Yamaha RXV 465 no display and power problem

[hemant_2222]

Re: Yamaha RXV 465 no display and power problem

Finally confirmed that the dsp ic was bad..with shorted dgnd and +3.3 dsp and in an attempt to remove itof the board with hit air gun..i think i have also fried the uP..now its all DEAD.

Now i will have to keep this aside but whenever i'll come across this model i will try getting its digital board repalced in cheap offers..may be or use its resources as spares for another yamaha model..

R_J, it was really nice working with you..i appreciate your help and expect the same goes on in furture.

Thanks again to this forum..

Soon will be back with another receiver.

Bye for now.
Hemant

[hemant_2222]

Re: Yamaha RXV 465 no display and power problem

Hi R_J,

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.

i am afraid if the DSP IC is bad then will i be able to get this changed or is it worth doing it ?

Kindly input your views.

Regards,
Hemant.

[manfriend]

Re: Yamaha RXV 465 no display and power problem

My kid is bi-polar and she threw the board (Control 2) at me and the top popped off the relay and something(s) came out and I never found what it was.I'm new and couldn't find the actual replacement. Everything I found was out of stock. Thank you for the help!

[R_J]

Re: Yamaha RXV 465 no display and power problem

Or 255-6211-ND Panasonic LKQ1AF-5V-TV-8

[R_J]

Re: Yamaha RXV 465 no display and power problem

Normally its best to start your own thread, but anyway, what is wrong with the relay?
Digikey Z5885-ND, Omron G5RL-1A-E-TV8 DC5 might be what you are looking for.

[manfriend]

Re: Yamaha RXV 465 no display and power problem

Also, let me apologize for butting in on another discussion. I just saw a thread on a Yamaha receiver and thought this would be a good place to make an inquiry. Thanks.

[manfriend]

Re: Yamaha RXV 465 no display and power problem

I'm also working on a Yamaha receiver but it's a RX-V479. I need a relay for it. A TV-8. Service manual sayeth replace with a DG5D1-O(M)-II. I cannot find one of these to save my life. Best I could do was find a place that was out of stock but might ship August 3rd. Is there anything I can use to replace this? It's a TV-8, 5V DC, 5V coil, 8A 250V AC, 8A 30V DC. See image for details. I appreciate any help!

[R_J]

Re: Yamaha RXV 465 no display and power problem

The line is 3.3 volts, you can use a 1.5 volt aa or aaa battery, Just connect it for a second or two and check the suspected parts. DON'T leave it connected.

[hemant_2222]

Re: Yamaha RXV 465 no display and power problem

Hey R_J,

i haven't tried injecting the voltage yet, as it could create further problems, because i dont have any PS that can give me small fixed current. I have a homemade LM317 supply but not sure of its ampere rating.

I agree with your isolation technique methode to locate the fault but then trying to arrange the rework station.

I will update you, in between, is there any alternative to such soldering.

I have seen halogen lamps used to remove smd components but not sure of its heat quantum.

Regards,

[R_J]

Re: Yamaha RXV 465 no display and power problem

I did'nt know they were smd, what about applying a small voltage, were you able to find any over heating parts?

[hemant_2222]

Re: Yamaha RXV 465 no display and power problem

I am trying to get ways to remove the coils out of the board but as i dont have a smd rework station.

Finding techniques to achieve the same.

Will keep you updated.

Regards,

[R_J]

Re: Yamaha RXV 465 no display and power problem

There are a few coils that might be removed to aid in isolating the short, Like L409, L405, L401 etc. If you are going to inject a voltage, I would keep it to a volt or two, and limit the current if possible, even at 1 volt the shorted component should heat up.

[hemant_2222]

Re: Yamaha RXV 465 no display and power problem

C470 also shows short, in fact few el caps too show short and at the last almost all the smd capacitors back side of DTS ic are short.

So now this is becoming difficult to track down.
The digital board has been totally removed from the rest of the unit. So, shall i inject external voltage close to 3 v to check which ic gets hot.

As this is somewhat extrem, i require your asistance..

Kindly do suggest.

Thanks,

[hemant_2222]

Re: Yamaha RXV 465 no display and power problem

if i remove the connector from CB20 the short is still there, so it is on the digital board.
i was suspecting R479 but is it ok and now out of the ckt.

now C470 is the suspect.

Before pulling C470 out is will first arrange the smds.

I will update this thread.

Thanks for your help, R_J.

Regards,

[R_J]

Re: Yamaha RXV 465 no display and power problem

If you unplug CB20 where is the short? on the digital board or on the operation board? If its on the operation board (page 115) it could be ic402, or one of the caps like C4012, C4016, C4017
If it's on the digital board it will be harder to track down.

[hemant_2222]

Re: Yamaha RXV 465 no display and power problem

Hi R_J,

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.

I should have not overlooked your suggestion to check for the +3.3DSP before, my BAD.

i will be tracing the short to ground problem but do you have any suggesstion to look for the comman area, where this can happen most probably.

NOTE : The STKs are still floating.

Regards,

[R_J]

Re: Yamaha RXV 465 no display and power problem

You can solder the ic's back, I would solder all the pins on one first, then test, if it is not shutting down, solder the other ic.
You did not mention if you have the display yet, so check if you have +3.3DSP for the display ic.

[hemant_2222]

Re: Yamaha RXV 465 no display and power problem

Q401,Q403 &Q404 are present. Shall i go ahead and solder the stks one by one.

Approx 50v plus and minus appear at the big power capacitors.

Or there are other things to be checked before.

Kindly advise.

Regards,

[hemant_2222]

Re: Yamaha RXV 465 no display and power problem

Check for missing +3.3dsp likely missing Q401, Q403 & Q404

This will be done today.

Thanks for your help,

Hemant.

[hemant_2222]

Re: Yamaha RXV 465 no display and power problem

Hi R_J,

Some observations made today,

Voltage at the gate was held at 3.3v all the time so i re-soldered 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.

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 )

Both STK Pins 123&8 still are floating.

Regards,