Macbook Pro M1 820-02020 - no display

[mon2]

also one more thing this macbook came to me without display flex cable so i found one that looks same but it's probably from a2189 or a1708 is this problem ?

Not recommended unless you are 100% sure it is the same. We have faced a similar issue with trackpad cables where the width of the cable was 100% but the pad to pad pitch was different than the original so the # of contacts did not match and respectively, the trackpad failed to function.

Find a known good cable for the actual unit under test.

[obelix24]

any idea anyone ?

[obelix24]

I've checked with screen connected and same result.

Also between LCDBKLT_FB (PIN2 on RP831) and PPVOUT_LCDBKLT there is no continuity, there is resistance 17k Ohms

also one more thing this macbook came to me without display flex cable so i found one that looks same but it's probably from a2189 or a1708 is this problem ?

[obelix24]

I've checked
PP1V5_UPC0_LDO_CORE - 1,5V
PP3V3_UPC0_LDO - 3,3V

PP1V5_UPC1_LDO_CORE - 1,5V
PP3V3_UPC1_LDO - 3,3V

FF200 on both sides stable 20V
FF201 on both sides stable 20V

But on all CP870, 71, 72, 73, 64, 65, 66 (PPVOUT_LCDBKLT - 0V (but i don't know if screen needs to be connected when testing this) - here no screen connected

Also on L5230 on both sides i don't have stable V .... CHRG_PHASE1 and PHASE2

on F5200 - both sides stable 12,04V

[obelix24]

I got one MacBook Pro M1 that was water damaged.

It was not turning on I've changed one CD3217 IC and now MacBook is taking 5V instead of 20V, I've also replaced U5700 as there was clicking sound when charger was connected.

But MacBook turns on (when I connect charger it's taking only 5V 0,04a) but there is chime and when I connect external screen over HDMI I can see login screen. Trackpad is working, keyboard backlight is also working and keyboard looks also ok (but not tested fully)

Issues are :

Touchpanel is of there is no sign of life...
Internal display is not working but previous owner told me that screen should be ok. He gave this MacBook to two other people to check and each of them make something (but it looks like no board level repair was done by them)

I'm trying to find out if the screen is ok.

I've checked
PP1V8_AON - stable 1.8V
PP3V8_AON - stable 3,8V

Is there anything that can cause no Touch Bar and no internal display only external ?