820-3462 no green light

MUUK

Member
820-3462

No green light. Light liquid damage. to pp3v42 area



R6920 + R6905 burnt.
Replaced these.

PP18V5_DCIN_CONN 2.3v
PPVIN_G3H_P3V42G3H 1.1v

pp3v42 = 0.008v

Replaced:
C6992
C6991
C69901
R6995
R6996
C6994
q6910
c6995
c6999
u6990
u6900

PPVIN_G3H_P3V42G3H diode mode to ground0.35v
pp3v42 diode mode to ground 0.305v

Got lost on this one now would appreciate any help.
 

MUUK

Member
Thank you duke.


d6905
pin1 0.68v
pin2 0v (no battery connected)
pin3 0.67v




d6990

pin1 0.007
pin2 0.007
pin3 0.003
pin4 0.004
pin5 0
pin6 0.635
pin7 0.044
pin8 0.635

The probe point next to C6991 looks bad so i ran a wire from D6905 to C6991 and C6992 but this didn't change anything. continuity checked out.
possible that PPVIN_G3H_P3V42G3H leaking through the probe point ?
 

MUUK

Member
Thanks Duke,

Yes R6920 was initially burnt and was replaced.


q6910
pin 5/6 2.36v
pin 4 0.7v
pin 1/2/3 0.657v

replaced q6910 again in case donor board duff - no change.


R6910 99k
r6911 10.1k
r6912 68k
all measure within spec.

replaced c6912
R6910
R6911

no change

I concur that Q6910 is not opening but i don't know what else would cause it not to.

Thanks again.
 

dukefawks

Administrator
Oops sorry didn't see that.
So the charger is shutting down/not turning on. Try with a Chinese charger or an external power supply hooked up to the magsafe connector. This will bypass the protection circuit in the original charger.
 

MUUK

Member
Chinese charger gets green light and machine boots. Still nothing with original 85w - worth pursuing or just supplying chinese charger ?
 
Top