to not even knowing of what his problem was and if he even HAD any 7VDC supply.
In your case you say that you HAVE that voltage present , but with it being high.
I can give you this start off, with the two supplied schematic snippets .

Observe the right GREY section for the derivation of the 7 VDC raw DC supply, which is using a linear AC line transformer derived voltage.
Good for 50 years if we use it regularly, to keep the electrolytic capacitors dielectrics reformed.

Now engage your brain into gear and note that they have an arrowed in 5K at 10 watt load resistor, temporarily utilized to gradually drain that C1320 of its charge, if you are wanting to work on this supply, shortly.
Now you need to follow the lil' RED " weenies" path to the left and down where it then enters into another section of circuitry.
Notice that this raw 7 VDC supply is now responsible for the input power needs of four lower voltage supplies.
It feeds into pin 5 of IC268 and 266 which regulate down to two stable . . .+5HDM and +5D power supplies out of their pin 4's.
Do note that these are SWITCHED supplies . . .ON or OFF . . .. that require an activating voltage at their pin 1 CONTROL inputs.

Now, drop down to the bottom two IC264 and 265 which are different and being self contained switch mode regulators
Your 7 VDC supply comes in to pins 2 of each of them AND if you have activation voltage on their pin 7's a variable power pulse train comes out of their pin 3 to ring the hell out of inductors L2601 and L2602, while schottky diodes D2602 and 2601 are busy collecting and rectifying those inductive rings peak voltages and busily passing them on as as rectified DC to the C2601-2602 and CC2603-2605 storage capacitors and creating the +3.3D and +1.2D supply sources.

Now refer to the top left corner and see that if you DON'T have the HTX_PON and 5D_PON and 5D_PON activations to the regulators, they will be idle and NOT pulling power from that +7VDC supply, so it will be higher in voltage, than in its normal operating conditions, with the regulators pulling power from it and its responding to the loading with a reduction of available voltage.

Now . . .go ye forth and check out those possibilities . . . . .as being the REAL cause of :
" The mysterious 7 volt supply aberration "

ADDENDA . . . . . .
He's Baaaaaaaaaaack ! (Sir Hermant)
And you won't be having that shorted capacitor as your problem, but add on an extra check for that capacitor in your unit, as a serious decline of its capacitance could account for it pulling down its supply voltage and creating extra ripple IF the other supplies are all enabled.



PERTINENT SCHEMATIC PORTIONS . . . . . FOR REFERENCING . . .
Or this large enough to be readable one . . . . just for as long as it stays free-hosted . . . .
https://i.imgur.com/fjn174C.png



73's de Edd
.....

 

[MarkHu]

Hi,

As per sir Edd notes,

My bridge diode D1309 was heating up and el cap C1320 was shorted.

Regards,

My power section is good，the digital board is broken or need . I use the self test and the TI Bus: Boot. TiVer：———— TiSum：————. Do you have firmware for Rx v371? Just want have last try, firmware update. The digital board is too hard for me.

 

[MarkHu]

Sir MarkHu . . . . .

Seems like he didn't come back and elaborate, my end comment was relevant to not even knowing of what his problem was and if he even HAD any 7VDC supply.
In your case you say that you HAVE that voltage present , but with it being high.
I can give you this start off, with the two supplied schematic snippets .

Observe the right GREY section for the derivation of the 7 VDC raw DC supply, which is using a linear AC line transformer derived voltage.
Good for 50 years if we use it regularly, to keep the electrolytic capacitors dielectrics reformed.

Now engage your brain into gear and note that they have an arrowed in 5K at 10 watt load resistor, temporarily utilized to gradually drain that C1320 of its charge, if you are wanting to work on this supply, shortly.
Now you need to follow the lil' RED " weenies" path to the left and down where it then enters into another section of circuitry.
Notice that this raw 7 VDC supply is now responsible for the input power needs of four lower voltage supplies.
It feeds into pin 5 of IC268 and 266 which regulate down to two stable . . .+5HDM and +5D power supplies out of their pin 4's.
Do note that these are SWITCHED supplies . . .ON or OFF . . .. that require an activating voltage at their pin 1 CONTROL inputs.

Now, drop down to the bottom two IC264 and 265 which are different and being self contained switch mode regulators
Your 7 VDC supply comes in to pins 2 of each of them AND if you have activation voltage on their pin 7's a variable power pulse train comes out of their pin 3 to ring the hell out of inductors L2601 and L2602, while schottky diodes D2602 and 2601 are busy collecting and rectifying those inductive rings peak voltages and busily passing them on as as rectified DC to the C2601-2602 and CC2603-2605 storage capacitors and creating the +3.3D and +1.2D supply sources.

Now refer to the top left corner and see that if you DON'T have the HTX_PON and 5D_PON and 5D_PON activations to the regulators, they will be idle and NOT pulling power from that +7VDC supply, so it will be higher in voltage, than in its normal operating conditions, with the regulators pulling power from it and its responding to the loading with a reduction of available voltage.

Now . . .go ye forth and check out those possibilities . . . . .as being the REAL cause of :
" The mysterious 7 volt supply aberration "

PERTINENT SCHEMATIC PORTIONS . . . . . FOR REFERENCING . . .

View attachment 41896

73's de Edd
.....

Hi sir,
Thanks for your reply, I will check it.

 

[MarkHu]

Hell Sir Edd and Sir Hemant,
I think I have found the problem but I can’t fix it anymore, the ti bus PCB lines and some of the small resistants (r2407) between ic243 and ic 241 was damaged, too small for me to repair. That’s why I got “ti bus :Boot” and can not read the ti Ver from the selftest. It’s dead now, but I learn something from it. Thanks for your great help!

 

[Nailbender1972]

Hello everyone I was following this because I'm having same issue after a brown out a friend said but things kinda left off after other issues and the thread kinda stopped would anyone mind giving me a few ideas where to go please cause I'm kinda lost and would like to test a few things without tearing it all apart if possible it has power and I hear two relays click when I turn it on but no sound out of speakers but it seams everything else works

 

[MrZepp]

Hi
I had same problem as thread starter originally.
In addition the amplifier turned itself off after certain time.
Following the instruction sin the thread i found out that my C1320 was shorted, replacing that (and C1507 in power board as its was recommended in many other threads) resulted:
- Power stays on.
- radio and HDMI inputs work ok
- All other inputs are "dead" -> meaning: No sound heard, and in case of optical inputs there is just text "Decoder off" in screen while there is audio coming in and it should say "PCM" instead.

atm i am bit lost. Most voltages are same / quite close to reference voltages in schematic.
The biggest coersions to reverences are at connector
CB131:
THM_PAT2 ref 2.7 measured 3.3

Mainboard:
Q201 and Q203 (at least) have no negative voltage (ref -11.7)

CB22 (bottom of main board):
C_MT F_MT S_MT measured 3.0V, ref 2.5

Maybe this helps.. I am also bit short of ideas atm.. So all suggestions welcome.