[tranhieu]

Last night everything worked fine, but this morning it struck me there's no sound playing from my fones at all. The B22 is still intact, and I doubt the likelihood something happened to my dac. I even tried switching to another OS yet things didnt get any better.
I tried measuring output voltage of the hiface while musing streaming via asio (yes the hiface still shows up in asio's list though), and apparently my dmm shows me a big fat 0 wheher in dc or ac mode.
Does that mean it's time I got another transport?

 

[Avro_Arrow]

Is the HiFace still getting power? Sometimes, when we are panicking over failed device, we forget
to check the simple things...

 

[tranhieu]

I checked its testpoint and looks like it's still getting power from the usb port. It's quite difficult since I don't have any spare DAC or transport lying around.
Just looked at my DAC board (buffalo 9008) and noticed some black juice leaking from C13, and the D1 didn't light up. I still feel some heat emitting from the ESS chip when the DAC is powered up though. Could that be the cause? And what is that black liquid which smells so nasty?

 

[Avro_Arrow]

If that cap is shorting it will take out the power to the audio section.
Unsolder it and see if the sound returns.
It will need to be replaced

 

[tranhieu]

Thanks for the suggestion. But why did it just die all of a sudden?
I will desolder it and see if things improve.

 

[Pars]

****ty cap or installed backwards? Or underspec'd for voltage?

 

[ijchan223]

IMO you shouldn't try to power it till you remove the dielectic grease because it is conductive. The only guess i can throw out is that the company that made the part isn't to spec or installed wrong. In my experience 90% of the time it is user error. I don't have experience with the board but usually when caps blows they act like a fuse and break the connection, so i wouldn't expect the board to work till you replace it.

 

[splaz]

Quote:

I checked its testpoint and looks like it's still getting power from the usb port. It's quite difficult since I don't have any spare DAC or transport lying around.
Just looked at my DAC board (buffalo 9008) and noticed some black juice leaking from C13, and the D1 didn't light up. I still feel some heat emitting from the ESS chip when the DAC is powered up though. Could that be the cause? And what is that black liquid which smells so nasty?

That black liquid...  it's highly concentrated condensed white smoke.

 
Perhaps put some pics up of the whole board and post what brand, series, voltage rating and capacitance the capacitor is and also a pic clearly showing what orientation it is in.
 
There may be a possibility that the capacitor is a symptom and not a cause of the failure. Perhaps it is the part that would be first to go or the only one that is showing obvious outward signs of damage or other parts may be tolerating a fault due to their specifications, circuit design etc.
 
Just some thoughts.
 

 

[Pars]

I had assumed this was a Buffalo I (twisted pear), because of the ESS9008. C13 on that schematic is not a PSU cap (nor an electro, probably). OP needs to be more specific.

 

[Avro_Arrow]

Pars is correct...I think I mistook C5 for C13 on the schematic...I didn't have it zoomed
in and I was scanning quickly for electrolytics...
On the other hand, a shorted C13 will take out the reference voltage going to the Left/Right voltage buffers.
 
I agree, a picture would be best...

 

[tranhieu]

Sorry for not being clear enough, I thought apart from the B24 TPA does't have any other dac that uses the 9008
below is my pcb photo, not the best picture out there but I think should be enough for troubleshooting

 

[Avro_Arrow]

Check the voltage at C13.
It should be GND on the side where it says "Lock" and
3.3 volts on the side where is says "C13".
The brown stain looks like old flux...

 

[tranhieu]

Quote:

Check the voltage at C13.
It should be GND on the side where it says "Lock" and
3.3 volts on the side where is says "C13".
The brown stain looks like old flux...

Yes, it's 3.3v.
The stain was not there last time I looked at the board before the dac went silent. Actually I already wiped part of it off to have a better look at the cap...
 

 

[Avro_Arrow]

Finish cleaning C13.
If it does not look discolored compared to the
other caps then I think it is not the problem.
Could the stain have been something that was spilled there?

 

[tranhieu]

Just finished cleaning the cap, there's no color change compared to the other caps. I don't remember spilling something onto the board in the past though. Also D1 is not illuminated even after cleaning.
Should I desolder C13? I still have some 1uf smd lying around.