DIY Projector Lamp
 

This maybe a little off the normal beaten path for this group but it has
some knowledgeable people and this certainly falls into the category of
DIY. I have already asked on AV Forums BTW.

You're probably going to think I am mad for even suggesting this but I
am toying with the idea of building an external light source for my
projector to reduce the cost of lamps.

I have a Philips cBright XG2 which has just finished it's first lamp
(cuts out after about 10 minutes). I went to buy a new one and nearly
passed out when I saw that it would set me back £450 at least . I pulled
the old lamp out and was surprised to see that not only did it look fine
but it consisted of nothing but the housing and lamp - I had expected
some fancy control circuitry for some reason.

Well that got me thinking.

Thought #1: Would it be possible to but a cheaper lamp for another
projector make and put it in the current lamp housing? Trouble is I
don't know the exact spec of the current lamp (it's 200W) or where to
look for it.

Thought #2: At the end of the day you just need to shine (a lot of)
light through the projector. The bulbs are expensive because they are
small and very bright to make the projector mobile. I don't need that
mobility so a huge cheap bulb wouldn't be a problem on that front.
Assuming that I can make a light box and position mirrors such that the
light is shone through as per the normal bulb my only problem would be
tricking the projector into coming on without a bulb in place and that
is where I am hoping to get some help.

I don't think the light box will be that hard to make. I realize that
the real bulb produces very white light etc etc. I was thinking of using
either low voltage halogen or perhaps short fluorescent tubes as both
produce fairly white light and I think a tweak of the color settings on
the projector should take care of the rest.

Anyway I think I have rambled on for enough for now. I am really
interested in getting this working so any ideas will be greatly
appreciated. My electronics skills aren't fantastic but I am willing to
learn what I need to make this work.

Thanks.

--

.¸¸.·´¯`·.¸¸.·´¯`· Shallow Sea Aquatics .¸¸.·´¯`·.¸¸.·´¯`·
.¸¸.·´¯`·.¸¸.·´¯ http://www.shallowsea.com ¸.·´¯`·.¸¸.·´¯`

"doozer" wrote in message
...
This maybe a little off the normal beaten path for this group but it has
some knowledgeable people and this certainly falls into the category of
DIY. I have already asked on AV Forums BTW.

You're probably going to think I am mad for even suggesting this but I
am toying with the idea of building an external light source for my
projector to reduce the cost of lamps.

I have a Philips cBright XG2 which has just finished it's first lamp
(cuts out after about 10 minutes). I went to buy a new one and nearly
passed out when I saw that it would set me back £450 at least . I pulled
the old lamp out and was surprised to see that not only did it look fine
but it consisted of nothing but the housing and lamp - I had expected
some fancy control circuitry for some reason.

Well that got me thinking.

Thought #1: Would it be possible to but a cheaper lamp for another
projector make and put it in the current lamp housing? Trouble is I
don't know the exact spec of the current lamp (it's 200W) or where to
look for it.

Thought #2: At the end of the day you just need to shine (a lot of)
light through the projector. The bulbs are expensive because they are
small and very bright to make the projector mobile. I don't need that
mobility so a huge cheap bulb wouldn't be a problem on that front.
Assuming that I can make a light box and position mirrors such that the
light is shone through as per the normal bulb my only problem would be
tricking the projector into coming on without a bulb in place and that
is where I am hoping to get some help.

I don't think the light box will be that hard to make. I realize that
the real bulb produces very white light etc etc. I was thinking of using
either low voltage halogen or perhaps short fluorescent tubes as both
produce fairly white light and I think a tweak of the color settings on
the projector should take care of the rest.

Anyway I think I have rambled on for enough for now. I am really
interested in getting this working so any ideas will be greatly
appreciated. My electronics skills aren't fantastic but I am willing to
learn what I need to make this work.

Thanks.



What voltage does the lamp take? I know the projector needs something like
a 250 watt UHP lamp, but you don't give a voltage, which would help. I know
of a few places that will sell you lamps of that wattage, and a whole lot
cheaper than the price you quote in your post, but I need to find out which
voltage is needed to compare their prices for you.

They will deliver directly to your door as well.

