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820-3115 Sound problem

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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 :)
 
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aprendiz

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