400 watt MH bulb question?????

Hello, I'm a newb on this site so if this isn't where I post this question I appologize in advanve. Ok, I have a 400 watt MH light. When I turn it on it starts and about 2 minutes into warming up the light shuts off but the ballest keeps on buzing. It happends just after the light turns white and it does seem a little slow getting to full brightness and soon after it gets to full brightness it shuts off. After it cools down for a bit, it will turn back on and do the same thing. oh yeah, it does flicker a couple times when warming up too.

Is it the bulb or ballest?

Any help would be great as soon as possible cuz I only have a few CFL's and (2) 4ft tubes on them right now, missing the 35000 lumens from the 400 watt MH.

HELP PLZ!

Sounds like its pretty much normal, my Digilux HPS kinda sparks up then gets brighter with little noise then nothing (although the fan hood cant really tell).

Oh crap didn't read it fully. I think that would be be the bulb as MH usually will cycle when they reach their life cycle. Get a new one or borrow one to be sure.

sound like either your bulb is shot and wont take a charge or your ballast is on the fritz or you dont have a MH ballast to run your light. Got pics?

I don't have pics. It is a common High Bay Light. It says on it MH or HPS 400 watt and I bought it used with the MH bulb in it, wired for 120v.
I just turned them to 12/12 and put this light in with the cfl's and tubes I veged them under. I figured they would bud better with the added light. I plan on buying a HPS bulb right away but I don't want to do that if someone knows anything about these ballests going bad like I explained what was happing to me. I mean if people think it is the ballest rather than the bulb then I will buy a different light,
but if this is a normal thing when the bulbs go bad then I will go ahead and get the HPS 400 watt bulb and happy growing again.....

What do you think?

Buy a new MH bulb from Home Depot, or another store with a lax return policy. Plug it into your ballast and switch it on. If it works - great. If not, return the bulb and pick up a new ballast.

Gr8 idea. I will do just that. Thanks!

If you are in flower, go with a HPS bulb and not a MH bulb. If it is the ballast, then you just buy ballast and have hps for flowering cycle. MH is for veg