Hey, What's wrong with the lights? HPS refurbished system about 5 years old from the old indoor sun co. Lights come on, run for an hour or so, cut off and then start cycling on again. They then run again for an hour or two and then cycle back off and on again. reminds you of a street light cutting off for no reason at all. What is wearing out in the ballast/unit and what does it take to fix?
Are you using new bulbs? That sounds kinda like a bulb that's dead, but it could also be the ballast. Try a new bulb and see if it cycles like that.
Sounds like the bulb to me too, if the ballast is bad the bulb won't light up at all. I had a 1000w hps that was doing the same thing, got a new hortilux bulb for it and it works perfect.
It's very possible the bulb isn't connected right, clean it, wipe of excess, clean the socket and then see. If this doesn't work, there are a few possibilities: The bulb isn't the right wattage for the socket and the ballast is shutting down due to electricity issues, the ballast isn't connected right and must be replaced, or, and this might be bad, the wall socket you're plugging into isn't providing enough energy for the light to remain on. Replace the bulb with a little lower wattage, maybe a 750w, if this doesn't solve it, get a new ballast.
You may also have a loose connection in the ballast or socket. I had a desklamp that was doing that to me for a while, could never figure out why. So I opened it up and sure enough, a wire was loose .