Replaced Ballast and Bulbs - now what?

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Old 07-15-13, 12:51 PM
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Replaced Ballast and Bulbs - now what?

T12 four-bulb four-foot fixture about 12 years old. One or both of the ballasts leaked, and bulbs started failing. Replaced both ballasts and all bulbs and get basically the same result as before I replaced the ballasts - outer two bulbs don't light properly (one dim, one nothing).

Being a wrap-around and part of a set in the masters closet, buying multiple new T8 fixtures is not cost-effective so would like it fixed. At a loss, because the only the only other component in the fixture as far as I can see is the connectors. Do they fail? Do I need to get the 'ol trusty continuity checker out?

Thanks
 
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Old 07-15-13, 03:21 PM
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Yes, it is possible for the sockets to fail. Check them with a meter if you know for sure the bulbs and ballast are good and wired properly.

Food for thought: You do not need to replace the entire fixture to run T8 bulbs. Just replace the two T12 ballasts for one single T8 4 lamp ballast. T8 lamps fit T12 bi-pin sockets. I have retrofitted thousands of T12 fixtures to T8.
 
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Old 07-15-13, 04:12 PM
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Thx ironhand - I will keep that in mind, but having sunk $30 into two ballasts, this is darn well going to work!!

Am getting conflicting info on web searches - what should the readings be - is it the 3.4-4.5v range? Consistent across all sockets? Thx
 
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Old 07-15-13, 05:06 PM
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You have a two U tube fixture and you replaced both ballasts.

The readings across the sockets don't mean a whole lot since the lamps arc at a high voltage.

I've noticed on some older fixtures that the clip that holds the tube in must be in place as part of the arc flashes to ground at the clip.

One plus with the new electronics ballasts as they don't use any type of lamp preheat. Basically the pins are tied together at the end of the lamp and the ballast sends a HV pulse to get the tube to arc. You can actually have cracked sockets and they'll still work.
 
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Old 07-15-13, 05:28 PM
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Can you post the model number and brand of the ballast?
If the ballasts are instant start they require shunted sockets meaning that each lamp holder only has one wire connected to it and the other pin is also connected to that wire (Shunted)
 
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Old 07-15-13, 06:04 PM
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Had a 3"ish"v reading on one end of the suspect bulb sockets and 0 on the other. Looked closely at the connector, did not seem damaged. Traced back the wiring and turns out that I had wire-nutted the two connector leads to each other instead of the ballast (d'oh!).

Voltage troubleshooting was the trick; despite my fears, no black magic in fluorescent bulbs. If you don't have voltage, you did it wrong! Thanks for your help folks!
 
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Old 07-15-13, 06:33 PM
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Glad you got it figured out.
 
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