How to Troubleshoot MH Ballast

[jrgilles]

Hey guys,

I was wondering if you had any advice on how to troubleshoot a metal halide ballast.

I have 2X250W MH (each with its own ballast.)

For some reason, neither turned on today. They have been working fine for the last year and a half. I just replaced the bulbs a couple of weeks ago, but all seemed to be working well.

Here is what I have observed:
Neither ballast seems to be producing any heat.

Outlets they are plugged in to read 116 V on my crappy multimeter.

When I plug into the output with the multimeter reading voltage (set to 500 volts AC) it gives me an error like I am out of range. When I shut the ballast off, the output goes to 0 volts.

Is there any way to use this multimeter to see if the problem is in the ballast or somewhere downstream in the wiring or something?

Seems very weird that both quit working at the same time. Can't really explain it. Bulbs (both new within a few weeks) look to be normal. Don't see any signs that they blew out.

Anyway, any advice would be great. Maybe a watt meter is what I want? Don't have one of those though unfortunately....

rob

 

[jrgilles]

This thread shows a picture of the ballasts I have. They seem to have a lot of issues, got the fixture/ballasts cheap when I set up my tank.

Odyssea Metal Halide Review - Reef Central Online Community

 

[mcoomer]

I'd simply pull them apart and look for broken wires, loose fittings, burnt connections, etc. Do not plug them in and try to check the voltage on the output. Have they been acting up for some time or were they working properly and simply chose not to turn on today? I had a dual PFO ballast that had one channel that would die intermittently. Turned out that the power switch was failing, and even though the ballast was on a timer, the switch was causing enough of an open that the channel would fail when it got hot.

Mike

 

[mcoomer]

No edit...what the?? Just noticed that you have two separate ballasts that are failing to fire. Are they plugged into a timer or directly to the wall? If a timer, plug them directly into the wall and try them. If they're already plugged into the wall is there anything else that's plugged into the same outlet that's working. Doesn't make sense that two ballasts would stop working at the same time.

Mike

 

[jrgilles]

yea, i agree it is weird that two of them quit.

There was actually a problem with one of them where the bulb connectors were a little burned up (used the bulb for maybe a few weeks about 9 months ago and looks like the connectors got a bit damaged.) Usually if I tapped the bulb with a paper towel covering my fingers for oil protection, that bulb would turn on.

The other has always worked fine. I have not switched the ballasts to the other bulbs to see if that fixes it.

It is all hooked up through my neptune. There is a powerstrip off the neptune where the halides are hooked up. A volt meter shows the outlets on the powerstrip are putting out 120V, but I agree with you. I will run an extension chord over.

Between an extension chord and switching the what lights go to what ballasts, hopefully I can figure this out.

rob

 

[jrgilles]

So I have tried both bulbs on each ballast, plugged directly into a working outlet. It feels like they are drawing power, but I can't get any lights.

Maybe I'll go buy a single ballast from barrier reef to use to troubleshoot this? Maybe something happened that blew out my two brand new bulbs? They look find though....

Replaced the boots about a year ago, and the lights were working just a couple of days ago, so seems unlikely that something bad happened in the wiring.....