Yamaha rxv 465 no display and no power..

[73's de Edd]

Sir Hemant Choudhary . . . . .

Considering that the Q200 FET is good and that the Q201 is missing , you need to get another in the circuit.
I'm sure that you won't have a digital transistor, so you can build one up with a common PNP small signal transistor, using the info I have given you below.

It seems that switched 3.3 VDC supply is relating to the SP_IMP circuitry of the unit.

Also check either by FEEL with a fingertip, or use a meter across a relay coil to confirm what relay is coming on and then dropping out.

I suspect they might be :
On page 117 of the schema . . . I see that one could be RY100, down in the right bottom corners power supply.

On page 121 In the sub supply, bottom left corner you see the RY371's coil . . .BUT . . . that relays contacts don't seem to be on that page.
Can you examine the circuitry foil paths of that relays contacts and track down to where they go ?
Thassssssssssit . . . .

MAKING THE DIGITAL TRANSISTOR




73's de Edd
.....

 

[Hemant Choudhary]

One thing that i recently found was, when tone control + direct + standby is pressed for a long time, i can hear 3 clicks and the receiver is turned on and voltage measurements can be taken.

But the voltage that appears across the two big capacitors is way less ie +25 and -34v than plus minus 50v.
Though the amplifier is turned ON, there is no display.

I will try making the transistor, as discribed.

Thanks for your inputs, Sir

 

[Hemant Choudhary]

Also, Do you mean to say, the +3.3S is ONLY generated at this point and will not be switched unless Q201 is supplied with a signal from micro.

Kindly advise,

Regards,

 

[Hemant Choudhary]

Hi 73's de Edd Sir,

The Q201 was made with KMPSA92 PNP transistor with 47Ks, as per the diagram, a little progress is achieved i guess , now with the very first press of the standby switch, the unit turns ON.

The Relays RY100 and RY371 show drop in voltage across their coils, i guess this is also OK, now.

In total i hear 3 relay click one after another. Now the whole board is to be turned upside down to take measurements at the power supply capacitor.

Further, the STKs pin number 123 & 8 are floating.

I will update the voltage measurements across power capacitor, stk input in the evening.

NOTE : The display is still OFF, no single sign of illumination.

Regards,
Hemant.

 

[73's de Edd]

Sir Hemant Choudhary . . . . .

• 1 . . . . . Also, Do you mean to say, the +3.3S is ONLY generated at this point and will not be switched unless Q201 is supplied with a signal from micro.

Here is the sourcing of both of your units 3.3 VDC MAIN and 3.3 VDC SWITCHED supplies.

FLOW THROUGH . . . .

+5VDC comes in at the top right corner via the RED line and passes to switchable IC21 which has its activation pin, 1 , being connected back to the +5VDC input, so that it permanently powers on , upon an initial +5VDC power presence.
It outputs at PINK 3.3VDC line and immediately passes upward thru L210 and provides a constant 3.3VDC main supply.
The 3.3 also immediately finds the PINK path to the left to the SOURCE of Q200 FET, where it is being open circuit over to the Drain of Q200.
Now where your once MISSING Q201 filled in, was in making a conductive C-E path for gate drive to Q200, if there was being base voltage activation via the GREEN / BLACK base path down to pin 96 of IC20 u/p. THEN the SOURCE to DRAIN conduction of Q200 has switched your 3.3 VDC SWITCHED power and outputted to the PINK / BLACK line..

• 2 . . . . . Further, the STKs pin number 123 & 8 are floating.

I initially suggested that you start with floating the power supply terminals right at the pins of the larger, and heavier taxed STK, with its additional hefty center channel.
SINCE first voltage readings initially detected a significant DC voltage presence on the protection sense sampling lines.
Therefore, that was indicative of an imbalanced voltage fault being within the power module.
Your floating them, then resulted in those sense lines, then being close to ZERO VDC, thus pointing to fault within the MAIN STK module, and the second STK unit . . . . . VERY likely will be good.
So you need to keep main STK power connections floating, since, after we clear up the " Faltering Relay Syndrome ", the one good STK should give us two channels of good music, then only leaving the BIG BAD STK to be replaced.

• 3 . . . . . But the voltage that appears across the two big capacitors is way less ie +25 and -34v than plus minus 50v.

Page 118 main power supply at the bottom of the page.

