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jwrxx · Mar 31, 2013, 07:59 PM

I have a fluorescent light fixture from an old coke machine that will not start. New bulb, new starter, and all the wiring is correct. It tries to light, but the filaments on each side of the bulb glow as it tries, but will not stay lit. Could it somehow have the wrong ballast, and could this be the trouble? Would the cold outside temperatures cause the bulb not to light?

hfcarson · Apr 1, 2013, 04:16 AM

So a new fixture similar to the one you describe is about $10...
Is this just for fun?

scott53715 · Apr 1, 2013, 05:36 AM

Change the ballast! You can save so much energy if you do, and get longer bulb performance too. Its easy to do too. If you need the light to function in lower temperatures, there are ballasts for 'cold start' available. Cheap light fixtures have cheap inefficient ballasts. Just like a compact fluorescent light bulb vs old type incandescent, money spent up front is money saved many times fold over the useful life of the product.

hkstroud · Apr 1, 2013, 11:21 AM

I have a fluorescent light fixture from an old coke machine that will not start.

Are you trying to restore an old coke machine or are you trying to use the fixture some where?

jwrxx · Apr 1, 2013, 07:47 PM

Originally Posted by hfcarson

so a new fixture similar to the one you describe is about $10...
is this just for fun?

It IS for fun, but it's a 1963 coke machine that I wish to keep as original as possible. The fixture is not an engineering marvel, but it won't work.

jwrxx · Apr 1, 2013, 07:55 PM

Originally Posted by hkstroud

Are you trying to restore an old coke machine or are you trying to use the fixture some where?

It's just an old coke machine that I want to work again. Kids have never seen one that lets you put a dime in and pull out a coke in a BOTTLE, of all things! The light fixture just hangs on 2 screws, and is such a simple thing. Should work!

jwrxx · Apr 1, 2013, 08:05 PM

Originally Posted by scott53715

Change the ballast!! You can save so much energy if you do, and get longer bulb performance too. Its easy to do too. If you need the light to function in lower temperatures, there are ballasts for 'cold start' available. Cheap light fixtures have cheap inefficient ballasts. Just like a compact fluorescent light bulb vs old type incandescent, money spent up front is money saved many times fold over the useful life of the product.

I replaced the ballast with one that looked the same, size-wise. That was my concern, are there differences in ballasts that are not apparent to the eye?
The filiments are glowing, but maybe there's not enough "kick" to make the bulb glow. How do you know which one to use?
What is the difference between regular and 'cold start' ballasts?

hkstroud · Apr 1, 2013, 10:12 PM

hfcarson can provide a lot more infor than I can, but essentially you need to match the ballast to the bulb. Since your are restoring, if you are trying to keep the old ballast may have to try to find an original blub (assuming the old ballast works). If you are replacing ballast and bulb it would probably be easier to simply buy fixture with size bulb you need and swap blub and ballast.

Fluorescent don't like cold but that shouldn't be a problem unless you are going to keep the coke machine out side in winter months, kids won't like that either.

Fluorescent don't have filaments. The tube is filled with fluorescent gas which conducts electricity, heats and glows. What you are seeing is the heated gas at the ends of the tube. Gas is not conducting well enough to heat entire tube. Old florescents used a starter (a capacitor) to boast voltage initially. Once heated gas conducts better and starter not needed. Current fixtures do not use starters, but bulb must be with in certain distance of metal frame. Metal frame must be grounded. Grounded metal frame is acting as starter.

That may be the problem, old ballast used starter, new one does not. Changing is probably an all or nothing type thing. Not sure but think bulb must be with in 1/4" of grounded metal frame to work with out starter.

Can't look at a ballast and tell the difference, have to read the data to match.

I remember the coke machines but seldom had the dime.

hfcarson · Apr 2, 2013, 11:13 AM

jwrxx,
Yes HK is right the ballasts are specific to the actual type and number of lamps you are connecting them to... they need to match.
The wiring diagrams are normally included on the ballast so if a starter is needed it will be on the diagram...
If the ballast does not have a diagram you may not be able to divine the correct wiring and should consider a new fixture...