Apple MBP16" A2141 820-01700 PMIC power cycles no boot no shorts
Bought myself a project thing. Apple MBP16" A2141 820-01700
No shorts, no visible waterdamage.
Dead. no history.
All USBC ports do 20V and charging battery.
If you plug battery/charger PPBUS is 12.6v and all power rails like RTC, 3v3, 5v etc are present. U7800 PMIC all voltages are present APART from PPVCCPRIMCORE_PRIM_REG (not sure if it has to be present at this stage?! resistance is 40 Ohm). SSD 2.5, 0.9, 1.8 are present on both wings. Charger meter shows 30ma or something like this on charged battery.
But what PMIC does is that it power cycles(dropping to zero for a second) all power outputs every 15-20 seconds to T2 and also 3v3 and 5v and SSDs. Its own power supply is fine so it is definitely some logic in it.
When battery is not charged - it starts ramping up current but as that PMIC reset happens it then drops and starts ramping again. You can fully charge battery overnight eventually.
You can put device into DFU either from keyboard or shorting pads and try to restore. In DFU there is no SSD and 5V rails present at first but when you proceed with restore they are coming on and present and PMIC is NOT resetting power anymore. But restore fails with 4014 error as timeout or saying got DFU when expected restore mode or vice versa. Tried different machine and cables and still same. I am observing DFU and restore modes in USB on other mac and can see iboot numbers etc so there's some life in there.
Not sure what the problem is. Should I clean the T2 ROM with external programmer? Not sure if that does any good. Any help is appreciated.
No shorts, no visible waterdamage.
Dead. no history.
All USBC ports do 20V and charging battery.
If you plug battery/charger PPBUS is 12.6v and all power rails like RTC, 3v3, 5v etc are present. U7800 PMIC all voltages are present APART from PPVCCPRIMCORE_PRIM_REG (not sure if it has to be present at this stage?! resistance is 40 Ohm). SSD 2.5, 0.9, 1.8 are present on both wings. Charger meter shows 30ma or something like this on charged battery.
But what PMIC does is that it power cycles(dropping to zero for a second) all power outputs every 15-20 seconds to T2 and also 3v3 and 5v and SSDs. Its own power supply is fine so it is definitely some logic in it.
When battery is not charged - it starts ramping up current but as that PMIC reset happens it then drops and starts ramping again. You can fully charge battery overnight eventually.
You can put device into DFU either from keyboard or shorting pads and try to restore. In DFU there is no SSD and 5V rails present at first but when you proceed with restore they are coming on and present and PMIC is NOT resetting power anymore. But restore fails with 4014 error as timeout or saying got DFU when expected restore mode or vice versa. Tried different machine and cables and still same. I am observing DFU and restore modes in USB on other mac and can see iboot numbers etc so there's some life in there.
Not sure what the problem is. Should I clean the T2 ROM with external programmer? Not sure if that does any good. Any help is appreciated.
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