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ONKYO integra TX-DS989 Help solve no sound

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outnfront11

Active Member
Hi All,



I have an Onkyo TX-DS989 AV Receiver that is not producing any sound.



I have tried the headphone plug as well, and no sound there either.



I hear 2 relay clicks when I power the unit on and press the "stand-by" button.



There are 7 identical capacitors that are either swollen to leakage or very close to it. These are (C5180-C5186) 2pF/500V caps which are on the power amplifier stage. The schematic below is one block on the PCB which is repeated 7x on this board.





I will be replacing these caps, but I'm a bit confused whether this is the cause of the problem or not because looking at the block diagram, I can see that the headphone jack taps off the signal before the power-amplifier board (schematic below). Are these blown caps likely to affect the circuit back in that direction? If not, can anyone make a suggestion on debugging this? I have a sig-gen and scope, but have not used them to debug an amplifier before.

The last interesting piece of data is that the speaker output does "sometimes" produce a terrible hum, but I can't work out why. Going into the speaker calibration menu selection and playing in there seems to affect it. I had the unit off overnight and now on and running for a good hour, and the hum has not returned, speakers are producing no sound.

The fan also is unpredictable about coming on.





Any help, even non-specific, general advice on amp debugging would be great! (I have a SansuiAU-717 that has a "no sound" issue as well and I hope to debug and restore).



Thanks!
 
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outnfront11 said:
I hear 2 relay clicks when I power the unit on and press the "stand-by" button.
Click to expand...
Welcome to AK.
Turn off stand-by. thats like putting the unit limbo till you turn it on again w/o powering the unit off.
Shoot us a close up pic of caps in question... if sleeves are shrunken possible going bad slight doming some caps it's normal.
 
Binkman said:
Welcome to AK.
Turn off stand-by. thats like putting the unit limbo till you turn it on again w/o powering the unit off.
Shoot us a close up pic of caps in question... if sleeves are shrunken possible going bad slight doming some caps it's normal.
Click to expand...

Clarification: the unit, when switched on, is already in "stand-by" mode. I push the stand-by button to bring it to life.

I've tried to capture a close-up photo of one of the caps in question (brown cap above the R5354). It doesn't look too bad here, but there is a definite bulge and seem to be holes in some, but not entirely sure. Also a photo of the overall power amplifier board. They are the dark brown caps that run perpendicular to the light brown ones (there are seven in total on this board).


Capacitor Onkyo.jpg

20190522_074546.jpg
 
Yeah, looks like links are in place for L&R&C channels.
Pixs are not real good, keep in mind that glue is often used to secure caps to the board.
I suspect you have a failure in the power supply thats taken out all channels, will try
and get some test points.
 
Need to check +/-15Vdc supply to opamps and also supply
to relay drive.

Check +/-15Vdc supply as per below.
upload_2019-5-22_9-45-50.png
 
Schematic is not real helpful.
Check relay drive at following pins.

Also confirm, after power ON (via STBY switch) do you hear a relay click 4-8 seconds after power-ON.

upload_2019-5-22_9-54-54.png
 
you could try and pull all the plugs off and back on power off of course just in case its a simple bad connection
 
mbz said:
Yeah, looks like links are in place for L&R&C channels.
Pixs are not real good, keep in mind that glue is often used to secure caps to the board.
I suspect you have a failure in the power supply thats taken out all channels, will try
and get some test points.
Click to expand...
Pics are not great. Good point about the glue possibly misleading me. I will get in there again with a maginfying glass.

mbz said:
Does the front panael light up ok?
Click to expand...

Yes, it is fine and I am able to scroll through all options and menu selections. Interestingly, when I first got it, it came on in "stand-by" and I could not get it to do anything further. I played around with the relays on the power-supply board and actually shorted the switch on the one I suspected was not working. After that, it worked again. No idea what/why/how...

mbz said:
Have you tried with tone bypass/direct selected?
Click to expand...
No, I have not. Is that a hard switch on the back or a soft-selection in the digital menu?
 
outnfront11 said:
Pics are not great. Good point about the glue possibly misleading me. I will get in there again with a maginfying glass.
Click to expand...
A good hi-res pic would help

outnfront11 said:
soft-selection in the digital menu?
Click to expand...
Expect the bypass option would be in the menu

outnfront11 said:
The only schematic I could find was really blurry!
Click to expand...
Schematic from hifiengine

outnfront11 said:
I've pulled off and on some of the plugs from the amp board to move it and access the underside.
Click to expand...
think the suggestion was to remove the pre-out/main-in jumpers and give them a clean

outnfront11 said:
Is this schematic from the Onkyo service guide? Or is it an example?
Click to expand...
Above screen shots are from the service manual, the shots give the connector number, ie, J9222, P30628, they should
be printed on the boards NAAF6828, NAAF6814 resp
 
Thanks, that helps. I've been trying to trace where the associated boards are in the unit to check the these two. Slow, but making progress.
Will check bypass option.
Cheers
 
mbz said:
Above screen shots are from the service manual, the shots give the connector number, ie, J9222, P30628, they should
be printed on the boards NAAF6828, NAAF6814 resp
Click to expand...

If I am getting good relay switch sounds (one click at when I switch on, and one click a few seconds later) are these probe points still meaningful to check? There access is really tough and will require quite a bit of disassembly.
 
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