MH Troubleshooting

[darknes]

I was wondering if anyone has a suggestion.
I have a 400 Watt Metal Halide light on my tank with a single-ended bulb. Lately, the light has only been coming on every once in a while. Even though there is power going to the ballast, and it gets hot, the light doesn't work. I know the bulb is good because it still works sometimes, and is only a few months old.
Any suggestions on what to check? Could there be something inside the ballast that isn't working?

 

[darknes]

It could just be a coincidence, but it seems to work when I unscrew the bulb, and screw it back in.

 

[scsinet]

This sounds like a bad bulb.
The way metal halide ballasts are wired, they still consume power and hence will get hot even if there is no bulb in the fixture. A metal halide bulb that is producing no light appears as an open circuit anyway, until it ignites.
That bulb is your primary culprit. Get a new one, and if it turns out not to be the bulb, you have a spare for a when your next bulb change comes along.

 

[darknes]

Thanks SCSI, I knew I could count on your electrical knowledge.

I was doing some reading, and I guess intermittent bulb starts is usually the cause of a bulb at the end of its life. It's a fairly new bulb, but I'd rather replace that than the whole ballast since it's all DIY wiring (not by me), and I'd probably have to replace the whole hood.
It could also be the reason why some of my corals have been looking pretty bad the last few weeks for no reason. :thinking:

 

[scsinet]

I'm just finding your user name combined with your plight somewhat comical.

Good luck!