Macbook A2442 820-02098 boot and display issue

[veedo]

Hi All
I have MacBook A2442 which had keyboard replaced and now it doesn't turn on correctly, it have sound chime from time to time and Apple logo shows on the display and there is no backlight on, apple logo appear and stuck on kind of boot loop. But if one of the display flexes is disconnected from the motherboard then MacBook turns of fine with the external monitor and it keeps working fine.
Without keyboard its still have same issue, I don't have second display to replace it and compare but does display can make issues with boot?
I found component UD290 ( SF0101-I2C) little bit green but after cleaning and soldering it back once again it not making any differences .
Where to look after now?
Thanks for any help
.

[mon2]

Perhaps you are disconnecting the flex on JP400 to make this unit function?

JP400 is linked to the ALS (ambient light sensor) and the camera controller logic.

Remove all power. Meter in DIODE mode (not resistance mode). Red meter probe, yes red, to ground. Black meter probe to the point to test.

With the flex cable attached onto JP400, measure the DIODE mode readings for:

I2C_CAM_1V8_SCL
I2C_CAM_1V8_SDA

I2C_CAM_1V8_SDA
I2C_CAM_1V8_SCL

Then disconnect the flex cable from JP400 and measure the above points of interest again.

Post each measurement.

[veedo]

so without flex connected is:

I2C_CAM_1V8_SCL 0.549
I2C_CAM_1V8_SDA 0.549

with flex is:

I2C_CAM_1V8_SCL 0.454
I2C_CAM_1V8_SDA 0.454

but the issue shows up when JP600 is connected, sorry not mentioned before which flex make that.

[mon2]

Diode readings are fine.

Carefully, review the voltage to ground measurements (not diode mode) for both sides of the level shifter @ UD290. This bidirectional FET level shifter is used to shift from the 1v2 to / from the 1v8 voltage domains.

[veedo]

I have 1v2 and I have 1v8 as well, with and without flexes connected.
RD296 and RD297 have 1v8 on both ends, RD295 AND RD294 have 1v2 on both ends.

[ronaldopdias]

Hi. Good morning.
I have got a Mac same model with same issue here.
Did you manage to solve the issue with yours?
Thanks

[veedo]

Hi, not I'm afraid, left it without repair

[mon2]

Share the voltage to ground of PPBUS_AON. What is the voltage and current draw showing on the USB Type C meter (if available for testing - if not, consider to source one on Amazon).

[obelix24]

I have exactly the same Macbook Pro 14" A2442 (M1 Pro)
water damage arround UP800, UR700,UR730,UR760

I've cleaned all corrosion but there is no backlight.

I tried to reball UP800 but doesn't help still the same. Chime and apple logo without backlight and after some time macbook restarts (bootloop)

I read this and i disconnected JP600 and i was able to restore system and fully start and test macbook (everything is working, camera, keyboard, lid sensor, microphone, speakers, wifi, bt, battery, ....)

I probably need to replace UP800 but i don't understand what is causing the bootloop on JP600.

Any idea ?

[mon2]

Remove all power. Measure each contact used by JP600 in diode mode. Red meter probe, yes red to ground. Black meter probe to the pin to test.

Confirm the diode mode measurements against the schematic to see if the diode measurement is ok or not. Start with the I2C / SMBUS lines.

Post your table of measurements with their pin #s / labels as shown in the schematic to make the review easier.

[obelix24]

1	GND
2	GND
3	OL
4	0.157
5	OL
6	0.510
7	GND
8	0.510
9	OL
10	GND
11	OL
12	GND
13	GND
14	0.800
15	OL
16	GND
17	OL
18	GND
19	GND
20	GND
21	OL
22	0.310
23	OL
24	0.348
25	GND
26	0.310
27	OL
28	0.346
29	OL
30	GND
31	GND
32	0.658
33	GND
34	0.315

Whole top Line of pins (except GND are OL) so i guess there is problem. According to BRD file all this pins go to oposit side to Resistors and Capacitors and then directly to CPU.

[obelix24]

ok so the OL should be ok after some research ... is it possible that issue is that UP800 is faulty ?

[mon2]

What is the voltage to ground of:

BL_PWR_EN (RP873)

I2C_LUXE_DEBUG_SCL
I2C_LUXE_DEBUG_SDA

SPMI_DISP_BKLT_CLK
SPMI_DISP_BKLT_DATA

[obelix24]

In Diode mode :
BL_PWR_EN (RP873) - 0.416

I2C_LUXE_DEBUG_SCL (RP841) - 0.417
I2C_LUXE_DEBUG_SDA (RP842) - 0.421

SPMI_DISP_BKLT_CLK (CP813 - cap is not here so i measured on pad) - 0.341
SPMI_DISP_BKLT_DATA (CP814 - cap is not here so i measured on pad) - 0.333

[mon2]

Voltage to ground - not diode mode.

[obelix24]

OK i've connected one USB-C port and connected power it was taking 20V

BL_PWR_EN (RP873) - 1,2V but drops to 0V

I2C_LUXE_DEBUG_SCL - 1,2V but drops to 0V
I2C_LUXE_DEBUG_SDA - 1,2V but drops to 0V

SPMI_DISP_BKLT_CLK - 0V
SPMI_DISP_BKLT_DATA - 0V

[obelix24]

any idea why the voltage is dropping from 1,2 to 0 ?

[obelix24]

i've replaced UP800 and it's the same ...

no backlight (i can hear the chime + apple logo is there but no backlight) after some time macbook restarts.

without JP600 connected it's working fine (on external screen)

any idea what can cause this strange issue ?

[obelix24]

when I test only motherboard and power connected over USB-C charger on RP833 (LUXE_UG2_R) voltage is not stable but it's falling from approx 3V to 0,5V. Next resistor RP830 (LUXE_LG2_R) I'm getting 0V

is this normal behaviour ??

Also I'm not sure if RP840 should be on board or no. (I don't have other board to compare but from photos on google it looks like it's not there ...

[obelix24]

OK so I probably found the problem. After checking with thermal camera and screen connected I noticed hot spot on U5000.
I've removed it (U5000) and 3 to of 4 pads for PP3V8_AON were missing and the one left was corroded

U5000 is useless as it's missing one pad

Is it possible to use U5000 from (MacBook Pro A2338 M1 - board number 820-02020) ?