MacBook can not turn on, no green light on the charger (820-2936-B)

[TerryLiu]

Hi,

Last week I tried to upgrade my MacBook pro 13' late 2011, yet screw touched battery jack and possibly burned the logic board. Now it can not turn on, and there is no green light on the charger.

I started to learn the board repair several days ago. Below is what I have now:

with only dc plugged:

1. PP3V42_G3H - 3.49v (is it too high?)

2. PPBUS_G3H - 0.16v

3. PPDCIN_G3H - 16.69v (is it too low? actually my J6900 pin1 (PP18V5_DCIN_FUSE) is the same reading)

4. SMC_BC_ACOK - 0v

5. SMC_RESET_L - 3.45v

6. R7010 pin2 (CHGR-ACIN) - 4V

7. R7021 & R7022 (current sencing check) - 10 ohm

8. Q7085 pin5 (PPDCIN_G3H_INRUSH_FET) - 0v

when only battery pluged:

1. PP3V42_G3H - 3.49v

2. PPBUS_G3H - 12.23v

4. SMC_BC_ACOK - 0v

5. SMC_RESET_L - 3.45v

I also notice after plugged in the battery, the PPDCIN_G3H_INRUSH will become 11.9v and once I plugged out the battery, the voltage keeps dropping very slow (seems like the capacitor is doing something). Does this mean anything wrong with Q7030? Do I need to change dc-in board, or U7000, or both? Is there any other possibility leads to the dead mac?

Thanks for your answering!

[reessi]

Re: MacBook can not turn on, no green light on the charger (820-2936-B)

I don't know the answer but have you checked Louis Rossman's Youtube channel, 1000's of videos on Mac Motherboard Repair.

Cheers.

[dellxps15]

Re: MacBook can not turn on, no green light on the charger (820-2936-B)

check:

1) 3.42 volt chip. it is a 6 pin and has 2 resistor for making 3.42 volts from 1.2 volt output.

2) check 2 mosfet on u7000 circuit q7030 q7035 if one of this is shorted and replace.

notebook start with battery only ?

edit: u7000 get hot ?

[malikmani]

Re: MacBook can not turn on, no green light on the charger (820-2936-B)

Check r7010 in resistance mode should be 30 ohms if it's read 25to 30 then
U7000 is bad as u7000 is responsible for sms-bc-acok to present what is voltage on pin 3 u7000 should be 4v

[malikmani]

Re: MacBook can not turn on, no green light on the charger (820-2936-B)

25 to 30 k ohms r 7010 then riststor ok u7000 need to replace

[TerryLiu]

Re: MacBook can not turn on, no green light on the charger (820-2936-B)

check:

1) 3.42 volt chip. it is a 6 pin and has 2 resistor for making 3.42 volts from 1.2 volt output.

2) check 2 mosfet on u7000 circuit q7030 q7035 if one of this is shorted and replace.

notebook start with battery only ?

edit: u7000 get hot ?

The MOSFET Q7030 and Q7035 are fine, no short to ground detected. The laptop can not turn on with the battery. U7000 is super hot when dc is plugged in. Didn't check the 3.42v chip since at this point I am pretty sure U7000 is faulty.

I will replace the unit first. In addition, could you provide some insight about why my PPDCIN_G3H is quite low?

Thanks!

edit: The chip won't get hot if the battery is plugged in

[TerryLiu]

Re: MacBook can not turn on, no green light on the charger (820-2936-B)

25 to 30 k ohms r 7010 then riststor ok u7000 need to replace

R7010 is 27.88 k ohms. Going to replace U7000 and see whether is works