Macbook Pro M1 820-02020 - no display

[obelix24]

ok so according Camera, touch bar and ALS not working ... i found that it's not motherboard related (most probably) as i put in this case know working M1 macbook pro (a2338) and there is exactly same issue (camera not detected, ALS not working, touch bar working but lights up after some time) it looks like these issues are related all together with something bad in display unit (probably will need new display

[obelix24]

Yes i've also not able to find any info about this IC. I've replaced it anyway and macbook is now starting and i'm getting error that i need to restore.

I've tried Revive, restore, via apple configurator 2 but problem is that i don't have other macbook with latest MacOS only one older one a1706 and there revive, restore is not finished and i don't know if because it's not newest macos or why

[mon2]

Personally have not come across this case. The schematics show that U7700 is part # 998-22526. No hits on any website nor Aliexpress. Perhaps a larger concern is what is the reason for this PMIC to get nuked. Respectively, very likely that downstream leg of the circuit is also killed. This may be a no fix case.

[obelix24]

This macbook died and after checking i found out there is small crack in U7700 (also after thermal camera check right in that place where U7700 is cracked it's getting hot) my question is if it's possible to replace U7700 with another one from donor board or it's paired with CPU or board ...

[obelix24]

mon2 do you think it's ok ?

[obelix24]

battery health is : 87%
Cycle count : 440
Condition : Normal
in app stats (from GitHub) it's showing health 81%

I don't have any other battery to test I expect this one is good.

I've checked with thermal camera when MacBook was turned off and there was only one spot near U7700 that was warmer ... It looks like it was one of the diodes

I've checked diode mode on near caps C746, 745, 744 and the result was 0,03V (battery connected)

But when I turned on MacBook and checked voltage there it was normal 1,06V (PP1V06_S2SW_DRAM)

[mon2]

How is the health of the battery? How many charge cycles? Can you test with another known good battery?

[obelix24]

ok today i received backlight and now when backlight is connected is working

But i noticed one thing when i turned macbook battery was 0% and i know that i've charged it few days ago to 100% ... so it's discharging ... is there any way how i can found what is discharging it ? there must be something draining battery but how to find what ?

[mon2]

Review the mated cables. Disconnect them all and use the bare minimum set of interconnects. You can attach a USB Type C hub onto which you can use a standard USB keyboard / USB mouse. They will work since USB keyboards / mice are USB HID class codes so all operating systems will recognize them.

[obelix24]

I found one thing i've disconnected Trackpad flex cable from motherboard but everything else stay connected (except keyboard backlight) macbook started and there was logon screen but keyboard was not working at all (even it was connected). When i connect trackpad flex keyboard was working again.
Is this normal behavior ?

[obelix24]

I tried DFU few times but the problem is still the same
i've tried to replace UR200 from donor board but after replacemet macbook behaves strange ... backlight was off, when i go near power button with my finger backlight starts but the screen was turning on and off i immediately returned old UR200 and it's working fine (but still the same issues no camera detected and touch bar working after 3 min or after closing and reopening lid)

[mon2]

Try the DFU to fix the Touch Bar.

[obelix24]

But this touch bar doesn't light up with desktop. I'm already in macos and the touch bar is still black (but it responses as whene i touch finger where icons should be i can operate volume, brightness, ...

Issue is that it lights up after some time (i've checked and it's approx 3 minutes) or when i close and reopen lid (then it's still on if macbook goes to sleep and wakes up it's still working. I've tried few times DFU (revive, restore, reinstall) nothing helped.

I don't know maybe it's connected to the camera that is not recognized (maybe it's waiting for some sensor from camera ...

i found here same issue as i have
https://boards.rossmanngroup.com/thr...0-02020.64122/

[mon2]

Careful - we have seen that the touchbar will light up AFTER the login screen and most likely after a device driver has been loaded on a recent repair in the shop. The touchbar is a standalone LCD panel with CTP for touch and it is quite possible the firmware is loaded much later in the boot cycle. We too thought to replace this client's touchbar but the owner reported there was no fault here since it lit up around the time we saw the desktop. You can perform a DFU if you suspect any firmware corruption.

[obelix24]

in the meantime waiting for backlight keyboard i'm wondering how can i fix touchbar ... It's working fine but when i turn on macbook touch bar doesn't light up, but it respond on touch, also when i close the lid (LCD is turned off i was slowly closing lid and i can see that screen turns off when there is small gap only) and reopen touch bar is visible. Also if i turn on macbook and leave it as is after approx 3 min touch bar is visible ...

I don't understand what can cause this strange issue. probably some doggy capacitor, resistor but how to find it ?

[obelix24]

ok so finally I got it working I've turned on thermal camera and slightly increased voltage input on PPBUS_AON from 1V to approx 2,3V and UR730 was getting hot (same as on video I've posted on previous page). Replaced UR730 reconnected everything and now MacBook is turning on and taking 20V

I've connected everything except keyboard backlight as I'm little bit scared if this haven't cause short on UR730 ... I will probably order keyboard backlight directly for a2338.

one thing ... when I turned MacBook there was popup and os is damaged and needs to be reinstalled.

[obelix24]

mon2any idea ?

[obelix24]

I've removed F5200 and checked in diode mode both pins on
PPVBAT_AON_CHRG_REG - 0,5V
PPBUS_AON - 0,07V

I've tried to inject 1V to PPBUS_AON side but it's taking nothing 0A

[obelix24]

Voltage to ground power adapter connected
PP1V25_S2 - 0V
PP1V8_S2 - 0V
PP3V3_AON - 0V

Diode mode
PP1V25_S2 - 0,280V (tested on CF735, CF230)
PP1V8_S2 - 0,340V (tested on CF503, CF403)
PP3V3_AON - 0,400V (tested on RD208, RD207)

but i'm still confused as on PPBUS_AON on F5200 i'm getting in diode mode only 0,07V (on other board that i have i'm getting there 0,506V) according to https://openboarddata.org/?a=showboa...pple/820-02020 0,5V should be ok)
When i inject voltage to F5200 there is no A draw )

[mon2]

Also need the voltage to ground of:

PP1V25_S2
PP1V8_S2
PP3V3_AON