820-00850 20v 0.04a

[No-Clean]

No history available.

Tried restoring T2 firmware under catalina and big sur but same problem

Checked for shorts on all rails and found nothing.

PP3V3_G3H: 3.3V
PP5V_G3S: 5V
PPBUS: 12.62V
PP0V9_SSD0: 0.9V
PP1V8_SSD0: 1.8V
PP2V7_NAND0: 2.5V* not sure if this is a problem

CPUVR_SWSA: 0V
PVCCIO_PHASE: 0V
P1V2_PHASE: 0V

 

[2informaticos]

So DFU completes correctly?

I suppose you don't get VCORE and VCCSA, apart of VCCIO.
1V2 for RAM must appear before.
Post U8100 basic voltages; pins 12, 16, 17, 6.

BTW, STOP to check voltages in the AC side of a coil; ALWAYS check on its output (DC side), where the filter cap is placed.

 

[No-Clean]

DFU fails, I tried on both Catalina and Big Sur.

U8100:1 PP1V2_S3 0V Not shorted
U8100:12 PP5V_EDRAM_V5IN 5V
U8100:16 PVDDQ_EN_R 0V Not shorted
U8100:17 MEMVTT_EN_R 0V Not shorted
U8100:6 P1V2REG_VREF 0V Not shorted

Thanks for the heads up, I will do that from now on.

 

[2informaticos]

U7800 doesn't send out PVDDQ_EN for some reason.
Maybe missing previous voltage rail, or power good signal.

Machine is recognized in DFU, but cannot complete restore, nor revive options?

 

[No-Clean]

Reballed and checked U7800 but PVDDQ_EN is still 0V.

Machine is recognized in DFU, but cannot restore nor revive in neither Catalina nor Big Sur.

 

[2informaticos]

Did you check if other previous voltages expected by U7800 are present?
We have posted on the forum two power on diagrams for T2 machines.
Are from different boards, but still help.