Macbook Pro M1 820-02100

[Comp_Pro]

Hello,

M1 Macbook Pro with 820-02100 board. Came in for liquid damage. Most of the liquid damage was located around UP800 backlight IC. Other than that not much other damage on the board. Computer turns on but shows no display. Originally I could get an image out of the HDMI port but now I only get a quick flicker when closing the lid and then the image disappears from the external monitor. In the brief moment I can see an image I do see the login screen. I tried re flowing and replacing UP800 with no luck. Do not see any shorts or other damaged components. BL_PWR_EN Is showing 1.22V but still no power light. Should be this 3V? Computer seems alive and well except for the display not having any backlight. Any ideas you guys could throw my way please?

[spidertnt]

worth checking angle sensor

[Comp_Pro]

So if I understand correctly, it's not possible to simply reset the existing angle sensor correct? A new one must be installed and programmed in order for it to work?

[spidertnt]

Are you saying the sensor has damage ? yes they need programming

[mon2]

See attached. The BL_PWR_EN is 1v2 when active so your measurement shows the correct voltage to enable the backlight circuit.

1) Confirm that the same voltage is present on each side of RP873 (smd resistor @ 0 ohms).

2) Measure the voltage to ground of PPVOUT_LUXE @ CP830 or similar large capacitor. If the voltage is not a boosted voltage for the backlight -> power down -> meter in resistance mode -> check the resistance to ground at the same test point of CP830 (to check for any possible shorted capacitor, etc.).

3) Carefully, measure the voltage to ground of the following points of interest:

I2C_LUXE_DEBUG_SCL
I2C_LUXE_DEBUG_SDA

SPMI_DISP_BKLT_CLK
SPMI_DISP_BKLT_SDA

PPBUS_AON_LUXE

Post each measurement.

[Comp_Pro]

Thank you much for the valuable input. I'm not sure if the angle sensor is damaged or not, but my guess is no as I just discovered that the display actually does have an image but just doesn't have any backlight. I would imagine if the angle sensor was the issue the screen would not be turning on either correct?

Thank you mon2. Here are the measurements I took per your indications:

RP873: All good, voltage on both sides of resistor.
PPVOUT_LUXE: 0V Diode mode 0.490 Diode mode with display removed: O.L.
I2C_LUXE_DEBUG_SCL 0.362
I2C_LUXE_DEBUG_SDA 0.365
SPMI_DISP_BKLT_CLK 0.278
SPMI_DISP_BKLT_SDA 0.275 <-Did you mean SPMI_DISP_BKLT_DATA?

I wonder if I got a bad/fake IC or maybe damaged it during install. Curious to try another.