2015 12 inch macbook - no liquid damage. No sign of life

[kevinklinkmuller]

Hi there!

Have a 2015 12 incher here without any liquid damage and no sign of life.

Customer had told me that battery life was all over the place the last time it worked and since then nothing!

It can't be the battery because when i disconnect the battery it still doesn't do anything!
I have an amp meter hooked up. Says it's 20V with or without battery connected. and pulls around 0.15A without battery and 0.4A with battery

So it seems to be charging the battery somewhat

 

[JohnB8812]

Check for a short on PP3v3R3V0_AON. If so, U4700 is very likely shorted to ground. It is a very very common issue on this model.

 

[kevinklinkmuller]

Thank you! unfortunately, it's not shorted. could it be the charging port? I have one on order and it's coming soon to test or am I wasting my time with that?

 

[2informaticos]

U4700 is not always really short.
It can cause a low value on PP3V3R3V0_AON and nothing work then.
I suppose the board in question is 820-00045, confirm that.

You need to measure some voltages on the board.
Start posting resistance to ground on PP3V3R3V0_AON line; in diode mode, with red probe on ground.
Any voltage at R7120, F7140?

 

[kevinklinkmuller]

Changed the charging port just in case, same issue.,

yes 820-00045 isd the board


PP3V3R3V0_AON in diode mode is 0.307 at r6952

R7120 is 20V
F7140 8.6 V on both ends

 

[kevinklinkmuller]

im getting 20v at C7002 even through according to my board view it's supposed to be PPVIN_G3H which is 8.6... am i onto something here?

 

[kevinklinkmuller]

could there be voltage leaking into PPVIN_G3H?

 

[kevinklinkmuller]

PPVRTC_G3H is closer to 3.3v than to 3v which is what it's supposed to be

 

[2informaticos]

"R7120 is 20V"
Means the USB-C port is OK, SMC already "talked" with charger.

C7000-2 are not connected on the PPBUS_G3H rail...
PPVIN_G3H_P3V3G3H is the input rail for PP3V3_G3H power supply.
It comes out from U7100 only to connect 3 filter caps (C7000-2).
The control block, drivers and output MOSFETs of PP3V3_G3H power supply are integrated in U7100.

"F7140 8.6 V on both ends"
As you already got correct PPBUS_G3H, follow the Power On Sequence now.
Check signals and powers at U7600 and PCH System Power Management block.

 

[kevinklinkmuller]

Sorry to be a pain, i'm really confused by your last post. I'm stuck

Could you rephrase? thank you!

 

[2informaticos]

"F7140 8.6 V on both ends"
If you also get 3.3V at PP3V3_G3H, forget about U7100; it does what supposed to do.

Now check the 4 PCH's RTC signals, 32KHz from U1900, PM_SLP_SUS_L, PM_RSMRST_L, SMC_ADAPTER_EN, PM_BATLOW_L.
Does PM_PWRBTN_L react when you trigger SMC_ONOFF_L signal?

 

[ronaldo]

I got same Mac with exactly same issue and behaviour.
It was fixed by replacing SN650801 - U7600.