If you get a lamp of the same brightness and focus quality, then it might
just be a case of adapting the little housing that holds the lamp in place
on the projector.

In article , doozer
writes
This maybe a little off the normal beaten path for this group but it
has some knowledgeable people and this certainly falls into the
category of DIY. I have already asked on AV Forums BTW.

You're probably going to think I am mad for even suggesting this but I
am toying with the idea of building an external light source for my
projector to reduce the cost of lamps.

As someone who has worked with optics for projectors, I can tell you
that it won't work. You need an immense amount of light intensity and it
has to be focused just so (if you've ever fired up the projection lamp
with the housing open, you will know just how bright it is - you can't
see anything else for a few minutes). Many man hours of research go into
producing efficient optics for the projection beam. The lamps are
discharge (arc) types and have control gear in the projector - you can't
just replace them with any old lamp.

What you can sometimes do is buy the lamp itself separately, as the
manufacturer replacement often includes the reflector and housing. This
can cut down the cost considerably. Find the manufacturer code from the
lamp itself and google for it.
--
Tim Mitchell

What voltage does the lamp take? I know the projector needs
something like
a 250 watt UHP lamp, but you don't give a voltage, which would help. I know
of a few places that will sell you lamps of that wattage, and a whole lot
cheaper than the price you quote in your post, but I need to find out which
voltage is needed to compare their prices for you.

They will deliver directly to your door as well.

If you get a lamp of the same brightness and focus quality, then it might
just be a case of adapting the little housing that holds the lamp in place
on the projector.



Ok, so not quite everyone thinks that I am mad which is a good thing. I
have checked out the manual and no joy on a voltage. Can anyone tell
what it might be from a couple of pictures?

http://www.crazysquirrel.com/images/bulb/complete.jpg
http://www.crazysquirrel.com/images/bulb/label.jpg

I have tried switching the PJ on without a bulb, BTW, and no joy. It
just tries to start the non-existent bulb three times and then gives up. :(

Thanks.

--

.¸¸.·´¯`·.¸¸.·´¯`· Shallow Sea Aquatics .¸¸.·´¯`·.¸¸.·´¯`·
.¸¸.·´¯`·.¸¸.·´¯ http://www.shallowsea.com ¸.·´¯`·.¸¸.·´¯`

doozer wrote:

You're probably going to think I am mad for even suggesting this but I
am toying with the idea of building an external light source for my
projector to reduce the cost of lamps.

In addition to the other points mentioned, you will probably find that
the logic control system of the projector will not allow it to operate
with no/or a defective bulb.

If you *can* just replace the lamp itself, that should be cheaper than
the whole housing.


Lee
--
Email address is valid, but is unlikely to be read.

"doozer" wrote in message
...
What voltage does the lamp take? I know the projector needs
something like
a 250 watt UHP lamp, but you don't give a voltage, which would help. I
know
of a few places that will sell you lamps of that wattage, and a whole
lot
cheaper than the price you quote in your post, but I need to find out
which
voltage is needed to compare their prices for you.

They will deliver directly to your door as well.

If you get a lamp of the same brightness and focus quality, then it
might
just be a case of adapting the little housing that holds the lamp in
place
on the projector.



Ok, so not quite everyone thinks that I am mad which is a good thing. I
have checked out the manual and no joy on a voltage. Can anyone tell
what it might be from a couple of pictures?

http://www.crazysquirrel.com/images/bulb/complete.jpg
http://www.crazysquirrel.com/images/bulb/label.jpg

I have tried switching the PJ on without a bulb, BTW, and no joy. It
just tries to start the non-existent bulb three times and then gives up.
:(

Thanks.



It looks like it is a 12 or 24 volts lamp, but I couldn't be that sure which
to say it is from the pictures.

Try contacting these people
http://www.wedgwood-group.com/slide_...ries_lamps.htm for more
help on this, and as Tim has said, ask if they do the lamp separately from
the holder.

These people are always helpful and give the best advice on these types of
things.