Note that RY100 operates its separate DPDT contacts such that there is initially the AC_BL low voltage tap on the power transformer feeding into the TOP of the FWB rectifier.

Same is true with the other relay contact set with the transformers other AC_BL LOW voltage tap on the other half of the transformer feeding into the BOTTOM of the FWB rectifier.

When a high logic level from the u/p comes into the SP_IMP at Q1015's base it turns on companion Q1016 to power up RY100's coil and transition its DPDT contacts to then connecting the top and bottom of the FWB to the the sets of AC_BH high taps .
THAT activated RY100 relay then will have ramped your + and - power amp supplies up to FULL supply voltages.
SO . . . . the unit is working off a set of power transformer low voltage taps initially, but RY100 relay activation then connects the set of higher voltage taps of the transformer to the FWB inputs.

• 4 . . . . . Relays being involved.

You can see and feel and measure coil voltages at / of all of the relays in the system . . . I can't.
A cluster of relays that I think that we can ignore will be the ones that disconnect the speakers, they are being .
RY341-42-43-44-45 .

Now unless I am overlooking one, the other two should be the one in the sub / standby power supply which I asked you to track down as to where its contacts are, but the coil is easily found.
The other relay is the one associated in switching transformer taps to level shift the STK power supply up to full voltage.
When you have power on the unit and just after having pressed the power switch, one or two relays close, and after a slight pause . . . of seconds . . . in having found a circuit fault . . . . . the activating / hold power is cut off from the relay coil .
I need to know which that relay (s?) that is being. Then we continue.


RELEVANT SCHEMATIC EXPLANATION . . . . with its hot and cold running flow paths . . .



73's de Edd
.....

 

[Hemant Choudhary]

Summary of todays work;

I soldered the pins 123 &8 of both stk's and the problem reappeared then i undid what was done but to no avail

The amp has returned into its previous state. .

One thing is for sure, i was tracing the pin 96 of the micro and found that there is 3.34v when the power switch is pressed and this voltage remains for 5 to 7 seconds then drops to zero, which i guess turns ON the Q201.

Further details along with your suggestions will be posted tommorow.

Thanks for your reply,

Regards,

 

[Hemant Choudhary]

Dear Sir,

Some observations made today,

voltage at the gate was held at 3.3v all the time so i resoldered all the pins of Q200 and now its is giving me 0v all the time, which is as per the schematic.

Now back i am getting the three relay click one after another with some time lags.

The display remains off. All the relays were confirmed to be working by touching them.

I have the diagram of RY100, on page 117 and not page 118, as you mentioned, may be if this matters.

If initially, RY100 is at AC_BL then now with the second relay click, it should give me AC_BH, hopefully i will get it ( i will confirm this ).

Also, when the entire board is turned upside down, all the three relays click together, is this an issue?.

Both STK Pins 123&8 still are floating.

Regards,

 

[Hemant Choudhary]

Dear 73's de Edd,

When all the three relays turn ON, i im getting plus minus aprox 50v and thats a good news.

Now, as the stk pins are floating, shall i go ahead and resolder it?

Please confirm, before doing this is there any other areas to be checked and confirmed.

Regards,

 

[73's de Edd]

Sir Hemant Choudhary . . . . .

Correction:
Page 118 was being 117 main power supply at the bottom of the page.

Now, as the stk pins are floating, shall i go ahead and resolder it?


With you referring to IT, you must mean only the IC 100 STK433-330-E, with you not having touched the pins of IC101 STK433-130-E.
And NO , you still want to leave the pins still floating, since you initially had enough DC voltage on the STK amps output line to trip the voltage protect function . . . . as per your voltage readings, of :
Q1007= 3.3
Q1008=3.9
Q1012 =2.8
Q1011=2.9
Q1006=1.3v
that you had given back on your post #8.

SO that IC 100 STK433-330-E must be bad, but we can just leave it disconnected from its power lines.

Back when you floated the main STK power input connections, you then noted :

Now there is only some milivolts not more than .5volts (DVM range 20 volts) on all the sensing transistors.

AS far back as post #18 you then said

Pin 1 and 3 of both STKs have been resoldered.

But now, I believe that the situation is being that the main IC 100 STK433-330-E has its power pins floating .
BUT with you having the IC101 STK433-130-E power pins soldered back.
Considering that the IC101 STK433-130-E has no fault and is not showing any > .5 VDC voltages on the
Q1006-7-8-11-12 sense transistors.

