[jfausmith]

I have three 8' florescent light fixtures in my garage. Each of the light fixtures has two florescent bulbs each (T12). About 4 years ago I had to replace all the light fixtures because two of them were going bad (bad ballast) so I decided to replace all three of them.

Last month one of them stopped working. At first I thought the bulbs were dead so I purchased a new set of the bulbs (T12) and installed them. The light still did not work so I figured that the ballast had gone bad and purchased a new ballast. After installing the new ballast I put the bulbs back into the light fixture and found that they still don't work. I am to the point of purchasing a new light fixture and replace the entire fixture.

My question is what could be the problem with the existing light fixture? There is a new ballast and new bulbs but it still doesn't work. I even took the bulbs out of one of the other "working" light fixtures and put them into the problem light fixture and it still doesn't work.

Very frustrating!

Thanks for any help you can offer.

 

[jbfan]

Take the lamps from a working fixture and try them.
It is not uncommon to get bad lamps.

I saw you tried this already.

Make sure the ballast is wired correctly

 

[Techy]

Socket or tombstone could have given up, aswell.

 

[jfausmith]

I will try anther pair of bulbs tonight and I will recheck the wires to make sure that they are connected correctly.

How do I check the sockets to see if they are still good? What should be the voltage that is going through them?

 

[Perry401]

Don't try to test the voltage on the sockets with any normal meter unless you know what you are doing. Florescent ballasts can generate 500-600 volts or more, beyond the safe voltage for some meters.

New lamp sockets are very inexpensive -- I bought a set the other day for under $3.00 at a big-box store. Take one along if you decide to buy new ones since there are several different models. Some are interchangeable, some are not. But you might want to simply check the connection at the existing sockets first. Most sockets use push-in contacts which can fail fairly easy. With the power off, simply grasp each wire and give it a yank. If it pulls out, poke it home again, and try the pull test again. Be sure to get wires into the right slots. Most florescent sockets have two poke-home holes for each connection, or four holes in all. Most ballasts have some type of fuse which melts if the ballast gets over heated. These are normally not replacable, and you would need to replace the entire ballast if it failed.

Make sure to check the wiring with the diagram that usually is included on the ballast (or can be down-loaded from the ballast manufacturer). Sometimes wire colors or arragement may change, especially between manufacturers. Some solid state ballasts have very strict wiring requirements which may result in short ballast life if not followed to the letter. You might also check the ground. Some ballasts require a high-quality ground to start the lamps, while others do not.

 

[frenchelectrican]

Just becarefull with some of the 8 footers they will come in two diffrernt verison one is slimeline the other is high output both are not interchangeable.

The slimine is single pin flourscent bulbs while the High output have black recessed bipin socket and both are not interchangeable.

However the wattage you have to watch out on them I know on slimlines the 60 watters are kinda pain in butt if not heeded due some of the ballast will not work on the reduced wattage bulbs { they need a bit more voltage to strike thru the bulb than full wattage verison }

For the high output bulbs it simauir situation as well they come either 90 or 115 watts verison

However the bulbs slection is slowly getting less on both type ditto with ballast the only way you can keep the T-12's is get electronic ballast verison the mangatic ballast is about history due engery pact.

If you have to replace the ballast just stop right there and get new luminaire with strip verison get 8 footer 4 lamp { F32-T8 } with electronic ballast they will have more light than old slimliners are.

The cost of new 4 lamper strip is about the same what you will get a brand new ballast slimine or HO ballast or whole luminaire.,,

And also make sure the bulbs is clean if dirty they may not light up as well.

Merci,
Marc