820-02016 - 5V / 0.02-4 A - No boot

[HeyWatchOutDude]

Hi,

I have an A2337 (820-02016) with 5V and 0.02-4 A on both USB-C ports.

- PPBUS_AON = 11.80-12.25V
- PP3v8_AON_VDDMAIN = 3.8V
- PP5v_S2 = Missing
- PP3v3_S2_UPC = Missing
- PP1v25_S2 = Missing
- PP1V8_S2 = Missing
- PP3v3_UPC0_LDO = 3.3V
- PP1v5_UPC0_LDO_CORE = 1.5V
- PP3v3_UPC1_LDO = 3.3V
- PP1v5_UPC1_LDO_CORE = 1.5V
- PPDCIN_AON_CHGR_R (without battery) = 4.1-5.1V

I noticed when the MacBook is fully assembled a clicking noise at the CPU/Audio board area.

Is the firmware bad? (When I turn on the MacBook - fully assemebled - it doesnt go into recovery/DFU automatically) - So I assume the firmware is good?

Edit: Not possible to get it into DFU mode.

 

[2informaticos]

Any history available?

Check diode mode to ground on secondary power rails.
Compare with good board, or refference table.

OpenBoardData Project

Do you get LDOs voltage from U8100 and U7700?

 

[HeyWatchOutDude]

Board looks clean and the previous owner told me he that he close the MacBook and on the next day it stopped working. (no boot)

- PP5v_S2 = 0.287
- PP3v3_S2_UPC = 0.447
- PP1v25_S2 = 0.268
- PP1V8_S2 = 0.330

I have checked the following:
- PP1V4_LDO_PREREG = Missing / 0.291
- PP1V5_VLDOINT_MPMU = 1.45V
- PP1V8_AON_MPMU = 1.8V
- PPVDD_PMU_LDO_PREREG = Missing / 0.291
- USBC0_3V3LDO_EN = 0.525
- USBC1_3V3LDO_EN = 0.527

- P5VS2_EN = Missing / 0.368
"P5VS2_EN is produced by the PMU, U8100.
A missing enable signal can mean U8100 is bad, or there is a communication issue with U8100 and the SOC/other components. A firmware issue can also * *likely* cause missing enable signals from PMICs on the M1 machines. As of 1/14/2022, this remains rare."
Source: https://repair.wiki/index.php?title=A2337_2020_MacBook_Air&mobileaction=toggle_view_desktop

So maybe the firmware is bad? Because the diode reading of the enable signal is good.

 

[2informaticos]

I expected output voltages.

Try again on page 34; U8100 (SYM 3 OF 6).
There are 3 LDOs to check, all other NC; also check VREF_ADC.
You've posted only one!

 

[HeyWatchOutDude]

- MPMU_VREF_ADC = Missing / 0.559

Which LDOs are missing? I can't find any LDOs (without NC) - could you please help me out. (im on page 34)

 

[2informaticos]

What about 1V2_S2 and 3V3_S2_UPC?
How did you find 1V8_AON_MPMU, but no other?

 

[HeyWatchOutDude]

- PP1V2_S2 = Missing / 0.336
- PP3V3_S2_UPC = Missing / 0.447

Clicking noise is coming from "Q5800" - When I connect the battery and USB-C cable (for charging) the values are 5V / 0.36A - Q5800 is getting hot.

I have already replaced it - no short on PPBUS_AON after doing the same (battery charging cable etc.) the short on PPBUS_AON is back again (only when battery is connected) - Any idea? Clicking noise is also back again .... even with a new Q5800.

 

[2informaticos]

Checking diode mode with power applied (battery connected)???
How could you have short if PPBUS_AON and 3V8_AON are generated?

U8100 is suspect, if doesn't generate all necessary LDOs.

 

[HeyWatchOutDude]

Ok not the battery is causing the "short" - only happends when the audio board is connected.

PPBUS_AON (with audio board connected) = 8.1V / Diode mode says "OL" (measured while turned off - not connected to charger/battery)
PPBUS_AON (without audio board connected) = 12.26V

I think I will order a new PMU IC (U8100 / 343S00438).

Edit: I have removed the short from the audio board - PPBUS_AON is now on 12.26V with audio board connected. (Clicking noise is gone)

 

[HeyWatchOutDude]

I have replaced the U8100 - PPBUS_AON is now on 1V ….

Output USB-C: 5V / 0.04A

 

[2informaticos]

You've did something wrong in the process.
Or U8100 is bad...

 

[HeyWatchOutDude]

Hmm IC looks good and perfectly soldered - I will re-do my work.

Edit: After re-do same result - so I guess the IC is faulty because PPBUS_AON is looping between 0.9 and 1.1V … I hope I will get a refund (source: AliExpress)

 

[HeyWatchOutDude]

I have re-soldered the original PMU IC .... PPBUS_AON is still looping between 0.9 and 1.1V - what the ... ?

The following are missing ....
- PP3v8_AON_VDDMAIN / 0.320
- P3V8AON_PWR_EN / 0.565
- CHGR_EN_MVR / 0.598

U5200 is good - Will be PP3v8_AON_VDDMAIN generated when PPBUS_AON is at 0.9 - 1.1V?

 

[2informaticos]

PPBUS_AON is the mother of all voltages from MLB; apart of CD3217 LDOs.

Did you test the board alone on the desk?
You had PPBUS_AON before.
Something happened when you've cgahnged U8100; maybe heat affected other components.

Post U5200 basic voltages; P_IN, AUX_DET, SMC_RST_IN, VDD/P, A/BMON.

 

[HeyWatchOutDude]

Yes I have tested it without anything connected. (no audio board etc.)

PPDCIN_AON_CHGR_R = 5.0-5.1V
CHGR_AUX_DET = 1.2V
CHGR_RST_IN = missing / 0.580
PPCHGR_VDDA = 5.0-5.1V
PPCHGR_VDDP = 5.0-5.1V
CHGR_AMON = missing / 0.591
CHGR_BMON = missin / 0.592

 

[2informaticos]

A/BMON look too high, if PPBUS_AON is not present.
Check resistance over C5220/60.
Remove F5200 and check C5254 voltage.

"CHGR_RST_IN = missing"
Why do you think that?
Looks good for me; if really no voltage there...

 

[HeyWatchOutDude]

C5220 = 0.520
C5260 = 0.580
F5200 removed / C5254 = 0.9-2.5V (looping)

Yeah true ... its a reset signal - sorry.

 

[2informaticos]

I meant resistance OVER the mentioned caps; between their pins, not to ground!

 

[HeyWatchOutDude]

C5220 = 2.3 ohms
C5260 = 180k ohms

 

[2informaticos]

C5260 = 180k ohms"
Fix the problem!
Check R5261/62 and their traces.