Fluorescent lighted sign repair.

[Rixter58]

I'm not an electrician, so bear with me please. I've got a collection of lighted signs. I'm currently working on an inoperative one that has 3, 7' bulbs. I put power to it and the ballast does not buzz. Stopped by HD to look at ballasts. They have ballasts for either 1 or 2 8 ft bulbs. Here are my questions
1. How does one check the ballast?
2. If that ballast is bad (which I'm currently working under the assumption that it is), how do I proceed to repair this light?
Thank guys!

 

[Erampu]

You might consider consulting with someone in a sign shop...

 

[nehog]

Have you opened the sign and looked at the currently installed ballast and noted what was marked on it? I suspect that you are using a ballast that is rated for 1 and 2 bulbs and there are two ballasts in the fixture, but it may be a 3 - 4 ballast too. You either want to match the current ballast or you will need to rewire the sign to match the requirements of the new ballast(s).

Suggestion: post a readable image of the current ballast's data, should be printed directly on the top of the ballast. Also post the information on each tube, I suspect they are 8 ft (not 7) but one needs to know if they are single pin or dual pin style.

 

[Rixter58]

Ok.... Update.
Was able to get a buzzing sound. Bulbs are f84T12/D/HO. Ballast has been warm enough at some point that paper on it appears somewhat burnt and is unreadable.

 

[Rixter58]

Next update.
With unit plugged in, multimeter reads 4.5 volts at terminals? Can that be right?

 

[Norcal]

If the ballast is bad, then you need a sign ballast, one source is Grainger but they "ain't" cheap, or try a electrical supply house.

A Advance cat # ASB-1224-24-BL-TP should work, 120V, 2,3,4 lamps, 12 feet min, 24 feet max. lamp length. A new ballast should mean new lamps also.

 

[Rixter58]

I've conceded new lamps, that's often a given with these signs. How does one check a ballast?

 

[nehog]

I've conceded new lamps, that's often a given with these signs. How does one check a ballast?

Replacement is the easy way. The odds are very high that the thing is bad. If you don't have the specifications for the original (appears you don't) you will have trouble determining whether the output voltage is correct or not.

Q: is this sign going to be in use, outdoors, or is it intended to be an indoor display item (shop decoration?) If decoration then you can possibly get away with a non-sign rated ballast.

 

[dipper]

i would just replace the ballast. checking for them to buzz is not a very good way to troubleshoot them. If they are just standard t5, t8 or t12 bulbs, then go to a lighting or electrical supply house (or buy online) a new ballast. You can get them in a 3 bulb version and they will usually have a diagram on them for wiring them up.

 

[Norcal]

i would just replace the ballast. checking for them to buzz is not a very good way to troubleshoot them. If they are just standard t5, t8 or t12 bulbs, then go to a lighting or electrical supply house (or buy online) a new ballast. You can get them in a 3 bulb version and they will usually have a diagram on them for wiring them up.

The sign uses F84T12/D/HO lamps which are not common, which means they are expensive. F72T12/HO, & F96T12/HO are pretty EZ to get.

 

[Steven Rothschild]

A lot of old ballasts buzz. Was the sign used for outdoor use? If so, nobody cared if it buzzed. The ballast will be specific to 7 ft lamps and the lamps will be pricey sign lamps too. Are you retrofitting the sign for historical accuracy or to light it up? If it is the latter there are LED kits that may work.

 

[onething]

From the Center of the Universe comes this link:

start reading at post #5887 through #5889

Not only how but why to fix your problem, I think.

 

[Rixter58]

Update. Checked the voltage on a few of my other working signs and they are all within .5 either way of this one. Step one will be to replace the bulbs and start from there.