We now need two more measurements:

Refer to page 121 and bottom left corner standby supply.
Find standby power supply filter capacitors C3712 or C3712 or C3716 and see if there is 5---5.6VDC present
when the unit is plugged in and it remains at all time. Turn on the set to get the different relays actions and see if that just measured voltage then remains, even after all of the final relay clicking.
If so measure across the coil of nearby RY371 relay and see if it activates just as soon as you press the units power on switch.
Then, see if it STAYS with that 5 VDC across it, or if it loses that voltage and the relay then clicks open ?


73's de Edd

 

[Hemant Choudhary]

Dear Sir 73's de Edd,

Thank you for such a nice explanation.

For the time being i moved forward in the direction of searching about the diaplay problem and guess what +3.3DSP is dead short to DGND.

Removed few el caps C452,C488,C489 and C430.. resistor R479 of 68 ohms but could not find the short.

Now, i im planning to put external 3 to 4 volts in one of the capacitor leads on the board to find if any ic ( which has +3.3DSP, as input supply) gets heated.

Your adivce is required, will wait till then.

Kindly suggest.

Regards,

 

[73's de Edd]

Sir Hermant Choudary . . . . .

By all means DON'T inject power into that 3.3 VDC supply buss to try to heat up a bad part for thermal emissivity..
This unit has SEVERAL specific parts that are now totally UNOBTANIUM.
Look at my schema snippet below and track down Schottky diode D63 and see if it is not being shorted and the reason for the loss of your +3.3D supply, if not, check the other likely suspect, the C73 electrolytic filter cap..

OPERATIONALITY . . . . .

Confirm that after turn on, that there is the 5.5 VDC supply voltage coming in at right top arrow and passing thru L39 and then doing the RED DOT flow into pin 3 of IC8 . . .SWITCH MODE SUPPLY I.C..
Now IF you don't have a shorted D63, or C73 . . . . . L32 gets its bell continually rung by Pin4 of IC 8 and a good diode in D63 and good C73 storage electrolytic should have created 3.3 at the end of the BLUE DOT line.
( Considering that pin 8 of IC 8 receives its enabling voltage.. )

Makee-----Testee-----Testee

SCHEMATIC REFERENCE PORTION IS EXCERPTED FROM PAGE 111 . . . . . . . .



73's de Edd
.....

 

[Hemant Choudhary]

Hi,

Just wanted to be sure that we are testing the short of +3.3 DSP to DGND or +3.3D to DGND.

For finding the +3.3DSP : i am not getting 3.3 v at the connector CB20, pin 24 infact it is shorted to DGND. Then tracing back i also found that the drain Q400 is also shorted to DGND ( before tracing, i also found that the Q400 was loosely fixed to the board, so i removed it and resoldered it)

The Q400 was checked outside the ckt and there was no short between source to Drain and Gate to drain.

The gate and source, both are at 3.3 volts in circuit.

NOTE : The STKs are still floating.

Kindly reply.

Thanks,

 

[73's de Edd]

Sir Hermant Choudary . . . . .

I now submit this more specific / complete analysis of your +3.3DSP voltages origin . . . on it you an see that IC8 is being the source of that +3.3DSP supply as well as +3.3D supply and for companion IC5, also being able to create its +1.2D supply .

See if unplugging connectors CB20 and / or CB 401 will assist you in isolating / separating the +3.3DSP wiring in the location of its dead short to ground .

Looking at Q400 proper and its adjunct interconnects, is showing it as being implausable to be having any direct paths to ground.
(Still suspecting my earlier mentioned components.)

NOTE : The STKs are still floating. . . . . . . . .KEEP those STKs floating , as its initially quite tricky . . .via use of BOTH solder sucker and solder braid wicking absorption . . . . . to get ALL of the pins floating free of their connector pads.


***** TECHNO REFERENCING ***** . . . . .



73's de Edd
.....

 

[Hemant Choudhary]

Sir Hermant Choudary . . . . .

I now submit this more specific / complete analysis of your +3.3DSP voltages origin . . . on it you an see that IC8 is being the source of that +3.3DSP supply as well as +3.3D supply and for companion IC5, also being able to create its +1.2D supply .

See if unplugging connectors CB20 and / or CB 401 will assist you in isolating / separating the +3.3DSP wiring in the location of its dead short to ground .