As someone who has worked with optics for projectors, I can tell you
that it won't work. You need an immense amount of light intensity and it
has to be focused just so (if you've ever fired up the projection lamp
with the housing open, you will know just how bright it is - you can't
see anything else for a few minutes). Many man hours of research go into
producing efficient optics for the projection beam. The lamps are
discharge (arc) types and have control gear in the projector - you can't
just replace them with any old lamp.

What you can sometimes do is buy the lamp itself separately, as the
manufacturer replacement often includes the reflector and housing. This
can cut down the cost considerably. Find the manufacturer code from the
lamp itself and google for it.

Hmmmm, that bodes badly then.

The bulb and reflector come as a single unit (see links below) so I
imagine the majority of the cost is in the bulb. I can't help getting
the feeling though that I'm being massively ripped off and its the
housing not the bulb that is expensive. I wouldn't be at all surprised
to find that practically every Philips projector uses this exact same bulb.

As for the light being focused. Yep I agree that it is focused but, and
here's the interesting bit, there is obviously a reflector in the bulb
but there is also a lense in front of the bulb that diffuses the light.
I am wondering just how accurately I would have to mimic the real bulb
to get a good solution.

I think there might have been a slight misunderstanding as well. I
wasn't intending to just stick a low voltage halogen into the hole
occupied by the PJ bulb as I realise that wouldn't be even close to good
enough and wouldn't work anyway. I was thinking more like a dozen in an
internally mirrored and forced air cooled box that sits under the
projector with a mirror array to take the light into the PJ. Surely that
would be bright enough!

http://www.crazysquirrel.com/images/bulb/complete.jpg
http://www.crazysquirrel.com/images/bulb/label.jpg

--

.¸¸.·´¯`·.¸¸.·´¯`· Shallow Sea Aquatics .¸¸.·´¯`·.¸¸.·´¯`·
.¸¸.·´¯`·.¸¸.·´¯ http://www.shallowsea.com ¸.·´¯`·.¸¸.·´¯`

"doozer" wrote in message
...
As someone who has worked with optics for projectors, I can tell you
snipped

I think there might have been a slight misunderstanding as well. I
wasn't intending to just stick a low voltage halogen into the hole
occupied by the PJ bulb as I realise that wouldn't be even close to good
enough and wouldn't work anyway. I was thinking more like a dozen in an
internally mirrored and forced air cooled box that sits under the
projector with a mirror array to take the light into the PJ. Surely that
would be bright enough!

http://www.crazysquirrel.com/images/bulb/complete.jpg
http://www.crazysquirrel.com/images/bulb/label.jpg



And bloody hot enough as well. Forced air cooled? You'd need to dip the
fans in a bath of cooling oil to keep them from melting, mate. :-)

doozer wrote:

As someone who has worked with optics for projectors, I can tell
you
that it won't work. You need an immense amount of light intensity
and it
has to be focused just so (if you've ever fired up the projection
lamp
with the housing open, you will know just how bright it is - you
can't
see anything else for a few minutes). Many man hours of research go
into
producing efficient optics for the projection beam. The lamps are
discharge (arc) types and have control gear in the projector - you
can't
just replace them with any old lamp.

What you can sometimes do is buy the lamp itself separately, as the

manufacturer replacement often includes the reflector and housing.
This
can cut down the cost considerably. Find the manufacturer code from
the
lamp itself and google for it.

Hmmmm, that bodes badly then.

The bulb and reflector come as a single unit (see links below) so I
imagine the majority of the cost is in the bulb.

a front view of the bulb would have been very helpful.


I can't help getting
the feeling though that I'm being massively ripped off

yep. Always check the run cost of products you buy: I think you will in
future :)


and its the
housing not the bulb that is expensive. I wouldn't be at all
surprised
to find that practically every Philips projector uses this exact same
bulb.

As for the light being focused. Yep I agree that it is focused but,
and
here's the interesting bit, there is obviously a reflector in the
bulb
but there is also a lense in front of the bulb that diffuses the
light.

Perhaps, but I expect it more likely to be condenser optics than
diffuser. If thats the case, youre fairly well stuffed. At best you
could produce a very dim image without that bulb.


I am wondering just how accurately I would have to mimic the real
bulb
to get a good solution.

Quite likely youd need the same intense small spot.


