Macbook A2141 820-01700 No Response to Amp Meter

[Instafixx]

Hello,
I have a Macbook 820-01700 not turning on. No response to the AMP Meter as well.

But very dirty. Cleaned it.

PPBUS_G3H is shorted.
PPBUS_G3H_SSD_SNS shorted.

Where do i start?

 

[2informaticos]

What is the exact ohm value of that short?
Compare with the readings on all big coils.
Don't forget L9080/580...

 

[Instafixx]

Its 0 ohms - PPBUS_G3H
Getting 5V on PPDCIN_G3H.
R7021 — 1.00 Ω

R7022 — 1.00 Ω

R7061 — 1.00 Ω

R7062 — 1.00 Ω

All above are 1.2Ohms.

Should i replace the U7000 from a donor board ?

 

[2informaticos]

Don't touch U7000 yet.
Did you do what I said about the coils from secondary power supplies???

Remove F7000/1 and check which side the short remains.

 

[Instafixx]

L9080 and L9580 - Normal Diode Mode Readings are .395

Removed the FUSE. Short is at Pin #2 PPBUS_G3H.
Diode Mode Readings on Pin #1 is .480

 

[2informaticos]

OK, check all other big coils.

What is C7050 voltage, with both fuses removed?

 

[Instafixx]

C7050 is 12.26V without the fuses

 

[Instafixx]

Randomly Checking Found - PPBUS_HS_OTH5V Shorted - C7600

 

[2informaticos]

What do you expect, if is connected to PPBUS_G3H???

I said to compare short value with the readings on all big coils to ground.

 

[Instafixx]

All Big Coils i am getting diode mode readings which seem normal .300-.500

 

[2informaticos]

I doubt you get so high values on CPU/GPU coils.
Please, post exact reading on each coil.

 

[Instafixx]

Red to Ground

L7030 .373 on Both Pins.
L7701 .183 on Both Pins
L8102 is .056 on Both Pins
L7660 is .304 on Both Pins
L8410 is .833 on Both Pins

 

[2informaticos]

You couldn't find all of them?
Where are the mentioned GPU and CPU coils readings???

GPU coils are hidden under black plastic, in the middle of the board.
Use boardview, please.

BTW, no need to check on both pins of a coil....

 

[Instafixx]

LA730
LA720
LA740
LA710

Readings of all are 0.02

 

[2informaticos]

I said to compare with the reading on PPBUS_G3H side.
If no close reading value, then is safe to apply voltage injection method.

But you MUST be very sure have checked ALL coils.
And is not the case here. you still miss some of them!
Really, didn't see L3500, LB700, LA860/70, LA950, L7330, LA750, L7211, L7410???

Of course, check only ONE coil when you have more tied together...

 

[Instafixx]

What do you mean by comparing with PPBUS_G3H? i didnt get you. PPBUS_G3H is 0.001.

L3500 0.418
LB700 0.418
LA860/70 0.036
LA950 .056
LA850 0.073
LA750 0.006
LA7231 0.04
L7330 0.014
L7221 0.002
L7211 0.003
L7420 0.005
L7410 0.005

 

[Instafixx]

I have a 5A PSU only. Let me try and revert back. I have those resin smoke devices that help determining a heating component . Will try that if needed.

 

[Instafixx]

Found C6466 getting very hot. Replaced that. PPBUS is no longer short. Put Back the Fuses. Machine is ON. Thanks.

 

[Instafixx]

Hi Got another similar Case.

Here the PPBUS Short Value is 0.014.

All big coils reading are similar to what posted above.

Should we inject 1V