820-01700 - No power - 20V 0.8A

[ronaldo]

Hi.
Got this Mac to repair which has no signs of liquid. No previous history.
Battery is dead, but I tested with a good working battery and still same.
PPBUS_G3 - 12.7V
PP3V3_G3H_RTC - 3.38V
PP1V8_SLPS2R - 1.8V Cycling.
T2 is glowing from one side and cycling.
SLPS2 and Awake is all cycling.

PP1V2_S3 - 0.082 On a good board it measures 0.160 and FlexBV 0.223

Do you think that would be an issue with the RAM modules?
Thanks

 

[2informaticos]

Test board (0.160) has the same RAM capacity?
You may have lower reading for 32GB than 16GB.

All U7800 LDOs cycle?

 

[ronaldo]

• LDO0: 0.8V Cycling
• LDO1: 3.0V Cycling
• LDO2: 1.2V Cycling
• LDO3: 1.8V ~ 1.78V
• LDO_RTC: 1.5V Stable
• VOUT_RTC: 3.3V ~ 2.69V
• LDO_CORE: 1.5V

 

[2informaticos]

Did you check diode mode to ground on all coils?
Don't forget L9080/580.

 

[ronaldo]

I forgot to mention at the beginning.
I've checked all the coils in diode mode and all seems fine.

 

[2informaticos]

You may have problems with T2, or U7800.

 

[ronaldo]

U7800 replaced an same issue.
Revive gets stuck on Installing system.
Do you think the T2 ic itself is faulty or it still could be software?

 

[ronaldo]

In DFU mode before staring Revive option all the power lines mentioned above are stable.
As soon as I press Revive or Restore it starts to cycle again.

 

[2informaticos]

Be sure to connect battery with some charge on it.
Possibly problem appears when DFU try to power SSD.

 

[ronaldo]

Good battery. Tried revive and still same.