I think there might have been a slight misunderstanding as well. I
wasn't intending to just stick a low voltage halogen into the hole
occupied by the PJ bulb as I realise that wouldn't be even close to
good
enough and wouldn't work anyway.

I'd try it, not very optimistically, but it might. The control gear
might assume its started and run the thing ok, and the central element
might be adequate to get something out. Might be your best shot, even
if not a very good one.

Youll need to match run voltages tho. Not sure what that one is, the
1=2E6kW Beck carbon arc I used was 40v 40A. sci.engr.lighting should be
able to give you more info on this bulb and any possible solutions.

If you get a dim image that way, you can then max the power out as much
as poss with an external supply, adding heavy forced cooling to avoid
meltdown.


I was thinking more like a dozen in an
internally mirrored and forced air cooled box that sits under the
projector with a mirror array to take the light into the PJ. Surely
that
would be bright enough!

if you can direct it all onto one spot, sure. Maybe you can do that
with mirrors.


I would probably be looking first at a legal solution. I would argue
that =A3450 for a 10 hour lightbulb, if its an essential spare part
supplied only by philips, was unreasonable. There is a law against
unreasonable prices in UK, but it is only invoked in cases of wild
excess, but I would think this does come into that category. Its
=A345,000 for 1000 hours of light. Compare that to a 1000hr GLS at 20p,
or a 2000hr halogen and =A31.

I would also consider contacting the mrfr, giving them an opportunity
to refund the goods cost, pointing out that you will be a publicity
rampage if they dont. Not much chance of them doing so, but it shows
youve given them a chance to resolve the situauion

Ianal tho, and wouldnt be surprised if you were right out of luck.

That is, assuming you dont want to build a carbon arc light... they
dont last any longer, but are way cheaper.


NT

In message ,
doozer wrote:

As someone who has worked with optics for projectors, I can tell you
that it won't work. You need an immense amount of light intensity and it
has to be focused just so (if you've ever fired up the projection lamp
with the housing open, you will know just how bright it is - you can't
see anything else for a few minutes). Many man hours of research go into
producing efficient optics for the projection beam. The lamps are
discharge (arc) types and have control gear in the projector - you can't
just replace them with any old lamp.

What you can sometimes do is buy the lamp itself separately, as the
manufacturer replacement often includes the reflector and housing. This
can cut down the cost considerably. Find the manufacturer code from the
lamp itself and google for it.

Hmmmm, that bodes badly then.

The bulb and reflector come as a single unit (see links below) so I
imagine the majority of the cost is in the bulb. I can't help getting
the feeling though that I'm being massively ripped off and its the
housing not the bulb that is expensive. I wouldn't be at all surprised
to find that practically every Philips projector uses this exact same bulb.


Many lamp replacement "kits" also include new (air) filters and possibly
other bits, so you have to include them in your comparisons too.

Went through this loop a few years ago with bulbs for NEC and BARCO
projectors. The Barco ones were £450 and had a rated life of just 720
hours. You could reset the warning up to 750 hours but after that the
projector put a big banner over the screen until you entered the serial
number of the new bulb. Actually, any old number would do, but since
these projectors were well over £15k new we didn't chance it.

We discovered that both the Barco and the NEC lamps (IIRC, certainly
the Barco ones) were simply re-packaged standard Osram bulbs, but at a
higher power rating than available through any of the usual outlets. I
forget the specifics, but we could get the bulbs up to (say) 250W, and
the Barcos needed 400W which were only available through Barco. Again,
needless to say, the bare bulbs were a fraction the cost of the
replacement lamp assemblies.

Eventually we managed to bulk-purchase the bulbs (we had 12 of the
Barcos IIRC, on 8+ hours a day) and got them at £250.

The NECs were better at £350 to start with (they came down too) and 2000
hour life. We had 16 of those.

*If* we could have got hold of the right sort of bulb we would have
tried it, BUT:

As for the light being focused. Yep I agree that it is focused but, and
here's the interesting bit, there is obviously a reflector in the bulb
but there is also a lense in front of the bulb that diffuses the light.
I am wondering just how accurately I would have to mimic the real bulb
to get a good solution.


