[SOLVED]820-3437-B no power

[aurel476]

Tried good know charger, IOboard, flat cable, no power no fan spin light green and after orange

PP3V42_G3H 3,42v
PPBUS_G3H 8,56v
SMC_ONOFF_L 3,42V
SMC_RESET_L 3,38V
SMC_BC_ACOK 3,38V
SMC_LID : 92,2Kohms

 

[aurel476]

L7520 0v,
l7560 3,3v

 

[SoloHarty]

Are you getting PP5V_S5?
L7520 seems to be powered by PP5V_S4RS3. If PP5V_S5 is missing then I dont think you would get P5VS4RS3 Have you checked the P5VS4RS3_EN on U7501?

I've only had a quick glance so I may be reading it completely wrong.

 

[aurel476]

PP5V_S5 : 5V
P5VS4RS3_EN_R on U7501 : 0V and pin 2 of U7501 P5VS4RS3 0V

 

[dukefawks]

History on the board? Is it power cycling, check carefully on L7520 best done with a scope as multimeter are too slow to catch. Inspect usual areas U6100, U1950 pin 8.

 

[aurel476]

Liquid damage, but clean by ultrasonic by customer, board seem clean

Pin8 of U1650 3,42V

U6100 clean

 

[dukefawks]

U1950 not U1650. Inspect whole board closely for corrosion damage.

 

[aurel476]

yes sorry pin8 of U1950 3,42V, find capacitors, resistors broken by corrosion solved thanks