820-00850-A DEAD

[Soji]

This A1989 came in dead
draws 5V found PPBUS_G3H is 6v...
i changed U7000 and the system draws 20V 0.00A
PPBUS_G3H is 12.31V
PP3V3_G3H_RTC is 3.3
PP5V_G3S not present
Want to try DFU but not entering DFU and T2 is warming up HELP!!.

 

[2informaticos]

T2 overheats?
Check voltage on the small coils around U7800.

 

[Soji]

T2 heats up to 38°c on thermal camera normal..
L7811-P0V8SLPDDR_SW0 is pulsing from 0V to 0.834V
L7806-PVDDCPUAWAKE_SW0 is pulsing from 0V to 0.758V
L7816-P0V9SLPDDR_SW0 is pulsing from 0V to 0.9V
L7814-P1V1SLPS2R_SW0 is pulsing from 0V to 1.1V

 

[2informaticos]

SLPS2R voltages must be stable.
PPBUS_G3H and 3V3_G3H_RTC pulsing too?

 

[Soji]

PPBUS_G3H and 3V3_G3H_RTC ARE STABLE

 

[2informaticos]

Check diode mode to ground on all big coils.
Don't forget L9080/580.

 

[Soji]

L9080=0.139
L8102=0.135
L8100=0.142
L7600=0.416
L7220=0.007
L7210=0.007
L7410=0.006
L7420=0.006
L7430=0.006

 

[2informaticos]

U7800 LDOs are stable?

 

[Soji]

LDO_RTC is stable

 

[2informaticos]

I mentioned the plural.
Can't you find other LDO lines of U7800?

 

[Soji]

I can only find two LDO'S
LDO_RTC and LDO_CORE

 

[2informaticos]

U7800 (SYM 1 OF 4) has various LDOs...

 

[Soji]

PP0V8_SLPS2R=0.798V stable
PP1V1_SLPS2R=1.1V stable
PP3V3_G3H_RTC=3.3V stable
LDO_RTC =1.5V stable
PP1V8_AWAKE=1.8V stable

 

[2informaticos]

All small coils around U7800 are pulsing?
None of them has stable voltage?
You may have T2 internal damage.