Optoma HD 72 Bulb just went... I Think...

Originally Posted by Tukkis

It's not the bulb. I just had mine come back from repair for the same thing. The screen went blank just after starting up. The projector kept running and fans were on.

I don't know exactly what they fixed but they replaced a part and not the bulb.

Woah what!.. so you are saying the my previous two bulbs that i thought were dead are still good? I need to send mine in asap.. thanks for the heads up.

Originally Posted by thomaskuhn

I talked to Optoma yesterday, explained the problem, and the person I spoke to said that that I was seeing was NOT NORMAL. HEreis what he told me in myown words...

He mentioned that it could be the sensitivity of the ballast that drives the light. After replacing a bulb, the new bulb is within the tolerance of the ballast for a while, until it slowly moves outside of the tolerance and the ballast shuts down.

So to everyone who has this problem, 1. Talk to Optoma, 2. I hope you kept yourold bulbs, as there might be quite a few hours left on them.

I will keep everyone up to date...


Tom


Update #1 - I went and looked for my old bulb and it has mysteriously disappeared. This is the second time that and old bulb has disappeared on me...

Originally Posted by morrisdl

Shipping was almost $100, hopefully they will give me something for the trouble.

Originally Posted by Ikari Warrior

I had this happen twice the other night. I thought my Xbox was turning of, everything just went black, the fan was still running as if it was on. I turned it off, and back on and the same thing happened again. Since then it hasn't happened anymore.

Originally Posted by morrisdl

From wiki - here: http://en.wikipedia.org/wiki/DLP_projector

The main light source used on DLP based rear screen {and front} projection TVs is based on a mercury vapor arc lamp. The arc lamp is replaceable by the DLPTV owner and as of 2006 costs between $140 and $300 USD. At start up the arc lamp is "struck" by a 5000V charge to start the arc in the arc tube. The arc starts and after warmup the "hold" voltage drops to approximately 60 Volts. At the end of life, mercury-vapor lamps commonly exhibit a phenomenon known as cycling. As a lamp gets older, the maintaining voltage for the arc eventually rises to exceed the voltage provided by the ballast module. As the lamp heats, the arc fails and the lamp goes out. Eventually, with the arc extinguished, the lamp cools down again, the gas pressure in the arc tube is reduced, and the ballast can once again cause the arc to strike. The effect of this is that the lamp glows for a while and then goes out, repeatedly. The RPTV ballast designs detect cycling and give up attempting to start the lamp after a few cycles. If power is removed and reapplied, the ballast will make a new series of startup attempts. This failure is then typically indicated via LEDs on the unit, and neccessitates replacement of the lamp.

Originally Posted by www.wikipedia.org

To display images, LCD (liquid crystal display) projectors typically send light from a halogen lamp through three LCD panels -- one each for the red, green, and blue components of the video signal. As light passes through the panels, individual pixels can be opened to allow light to pass or closed to block the light. The combination of open and closed pixels can produce a wide range of colors and shades in the projected image.

Halogen lamps are used because they output an ideal color temperature and a broad spectrum of color. These lamps also have the ability to produce an extremely large amount of light within a small area: current projectors average about 2,000-4,000 ANSI lumens.

Newer technologies, such as DLP and LCOS are becoming more popular in video projection. In practice, the term "LCD Projector" is often used as a catch-all for any type of computer projector, regardless of the technology being used.

Originally Posted by www.wikipedia.org

One invention that addressed the problem of short lamp life was the halogen lamp, also called the tungsten-halogen lamp, the quartz-halogen lamp or the quartz-iodine lamp, wherein a tungsten filament is sealed into a small envelope filled with a halogen gas such as iodine or bromine. In an ordinary incandescent lamp, the thickness of the filament may vary slightly. The resistance of the filament is higher at the thinner portions which causes the thin areas to be hotter than the thicker parts of the filament. The rate of tungsten evaporation will be higher at these points due to the increased temperature, causing the thin areas to become even thinner, creating a runaway effect until the filament fails. A tungsten-halogen lamp creates an equilibrium reaction in which the tungsten that evaporates when giving off light is preferentially re-deposited at the hot-spots, preventing the early failure of the lamp. This also allows halogen lamps to be run at higher temperatures which would cause unacceptably short lamp lifetimes in ordinary incandescent lamps, allowing for higher luminous efficacy, apparent brightness, and whiter color temperature. Because the lamp must be very hot to create this reaction, the halogen lamp's envelope must be made of hard glass or fused quartz, instead of ordinary soft glass which would soften and flow too much at these temperatures.

The envelope material can be selected and modified (by means of optical coating) to achieve whatever lamp characteristics are required. Halogen bulbs are widely used in automobile headlamps, for example, and because headlamps often contain plastic parts, halogen headlamp bulbs' envelopes are made out of hard glass, or out of quartz 'doped' with additives to block most of the UV output (hard glass blocks UV without need of dopants).

Conversely, some applications require ultraviolet radiation, and in such cases, the lamp envelope is made out of undoped quartz. Thus, the lamp becomes a source of UV-B radiation. Undoped quartz halogen lamps are used in some scientific, medical and dental instruments as a UV-B source.

A typical halogen lamp is designed to run for about 2000 hours, twice as long as a typical incandescent lamp.

Originally Posted by ahro

...why is the bulb working?

BTW the lamp hours were reset. How do I find out how many actual hours I have on the bulb? They probably didn't replace the bulb, but there's no place to actually fnd out the lamp houurs after a reset, or is there?