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820-01958 A2179 - No Audio

I

iMuhtaseb

Member
Came in for liquid damage on Right I/O experiencing no Audio at all;
Mic is working, output is shown in system settings, audio jack working OK.

Tried known-good Right I/O with good known speakers with good cable and still issue is not resolved
Tried DFU and restore with fresh macOS; still same issue

Diode mode reading on MLB it's OK (no I/O board was connected atm)
I measured diode readings on bad I/O and found SPKRAMP_INT_L diode reading is high 0.780 instead of 0.413.
 
2informaticos

2informaticos

Administrator
Staff member
Usually one of T2 lines connected near PPBUS_G3H on the audio flex, gets damaged.
In such case you should find a very low value to ground on that line.
However, higher value than normal may denote a problem too; but not usual to find...
 
I

iMuhtaseb

Member
Those voltage readings are with a known-good I/o and known cable whilst computer is awake

SPKRAMP_INT_L = 1.8v
AUD_PWR_EN = 1.8v
CODEC_WAKE_L = 1.78v
CODEC_INT_L = 1.78v
CODEC_RESET_L = 1.8v

CODEC_INT_L means Codec will initiates when the line is low, correct? but the line is not low..

Sadly I don't have a known good A2179 to compare readings

Do I just go ahead and try to replace T2?
 
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