Re: How to turn off lamp in ScanJet IIcx

Jonathan Buzzard (
Sun, 21 Dec 1997 18:43:14 +0000 said:
> The reason that the light is left on is that there is too much
> variance in the amount of lumens and also the color spectrum of light
> between a cool flourescent tube and a warm one. This makes
> consistency and quality swing wildly so most engineers elect to
> simply leave the light on. The only exception would be scanners that
> use a much more expensive LED lightsource.

The flourescent tube in my Astra 600 has a lifespan of only 10000 hours,
the last time I looked the MTBF of an LED was 10e9 hours or about ~1 million
years. If I had an LED lightsource you could leave it on forever, with
a flourescent tube this is not an option, especially if it is not a user
replaceable part. LED's last forever, I have an LED clock that has been on
nearly continously now for 10 years

I would not worry about the variance in the light output, but the colour
spectrum is more important.


Jonathan A. Buzzard                 Email:
Northumberland, United Kingdom.       Tel: +44(0)1661-832195

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