[aichambaye]

This one has me scratching my head.

I replaced a ballast in a 4 lamb 48" fluorescent fixture this morning. I replaced it with the exact same model as originally in the light fixture and wiring was pretty straightforward.

When I first turned it all back on, only the two outer bulbs were in it, and they both lit. Put the bulbs back in the inner sockets and ... nothing. So I turned it all off again, and turned it all back on, thinking that firing it up with only two bulbs did something to it. Well, then both inner bulbs came on, but not the outer. Now, I had not moved the bulbs around. So I took them all out, checked all the connections, and then the inner bulb in one set of two and the outer bulb on the other worked. So I got up there to see if I should switch the bulbs, and unscrewed one of the ones that was on... and the one of the pair that was off switched on.

What gives?? ballast is a 4 bulb one.

 

[aichambaye]

I've been thinking about just getting LED bulbs anyway and bypassing this dang ballast. Should I?

 

[Wiredindallas]

LED is best, but maybe try to get the new ballast working since you already spent the money. Was the old ballast and new one both electronic type. Trace the wiring via the label diagram. It may not be the same as the old one.

 

[aichambaye]

They are both exactly the same (old and new ballast). Same brand, model, diagram, and label, even. No change from the old to the new except the label is on the side in the old one and on the front in the new.

 

[surferdude2]

Verify that the ballast is getting a good ground connection, clean of the paint at the screw area. Some of the new ballasts are more particular about that than others. It has to do with the necessary capacitor effect between the tube and the ballast, which is enhanced by connecting the ballast housing firmly to the grounded fixture.

And of course make sure the fixture is grounded properly to the box it's fed from.

I've had them fail to start except when the tube was touched, in fixtures that had no ground wire connected.

SD2

 

[aichambaye]

Will check that all again tomorrow. I had to walk away before I started working on it with a sledge hammer. :devil3:

 

[RAL238]

Are the tubes themselves good? Have they been replaced recently?

 

[aichambaye]

Yes. Replaced those first, earlier this week. Also, every tube works. If I rotate one to remove it, the other of the pair pops on. It's clearly an electrical circuit issue. (Hubs is an electrical engineer - I'm the practical one who will get on a ladder with a wire stripper, lol).

 

[JBoot]

For your review. This guy makes it simple.

 

[surferdude2]

His fixture feed method is particularly informative. I guess you don't need a ground conductor after all... or even a conduit or cable. That's real economy! :biggrin2:

 

[Porsche986S]

My opinion the $$ you spent on the new ballast should have gone towards LED bulbs instead . I like the KISS principle , eliminate the ballast and you have eliminated the major portion of any future failures . The price of LED bulbs has become so reasonable that cost doesn't really enter the picture any more , that used to not be the case .