I have an intermittent florescent fixture that's been plaguing me for several years. It behaves in an odd way. It's a dual 40 watt (4 ft) bulb unit. At first I replaced the bulbs 3-4 times in about 8 years. Then replacing the bulbs didn't fix it so I replaced the ballast. That worked for about a year then it began giving bad bulb signals and I replaced the bulbs again. Since then (one year old ballast and new bulbs) it's come on fine sometimes and not other times. It seems random with it not working more times than it works. When it doesn't come on the bulbs are dimly lit like failing bulbs. I tried changing the bulbs with a pair from another fixture that I new were working, no change.
It's been this way for about 5 years, so I changed the ballast again. The behavior is still the same. When I first turned it on after changing the ballast it worked fine. I turned it off, then turned it back on within a minute -- it was dim. When it's not working right, turning it off and on doesn't seem to have any effect. When it is working turning it off seems to make it stop working.
Here are some facts.
o When the bulbs are dim they are both dim but one is obviously dimmer than the other.
o I have twisted the bulbs around in the contacts many times to no effect.
o The current bulbs have this information on them [But, I've had 3 different new bulb pairs perform the same way]:
Phillips F40T12/Home Light Cool (Capital E in a circle)
40 Watt USA 7Jo The ballast information is:
Brand: Advance Class P Type 1 Outdoor High Power Factor Sound Rated A Rapid Start Lamps
120 Volts, .73 AmpsThis ballast was bought at an electric supply house and it was the best one they sold.
The resistance between the two pins on the same end of each bulb is 1 ohm on both bulbs (4 pairs). From the pin on one end to the pin on the same position on the other end is open (infinite ohms) for all 4 pairs.
-------------------------------------------- 38v || fixture || 40v 38v || || 40v --------------------------------------------
These measurements were made with the bulbs removed.
View above text sketch in fixed pitch font.
jim ___ Have a home upkeep question? Try my help page. It's sort of an alt.home.repair FAQ.