820-00850 water damage fan work but dead

yair37

Member
i got the board after cleaning, sew just damage at pp5v_g3s_alscam. i get 19v at charging, fan spinning but charging sound (no Caps lock light)

all 5v rail are missing
all g3s 3v-1.8v 5v missing
PP3V3_S4SW_SNS- 0v
PP3V3_G3S - 0v
PP3V3_TBT_X_S0 - 0v
PP3V3_TBT_T_S0 - 0v
PPVCC_S0_CPU - 0v
PPVCCGT_S0_CPU -0v
PP1V2_S3 -0v
 

yair37

Member
o.k i was changed U7650 an now...

PPVIN_G3H_P5VG3S - 12.2v
PPVIN_G3H_P3V3G3H -12.2v
PP5V_G3S - pulsing(voltage appear for half sec. then 0v for 2 sec and loop)
PP5V_S4SW - 0v
PP5V_S5_LDO - 2.7v then show 5v for half sec and back to 2.7v and loop
PP3V3_G3H_RTC - 3.4v
PP3V3_G3H_SSD0 - 3.4v
PP3V3_G3H - 3.4v
 

2informaticos

Administrator
Staff member
"PP5V_G3S short with charger"
Do NOT say you are checking diode mode (or ohm scale) with board powered on...
 

yair37

Member
im chacking with diode just without powered board! ....but at this rail by mistake i was check it...
I thought im at V check..
 

yair37

Member
yes there is 12.2v on ppbus.
o.k weird thing:
naked board charger ge 5v then 19v .
when i put the board back with all the connectors: without the battery its 5v on-off loop, and when i plug it with battery connector is 5v then 19v and fan run for a secound.
 

2informaticos

Administrator
Staff member
Test the board alone on the desk; it should start when charger is connected (no battery present).
Use an USB macOS pendrive with Link LED, to check for USB activity (if is the case).
Check voltage (at least pulse) at all big coils, in the first seconds.
 

yair37

Member
at this model its hard to check the board on the desk and check the fans...
its still weird.. on the desk(with nothing connected) charger show 19v, at the body with just the keyboard connected (because its connected with the fans) its show 5v and loop.
o.k the loop problem is when i connect the Battery Daughter Board Cable.
when its off its show 19v.
there is NO usb activity.

Check voltage (at least pulse) at all big coils, in the first seconds.
the fans working for a secound just with battery connected, and when the board on the desk its show 19v stable and just the pp5v_g3s is 5v looping ppbus is 12.2v stable
 

2informaticos

Administrator
Staff member
I mentioned fan spin as you said does it for 1s; so voltages should appear, at least pulse that time.
No need to connect fan, nor other thing; just check voltage in that time you know fan was spinning.
Fan requires 5V to spin, other voltages try to appear at least?
 
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