Testing a Fluorescent Bulb

Um, how about bringing a small portable bedside lamp (or similar) to the store and us it to test the lamps. Depending on the store this may be practical.

Don't try a full size floor-standing lamp or you may get funny looks.

Alternatively, perhaps do the same but power the lamp and bulb under test using a car inverter in the parking lot before you leave.

Ask the store to test them for you, before you buy them.

"They" make testers but those cost more than you may want to spend.

Hi netmaker,

You wrote, "... with two prongs and in the shop we use the 8' with just the pin ..."

You mean tubular fluorescent lamps, like these? (I call 'em bulbs too)

It may be tough finding a store that has the means to test the 8-foot lamps, but if the store has a lighting aisle (Lowes, Home Depot, etc) they may have a wired display fixture they can use to test the lamps.

If the store sells lamps from different manufacturers, try a different mfr's lamp. It can make a big difference! For the longest time Philips' incandescent bulbs were crap - they didn't last a month! Sylvania's incandescent bulbs, OTOH, had fairly typical lifetimes (and to be fair, Philips makes great LED bulbs - their L-Series).

The newer fluorescent bulbs have a smaller diameter, which is supposed to make them more efficient. In my experience, though, this type often doesn't work in older lamp fixtures. You can still find the older style lamps, but you may have to shop around to find them.

This is where the demise of specialist shops is missed. We used to have a lighting shop in town that had a board which could test every type of bulb or tube, I think they just kept screwing bits to it whenever a new type was introduced. They would test every bulb they sold. Unfortunately they closed not long after the new retail park opened.

Thank you all for the suggestions....it looks like if they can't or won't test the bulbs, then its just crap shoot. I was sure you all had a method of using my tester on these things. .

Thank you all as usual. Its not a big issue for the wife as she likes any excuse to go to town... as for me , I am a home body!

HDT 7100 lamp tester. Google will get you a ton of results. I can't recall exactly what I paid, but it wasn't that much when you consider your other costs. Probably other ones out there as well.

I checked up on the website and found a lot of tools for under $80.00........... thank you for the information.

No problem. I went through all of the same crap and found that the tester pays for itself over and over, especially at my plant earlier. Lately though, I have been switching everything over to HID and LED just to get away from the maintenance hastles.

What is a HID light?

High Intensity Discharge. essentially an Arc lamp updated a bit. requires replacing the entire fixture.

....OK. Thank you. Now I know about HID

That tester looks to be testing for envelope failure only. If the low-pressure gas in the lamp glows, then the envelope is intact, but envelope failure isn't the only failure mode. Bi-pin fluorescent lamps have filaments at both ends and these can fail also. I'm now curious as to how netmaker's lamps failed?

Me too, any time you get a string of failures it's time to look at the fixture. The contacts could be corroded, the starter shot, if it's a starter-less ballast a poorly grounded fixture is often to blame since the metal frame forms a part of a capacitor that helps the arc strike.

I don't think I've had a DOA flourescent in a long time; a bad fixture, contact, or ballast may be the cause of the fail to start.

Nope! These DOA's were bought and placed in different light fixtures at different times and in different sizes and shapes. As soon as I put in a new one, they lit up.

Could they be putting the bad ones back in circulation by accident ??? I would hope that this is NOT the case. However, it has happened now several times at the same store.

I am going to try a different store and different brands...

If you want to be sure you could put a mark on all the returns and see if they're putting them back in stock, but it's better just to find another store and hope for the best.

wouldn't the old kids science trick of static electricty from a flannel rag be a simple in store test to see if they light up?

tell me more.....

Does that light them or just make the phosphor glow?

That won't tell you if the heater filaments on the ends have been broken.

A simple science experiment using static electricity. You generate the static charge by rubbing a piece of flannel rapididly on the flourecent bulb. The bulb then begins to glow. You can do it with a baloon too.... It replaces the power source so I don't think it will help if the electrodes in the bulb are bad.

I think I would buy 10 if I needed 2, test them all when I get home, & mark bad ones. Now if you have 8 good ones, use 2, and you have a known good supply for awhile. Mark dates on the new lamps also, in case some fail prematurely. When you need to go to town for something else, return the bad ones, no special trip. No engineering involved.