Water damaged M1 MacBook Pro (820-02020)

[iMuhtaseb]

USB-C ammeter takes 5V
PPBUS is 12.3V
3V8_AON is present
1V8_AON is present
PP3V3_S2 was not present but I found UC710 corroded so I replaced it and now I got 3V there but no 3.3V.. enable P3V3S2_EN is not present.. generated by U8100, master PMU.
I swapped the master PMU and slave PMU from a known-good donor board and my bad board still takes 5V..
I put the master and slave that I have removed from by bad board to the donor.. and it takes 20V. Meaning the chips are probably OK.

PP3V3_S2_UPC missing..
PP1V8 S2 missing
PP1V25_S2 missing

I don't know where else to look at..
I currently have U8100 removed to have some diode mode measurements to try and help me..

Please give me a lead or a hint on where to look next

[mon2]

Re: Water damaged M1 MacBook Pro (820-02020)

Hi. See here for some ideas,

https://boards.rossmanngroup.com/thr...r-cycle.62721/

https://boards.rossmanngroup.com/thr...ower-5v.60471/

[iMuhtaseb]

Re: Water damaged M1 MacBook Pro (820-02020)

As I mentioned I have removed U8100 from board and measuring in diode mode now.
After I have removed U8100, PP3V8_AON_MPMU_ISNS_VIN is reading low in diode mode.. is that normal because I have lifted the chip?

[iMuhtaseb]

Re: Water damaged M1 MacBook Pro (820-02020)

Nah.. I still put the Master PMU on and diode mode are reading low.. I think I'm into something but I don't know what could it be causing this..
Also voltage reads 3.8V normal.. could it read normal voltages but low in diode mode?

[mon2]

Re: Water damaged M1 MacBook Pro (820-02020)

If you have 3v8 on PP3V8_AON_MPMU_ISNS_VIN then it appear to be normal and ignore the diode reading.

USB-C ammeter takes 5V
PPBUS is 12.3V

With a 5v feed from the external power delivery adapter, the ISL9240 @ U5200 is working in BOOST mode (5V in -> 12v3 out). The external adapter needs to be in 20V to be considered normal.

For 20V power delivery (PD) contract, each of the CD3217 needs to be working properly.

Attach the power adapter to the local CD3217 (UF400 or UF500) and check the presence of the LDO rails on this ACE controller.

Repeat with the next USB Type C connector and ACE controller.

Would not hurt to flip the type C connector by 180 degress to validate the opposite of the Type C connector blade. That is, there are CC1 / CC2 lines used for the power delivery communication. One such CCx pin is one side and the other on the opposite side.

[iMuhtaseb]

Re: Water damaged M1 MacBook Pro (820-02020)

Both both CD3217 have their LDOs showing proper voltages.
I have noticed a fluctuating on PPDCIN_USBC_AON going up to 5v then dropping 4.8-4.6v then going up 5v then down 4.8-4.6v
I have replaced both CD3217s just in case and it's same issue, now I have returned the originals.

What could be causing the fluctuating?

[mon2]

Re: Water damaged M1 MacBook Pro (820-02020)

Remove all power / no battery.

Meter in resistance mode -> check the resistance to ground of PPDCIN_USBC_AON.

Post the measurement.

[iMuhtaseb]

Re: Water damaged M1 MacBook Pro (820-02020)

PPDCIN_USBC_AON = 135 kOhms

[mon2]

Re: Water damaged M1 MacBook Pro (820-02020)

Resistance is fine. Is the power adapter being used the original and recommended one for this unit? Would you have another Type C power delivery adapter for testing ?

90W+ would be great to test. The 5V (PPDCIN_USBC_AON) which is direct from the power adapter should not be fluctuating.

[iMuhtaseb]

Re: Water damaged M1 MacBook Pro (820-02020)

The original 96W adapter is being used with Keweisi USB-C ammeter. They're working fine on other MacBooks.
And I've used another 96W and another USB-C ammeter (another brand) and it's doing the same thing.

