820-00840 no power. Stuck at 5V

BCN_Techs

Member
No water damage. Just stopped working. visual inspection with no result, board seems ok.


Power rails:

PPBUS - 0V ( not shorted)
PPDCIN_G3H - 5.2V
PP5V_S5 - 0V (not shorted)
PP3V3_G3H - 0V (not shorted)
BUF_SMC_RESET_L - 0V
SMC_RESET_L - 0V


CD3215 no LDO have voltage.
 

2informaticos

Administrator
Staff member
So you don't get voltage on any CD3215 LDO?
Compare diode mode readings on all LDO with another board.
Any voltage at R7020?
 

2informaticos

Administrator
Staff member
Any board with CD3215 should have similar readings!

Post few basic voltages on U7100; TBA_AUX_DET. TBA_VDDA/P, PPVIN_G3H_P3V3G3H, PM_EN_P3V3_G3H.
 

BCN_Techs

Member
got same board today (working)

U3100
PP3V3_UPC_XA_LDO 0.505 (0.505--> will put here working board)
PP1V8_UPC_XA_LDOA 0.525 (0.521)
PP1V8_UPC_XA_LDOD 0.486 (0.482)


U3200 are same almost may be with 0.001-0.003 difference that i think doesnt matter.



TBA_AUX_DET - 1.2V

TBA_VDDA/P 5V (both)

PPVIN_G3H_P3V3G3H 1.2V

PM_EN_P3V3_G3H 2.2V
 
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BCN_Techs

Member
PPVIN_G3H_P3V3G3H - 0.150

R6906/05 are ok. About D6905 is very strange because replaced it from donor board and not usb pulsing ( i have usb-c adapter that show V and Amps and it is blinking every 4-5 seconds ) and not recieving voltage, put back original and get 5V again. D6905 ?
 
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2informaticos

Administrator
Staff member
"PPVIN_G3H_P3V3G3H - 0.150"
That's no good.
Suspetcs are C6990/91, U6990, C7078, U7000; remove them (one by one), in this order.

Why don't you check diode integrity, instead of changing???
 

BCN_Techs

Member
I would like to use it but I dont know very well how diode integrity is working.


What make you think that 0.150 is failing C6990/91, etc?
 

2informaticos

Administrator
Staff member
Should be much higher; similar issue 2-3 weeks ago in other thread.
You should read all, nor only personal threads...
 
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