"Chuck Chandler" wrote in message
...


What are you using to ballast the new bulb? I'd be very hesitant to go
up
in
wattage, in that unlikely scenario that it catches fire, you're pretty
well
screwed.

I'm not sure what you mean, but both are video projector bulbs- they use
25KV to start an arc, then about 20-50 volts to maintain the arc. So of
course I am using the original ballast (100 watt) with the slightly higher
(120 watt) bulb. The ballast is specifically designed to limit current, or
you could say regulate current, so I am pretty sure it is only putting out
100 watts, although it might be generating a slightly different voltage to
do so, which is really a function of the electrode gap. Thus it might be
getting a little hotter, hence the extra fans. This LCD projection tv had
30,000 hours on it when I got it for $1.25, but it really does look great.
I
have no worry about it catching fire, but there could be a component
failure
in it's future.

Ah, I thought you were using something else as the post was originally about
tricking the projector into thinking the lamp had started.

Using a lower wattage lamp is safe, though often you'll get a nasty color
shift if you operate a metal halide out of spec but that depends on the
design of the lamp. Also, surprising as it may be, operating them under
wattage will usually drastically decrease lamp life because the electrodes
run too cool and sputter heavily as the arc restrikes between the
half-cycles. YMMV though, for what you have invested in it it's a worthwhile
experiment.