I've taken a video of it:
https://share.icloud.com/photos/07fs...nr9FAtqZTVeuGw

[mon2]

Re: Water damaged M1 MacBook Pro (820-02020)

What is the DIODE mode reading of PPDCIN_USBC_AON?

Remove all power. Meter in diode mode.

Red meter lead, yes RED, to ground.
Black meter lead to PPDCIN_USBC_AON.

Post the measurement.

[iMuhtaseb]

Re: Water damaged M1 MacBook Pro (820-02020)

PPDCIN_USBC_AON in diode mode 0.579
Red probe on ground. Black probe on PPDCIN_USBC_AON.

[mon2]

Re: Water damaged M1 MacBook Pro (820-02020)

The value is not exactly the same as in this table here:

https://openboarddata.org/?a=showboa...pple/820-02020

Perhaps of concern.

See attached. Check if the fuses are still working with a resistance check. If they are ok, remove each and check the diode mode reading again to see if it matches the above table of values.

Also, with no power -> meter in diode mode -> check the diode mode readings of each CCx line.

CC1 and CC2 pins on the Type C connectors are used for the single wire BMC power delivery communication with the external adapter. If the CCx pin is not functional - perhaps due to a transient surge which will then kill the TVS diode, then the default adapter voltage will of 5 volt will be static (not possible to reach 20v or any other value).

The CCx diode values can be compared against the above table of values.

From the above table:

USBC0_CC1 Default d 0.588
USBC0_CC2 Default d 0.569

USBC1_CC1 Default d 0.584
USBC1_CC2 Default d 0.584

[iMuhtaseb]

Re: Water damaged M1 MacBook Pro (820-02020)

I've compared the diode readings of PPDCIN_USBC_AON with a known-good board I have here.
Bad board is 0.579
Known-good board is 0.577

Maybe the difference is there because of other types of multimeters were used?

Both fuses are working as they should with zero resistance in resistance mode reading.

I measured both CC1 and CC2 (CF413, CF414, CF513 and CF514) in diode mode.

I once again compared the numbers on the bad board with the known good board..
Bad board had
CF413 0.603 CF414 0.603
CF513 0.601 CF514 0.601

Known-good board had:
CF413 0.597 CF414 0.597
CF513 0.595 CF514 0.595

Known-good board POSTs and takes 20V.

[mon2]

Re: Water damaged M1 MacBook Pro (820-02020)

The reading look very close to the reference document so they may be ok.

Suggest to remove the fuses and check if the 5 volt is then stable.

The video you posted does show some power cycling and the Type C meter may be missing it due to slower sampling rate.

You will have to check the 5 volt at the type C connector area once the fuses are removed.

If the 5 volt is stable, then solder back one of the fuses and check if the power cycling returns or not.

[iMuhtaseb]

Re: Water damaged M1 MacBook Pro (820-02020)

Removed both fuses and tested connector's 5V side and they were very nice smooth 5.1V on each one.

I've returned one of the fuses FF200 and tested on AON side and cycling is back..

What does that mean? Guess it means that the cycling is caused by the other side? What ever is after PPDCIN_USBC_AON, no?

[mon2]

Re: Water damaged M1 MacBook Pro (820-02020)

Each fuse is linked to a local CD3217 ACE controller.

FF200 fuse is linked to UF400.
FF201 fuse is linked to UF500.

Remove FF200 fuse and solder in FF201 to activate the next ACE controller.

Is the 5 volt stable or pulsing like before ?

If stable with FF201 fuse, then it appears the CD3217 linked to the FF200 fuse is considered defective.

Do you have a thermal camera? Perhaps the local CD3217 is heating up that is resulting in the power rail pulsing.

[iMuhtaseb]

Re: Water damaged M1 MacBook Pro (820-02020)

FF200 fuse removed and I soldered FF201 on. I measured 5v and its pulsing.
I have a thermal camera but sadly there isn't any heat or even amp consumption to generate heat whatsoever.
Note: in the video I took it said somewhere like a 60 mAh was pulled apparently that was caused by the defective USB-C ammeter I took the video of. This does not harm the troubleshooting in any way or form because I used THIRD known-good ammeter.