This one Molli:
http://www.growking.com/images/ss7_photo.jpg (I just looked for a
picture and found this one.)
It's a Sun System VII. It runs both bulbs at once for a total of 800
Watts.

Steve
PS I found an e-mail address for the company on their web site:
http://www.sunlightsupply.com/horticulture/index.shtml
I wrote to ask them about the problem. I also noted they have a 5 year
warranty on their ballasts. I'll have to go look and see when I got mine.

molli wrote:
Which combo fixture did you get? I just got the Hydro one and am hoping I
don't run into the same problem (mine is a switchable ballast) my HPS bulb
works great, but my MH I have to 'fiddle' with or it doesn't come on. I"m
using MH one week and HPS the next, trying to cover all bets here