A1502 820-3536-A no power

[hgoncalves]

Hi,
I have an A1502 820-3536-A that had liquid contact, and the client had already made an ultra-sound.
It has green light, consumes 25mA in PSU, has no USB activity and doesn't power on.
I get this measurements:
PPBUS_G3H - 12.58
PPBUS_S5_HS_COMPUTING - 12.58
PPBUS_S5_HS_OTHER5V - 12.58
PPBUS_S5_HS_OTHER3V3 - 12.58
PPDCIN_G3H_ISOL - 19.7
PP3V42_G3H - 3.4
PPVRTC_G3H - 3.3
PP5V_S5 - 5
PP3V3_SUS - 3.3
PP1V05_SUS - 1.0
PP3V3_S5 -3.3
PP5V_S4 - 0
Can you help?

 

[2informaticos]

You should reball SMC, as basic step for liquid damaged boards.

Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L.
If yes, check for pulse at all PM_SLP_Sx_L signals at same time.

 

[hgoncalves]

Hi,

I get 140V on L7130/1. Is it normal? I also had 94V on L7630/1, but as it seams a little broken i replaced, and after replacement i now have 14.5V. Is it normal?
I don't think that this values are ok, but don't know what to do...

 

[2informaticos]

Change the multimeter, or its battery at least.

 

[hgoncalves]

I already changed the battery with the same result. It's strange, because all the other measures seams to be right (even on the same coill on pad2 i get 12.5V). On U7100/23 i also get a strange value of 185V.
Checked with a new multimeter (same model UT61E), with same high values.
Do you think that it are the multimeters?

 

[2informaticos]

Possibly wrong settings on the multimeter; get a cheap one.
On the coils, check DC voltage on output pin.

 

[hgoncalves]

with a different multimeter model i have 12.5V on both pins

 

[2informaticos]

Do you get any pulse at 5V_S4 coil?
Check diode mode to ground.

 

[hgoncalves]

HI, it was the R1963. I notice the it was a little dark and replaced, and after replacement it started to work.
Does it make sense to you, or could it be the heat applied to the U1950?

 

[2informaticos]

Broken R1963 will stop the power on sequence; it must be 0 ohm.
Problem should be fixed now...