[kamikaxe]

Here's some crappy pics, best I can take. I've been looking for short but no results yet
 
https://lh5.googleusercontent.com/-X4zneoTqduU/UJaOPBQKWGI/AAAAAAAAFIc/j-H-4vNklc4/s639/1.JPG
https://lh5.googleusercontent.com/-6QxtKXyGDgI/UJaOSXot04I/AAAAAAAAFJc/p9bJ8tnYAdA/s903/IMG_1549.JPG
https://lh3.googleusercontent.com/-HoIcwLJzi38/UJaOTEY8FkI/AAAAAAAAFJY/xvTmfrmNrmA/s903/IMG_1548.JPG
https://lh6.googleusercontent.com/-tqiXYpf7prY/UJaOUSRaWcI/AAAAAAAAFJU/lqt6Ik5P6Rk/s903/IMG_1547.JPG
https://lh6.googleusercontent.com/--nNvHh5QwaM/UJaOVSWSu7I/AAAAAAAAFJQ/81RZZl-qx8s/s903/IMG_1546.JPG
https://lh3.googleusercontent.com/-A20JOki6sM8/UJaOWoZ-psI/AAAAAAAAFJE/SKo7BLeIHMo/s903/IMG_1542.JPG
https://lh3.googleusercontent.com/-XiENa5oHnJU/UJaOh_MlhqI/AAAAAAAAFJM/gH4pS4YoYfk/s903/IMG_1544.JPG

 

[tomb]

1. It appears the first photo shows two pins bridged in the middle of the left side PCM2706/7.  As best I can tell, none of the pins on that side should be bridged.
2. Any one of those electrolytic caps could be shorting out parts.  Yes, they have a plastic wrap and a rubber plug on the bottom, but if the wrap is not completely covering the bottom edge of the can, you can get a short.  If you are going to attempt caps that obviously do not fit, you'd be better off taking them out, soldering new leads on the caps (since the existing have already been trimmed), and bending them over at a right angle.  Hanging them off the edge of the board in a horizontal position would be safest.
3. Your fourth pic looked pretty bad for the regulator, but the fifth pic seems to confirm that it's OK.  Still, it would be helpful if you went ahead and cleaned the PCB of the residual flux and then took some pics again.
 
I think that bridge on the PCM chip looks the most suspicious, though.  Get some caps of the right size when you can.

 

[kamikaxe]

I separated the PCM two pins and now windows recognizes the device. The regulator also stays cool now. But there's not coming any sound out, and the voltage at the led is still 3,3v

 

[tomb]

Quote:

I separated the PCM two pins and now windows recognizes the device. The regulator also stays cool now. But there's not coming any sound out, and the voltage at the led is still 3,3v

What do you have connected at the output?  None of your pics show anything.
 
What exactly are you measuring to get 3.3V at the LED?

 

[kamikaxe]

I soldered the RCA's to make some test. Cables and sound device of the PC are triple checked.
Maybe I just have to start look the smallest pins again if there is some short left.
The 3,3V at the led is measured between led legs. Is this right?

 

[tomb]

Quote:

I soldered the RCA's to make some test. Cables and sound device of the PC are triple checked.
Maybe I just have to start look the smallest pins again if there is some short left.
The 3,3V at the led is measured between led legs. Is this right?

Yes, that's true.  I agree with your guess, too - there's still a short somewhere.

 

[tomb]

BTW, if you take another look at this thread, I'd advise you to remove those large caps for the time being.  I don't think it will hurt anything and it will let you and everyone else get a better look at the PCB.

 

[cobaltmute]

The 3,3V at the led is measured between led legs. Is this right?

You are indirectly measuring the voltage drop of the LED by measuring the legs of the LED.

 

[tomb]

Oops - cobaltmute is exactly correct.  3.3V is only a partial voltage drop in the full path between USB power and Ground.  There's the R5 resistor, which actually sets the current (more or less) for the path to ground.  So, the full voltage drop of the USB 5V would be the voltage drop across the R5 resistor plus the LED.

 

[daves440]

I was wondering if any one has a suggestion on what might have happened and what to try and replace on my grub dac, I disconnected the rca's from one of my amps and connected to a different amp. Both amps where on and usb connected to the computer. One channel is now not working when I switch over. I have to say I learned now not to do this with the equipment on, this is the second time I have done this scenario, the first was with my Bantam dac, I did the same thing and the same outcome, one channel out . Now I have two that I would like to repair but I do not know how to trouble shoot.Can someone suggest what and how to check or what to try to replace?

 

[tomb]

Quote:

I was wondering if any one has a suggestion on what might have happened and what to try and replace on my grub dac, I disconnected the rca's from one of my amps and connected to a different amp. Both amps where on and usb connected to the computer. One channel is now not working when I switch over. I have to say I learned now not to do this with the equipment on, this is the second time I have done this scenario, the first was with my Bantam dac, I did the same thing and the same outcome, one channel out . Now I have two that I would like to repair but I do not know how to trouble shoot.Can someone suggest what and how to check or what to try to replace?

Let me guess - was one of the amps the Starving Student?
 
Regardless, given your description of the symptoms - replace the DAC chip.  Luckily, that's not such a big deal on the grubDAC.

  The Wolfson chip is almost the same as de-soldering soldering an SOIC-8 opamp.  Plus, it's very cheap.  On the Bantam, though, you might as well just build another.

 

[daves440]

Thanks Tom, I will order one and replace it, do you know what number to get for the Wolfson dac chip?  I have ordered the Pup Dac, but still will like to get the Grub dac working again. It was disconnected from an old Marantz 2235 and connected to a lepai, some time between this it happened. I never had a problem with my NAD surround.  I guess it is the disconnecting and re connecting of the amps that are on instead of turning them off?
Thanks

 

[scootsit]

Quote:

Thanks Tom, I will order one and replace it, do you know what number to get for the Wolfson dac chip?  I have ordered the Pup Dac, but still will like to get the Grub dac working again. It was disconnected from an old Marantz 2235 and connected to a lepai, some time between this it happened. I never had a problem with my NAD surround.  I guess it is the disconnecting and re connecting of the amps that are on instead of turning them off?
Thanks

Tomb (at least used to) sell that chip on Beezar...

 

[daves440]

Thanks Tom , Could you tell me what Wolfson dac chip to order?  Thanks for your help!

 

[daves440]

O.K.Yes it is availible at Beezar, Thank you Tom and Scot. I will let you know how it worked out.!