820-3330-B missing PP3V3_SUS

[dudipupan]

Hello everybody

actually I struggle at an old Macbook Pro (820-3330-B).
Is takes 19-20 mA and PP3V3_SUS is missing (40mV).

On Q7820 i got PP3V3_S5 3.37V and P3V3SUS_SS 3.34V.
I need some hints why my PP3V3 is so low :-/

Thank you
dudipupan

 

[2informaticos]

Which is the exact PPBUS_G3H voltage?
Are you using original 85W charger?
Check PM_BATLOW_L voltage.

Is the battery charging?
Did you try to start in SMC bypass mode?
Also try to start with charger and battery connected.

Check the 4 PCH's RTC signals.

 

[dudipupan]

PPBUS_G3H is stable with 12.73V.
I already tried it with the original 85W charger but in general i'm using a 10A PSU on 18.5V.
PM_BATLOW_L is also low (~10mV)

The battery is chargin.
Didn't tried SMCbypass mode yet.
Dows not tun on with charger and battery connected.

The 4 RTC signals:

RTC_RESET_L: 3.35V
PCH_SRTCRST_L: 3.35V
PCH_INTRUDER_L: 3.05V
PCH_INTVRMEN_L: 3.25V

PPVRTC_G3_PCH: 3.35V

I noticed now that if i connect battery and charger for some time (~5 min) the fans start spinning for ~1second repeatedly all 3 seconds.

 

[2informaticos]

Try with known good working battery.

 

[dudipupan]

Is it normal that this MBP only powering on with a battery connected? Got several MBP from 2009/2010 not powering on without battery.

 

[2informaticos]

The board should start without battery, but needs 85W charger.
However, battery is required for proper work pn this board.

 

[dudipupan]

So I just looked again at this problem (with a new battery and still not powering on) and measured the RTC signals again:

RTC_RESET_L: 3.30V
PCH_SRTCRST_L: 3.30V
PCH_INTRUDER_L: 3.05V <---- seems not stable... slowly decreasing.
PCH_INTVRMEN_L: 3.25V <---- seems not stable... slowly decreasing.

Also tried SMC bypass mode - without success.

 

[dudipupan]

Maybe also interesting:
Battery is only charging when i connect the battery first.
On other boards the battery is also charging when I connect the battery after the magsafe.

 

[2informaticos]

These boards have strange behaviour without battery, or fake chinese battery.

RTC signals look good.
PM_BATLOW_L still missing?
You can test with 2011 battery, if original not available.

BTW, do not force your luck connecting/disconnecting battery once charger is present.
SMC can be damaged through I2C battery bus.

 

[dudipupan]

I have tried it already with all batteries for 15" MBP i got ? Known good original ones and new third party ones.

PM_BATLOW_L is still missing ?

Okay, that is good to know, thank you ? Will try to avoid it in future ?