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820-00281 Not turning on...No Liquid Damage

peeka79

peeka79

Member
Hello, I have a 820-00281 that has No Liquid Damage at all and Will Not turn on...Board reads 19.94V - 10mA to 61mA... Here are some Measurements I have taken with the Board out of the Machine.

PPDCIN_G3H = 20V
PPBUS_G3H = 12.56v
PP3V3_G3H = 3.39v
PP5V-S5 = 5V
PP5V_S4 = -0.00V
PP5V_S0 = 0.012V
PP20V_USBC_XA_VBUS = 0.000V on F300
PP20V_USBC_XB_VBUS = 0.000V on F3001
(BOTH SIDES OF F3000 & F3001 Read the same)

USB-C Ampmeter reads 19.94V and goes from 10mA to 61mA and back to 10mA...61mA....And

PLEASE HELP ?
 
peeka79

peeka79

Member
Thank You for Your response 2informaticos.... I Just Noticed U8200 for 3.3v SUS Switch is Completely Missing on the Board!! Can I replace U8200 from another 820-00281 Board or a 820-00928 Board? I have Both donor boards here.
 
peeka79

peeka79

Member
I replaced U8200 off of a Donor board and when the board was plugged in it Blew out U8200 so I Immediately unplugged the charger and removed the U8200... I am still getting the same measurements as before I put the U8200 on...Here are the Measurments on the pads of U8200 with it off...
Pin 1 (PM_SLP_SUS_L) = 3.2V
Pin 2 (PP3v3_S5) = 3.2V
Pin 3 (PP3v3_SUS) = -0.000
Pin 4 GROUND

Was it a Bad U8200 Chip? It has a Little hole in the U8200 chip now...
 
2informaticos

2informaticos

Administrator
Staff member
Did you check 3V3_SUS rail for short???
Never power up a board directly after change a component; think why it was burnt...
 
peeka79

peeka79

Member
I Have a Couple more U8200s But I believe your right and there is a shirt on the 3v3_SUS line....any ideas where in the board I should start to find out what?s causing the short?....I REALLY APPRECIATE all your help :)
 
2informaticos

2informaticos

Administrator
Staff member
Inject voltage there.
Start with 1V and go up, maintaining ampers bellow the limit of your bench power supply.
Do NOT inject more than 3.7V in any case.
 
2informaticos

2informaticos

Administrator
Staff member
Did you hear about Ohm law???
Do you want to adjust V and I at same time, when R is constant?
V=IxR, I=V/R, R=V/I, depending how you like to write it...

Adjusting V, automatically modifies I accordingly; no matters how many Amps you want to have.
 
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