The additional problem with the Barcos was bleaching of the dichroic
filters. No, I don't know how you can bleach a diffraction device
either, but they seemed to do that quite regularly, especially if the
projector had been apart for any reason (cleaning beyond the air filters
for example). It is just possible that if it wasn't put back together
absolutely perfectly a "hot spot" would develop. The dichroics were £150
each, again IIRC. With a DIY cobbled-together lamp assembly I suspect
that the problem would have been even worse.

This is still a problem with projectors. Yes, you may be able to get a
basic SVGA model for £500 from the right place, but if you are doing
more than watching a couple of hours of television in the evening you
really need to think about the running costs.

I think there might have been a slight misunderstanding as well. I
wasn't intending to just stick a low voltage halogen into the hole
occupied by the PJ bulb as I realise that wouldn't be even close to good
enough and wouldn't work anyway. I was thinking more like a dozen in an
internally mirrored and forced air cooled box that sits under the
projector with a mirror array to take the light into the PJ. Surely that
would be bright enough!

Have you ever *seen* the light from a discharge lamp? Ignoring the
problem of UV exposure (they produce gallons of the stuff) they have to
be the brightest source I've seen, Watt for Watt.

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Two free issues: http://www.livtech.co.uk/ Living With Technology
.... What can you do at 3 AM? Psssttt - got a modem??

Martin Angove wrote:

Have you ever *seen* the light from a discharge lamp? Ignoring the
problem of UV exposure (they produce gallons of the stuff) they have to
be the brightest source I've seen, Watt for Watt.

Hwyl!

M.

Just thinking. Do white LED's yet come anywhere close (even in an array?)

---
Adrian

Adrian C wrote:
Martin Angove wrote:

Have you ever *seen* the light from a discharge lamp? Ignoring the
problem of UV exposure (they produce gallons of the stuff) they have to
be the brightest source I've seen, Watt for Watt.

Hwyl!

M.

Just thinking. Do white LED's yet come anywhere close (even in an array?)

---
Adrian

I did think of white LEDs as you can get extremely bright ones (used
mostly on the tips of plane wings I believe) but they are even more
expensive than the real thing and also don't last that long. A large
(maybe even huge) array of small white LED's might work but I am not
sure it would be that cost effective as they fail fairly quickly if they
get hot. I think the cheapest solution is short florescent tubes. I
could probably pack quite a few into a small area. Another possibility
is just powering up the cheapest projector bulb money can buy. I haven't
really decided because until I know how to get the projector to come on
without a bulb in place the whole things a bit moot.

--

.¸¸.·´¯`·.¸¸.·´¯`· Shallow Sea Aquatics .¸¸.·´¯`·.¸¸.·´¯`·
.¸¸.·´¯`·.¸¸.·´¯ http://www.shallowsea.com ¸.·´¯`·.¸¸.·´¯`

Many lamp replacement "kits" also include new (air) filters and possibly
other bits, so you have to include them in your comparisons too.

Went through this loop a few years ago with bulbs for NEC and BARCO
projectors. The Barco ones were £450 and had a rated life of just 720
hours. You could reset the warning up to 750 hours but after that the
projector put a big banner over the screen until you entered the serial
number of the new bulb. Actually, any old number would do, but since
these projectors were well over £15k new we didn't chance it.

We discovered that both the Barco and the NEC lamps (IIRC, certainly
the Barco ones) were simply re-packaged standard Osram bulbs, but at a
higher power rating than available through any of the usual outlets. I
forget the specifics, but we could get the bulbs up to (say) 250W, and
the Barcos needed 400W which were only available through Barco. Again,
needless to say, the bare bulbs were a fraction the cost of the
replacement lamp assemblies.

Eventually we managed to bulk-purchase the bulbs (we had 12 of the
Barcos IIRC, on 8+ hours a day) and got them at £250.

The NECs were better at £350 to start with (they came down too) and 2000
hour life. We had 16 of those.

*If* we could have got hold of the right sort of bulb we would have
tried it, BUT:


These bulbs, LCA 3111 for the interested, last about 1500 hours and I
believe they are now out of production so I don't see the price coming down.


