820-02773 boot loop

[Sr. Robot]

820-02773 that boot loops to half loading OS, sometimes not even that. With battery disconnected the loops are seconds long.

Tried disconnecting everything. No change.
Tried booting in safe mode, it also shuts down on loading boot options.
Wont go into DFU mode.

 

[2informaticos]

Try to enter DFU mode using DFU blaster.

 

[Sr. Robot]

I noticed sometimes it went into de OS.

DFU did nothing.


PPDCIN_USBC_AON goes to 0v when it shuts down, then to 5v an then 20v.

PPBUS_AON starts at 10v and then goes down to 9v when loading OS. When shutting down it goes to 5v

 

[2informaticos]

Any behavior change w/ and w/o battery?

 

[Sr. Robot]

PPDCIN_USBC_AON does the same but loops faster.

PPBUS_AON starts at 12.2v. Goes down to 8v and then 5v when shutting down.

I replaced U5200 just in case. No change.

 

[2informaticos]

Any fault history available?
Is the battery charging?
Tested with known good battery?

 

[Sr. Robot]

No history available.
Tried with known working battery and now it boots to OS but it isn't charging the battery.


SCL and SDA lines are 3.2v and pulse down to 2.7 each second.

Resistance over C5260 is 1.9 ohms and C5220 2.8ohms

RD207/8 are good.

The charger is recognized as 87w apple in the OS. The mac does take charge from the battery. It says 9h until fully charged.

 

[2informaticos]

"It says 9h until fully charged"
That means is charging.
What is the consumption current from charger, with machine turned off.

Sometimes, DFU can solve charging issues.

 

[Sr. Robot]

DFU restore made no change, only now is not displaying the 9hr timer anymore.

With machine turned off consumption oscillates between 30 and 130 mah

 

[2informaticos]

Do you get stable PPBUS_AON and 3V8_AON with charger alone?
Any history available?

 

[Sr. Robot]

With charger alone PPBUS_AON is 12.27 and cycles down to 5v.
3V8_AON is stable 3.8v

No history available.

 

[2informaticos]

Try reflashing/changing TBT ROM.