Looking at Q400 proper and its adjunct interconnects, is showing it as being implausable to be having any direct paths to ground.
(Still suspecting my earlier mentioned components.)

NOTE : The STKs are still floating. . . . . . . . .KEEP those STKs floating , as its initially quite tricky . . .via use of BOTH solder sucker and solder braid wicking absorption . . . . . to get ALL of the pins floating free of their connector pads.


***** TECHNO REFERENCING ***** . . . . .

View attachment 41875

73's de Edd
.....

Hi 73's de Edd Sir,

I am getting 5.5v at pin 3, 3.3v at pin 4 and 3.3 at pin 8 of IC8.

Regards,

 

[73's de Edd]

Sir Hermant Choudhary

I am getting 5.5v at pin 3, 3.3v at pin 4 and 3.3 at pin 8 of IC8.

If you are . . .that means that you must have found and cleared up the direct short to ground in the Q400 circuitry area.

Was it due to poor soldering . . . . or solder spash(es) ?

REFERENCE POST 31 Mini Schematic . . . . .

So now you can plug in the unit and turn on the POWER switch and at IC8 the 5.5 supply stays on continually and the pin 4 has its 3.3 volts remaining continually, which would be the source of the +3.3D supply.
AND ALSO the output on pin 8 would be the enable voltage for activating pin 3 of the IC5 regulator, and it should then put out its 1.2D supply voltage.
Can you confirm that is happening at IC5 pin 1 ?
Any chance that you have the front display lighting up now ? If not . . . . . .

REFERENCE POST 33 Mini Schematic . . . . .

With the just mentioned +3.3D supply present and if there is a DSP_ON 3.3 voltage present at the base of Q401.
Will Q400 then get turned on and create the +3.3DSP supply at its DRAIN ?

73's de Edd
.....

 

[Hemant Choudhary]

Sir Hermant Choudhary


If you are . . .that means that you must have found and cleared up the direct short to ground in the Q400 circuitry area.

Was it due to poor soldering . . . . or solder spash(es) ?

REFERENCE POST 31 Mini Schematic . . . . .

So now you can plug in the unit and turn on the POWER switch and at IC8 the 5.5 supply stays on continually and the pin 4 has its 3.3 volts remaining continually, which would be the source of the +3.3D supply.
AND ALSO the output on pin 8 would be the enable voltage for activating pin 3 of the IC5 regulator, and it should then put out its 1.2D supply voltage.
Can you confirm that is happening at IC5 pin 1 ?
Any chance that you have the front display lighting up now ? If not . . . . . .

REFERENCE POST 33 Mini Schematic . . . . .

With the just mentioned +3.3D supply present and if there is a DSP_ON 3.3 voltage present at the base of Q401.
Will Q400 then get turned on and create the +3.3DSP supply at its DRAIN ?

73's de Edd
.....

All the pins of transistor Q401 is held to approx 3v.
1.2v is present at pin 1 of IC5.
Also, the drain of Q401 is shorted to DGND, as informed before.

Regards,

 

[Hemant Choudhary]

Hello 73's de Edd Sir,

Here are further updates on this long Pending problem,

Upon isolating few components i found

When L405 was removed, the short remained between +3.3DSP and DGND

When L409 was removed, the short to DGND at one pin of L409 is gone but other pin is shorted to DGND and when L408 was removed, L408's one is shorted to DGND.

C488 and C489 were removed of the ckt and tested, they are good.

So now, either one or more of the SMD capacitors are SHORTED or the DVDD, CVDD and VSS pins of the "No Replacement Part Available" DSP IC ( IC 44 ) is BAD.

Sir, i will wait for your conclusion before making mine.

Regards,
Hemant.

 

[73's de Edd]

Sir Hermant Choudhary . . . . .

When L405 *** was removed, the short remained between +3.3DSP and DGND
( *** L405 is located in the schemas 7- L area of its page 113)

When L409 was removed, the short to DGND at one pin of L409 is gone but other pin is shorted to DGND and
when L408 was removed, L408's one is shorted to DGND.

C488 and C489 were removed of the ckt and tested, they are good.

So now, either one or more of the SMD capacitors are SHORTED or the DVDD, CVDD and VSS pins of the
"No Replacement Part Available" DSP IC ( IC 44 ) is BAD.