As for the light being focused. Yep I agree that it is focused but, and
here's the interesting bit, there is obviously a reflector in the bulb
but there is also a lense in front of the bulb that diffuses the light.
I am wondering just how accurately I would have to mimic the real bulb
to get a good solution.



The additional problem with the Barcos was bleaching of the dichroic
filters. No, I don't know how you can bleach a diffraction device
either, but they seemed to do that quite regularly, especially if the
projector had been apart for any reason (cleaning beyond the air filters
for example). It is just possible that if it wasn't put back together
absolutely perfectly a "hot spot" would develop. The dichroics were £150
each, again IIRC. With a DIY cobbled-together lamp assembly I suspect
that the problem would have been even worse.

This projector have already been through two sets of analysers and
polarizers for the blue and green channel but they were replaced under
warranty (the parts are about £20). After the second change though
something was different (the projector was much cooler) so I assume the
guy who replaced them did something else as well they he didn't report.


This is still a problem with projectors. Yes, you may be able to get a
basic SVGA model for £500 from the right place, but if you are doing
more than watching a couple of hours of television in the evening you
really need to think about the running costs.


We only use it to watch a film 3 or 4 times a week (tops) so the bulb
has lasted about 2.5 years. Even so I still would much rather not have
to shell out £450 as I am sure you understand.


I think there might have been a slight misunderstanding as well. I
wasn't intending to just stick a low voltage halogen into the hole
occupied by the PJ bulb as I realise that wouldn't be even close to good
enough and wouldn't work anyway. I was thinking more like a dozen in an
internally mirrored and forced air cooled box that sits under the
projector with a mirror array to take the light into the PJ. Surely that
would be bright enough!


Have you ever *seen* the light from a discharge lamp? Ignoring the
problem of UV exposure (they produce gallons of the stuff) they have to
be the brightest source I've seen, Watt for Watt.


Just seeing the amount of light that comes out the front (and back)
tells me it's extremely bright. At least my solution would probably have
less UV which should help the projector last longer.

Hwyl!

M.



--

.¸¸.·´¯`·.¸¸.·´¯`· Shallow Sea Aquatics .¸¸.·´¯`·.¸¸.·´¯`·
.¸¸.·´¯`·.¸¸.·´¯ http://www.shallowsea.com ¸.·´¯`·.¸¸.·´¯`

In message , Adrian C
writes
Martin Angove wrote:

Have you ever *seen* the light from a discharge lamp? Ignoring the
problem of UV exposure (they produce gallons of the stuff) they have to
be the brightest source I've seen, Watt for Watt.
Hwyl!
M.

Just thinking. Do white LED's yet come anywhere close (even in an
array?)

It would probably cost more than a new bulb to get sufficient output

Also, the spectral distribution would be different and the colours might
be a bit strange

--
geoff

"Adrian C" wrote in message
...
Martin Angove wrote:

Have you ever *seen* the light from a discharge lamp? Ignoring the
problem of UV exposure (they produce gallons of the stuff) they have to
be the brightest source I've seen, Watt for Watt.

Hwyl!

M.

Just thinking. Do white LED's yet come anywhere close (even in an array?)

Discharge lamps are about five times brighter than the equivalent
fluorescent tube.
Just imagine 200W of tubes in a 1" cube.

In article ,
doozer writes:

Ok, so not quite everyone thinks that I am mad which is a good thing. I
have checked out the manual and no joy on a voltage. Can anyone tell
what it might be from a couple of pictures?

http://www.crazysquirrel.com/images/bulb/complete.jpg
http://www.crazysquirrel.com/images/bulb/label.jpg

I have tried switching the PJ on without a bulb, BTW, and no joy. It
just tries to start the non-existent bulb three times and then gives up. :(

I don't know what sort of lamp this is, but if it's a short
arc HID tube, it is started with a very high voltage pulse
(many 10's of kV) which is a safety risk. Also the bulb itself
is pressurised even when cold and will not just break, but
will explode if dropped or scratched, and you should be
wearing eye protection whilst handling it. If you damage it
in handling, it can also explode later when running (at even
higher pressure).

