820-4924 - No Power, No Liquid Damage

bcherdak

Member
"Didn't get 12.5V on PPBUS_G3H yet?"

FINALLY 12.58V on both sides of the F7140 fuse

Any more measurements you are looking for me to take?

PP5V_S4 still 0V
S4_PWR_EN - 0V
 
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2informaticos

Administrator
Staff member
3V3_S5/SUS, PM_RSMRST_L, PM_PWRBTN_L, PM_BATLOW_L?
Trigger SMC_ONOFF_L and check for reaction (drop pulse) at PM_PWRBTN_L; use R5115/16 pads, instead of power button.
 
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bcherdak

Member
Thank you so much for the continuous support you are giving me! I very much appreciate it.

VOLTAGE // OHMS MODE // DIODE MODE

PP3V3_S5 = 3.34v // 300Ohms and climbing // 0.1V (diode mode)

PP3V3_SUS = 3.34v // 10K Ohms and climbing // 0.425V (diode mode)

PM_RSMRST_L = 3.34v // 130k Ohms and climbing // 0.625V (diode mode)

PM_PWRBTN_L = 3.4v // 2k Ohms climbing slow // 0.5V (diode mode)

when triggering SMC_ONOFF_L the PM_PWRBTN_L = drops from 3.4 to .35V

PM_BATLOW_L = 0.1V // 10k Ohms and climbing // 0.5V (diode mode) (NO BATTERY CONNECTED???)
 
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2informaticos

Administrator
Staff member
PM_BATLOW_L must be high if proper charger connected.
If not, PCH doesn't start power on sequence.
Be sure to use original Magsafe 2 60/85W charger.
 

bcherdak

Member
"Be sure to use original Magsafe 2 60/85W charger."

It won't even start with a fully charged original battery from a working housing/chassis. It starts for a few seconds, pressing trackpad, cpu heats up and then goes back to nothing.

Will test with a brand new charger from apple store, will go out and buy one today.
 

bcherdak

Member
"So starts at least, with charged battery?"

With OEM battery connected, it starts kind of, trackpad is clickable (Taptic feedback), cpu heats up, then trackpad stops clicking and cpu cools down.

And doesn't even start with charger alone?"

When no battery connected but 85w MagSafe is connected, it does not start at all.

Does not start In general, it tries to start up to post but shuts off during start up phase.
 

2informaticos

Administrator
Staff member
So it tries to start on charger only.
Which voltages appear in that short time?
You should be able to catch some signal reaction, triggering SMC_ONOFF_L.
No change in SMC bypass mode?
 

bcherdak

Member
"So it tries to start on charger only."

When in the housing with an lcd connected and a trackpad and keyboard, NO BATTERY connected, it does not try to start up, trackpad is not clickable. CPU does not heat up.

When its on battery in the housing, it trys to start up, Taptic feedback trackpad clicks and cpu heats up then everything turns off.

No change in SMC bypass mode, not sure how to exactly trigger that, can you explain how to on a 2015 MacBook Pro retina 13"???
 

2informaticos

Administrator
Staff member
"it tries to start up to post but shuts off during start up phase"
You've posted this under charger alone option...
 

bcherdak

Member
Bought an OEM 85W magsafe 2, CPU heats up for a few seconds then cools back down and does not heat up again only until I unplug charger and replug it in.

If I do it enough times plugging it in and unplugging it, cpu heats up and fan spins for a second and then stops.

Any other voltages looking to test?
 
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bcherdak

Member
Will try new Bios chip,

Will bad bios cause no startup or partial startup?

any voltages you are wanting me to measure with this new Magsafe charger?
 
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