The kitchen has a dropped ceiling with two pairs of standard 4-foot bulbs - I
guess that's what is called T12. This fixture has never been very reliable in
the 20 years I've owned the house. Bulbs don't last as long as they should,
and on colder winter mornings, while the heater is still warming up the house,
they often take several minutes to come on.

The last straw came two days ago when a two-week-old pair of Phillips bulbs no
longer would light, period. One of those tubes already has blackened ends.
The other pair in this fixture is working OK.

What is likely to have failed to cause such an early failure on these bulbs?
I assume the ballast, but would like an expert to confirm. I'm interested in
purchasing electronic replacements, while realizing they are more expensive
than traditional magnetic ballasts, but an intimidated by unfamiliar concepts
such as "ballast factor".

Can anyone provide practical troubleshooting and replacement/selection advice
so I can purchase the correct pair of ballasts?

Art

Arthur Shapiro wrote:

What is likely to have failed to cause such an early failure on these bulbs?
I assume the ballast, but would like an expert to confirm. I'm interested in
purchasing electronic replacements, while realizing they are more expensive
than traditional magnetic ballasts, but an intimidated by unfamiliar concepts
such as "ballast factor".

While you're at it, you might consider switching to T8 bulbs. You'll
need to replace the bulb holders as well, but you'll get electronic
ballasts automatically.

Chris

I believe aT-8 will fit in the fixture without changing the sockets then
change the ballast over. I have done many fixtures with out changing the
sockets
"Chris Friesen" wrote in message
...
Arthur Shapiro wrote:

What is likely to have failed to cause such an early failure on these
bulbs? I assume the ballast, but would like an expert to confirm. I'm
interested in purchasing electronic replacements, while realizing they
are more expensive than traditional magnetic ballasts, but an intimidated
by unfamiliar concepts such as "ballast factor".

While you're at it, you might consider switching to T8 bulbs. You'll need
to replace the bulb holders as well, but you'll get electronic ballasts
automatically.

Chris

On Jul 16, 12:43 pm, (Arthur Shapiro) wrote:
The kitchen has a dropped ceiling with two pairs of standard 4-foot bulbs - I
guess that's what is called T12. This fixture has never been very reliable in
the 20 years I've owned the house. Bulbs don't last as long as they should,
and on colder winter mornings, while the heater is still warming up the house,
they often take several minutes to come on.

The last straw came two days ago when a two-week-old pair of Phillips bulbs no
longer would light, period. One of those tubes already has blackened ends.
The other pair in this fixture is working OK.

What is likely to have failed to cause such an early failure on these bulbs?
I assume the ballast, but would like an expert to confirm. I'm interested in
purchasing electronic replacements, while realizing they are more expensive
than traditional magnetic ballasts, but an intimidated by unfamiliar concepts
such as "ballast factor".

Can anyone provide practical troubleshooting and replacement/selection advice
so I can purchase the correct pair of ballasts?

Art

Doing a value analysis with new fixtures will quickly lead you to
conclude that the old fixture repair is a hopeless proposition.
Avoiding the off shore super cheapies at the box stores ought to get
you some attractive, modern, and reliable lighting. Of course, if you
like to tinker, that's a whole different thing. HTH

Joe

In article , Arthur Shapiro wrote:
The kitchen has a dropped ceiling with two pairs of standard 4-foot bulbs - I
guess that's what is called T12. This fixture has never been very reliable in
the 20 years I've owned the house. Bulbs don't last as long as they should,
and on colder winter mornings, while the heater is still warming up the house,
they often take several minutes to come on.

The last straw came two days ago when a two-week-old pair of Phillips bulbs no
longer would light, period. One of those tubes already has blackened ends.
The other pair in this fixture is working OK.

What is likely to have failed to cause such an early failure on these bulbs?
I assume the ballast, but would like an expert to confirm. I'm interested in
purchasing electronic replacements, while realizing they are more expensive
than traditional magnetic ballasts, but an intimidated by unfamiliar concepts
such as "ballast factor".

Can anyone provide practical troubleshooting and replacement/selection advice
so I can purchase the correct pair of ballasts?

Many residential dual-T12 4-foot fixtures have some call the
"residential grade" ballast. It is maybe 1.5 inches shorter than a "full
size" dual-4-footer fluorescent lamp ballast. I call those ballasts
"stool specimens" to put it politely.

Ballast factor is ratio of light output using the ballast in question to
light output on a "reference ballast", which is some standard used to
determine the catalog figure for rated light output.

Most ballasts for which ballast factor is made known are for T8 (1 inch
diameter) bulbs. T8 ballasts tend to be electronic and better. I would
recommend replacing the ballast with an electronic one for T8, and use T8
bulbs.

As for a usual dual-4-footer rapid start magnetic ballast becoming prone
to blacken the ends of the bulbs quickly: The output series capacitor is
probably shorted. The ballast can easily overheat from this. The ballast
needs to be replaced.

- Don Klipstein )

In article , Chris Friesen wrote:
Arthur Shapiro wrote:

While you're at it, you might consider switching to T8 bulbs. You'll
need to replace the bulb holders as well, but you'll get electronic
ballasts automatically.

T8 and T12 bipin fluorescents take the same lampholders.

- Don Klipstein )

In article om, Joe wrote:

Doing a value analysis with new fixtures will quickly lead you to
conclude that the old fixture repair is a hopeless proposition.
Avoiding the off shore super cheapies at the box stores ought to get
you some attractive, modern, and reliable lighting. Of course, if you
like to tinker, that's a whole different thing. HTH

I prefer to change the ballast myself because too many fluorescent
fixtures sold in retail establishments for use in homes (or home garages)
have what many call "residential grade" ballasts, which I call "stool
specimens".

- Don Klipstein )

While you're at it, you might consider switching to T8 bulbs. You'll
need to replace the bulb holders as well, but you'll get electronic
ballasts automatically.

I've had it with 22" & 32" circs and 6"-48" T whatever.
When ANY part fails, I pull the guts and add 1-4 standard
edison base sockets, and screw in 5w to 32w CFL's as needed.

Cost less that replacing the bad part and my box of $2
5/13/24w cfl's (HD 6 & 8 packs) will now replace everything.

-larry / dallas

In article , larry wrote:
While you're at it, you might consider switching to T8 bulbs. You'll
need to replace the bulb holders as well, but you'll get electronic
ballasts automatically.

I've had it with 22" & 32" circs and 6"-48" T whatever.
When ANY part fails, I pull the guts and add 1-4 standard
edison base sockets, and screw in 5w to 32w CFL's as needed.

Cost less that replacing the bad part and my box of $2
5/13/24w cfl's (HD 6 & 8 packs) will now replace everything.

I have seen quite a share of problems and insufficiencies with
fluorescents 22 watts or less, especially less than 15 watts, and ones
between 22 and 32 watts are a bit oddball and expensive.

4-footers are less expensive and 2-foot F17T8 I have been quite happy
with. My main problems with 4-footers are that some ballasts for F40T12
are lousy, and F34T12 can be "cranky", especially in cold or with a subpar
ballast.

Use of "true 40 watt" F40T12 or better still 17 and 32 watt T8 with
decent ballasts should do well where the fixtures fit well and look good.

A 4-footer usually costs less than a CFL and usually outlasts a CFL, is
more efficient than a CFL and has less of warmup issues than a CFL. What
CFLs are good for is where a good linear fixture is impractical, too big
or does not look good.

- Don Klipstein )