Fading lamp

[FMEng]

I learned something new the other day. My church has a projector that is around 13 years old. It is rated at 2500 lumens, but was running very dim recently. I checked the lamp hours and it was at only about half the rated life. I decided it was worth the gamble to buy a new lamp and the results were astounding. It is like a new projector again. Apparently, metal halide lamps can age with idle time and not just use time.

Looking back, I think it was getting gradually more feeble the last couple of years so I would replace the lamp at the ten year mark, regardless of how many hours it has on it.

 

[howlingwolf487]

It is quite possible that the lamp hour counter was reset due to the nuisance warming it gives after a certain runtime, but that the lamp itself was never replaced - at least at the same time.

Check the air filters, too...


- Jordan Wolf

 

[ruinexplorer]

Yes, these lamps have a shelf life. In addition, the number of arc cycles they go through will reduce their lifespan. A lot of churches and other non-profit organizations will turn off their projector at every instance that they are not in use to try to save lamp hours. What they end up doing is shortening its life, especially if the lamp does not cool properly before being struck again. In addition to the reduced output, there will be a color shift over the life of the lamp.

One other thing to note, UHP metal halide lamps generally contain mercury. If one explodes, you may need to contend with toxic mercury vapor as well as the broken glass. It is good to check with your lamp manufacturer to see if there is recommended PPE and procedures for cleaning up a broken lamp. Also, make sure to properly dispose of them in accordance to your local laws for hazardous waste.