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820-02100 no backlight

I

iMuhtaseb

Member
hello,

this board came in for liquid mainly on the trackpad connector / battery.. PPBUS was shorted to ground until I removed the trackpad connector on MLB and it was gone.. I noticed that the backlight IC had minor corrosions around it.. I ordered a bunch of ICs online and replaced it..

the computer switches to 20V and shows Apple logo (no BL) and shuts off then restarts and does the whole thing again; 5V > 20V > Apple logo > restart

No voltage on PPVOUT LUXE

PPBUS is there
PPBUS LUXE is there
3v8 AON is there
BL PWR EN is there
5V S2 is there
 
I

iMuhtaseb

Member
Yeah disconnecting the internal LCD it gives an image normally to an external monitor..

note: lid angle sensor is clean
 
I

iMuhtaseb

Member
Is there are any major mandatory rails prior to backlight that need to be present that i must look up? Please enlighten me
 
2informaticos

2informaticos

Administrator
Staff member
UP800 requires BL_PWR_EN_R and correct communication through SPMI_DISP_BKLT_CLK/DATA bus.
All QP800-03 and adjacent components and traces must be good too.
5V_S2 must also arrive to UP800 and PPBUS_AON to QP800.

Check if UP701/30 deliver correct voltage.
 
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