Here is most of the relevant power supply routing being all condensed in this one area of the very bottoms pictorial.

The YELLOW box shows that the +3.3D supply comes in and passes thru L406 to go to the Q400 fet to be
switched on as the +3.3DSP power supply if Q401 is driving it.
The +3.3DSP power supply mostly feeds the DSP IC44 over to the right. but the IC46 shown just below the YELLOW box, derives its power from that supply.
Also looking over to the left center side of the IC44, the IC50 there is getting its power from that supply also.

While being there, also look at the PINK +3.3 DSP supply feed that goes thru L405, which then passes power over to the right to PINK pin 27 of IC44.
You have 3 bypass capacitors of C452 - C453 and C454 to ground.
I hope that one of the first two is a tantalum and is being dead shorted, EXTREME slim chance of any problem with the last 0.1 / 16V ceramic unit.
That is one +3.3 DSP supply feed path into IC44, now go to the other side of the IC and you will see that the bottom right corner has the PINK +3.3 DSP supply entering thru L409 and immediately exiting over and up to the right as the +3.3 TI supply . . .to be covered later.
The +3.3 DSP supply is immediately filtered by C489, which you say is NOT being our short to ground.
While the +3.3 DSP then routes to the left to the two arrow path routes and feeds all of the RED rectangle areas that I have marked up and each is bypassed with a 0.1 ufd / 16 ceramic bypass cap.

Now referring back to the very top observation that you made

When L405 was removed, the short remained between +3.3DSP and DGND

Tells us that IC44 PINK pin 27 and its filtering capacitors is not the dead shorts source back at Q400..

I cannot precisely comprehend this below, due to the "at one pin" (WHICH specific pin connection?) and the " other pin"

When L409 was removed, the short to DGND at one pin of L409 is gone but other pin is shorted to DGND and when L408 was removed, L408's one is shorted to DGND.

Also, you involved L408 which is being associated with a completely different +1.2 DSP supply circuitry.

We had better retest the IC44 area and just involve the two +3.3 DSP feeds into it.
If you lift one leg of the L409 inductor out of circuit and test the RED node at C489, as I think that you said, there will be no short to ground showing at that node, thus clearing a whole bunch of connections of any fault.
One would expect the short to then be showing on the L409 inductor lead end that runs up to the incoming +3.3DSP supply.
If this is true, then move over to the left side of the IC44 area and lift up one lead of the L405 inductor and measure the PINK pin 27 and see if it or its cluster of bypass capacitors or pin 27 is shorted to ground. If they are not the source of the short, than move back to the L405 lead side that connects to the +3.3DSP supply over there and see if the short to ground exists.
If so . . .now that we have the out of circuit inductors isolating all of the relevant connections into the IC44, check out the two IC's earlier mentioned, that are also deriving their power from this same +3.3DSP, as they could be the source of the short across the supply that you are reading back at Q400.
If this testing sequence does not reveal all, time to see how the branch off +3.3TI from this supply is involved, but your lifting of L409 should show its significance.

+3.3 DSP Supply Sourcing and Distribution . . . . .
(This has some irrelevant areas / unused pins of IC44 being condensed down for space saving . . .)

73's de Edd
.....

 

[Hemant Choudhary]

Hi,

Testing as per the details above shows, The capacitors C452 - C453 and C454 are not shorted to DGND.

the IC50 there is getting its power from that supply also.

Only DGND connects to its pin 3
"

The +3.3 DSP supply is immediately filtered by C489, which you say is NOT being our short to ground.

C489 and C488 are tested outside the ckt and they are not short to DGND.

Summarizing;
Removed components are L409,L408,C488 and C489 and R479.

Now, when tested for short between +ve terminals of C489 and C488, both are short to each other as well as DGND.
I think both the lines of +1.2DSP and +3.3DSP are shorted to each other and to DGND.

Component L409, being SMD, was fully removed. one end of L409 connects to capacitor C489 and other to +3.3DSP.

But "L409 connects to capacitor C489" "this point" is shorted to DGND.

Sir, please let me know, any possible way to isolate the lines of +1.2DSP and +3.3 DSP, going to IC44.

If the above lines are confusing, let me know, i'll try putting them with diagram.

Regards,
Hemant.

 

[Hemant Choudhary]

You have 3 bypass capacitors of C452 - C453 and C454 to ground.

These are all good.