820-01521 - A1932 Stuck at 5V

[Instafixx]

Machine Stuck at 5V with 0 AMP Draw

PPBUS and PPDCIN are 0V.
No Shorts

 

[2informaticos]

"PPBUS and PPDCIN are 0V"
R7020 with 0V?

 

[Instafixx]

Yes

 

[2informaticos]

First, check F3000/10.
If good, check U3100/200 LDOs.

 

[Instafixx]

Fuse Diode Readings 0.148
Voltage
F3010 is 20V
F3000 is 0V.

U3100 LDO Diode Mode Readings

PP1v8_UPC_XA_LDOD is .034
PP1V1_UPC_XA_LDO_BMC is 0.526
PP3V3_UPC_XA_LDO is 0.026
PP1v8_UPC_XA_LDOA is .531

 

[2informaticos]

"F3000 is 0V"
Did you test connecting charger on its port?

"PP1v8_UPC_XA_LDOD is .034
.......................
PP3V3_UPC_XA_LDO is 0.026"
Replace U3100...

 

[Instafixx]

Replaced U3100.
Get Voltages at the shorted LDOs now.

Without Battery:

Machine still stuck at 5V.
When plugged into the USBC port corresponding to U3100 - I get PPBUS at 12.3V
When plugged into the USBC port corresponding to U3000 I get pubs at 1.8V

Both Fuse give 5V when plugged into their corresponding ports.

With Battery :
I get intermittent very high fan spin.

Tried DFU Revive but it gets stuck midway without giving any error message.

U3000 LDO is stuck at 2V instead of 3.3V

Is U3000 bad too ?

 

[2informaticos]

"U3000 LDO is stuck at 2V instead of 3.3V"
Do you mean U3200???

 

[Instafixx]

Yes U3200 . My Bad

 

[2informaticos]

It is bad probably...

 

[Instafixx]

Replaced both. Now pulling 20V. Fan Spins very high and then goes down. Amp Draw goes upto .543 amps and then goes down to .077.

 

[Instafixx]

Wifi Ic was shorted. Removed that. All shorts gone. Device now in recovery mode. Revive was successful and I get Lock icon. But still not on.

Did DFU Revive without Wifi IC present.

 

[2informaticos]

Machine should boot without WiFi chip.

What is amp draw behavior now?

 

[Instafixx]

20V Goes upto .300 Amps and then settles at 0.011 amps eventually

 

[2informaticos]

Do you get voltage on any big coils?
Check them for pulse at least.

 

[Instafixx]

L7410/30
L7210
L8102
L8410 (Checked with board on bench)
L8100

All are 0V. No Pulse
Stable Voltage at L7670/90.

 

[2informaticos]

If data is important, it can be recovered in DFU mode; by an authorized Apple service center.

 

[Instafixx]

Or else Restore ??

 

[2informaticos]

Restore will erase SSD; if completes without error.