What causes early projection
lamp failure in your a/v equipment
by Bob Carlson
One of the
more frequent questions I get in the service department at United
Visual is what causes early projection lamp failure. A lot of
people are making simple mistakes that are costing them a lot
in burned-out lamps. For instance, did you know...
the machine while the lamp is on or even shortly after turning
it off can cause premature failure. A hot lamp filament will
fall apart if the machine is handled roughly.
lamp life means just that. In a test done by GTE/Sylvania
on 10 ENX lamps, the range of life was 34.3 hours to 76 hours.
The average lamp life for this batch was 68.7 hours, higher
than the published average of 65 hours. However, the lamp
that lasted only 34.3 hours is not considered to be
overhead projector lamp does not burn out immediately, but
burns out within an hour, the lamp is probably defective,
not the projector. In recent years diode failures (a component
in most newer overheads) have been the cause of many burned
out lamps. However, a diode failure will always cause a lamp
to burn out instantly!
should never move a lamp changer lever (if your machine is
so equipped) while the on/off switch is in the "On"
position. This will jar the lamp and cause a hot lamp filament
to fall apart. Moving it when the power is off will assure
the lamp filament is cool and able to handle rougher treatment.
heat will shorten lamp life. A fan running slow due to lack
of lubrication or a dirty motor will not cool a lamp sufficiently.
Regular maintenance at United Visual will prevent this from
should never allow anything to block the airflow of your projector's
cooling fan. The intake and output grills must not be obstructed
or overheating will occur, shortening the lamp life.
than normal AC line voltage will tremendously decrease lamp
life. Whereas higher voltage might not affect other appliances,
an increase of only two volts will shorten lamp life by as
much as 20%, five volts as much as 58%! If you notice a problem
with short lamp life, it's worth having an electrician test
that is not properly seated in its socket may seem burned
out. Not only may the lamp not make good enough contact to
light, it may make enough contact to arc and burn its pins
or the contacts of the socket. If arcing occurs, the lamp
may not light even after it is seated correctly.