820-00928 No audio - High fan - Slow/sluggish

[Victor Holley]

Device arrived with complaints Audio is out. Reported new headphone jack and speakers.
System report AUDIO output says "Devices" and box is blank.
Sound settings show no output devices. Volume slider and mute box greyed out. Mute is checked
Slider on display and touch bar volume buttons function correctly.
Safe mode generates no difference.
U6200 and u6300 replaced to rule out still no change.
Could this be software related?



Device is on Big Sur. After weekend when trying to login normal device encountered a problem stating critical update needed and fails.

 

[2informaticos]

Try first disconnecting webcam.
ALS failure can cause critical update error.

Just in case. check U6360 output voltage.

 

[Victor Holley]

disconnected Display and used external monitor. Fails update. IS there another way to disconnect webcam?

btw
u6360
pin 1: PP1V8_S0_LDO_AUD "input" 1.8v
pin 2: GND_AUDIO_CODEC 0v
pin 3: L83_LDO_EN "output" 3.2v
pin 4: 3V3_S0_AUD "output" 3.2v
pin 5: GND_AUDIO_CODEC 0v

 

[2informaticos]

1V8 output is good.

Be sure U6300 gets all voltages; check L6300-2.

Audio codec not recognized, should mean there is a problem with U6200.
Check its resistors and traces to PCH.

 

[Victor Holley]

U6300
PP1V8_S0_LDO_AUD, C6301,L6300,L6301 - 1.8v
PP3V3_S0, L6302, 3.294V

U6200 Has many resistors. Is there any in particular? I2C,ASP_CLK etc?

 

[2informaticos]

Look at the left side "To PCH" marked lines...

 

[Victor Holley]

R1310 HDA_BIT_CLK , .907v
R1311 HDA_SYNC, .20v
R1312 HDA_RSTL , 1.795v
R1313 HDA_SDOUT , 0v

Checked twice. Yesterday and today values remain same

 

[2informaticos]

These resistors have correct ohm values?

 

[Victor Holley]

r1310, 32.7k
r1311, 32.7k
r1312, 33.1k
r1313, 33.6k

 

[2informaticos]

You meant 33 ohms I hope.

Did you also check R6203?
You can have bad U6200, or solders/traces.
Even bad PCH is possible.

 

[Victor Holley]

R6203 climbs to "0.012v" and then back to 0v. 33 ohms.

 

[2informaticos]

Do you still get critical update error message?

You should try known good BIOS.
Just in case, to discard BIOS upgrade failure.