--
Andrew Gabriel

dennis@home wrote:

"Adrian C" wrote in message
...
Martin Angove wrote:

Have you ever *seen* the light from a discharge lamp? Ignoring the
problem of UV exposure (they produce gallons of the stuff) they have to
be the brightest source I've seen, Watt for Watt.

Hwyl!

M.

Just thinking. Do white LED's yet come anywhere close (even in an array?)

Discharge lamps are about five times brighter than the equivalent
fluorescent tube.
Just imagine 200W of tubes in a 1" cube.

They are about as efficient though, the source is just much smaller.

Adrian C wrote:
Martin Angove wrote:

Have you ever *seen* the light from a discharge lamp? Ignoring the
problem of UV exposure (they produce gallons of the stuff) they have to
be the brightest source I've seen, Watt for Watt.

Hwyl!

M.

Just thinking. Do white LED's yet come anywhere close (even in an array?)


Perhaps.
But.
IIRC, the luxeon 1W chips are about 1.5mm^2.
That's about .2W power, when you compare it to a discharge bulb, as
it's much less efficient.

1.5mm*1.5mm means you get about 36/cm^2, or 8W equivalent.
Some new 'vapourware' LEDs claim about 3 times that, or 24W/cm^2, but
that means a source size of over 3cm diameter to hit 240W.
And if you're doing it at all, you probably don't want to use white
LEDs, but work out some way to do it with RGB ones, and eliminate the
insanity of wasting 2/3 of the light on a filter wheel.
And the other problem I glossed over is that LEDs need kept well under 100C
to function.
The discharge bulb will be quite happy at a wall temp of 300C.
And, with the better part of a kilowatt going into an area smaller than
the contact patches of some CPUs, thermal design is going to be a real
bitch.

"Andrew Gabriel" wrote in message
.. .
In article ,
doozer writes:

Ok, so not quite everyone thinks that I am mad which is a good thing. I
have checked out the manual and no joy on a voltage. Can anyone tell
what it might be from a couple of pictures?

http://www.crazysquirrel.com/images/bulb/complete.jpg
http://www.crazysquirrel.com/images/bulb/label.jpg

I have tried switching the PJ on without a bulb, BTW, and no joy. It
just tries to start the non-existent bulb three times and then gives up.
:(

I don't know what sort of lamp this is, but if it's a short
arc HID tube, it is started with a very high voltage pulse
(many 10's of kV) which is a safety risk. Also the bulb itself
is pressurised even when cold and will not just break, but
will explode if dropped or scratched, and you should be
wearing eye protection whilst handling it. If you damage it
in handling, it can also explode later when running (at even
higher pressure).


Andrew Gabriel


It is under pressure Andy, that's what the UHP stands for on the lamp. It
is Argon gassed to quite a bit of pressure in fact.

In message ,
"BigWallop" wrote:


"Andrew Gabriel" wrote in message
.. .

I don't know what sort of lamp this is, but if it's a short
arc HID tube, it is started with a very high voltage pulse
(many 10's of kV) which is a safety risk. Also the bulb itself
is pressurised even when cold and will not just break, but
will explode if dropped or scratched, and you should be
wearing eye protection whilst handling it. If you damage it
in handling, it can also explode later when running (at even
higher pressure).


Andrew Gabriel


It is under pressure Andy, that's what the UHP stands for on the lamp. It
is Argon gassed to quite a bit of pressure in fact.


Been there, done that. At the same place where we had all the video
projectors, we also had some theatre-type lamps. The Mac2000s (robotic
lights) had a very bright discharge lamp, but unlike the projectors,
they didn't have an automatic timer-based safety cut out. Result (before
I got into the habit of logging every bulb change) was that a bulb
exploded inside one of the projectors, destroying the ceramic
lampholder, rear reflector and (inch-thick) front lens. Bits of glass
got into the rest of the projector and caused damage to servos, wiring
and electronics. You can imagine the repair cost in parts alone.

The other thing to note with these type of lamps, and with other high
temperature lamps which often have quartz-glass, is not to get
fingerprints on the bulb. I hate to think of the mechanism, but it seems
to soften the glass around the grease mark, causing the envelope to
bulge and thin and eventually break.

