Alert! Alert! On-off cycling of an HPS lamp probably indicates it has reached the end of its life. Repeated cycling can damage the ballast. For many reasons, HPS lamps should be replaced before they reach this stage. Track your average usage and replace before the end of the listed lifetime.

yes...especially HPS...they have ignitors which will go out easily too

-j-

The lamp is only a year old. That's the reason for my concern that it might be the ballast and not the lamp.

Could be either. My halide ballast fried like an egg after one year.

I don't think so.
A HPS or MH bulb will take 10-20 minutes to re-ignite...If you get it up to temp, approx. 20-30 minutes and turn it off or have a power interuption, It'll take 10-20 minutes for it to light again. And it will sometimes "flash on, then off" if you continue to turn the power on and off. Only 1 year old, even if you ran it 24/7, you should not be experiencing this type of problem...Granted the bulb has lost alot of punch, but flashing, no.

Good luck!