820-3115-B Audio Jack Issues

Sr. Robot

Member
Hi, i have an 820-3115-B with issues on the audio Jack. The jack itself and the board look pristine.

The jack only works before playing any audio (if i plug it after playing something it will not detect). If i close/open the lid it is detected again. The audio has a ton shit of noise. The jack is receiving 3.3v. Also tried another OS installation.

I compared the diode mode on the data pins with a good working motherboard of the exact model and i got this:

Good Board / Bad Board

AUD_CONNJ1_TIP: 0.592 / 0.753
AUD_CONNJ1_TIPDET: 0.596 / 0.754
AUD_CONNJ1_RING: 0.599 / 0.755
AUD_SPDIF_OUT: 0.6 / 0.6
 

2informaticos

Administrator
Staff member
Do you note to have the red light on inside the jack?
Usually bad contacts; check Youtube about how to clean it.
Remove R6805 and test again.
 

Sr. Robot

Member
Red light is not on with headphones unplugged.

Cleaned the jack with contact cleaner and alcohol.

Removed R6805 no change.
 

piernov

Moderator
Staff member
I have a somewhat similar issue on a nightmare-ish 3115 (jack not detected when hot plugged, need to put the machine to sleep then it is detected but with heavy distortion on the headphones, speakers work fine) but with heavy liquid damage. Haven't solved it yet, I'll come back at it in a while. Voltage measurements showed some discrepencies compared to a known good board on the audio jack analog outputs, one of them is also used for jack detection when shorted to one jack detect line IIRC. In my case the jack itself looks fine (and static resistance/diode mode measurements look fine too) and replacing the audio codec IC didn't make any difference. Will keep you updated if I get more info on this.
 

piernov

Moderator
Staff member
Here are some additional notes about my board if it can help you:

Liquid damage on at least a third of the board, all over the edge near display (on both sides but mostly underside), some around PCH, some other parts affected like Q7840 and a bit around audio codec IC, lots of damaged parts and a several burnt vias. Almost fully working but the audio jack… Internal speakers work fine. Headphones won't get detected unless I put the machine to sleep and wake it up. But headphone output is distorted, more on the left channel btw. It "pops" when audio codec wakes up/goes to sleep, pretty much when DC gets sent out. Sure enough, it looks like there's 2VDC on both channels. Replaced the audio codec IC, same thing. There's also 2VDC on HPREF, which I assume is what causes 2VDC on the output. I thought it may have been caused by U6400 so I removed it, same thing. I cut the trace just before TP[1]HPAMP_REF to isolate the audio codec IC, I now have 3V on the audio codec IC HPREF pin and 0V on the rest of the line. Now it's stuck in optical out. Previously L6400 was missing which caused U6400 to pull the SDA line low but that's been taken care of.
 

2informaticos

Administrator
Staff member
When sounds no good, can you still see macOS switching correctly headphones/speakers?
Just in case, disconnect BIL and check if the issue is still present.
 

Sr. Robot

Member
macOS will only switch to headphones when i start playing the audio (not when connecting), and after i disconnect it goes back to speakers.

If i reconnect without turning off/closing the lid the headphones wont work and it wont switch from speakers either.

Disconnected BIL same thing.
 

Sr. Robot

Member
Here are some additional notes about my board if it can help you:

Liquid damage on at least a third of the board, all over the edge near display (on both sides but mostly underside), some around PCH, some other parts affected like Q7840 and a bit around audio codec IC, lots of damaged parts and a several burnt vias. Almost fully working but the audio jack… Internal speakers work fine. Headphones won't get detected unless I put the machine to sleep and wake it up. But headphone output is distorted, more on the left channel btw. It "pops" when audio codec wakes up/goes to sleep, pretty much when DC gets sent out. Sure enough, it looks like there's 2VDC on both channels. Replaced the audio codec IC, same thing. There's also 2VDC on HPREF, which I assume is what causes 2VDC on the output. I thought it may have been caused by U6400 so I removed it, same thing. I cut the trace just before TP[1]HPAMP_REF to isolate the audio codec IC, I now have 3V on the audio codec IC HPREF pin and 0V on the rest of the line. Now it's stuck in optical out. Previously L6400 was missing which caused U6400 to pull the SDA line low but that's been taken care of.
Thank you very much for your help. Im trying to understand it but im relatively new to this.

Yeah, mine pops too when connected.
 

piernov

Moderator
Staff member
In my case replacing U6400 and C6405 seems to have fixed the problem. U6400 is involved with the bias circuit and C6405 was corroded. I think U6400 was actually the culprit but since I missed the corroded C6405 at first I replaced it at the same time.
 
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