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Check according to
troubleshooting flow of
“Machine cannot power on”
[ Flow chart 6 ] Symptom: black screen
Trouble description: after power on, screen has no display and backlight cannot be on
Black screen
After
power on, whether
indicator
circuit working
is normal
Check
whether CN103 pin 6
power supply is
normal
Check 12V power supply
loop
Check
whether CN103_3 is
high level
Change Q102
Check
whether boost
board has high
voltage output
Check boost board
Change display screen
Y
N
N
Y
N
Y
N
Y