820-3115 Sound problem

stephsa

New member
we have a board with U6201 dead. some burning traces are on pins 38 and 39.
lost DZ6704 and DZ6705

I repair the area and change the two DZ and I changed and repair the area of the U6201.

Now we have sound (chime) on the boot and immediately a "crash sound" after the chime like a disconnection. And on the OS X there are no sound card just the spdif outpout.

We don't now how to find the problem. Thanks to help us :)
 

aprendiz

Moderator
this could be a bad headphone jack, do you have sound on headphones??, remove R6805 and check if sound comes back...
 

stephsa

New member
always the same problem. The output was ok on u6200 and I test all pin on the u6201 .
Does it possible to test the jack ?
 

dukefawks

Administrator
Audio jack will not cause distortion on audio through speakers. Is the 4.5V getting to U6201? Are all other supply voltages getting to U6201? Was U6201 replaced?
 

dukefawks

Administrator
I'm not sure what that should be but it seems to be for A/D conversion which would be tied in with the 4.5V supply. I still have no clear answer if you have 4.5V on pin 24,25 U6201.
 

stephsa

New member
Yes sorry the 4.5v was on the pins 24 and 25

perhaps the U6400 was the problem ? Does it possible to test it ? or does it possible to disconnect it and what we can see in this case on OS X ? I find this logic board with dead DZ6704 and DZ6705 and output 38 and 39 of the U6201 and the U6400 was on the way
 
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stephsa

New member
I find the pin 2 of the R6805 disconnected. So the test was the same and I solder this pin but it is the same result. A "slash" or "tac"before and after the bip sound when I don't place DDR or before and after the chime :-(
 

dukefawks

Administrator
I do not quite understand what you mean. You can leave R6805 out, it is only needed for SPDIF and no one uses this. Can you make a video of this "sound"?
Does audio work in OSX with R6805 removed?
 

stephsa

New member
I have replaced the U6201 and removed the R6805 and the result was the same.
for the video I have a message here "invalid file". And same message with just audio :-(
 

dukefawks

Administrator
It is possible that U6400 is pulling down the REF voltage for U6201. Is there low resistance/short on HPAMP_REF. You can remove U6400 too, just a mic will not work anymore but who cares about that.
 

stephsa

New member
I have changed the J6700 and under this I found a hole on the circuit board. I have repaired the circuit for this J6700 and replace the J6700. Now I have the sound on the left and right channel on the head set or on the MBP speakers but I found the same problem on the start and the stop of the sound playing. "Tchak...... tchak"

Other ideas please.

and thanks for all. I am just a junior :)
 
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