fluorescent light

[Steve McCarron]

Hello all. I am wondering if some one can tell me how to test a fluorescent fixture that has gone dark, no light. I have changed the bulbs with no luck. I figure there should be voltages at the terminals, but how hot should they be, 120 volts or a lot more. I don't really want to replace the fixture if I don't have to. The ballasts are more expensive that an entire new fixture, so I want to be right, only replace if necessary. If I have to replace the fixture, it will just be the ballast, I will buy an el cheapo fixture and rip it apart and use it for parts.

Comments please

[Leo Van Der Loo]

Steve try the lamps in another light and if they work there your ballast is gone, there's nothing else really that would just go bad.
I just replaced the ballast in a bathroom fixture couple of weeks ago, replaced the old tar filed one with an electronic one, got it at HD for less than replacing the whole fixture, just make sure you check the wiring layout, as the one I got had to be rooted just a little different than the old one was, good luck, and take care

[Lost in the Woods]

What Leo said, but you also need to make sure whatever route you take, you look for a class A ballast. I put an 8 footer in that is a B class and it hums a little on the annoying side, but with machinery or tunes on in the shop is tolerable. When I'm in the shop and trying to think without music blarring, I turn off that light, otherwise it's distracting.

[David in Mississauga]

Check and see if your fixture has a starter in it. 9 times out of 10, I find that the starter goes before the ballasts (for units with starters).

[willr]

Originally Posted by Steve McCarron

Hello all. I am wondering if some one can tell me how to test a fluorescent fixture that has gone dark, no light. I have changed the bulbs with no luck. I figure there should be voltages at the terminals, but how hot should they be, 120 volts or a lot more. I don't really want to replace the fixture if I don't have to. The ballasts are more expensive that an entire new fixture, so I want to be right, only replace if necessary. If I have to replace the fixture, it will just be the ballast, I will buy an el cheapo fixture and rip it apart and use it for parts.

Comments please

You did not say what type of fixture and bulb length...

Here are the ballasts.

http://www.homedepot.ca/webapp/wcs/s...partial&s=true


You can get them elsewhere as well.

[Steve McCarron]

Thanks for the comments guys. Done deal. Had a ficture on the shelf in the basement that I was not using, so took the ballast out of it and replaced the defective one. It was a 2 by 34 and I see that is really cheap at HD.

HAve a great day

[Rod Sheridan]

Originally Posted by Steve McCarron

I figure there should be voltages at the terminals, but how hot should they be, 120 volts or a lot more.
Comments please

Hi Steve, please be careful when testing fluorescent ballasts.

Modern T8 electronic ballasts have an open circuit voltage of approximately 600 volts.

This is high enough that your skin has absolutely no insulation value, 600 volts will puncture gloves or skin with fatal results.

Regards, Rod.

[Steve McCarron]

Rod: Thanks for that advise. I have an electrical background and I know the risks. The ballast was toast and is now ready for the recycle bin.