Which Ballast?

Old 04-01-16, 08:07 AM
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Which Ballast?

I have 2 florescent fixtures that are 48" long that have 4 bulbs in each. 2 bulbs that are size 12 type do not light up and I have put new bulbs in each. It has 2 ballast in each, how can I tell which ballast is bad?
Old 04-01-16, 09:09 AM
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You can turn on the fixture with only the working bulbs in place. Leave it on for a while. The hotter ballast is the working one. Otherwise you can pull the socket brackets out and trace the wires.
Old 04-01-16, 10:55 AM
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If they are really old fixtures..... they may not light with new tubes. New tubes need a good kick to get them going and the older ballasts don't supply it.

Consider replacing the ballast with a four tube T-8 model and replace the tubes with T-8's. The tube sockets are the same.

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