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820-00840: PPBUS_G3H missing. PPDCIN_G3H 5.1v.

M

macRepairAmb

Member
Hello Gents

Received a unit that doesn't power up. Only history i have was that someone was trying to work on the board and messed it up while trying to remove the screws. Trackpad cable is all messed up. R7745 was turn off, Also C6408.
I've replaced R7745, since C6408 deals with speaker, decided to hold off till i restored power.

So far, the only voltage measurements i've gotten are:

PPBUS_G3H: 0v
PPDCIN_G3H: 5.19
PP20V_USBC_XA_VBIS: 5.19

Any suggestions?
thanks
 
2informaticos

2informaticos

Administrator
Staff member
3V42_G3H and SMC_RESET_L present?
Check diode mode to ground on F7000.
Probably problem with CD3215 chips from USB-C power input.
 
2informaticos

2informaticos

Administrator
Staff member
Ooops, even if CD3215 chips are good, SMC is not working.
You need 3V3_G3H first.
Diode mode to ground?
 
J

JohnB8812

New member
PPBUS will always be missing if DC-in is 5 volts. As 2informaticos asked, diode mode on PP3v3_G3H? Resistance to ground in ohms would be ok too.
 
2informaticos

2informaticos

Administrator
Staff member
Post U6990 voltages; pins 2, 10, 1, 3, 9.
Do you have short at C6990/91?
Could be bad U6990, or U7000.
Don't forget to check R6906 and D6905.
 
M

macRepairAmb

Member
U6990
1 - 0
2 - 5.04
3 - 0
5 - 0
10 - 0

R6906 - 5.19
D6905 pin 1 - 0.4, pin2 - 5.18

So when i plug the battery, PPBus_G3H is now about 10v, but only with the battery,
 
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