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[SOLVED]820-3787 no audio output or input - bluetooth sound works

ytesfay80

ytesfay80

Member
This machine doesn't appear to have any liquid damage and the customer says no sound works on here but it does work with bluetooth audio. No ouput or input devices are detected on the sound page. I have done an SMC and PRAM reset but that didn't fix the issue.

I tried shorting pins 1 and 2 of the headphone socket to see if that would fix the issue as it worked on a previous machine I had with a similar issue but that didn't solve this issue.
I checked the voltages on L6607/8 with a headphone plugged in. With no headphone plugged in I get 0v on both.
L6607 - 0.10v
L6608 - 0.37v
 
ytesfay80

ytesfay80

Member
PP3V3_S0_AUDIO_ANALOG - 3.25v
PP4V5_AUDIO_ANALOG - fluctuating quickly from between 1.31v to 1.49v.
PP5V_S0_AUDIO_AMP_L - 5v
PP5V_S4_AUDIO_XW - 4.94v

L6200/1 both have correct voltages on both sides of them.
 
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ytesfay80

ytesfay80

Member
Update: I just touched the U6201 chip after turning the machine on and it gets extremely hot so I will have to replace this chip. I see this is a BGA chip and I don't have a stencil to reball one from a donor nor am I good at reballing these chips.

Do you know of a trick or easier way to replace this chip?
 
ytesfay80

ytesfay80

Member
How do you reball it by hand without a stencil? I manually put solder balls on each pad of a donor chip and as soon as I put even the smallest amount of hot air near it the solder balls slid off the pads.
 
ytesfay80

ytesfay80

Member
Do you have a link to where I can purchase this stencil you use and what size solder balls are best for this chip.
 
ytesfay80

ytesfay80

Member
Okay I replaced u6201 and now I get a chime through the speakers but when I login to the OS there is no sound through speakers and it stays on "digital output". If I plug in headphones it switches to headphones and i can hear sound through them but when I unplug the headphones it goes back to digital optical output.

I'm not sure if this is due to a chip not being on correctly but I think I soldered it on on correctly as I've done plenty of LP8550's but I have 1 more of these chips left so I don't want to use it yet if that isn't even the issue.
I measured r6324 and it was only showing .22v on both sides even though the resistance measured fine. I replaced it along with r6323/ r6332 and now I get 3.3v on both sides of r6324.

I also tried shorting pins 1 & 2 of the headphone socket to see if that would work as it did on a similar issue I had in the past but that didn't work either.

I get 0v on both sides on L6607/08 with and without headphones plugged in. Diode mode of L6607 is 1.09v and on L6608 it is 0.61v

I did a reflow on the U6201 chip but that didn't fix this. Also, I am getting a red light appearing from the headphone jack.
 

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ytesfay80

ytesfay80

Member
I've been doing these tests without the I/O Board plugged in. Does that board matter on these Retina Macbook Pro's?
 
A

aprendiz

Moderator
wow, so sorry, i was confused, this could be a bad headphone jack, also inspect for ripped components around headphone jack...
 
ytesfay80

ytesfay80

Member
I don't see any damaged components around the headphone jack but is there any way I can check if the headphone jack is the issue without removing it?
 
ytesfay80

ytesfay80

Member
Not sure what you were asking in the first part but there is continuity from L6604 to L6608. In diode mode both L6604/08 were 0.61v
Diode mode of L6607 is 1.09v and on L6608 it is 0.61v
 
ytesfay80

ytesfay80

Member
aprendiz dukefawks

Any other ideas on this or should I just go ahead and replace the headphone jack?

Update: I removed both L6607/08 to see if that would fix this but that didn't solve the issue. I went ahead and just removed the headphone jack but that didn't fix the issue either.
Could it just be an issue with the U6201 chip I put on?
 
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ytesfay80

ytesfay80

Member
Is there anything else I can check for on this before I try replacing U6201 again?

I'm not very familiar with audio circuit and I can't find much information on the web on this similar issue.
 
ytesfay80

ytesfay80

Member
I put another headphone jack on as well as L6607/08 and the issue still remains. I still get sound when I plug in headphones.

I get 0v on L6604/08 and L6607
Diode mode reading of L6607 and L6608 is 0.597 & 1.17v
 
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