Fluorescent Fixture Puzzle

Are you sure you have the new ballast wired to the same two tubes and not somehow cross-wired to one end of a tube still on the other ballast. Otherwise, I have done exactly what you did with no problms. Do you have the input wires reversed? Even if not, maybe you should try the fixture on the benchgtop with the wires to the new ballast reversed, there is a capacitance effect that they use to help start the bulbs, and a reversal of wires negates the starting effect. If all else fails, reinstall the ballast in the cheap fisture to make sure it still works.

H. R. (Bob) Hofmann

Hey John, You can get instant start electronic ballasts for

issues.

the

bought

replace

ballast?

Those cheap shoplights have garbage ballasts, that's one of the first parts they cheapened up. I assume this is the rapid start type and not the old preheat style? Ground to the reflector is very important, but you said you checked that. Since you used a junk ballast I would recommend replacing that with something good, there's a reason real ballasts cost more. Personally I've been using Advance T8 electronic ballasts. The 4 lamp style is under 20 bucks. You have to buy T8 tubes instead of your old T12s but you get more light, less power consumption, no flicker and instant starting.

Wow I should have read that before I replied, you even used almost exactly the same wording.

Actually though there's a wide variety of phosphors available in the old style T12 tubes, including some not found often in T8, but for some reason the T8 stuff is almost all premium trichromatic phosphors so you don't have to special order stuff other than the basic CW and WW halophosphate stuff.

One thing to look for is pick up 80 series stuff with 80+ CRI, the color rendering really is much nicer than the 70 series stuff. Most of them are numbered in a way that makes it simple, F32T8-835 for example is fluorescent, 32 Watt, tubular 8 eighths inch diameter, CRI 80+ with a color temperature of 3500K.

John,

Check the sockets, had one out in my barn that drove me crazy, did the same thing, got a cheapo shoplite from homedepot for les than 15 bucks, switched out the guts, found one bulb heater wasn't making connection. disconnected the power for the umpteenth time and scraped the socket contacts, works like a champ. A quick check would be to put in all the bulbs, fire it up for 5 minutes then take out the bulbs to see if all of the ends are warm from the filaments. Oh yea, my barn gets real cold in the winter, learned to stay away from those 34 watt bulbs, they don't work very well when cold. There is only a few volts at the filaments, 6 volts I believe or less, however, they sit around 600Volts above ground, so , be careful if you think about using a meter to measure the filament voltage. Mine all checked fine, contact was corroded in the spot where the pins rest when the bulb is locked in.

Take care,

Markus

Not saying this is the answer but we had a similar problem with a basement light. Worked for years and started to have same symptoms as you described. If we touched the fixture it would start. Found that the fixture was not grounded. Your mileage may vary.

described. If

grounded.

Normally that'd be my first guess, he did say the ground was ok though.