Macbook A2681 Water Damage

[Instafixx]

Device came in as water damaged. There is no corrosion as such. cleaned the board.
Drawing 5V and almost 0 amps.
PPBUS and 3v8_aon not shorted.
PPDCIN is 5V.

 

[2informaticos]

Did you test with a charged battery?
Which voltages do you get on the MLB?

 

[Instafixx]

I only get voltage up till PPDCIN. Rest I don't get any voltages.

 

[2informaticos]

Post U5200's basic voltages: P_IN, AUX_DET, SMC_RST_IN, VDDA/P, EN_MVR, AUX_OK, A/BMON.
Remove F5200 and check C5252 voltage.

 

[Instafixx]

Voltage is 0.3V at C5252.
U5200
PPDCIN_AON_CHGR 5V
CHGR_AUX_DET is 0v
CHGR_RST_IN IS 0V
PPCHGR_VDDA/P IS 5V
CHGR_EN_MVR IS 0V
CHGR_AUX_OK - COULDNT CHECK.
CHGR_BMON IS 0V

 

[2informaticos]

"CHGR_AUX_DET is 0v"
Fix that.

What is CHGR_AUX_DET_SHORT_3V3 voltage?

 

[Instafixx]

CHGR_AUX_DET_SHORT_3V is 0V. No shorts.
UPC0/1_CHGR_AUX_DET_SHORT is also 0V no shorts.

Bad CD3217s ?
Both FF200/1 have 5V

Checking the LDOs PP3v3_s2_LDO is 0V

 

[2informaticos]

Check R5215/6 values (ohm scale).

 

[Instafixx]

I had replaced R5215 as it seemed burnt.
Resistance across pins
R5215 starts at 8M Ohms and goes down to 200k Ohms.
R5216 is 0.800 kOhms

 

[Instafixx]

Replaced R5215 again.
CHGR_AUX_DET is 5V
CHGR_EN_MVR is 5V
But CHGR_AUX_DET_SHORT_3V3 is still 0V

Now getting 12.3V at C5252

 

[Instafixx]

Put back the fuse. tuend it on. Amp meter went to 20V once and rebooted. them stuck at 5v.
Getting 5v now at C5252.
Removed the fuse. its 3.3V at c5252.

Something else is damaged as well.
CHGR_AUX_DET is 5V
CHGR_EN_MVR is 0V.
Now its 0.8V at C5252

 

[2informaticos]

CHGR_AUX_DET must be 0.9V aprox, with 5V input.
It goes to aprox 3.5V when input switches to 20V.

Replace R5216; it is open probably.
Be sure R5215 has aprox 800Kohm.
BTW, high value resistors must be checked out of board.

 

[Instafixx]

What should be the resistance of
R5125 and R5126 when measuring off the board.