I've got two of these with the exact same symptom. The backlight cuts out
a few seconds after powering, and stays out until the the unit is turned
off/on again. There are two boards in this; the power supply, and signal
processing/CPU. I subbed the power supply board with a confirmed good one
from another unit and got the same result, ruling out that board as the
cause. Also tried disconnecting the backlight cables one at a time, but no
change. It appears that a signal from the CPU board is causing the backlight
to shut off. Is there any solution other than replacing the CPU board?