Here is a very good resource for troubleshooting these light fixtures (HIDs).
It is written for skilled electrical workers, so don't fuck with electricity if your not trained in electricity and electrical safety.

http://www.hydroponics.net/productdo...cket_Guide.pdf

Shovelhandle
Shovelhandle Reviewed by Shovelhandle on . Dead HPS ballast, 1000 watt-HELP! i just switched my 14 plants from an extensive flouro gig to a 1000 watt HPS about 4 days ago. Everything was fine until today when i discovered that the circuit i was running off of was also running some other things which we thought were on their own circuit. I had alot of other things running on the circuit, I just didn't know it was the same circuit. One of the things is a computer with a UPS ( a battery) for power outages. If there is a drop in current the UPS makes a beeping sound. ( i Rating: 5