Flickering backlight is a typical symptom of one or more LED failures. This does not mean only open or short LEDs but those LEDs also who light up but still have high internal resistance. Any such LED affect current flowing through entire series branch which is sensed by driver IC. The driver IC then tries to push more current by increasing LED driving voltage. If somehow this loop is not settled within short time, error is generated & set goes to stand by, exhibiting 1 time blink. So check voltage across each LED. It should be between 3V to 3.3V. You can connect external supply to check LEDs in a particular series branch. eg 10 series LEDs will require 33V external.
Also check PFC voltage in power supply, it should be @ 390V across mains capacitor. Also replace LED driver capacitor.Hope this helps,
P R Gore.