820-4924 Liquid Dead

[Ryanlen2]

This board came in dead, no power. Q7180 was dead so I replaced and now have PPBUS and PP3v42. There was corrosion present under the SMC, so I have done a reflow on it as well. No more 4924 donors to replace it. Here are measurements.

PPBUS - 12.58V
PP3v42 - 3.428V
PPVRTC - 3.336V
PPVIN_S5_HS_Computing - 12.58V
PP18vDCIN - 16.6V
PP5V_S5 - 5.02V
PP5V_S3 - 0V
PP3v3_s5 - 3.35V
pp3v3_3 - 0V
SMC_RESET_L - 3.396V (Charger turns green then back to amber when I measure this)
SMC_ONOFF_L - 3.412V

Thank you.

 

[dukefawks]

The usual suspects apply, U1900, U1950, U6100 and termination resistors and traces. Maybe pull SMC and reball, it seems to be running as PPBUS is 12.56V.
Check PPVRTC too.

 

[Ryanlen2]

Hey Duke. Swapped SMC and now this board will now boot/chime, PRAM, caps lock on external KB; but only with Chinese charger. Im not sure if it would have booted before swapping the SMC with a Chinese charger... I didn't think to try. Also no video at all. 0 volts going to LCD. Thanks man.

 

[dukefawks]

Get a green/orange light with an original charger?

 

[Ryanlen2]

Im pretty sure I do. Im not at shop now, but Im pretty sure I do. Thanks Duke.

 

[Ryanlen2]

Green/Orange light with original confirmed. Thanks.

 

[dukefawks]

SMC came from identical donor? Tried a known good LCD for 2015! model?

 

[Ryanlen2]

SMC came from 4924 donor. I have not tried another lcd yet. Wanted to figure out power issue first. Why would it power on with chinese and not original? Using 85W original charger. Maybe its my charger?

 

[dukefawks]

Voltage on PPDCIN_G3H_INRUSH with original charger?