Re: A2251 820-01949 No Power

Got it to start powering up!

I was looking through the schematics and boardview, found a resistor "R8050" that delivers PPBUS_G3H to PMU_VDD_HI. From what I understand now that I got it working (almost) is that T2 has something to do with creating PP3v3_G3H, not like the old non T2 boards that had a dedicated IC for that.

New Readings:
PPBUS_G3H: 12.6v (was 12.3 due to bad resistor "R8050" and T2 boosted PPBUS to 12.6v)
PP3v3_G3H: 3.4v (I was trying to find this source for so long when it...

Re: A2251 820-01949 No Power

Well, I made a mistake. I rebuilt the whole U7000 area as it was totaled from corrosion and when I put new resistors on for R7015 I had it positioned the wrong way. CHGR_AUX_DET wasn't getting PPDCIN_G3H and was just connecting back to itself and only just noticed that when looking at the boardview and schematics.

Fixed that and now the charger is going nearly instantly to 20v 0.00a 100% of the time.

Current readings:

PPBUS_G3H: 12.35v
PP3v3_G3H: [B]0.98v[/B]
PP3v3_G3H_RTC: 3.4v

[B]Now...

Re: A2251 820-01949 No Power

No worries, thanks for all your help so far. I am using a "Keweisi KWS-1802C" bought from Louis Rossmanns store. In the past its been able to show small amperage.

I'll post some updates tomorrow.

Re: A2251 820-01949 No Power

Well, this board just doesn't want to get fixed now it's back to being stuck at 5v 0.00a.

PP3v3_G3H is 0v
PP3v3_G3H_RTC 0v

Not getting PPVIN_G3H_P3V3G3HRTC for U6903. Guess I'm really getting my practice in on this one.

Re: A2251 820-01949 No Power

Took measurements from a working 820-00850 and get ~120k to ground on pin 1 L7660, not sure if that helps or not.

Re: A2251 820-01949 No Power

Looks like its getting ~100k ohms to ground

Re: A2251 820-01949 No Power

Yeah, tried DFU mode and got nothing. Guess I need to dive into the schematics for the T2, thanks for the tip. I'll update the thread with any more information as I go in case others have a similar issue in the future. Any extra pointers you may have about T2 would be great, normally only work on non T2 MacBooks and trying to learn the new process.

Thanks!

Hello, I have an 820-01949 Macbook Pro that has MAJOR liquid damage. Luckily, the CPU and T2 seemed to have dodged it somehow. Initially, it only got 5v on the charger but I replaced U7000 and now I get 20v but not consistently, though generally if I just let it sit for a few minutes it goes to 20v. Still going through and fixing pads so it could just be a poor connection somewhere. I don't have much experience with T2 models but luckily it seems they are basically the same as non-T2 USB-C model. I ran it through my ultrasonic cleaner to help clean up the board.

Input: 20v 0.00-0.01...

Re: New Members - please post your introductions here

I am in college and trying to learn board level repair. Found this site when looking for boardview files and various schematics.