How can he know that?

[SirBenjamin]

I bought a Data Projector of ebay last week,the guy had three of them all secondhand. He stated individually on each of them that the lamp had 700,850 and

1500 hours to go.

How can he know this?

Thanks.

[Ian Stirling]

The lamps have scheduled change times. They should generally not be left till they stop working, as they can explode.

[visionset]

Because some have little integral (mercury?) meters that track usage.

-- Mike W

[Ron Lowe]

Our projectors at work have a lamp timer function in them. They start to nag you as the expected lifetime comes near.

If you go to the service menu, you can see how may hours they have used, how many remain, set the number-of-hours-remaining-before-I-nag-the-hell-out-of-you etc etc.

All depends on the timer being re-set truthfully when the lamp is replaced with a new one, though! Nothing to stop an unscrupilous seller from re-seting the lamp timers without changing the lamp.

[SirBenjamin]

Hah! thanks Ron,didn't know that as this is a new field this DP lark.

So basically I could end up with 20 hours? instead of 700. ;-(

[Ron Lowe]

Well, yes, in theory you could.

I'd be more suspicious if they all had 2000 hours ( or whatever the nominal lamp life is ) remaining. To get the numbers you quote, they'd need to re-set them and then burn them for some hundreds of hours. I doubt they'd do that just to make the numbers 'more beleivable', at the risk of actually killing the thing stone dead.

I'd be inclined to believe the hours.

However, we often have lamps that fail in one way or another before they are at their nominal life. Some go so dim they are un-useable. Some melt into wierd and wonderful shapes, making replacement difficult. It's a bit of a lottery.

For reference, what I'm using at work is a bunch of approx. 3-yr old Sony VPL-21 projectors. ( I work as a technical instructor in the training school for an oil service company. We have several classrooms in the training centre, with these things ceiling mounted. They get a hard life. )

[Dave]

I believe the lamps cost an arm and a leg or two to replace. Have you considered this?

Dave

[Phil L]

George has many, many arms and legs