# F96T12 Ballast Changeout



## SHOCKnAWE

Just lost some hair and made some grays over this ballast change. Customer had a failed magnetic ballast and I ordered in a replacement, and of course, this one is electronic...no problem, right?

I verified the wiring diagram and it was the same as the magnetic, so I added in the quick disconnect, installed it, reassembled and nothing. After several times of doing this, I called tech support on the box. Unbelievable that I'd call support on a ballast change, but I did. They said that the fixture cannot be lamped while energized or it trips the internal-end-of-life switch; turn off the light and turn it back on. So I did, and nothing.

My last resort was to change the ends. They looked good, but apparently they weren't, because that did the trick. I suppose there was a bad connection in an end and possibly that simulated a lamp change and locked out the ballast.

Moral of the story: When a ballast fails on a F96T12HO fixture, buy a complete new fixture and replace the whole thing or scavenge the parts, including the ends.


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## Speedy Petey

With 2/96HO electronic ballasts you MUST make sure the correct wires go to the sprung ends, the yellows I think. It is the opposite of what would be typical of a mag ballast.
I had this problem with several ballasts and only found out after reading every word on the label.


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## SHOCKnAWE

Reversing ends was another option I had left to try, although I did ohm out each end an they were all the same, so I don't understand how switching ends would have made a difference. Please explain if I'm overlooking something in that regards.

This is the first electronic ballast I've worked with that locks out the ballast when relamping. Is this only consistent with the high outputs or is it being introduced into other ballasts?


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## Speedy Petey

I have no idea why it matters. Maybe it has to do with contacting the sprung end first.


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## kaboler

A lot of people change out these bulbs hot, and I find it cooks the ends. Because of the startup voltage? But it cooks the ends.


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## noarcflash

these days, anything 96" and T12 is garbage.


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## Electric_Light

Perhaps the original ballast wasn't faulty at all? Magnetic rapid start ballasts are designed to put out just enough voltage to start the lamps with all electrodes heated up, so if the cathodes aren't heating up, they don't start. 

To get technical, high frequency A/C arc behaves like DC. The zero crossing time is so short that arc does not extinguish like 60Hz arc, so when a lamp is pulled while energized it will pull a nice inch long arc and start a fire. So, as a safety feature some ballasts will check that all electrodes are intact as a means of making sure lamps are properly installed as well as detecting failing lamps.


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