MH won't stay lit!

[archaeoreefer]

Anyone experieced this before? My new 175w halide hood will ignite but then only stays lit for a short time (< 1 hour) before powering down. It won't light again unless I let it sit for about 30 mins. The bulb (20k) is brand new. Is the problem more likely to be with the bulb or ballast? Any help would be appreciated.

[archaeoreefer]

Also, when lit, the bulb won't stop pulsing/strobing.

[Sugar Magnolia]

Have you checked to be sure the bulb is fully seated in the socket?

[archaeoreefer]

Yes, it's fully seated. I might be able to force it in a little more, but I don't want to over-torque it.

[jgsensor]

I had the same problem before, except mine would only light for about ten minutes. I tried replacing bulbs, switching ballasts and nothing worked. Finally, I switched to a different power socket to power the ballast and it worked. No problems since then. The funny thing was the socket are all on the same wire strip. Can't explain it, but it worked.

[archaeoreefer]

Hmm. I tried switching sockets but that didn't help. There were on the same circuit anyway. I suppose I could temporarily string together a few extension cords an pull it in to a socket on the other side of the house.

[David Grigor]

To be more specific with an earlier post,

Have you played with the screw in the inside of the mogul to adjust to make better contact with the end of the bulb ? Also may try the socket lubricant which will help with screwing it in and is a conductor......

I have had this happen on new bulbs before and this was the fix, however, it was usually within the first few minutes not an hour into the lighting period.....

Does this fixture have more than 1 MH so you can tell if the problem follows the ballast or the bulb ?

[archaeoreefer]

David,

The fixture has only the one bulb, so I can't tell if it's bulb or ballast. I haven't played with the screw inside the modul socket itself, although I will try this now. What kind of lubricant do you use when seating the bulb?

[mckeec]

A poor power supply will cause a lot of problems for MH lighting. It can cause pulsing, short life span of bulb and ballast, bulbs will have trouble firing and staying on. Check your outlet power. I had a dedicated 20A line for my lighting. Try spreading your equipment load over a couple breakers.

[archaeoreefer]

Here's some more information on my system in case this is helpful:

Ballast is a 175W rated ANSI M57 (core and coil probe start).
Bulb is XM 20K SE mogul (I conntacted XM and they say it is designed to run on an ANSI M57; which means, I guess, that it has an igniter).
Socket is an E-D 1500w rated pulse mogul (came stock with system).

Questions: (1) does the socket need to be rated higher, say 4000w?; (2) do I in fact need a new ballast? (I'm not inclined to fork out another $125 bucks for a new ballast...); (3) does the placement distance of ballast to fixture matter?; (4) should I just order a different bulb? If so, which?

[archaeoreefer]

Loose connection inside the ballast. Now fixed. Thanks everyone!