Philips HTL4111B/12 Service Manual page 20

LED no display on LED
no display on LED
Check every supply voltage on
main board whether normal or
not
+18V +5V +3.3V +1.25V
Check every
voltage on front board
whether normal or not
Check every
voltage on the LED Driver
Pin25 +5V
Check the LED Driver
whether normal or not
Check the LED Display whether
normal or not
yes
yes
supply
yes
supply
yes
yes
5-2
no
check the power supply board
no
check the FFC connector from
main board to front board
no
Replace the R17
no
Replace the U2
Trouble shooting Chart