820-00244: Not Powering up, PPVBUS_LIO - 0v

Have another 00244 logic board, except this one isn't showing any sign of life. Also no sign of liquid damage.

PPVBUS_LIO - 0v.

I've compared resistance at F3050 with a known good board and it checks out. Any suggestions as to where to start with this type of failure?
 

JohnB8812

New member
CPU getting hot on this one too? If no, check if you have 5 or 20 volts on DC in first as well as what voltage you get on PPBUS_G3H
 
PPVBUS_LIO is the main dc line from j9600. Also ppbus_g3h is also 0V.

PPVBUS_LIO does initially spike to almost 1v then drops to 0v when the charger is first plugged in.
 

2informaticos

Administrator
Staff member
Check resistance to ground (diode mode) on PPBUS_G3H and all power rails of U3100.
Also test the same at F7040 and L6995.
 

2informaticos

Administrator
Staff member
"PPBUS_G3H - 0.02v"
Is that diode mode, or voltage reading?
Don't post end "V" for diode mode readings...
 

2informaticos

Administrator
Staff member
Charger gets protected, so no voltage apllied to board.
There is no reason to check voltages on the board; just diode mode...
 
Value to the left is with positive multimeter probe to ground pad. Value to the right is with multimeter ground probe to ground pad.


PPBUS_G3H - 0.461/OL

PPVBUS_LIO - 0.592/OL

PP1V8_SUS - 0.424/1.40

PP3V3_UPC_VIN - 0.586/1.536

PP5V_S4 - 0.3172/1.9

PP3V3_S4 - 0.4831/1.5

PP3V3_UPC_XA_LDO - 0.5281/1.6

PPDCIN_G3H - 0.5787/OL

P1V2S5SW_HSMUX_EN - 0.77/1.44

PP1V8D_UPC_XA_LDO - 0.491/1.4
 
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