Re: Pot-Belly Bulbs

[P3D Gregory J. Wageman <gjw@xxxxxxxxxx>]

Kevin Evans wonders:

>The replacement lasted three seconds, and
>the spare lasted for a couple of hours.  Each time the bulbs were blown
>when I powered up.  The blown bulbs have sort of distended pot-belly
>bubbles on their front sides.  I was careful to handle the bulbs with
>gloves while installing them, and I even switched the one remaining
>original to sort of empirically test the receptacle prior to the last one's
>self-destruction.  So I have a few questions...
>
>Is the projector circuitry faulty, or are the "south of the border" bulbs
>the problem?

If these are line-voltage-powered bulbs, and you're supplying them the
appropriate line voltage, there's nothing the projector circuitry can do
to blow the bulbs.  From your description, it sounds like the bulbs may
have been contaminated with oil during manufacture or afterwards.  Next
time, give the bulbs a thorough cleaning with alcohol before installing,
and handle them using only clean tissue paper or cloth (I know you said
you used gloves, but gloves can transfer skin oils if they are not clean).

Make sure too that the ventilation is unobstructed.

Quality of lamps varies incredibly.  Our dining room chandelier uses
25W candelabra base clear round bulbs.  When the originals started
burning out, we bought a box of off-brand Taiwanese replacements.
Within a month, the "new" bulbs began burning out!  The next box
was General Electric bulbs, and they are all still going strong
many years later.  They cost more, but they were worth it many times
over.

        -Greg W.


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