About three weeks ago, my PT795's screen went black, and the LED went from
its normal green (signifying full power) to an alternating amber and green,
for which the manual has no explanation.

At that time, power cycling cleared the problem, but yesterday it happened
again, and this time it's apparently for good.

Symptoms:
1) When turned on, the monitor makes its normal loud sound, but the screen
is always black no matter what.
2) When hooked to a working PC, the monitor's LED alternates between amber
and green at a half-second internal.

I've eliminated all other variables, such as the PC and cable.

The Viewsonic PT795 is an aperture-grille type, and it's been in use since
1999.

Thanks for any ideas. I've searched online for the service manual or any
other hint about what's going on here, but have come up empty.