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Two free issues: http://www.livtech.co.uk/ Living With Technology
.... How come all the buttons keep flying off my shirt?

In article , Martin Angove
writes
In message ,
"BigWallop" wrote:


"Andrew Gabriel" wrote in message
.. .

I don't know what sort of lamp this is, but if it's a short
arc HID tube, it is started with a very high voltage pulse
(many 10's of kV) which is a safety risk. Also the bulb itself
is pressurised even when cold and will not just break, but
will explode if dropped or scratched, and you should be
wearing eye protection whilst handling it. If you damage it
in handling, it can also explode later when running (at even
higher pressure).


Andrew Gabriel


It is under pressure Andy, that's what the UHP stands for on the lamp. It
is Argon gassed to quite a bit of pressure in fact.


Been there, done that. At the same place where we had all the video
projectors, we also had some theatre-type lamps. The Mac2000s (robotic
lights) had a very bright discharge lamp, but unlike the projectors,
they didn't have an automatic timer-based safety cut out. Result (before
I got into the habit of logging every bulb change) was that a bulb
exploded inside one of the projectors, destroying the ceramic
lampholder, rear reflector and (inch-thick) front lens. Bits of glass
got into the rest of the projector and caused damage to servos, wiring
and electronics. You can imagine the repair cost in parts alone.

The other thing to note with these type of lamps, and with other high
temperature lamps which often have quartz-glass, is not to get
fingerprints on the bulb. I hate to think of the mechanism, but it seems
to soften the glass around the grease mark, causing the envelope to
bulge and thin and eventually break.

It just creates a hot spot because some of the light is absorbed by the
fingerprint. If a lamp does get touched you can clean off the
fingerprint with an alcohol wipe (before firing it up!) to prevent any
problems.

Regarding the original question and having looked at the pictures, the
reflector, lamp and housing look like a custom part. I don't think you
would be able to get the lamp bit separately. Have you tried googling
for the lamp code?
--
Tim Mitchell

Tim Mitchell wrote:
In article , Martin Angove
writes

In message ,
"BigWallop" wrote:


"Andrew Gabriel" wrote in message
.. .


I don't know what sort of lamp this is, but if it's a short
arc HID tube, it is started with a very high voltage pulse
(many 10's of kV) which is a safety risk. Also the bulb itself
is pressurised even when cold and will not just break, but
will explode if dropped or scratched, and you should be
wearing eye protection whilst handling it. If you damage it
in handling, it can also explode later when running (at even
higher pressure).


Andrew Gabriel


It is under pressure Andy, that's what the UHP stands for on the
lamp. It
is Argon gassed to quite a bit of pressure in fact.


Been there, done that. At the same place where we had all the video
projectors, we also had some theatre-type lamps. The Mac2000s (robotic
lights) had a very bright discharge lamp, but unlike the projectors,
they didn't have an automatic timer-based safety cut out. Result (before
I got into the habit of logging every bulb change) was that a bulb
exploded inside one of the projectors, destroying the ceramic
lampholder, rear reflector and (inch-thick) front lens. Bits of glass
got into the rest of the projector and caused damage to servos, wiring
and electronics. You can imagine the repair cost in parts alone.

The other thing to note with these type of lamps, and with other high
temperature lamps which often have quartz-glass, is not to get
fingerprints on the bulb. I hate to think of the mechanism, but it seems
to soften the glass around the grease mark, causing the envelope to
bulge and thin and eventually break.

It just creates a hot spot because some of the light is absorbed by the
fingerprint. If a lamp does get touched you can clean off the
fingerprint with an alcohol wipe (before firing it up!) to prevent any
problems.

Regarding the original question and having looked at the pictures, the
reflector, lamp and housing look like a custom part. I don't think you
would be able to get the lamp bit separately. Have you tried googling
for the lamp code?

Thanks for the warning about explosions and finger prints. I knew about
both but I didn't realize they exploded with quite that much force. I
will handle it with more care from now on.

If it helps, and someone else asked, I have included a picture of the
front of the bulb here

http://www.crazysquirrel.com/images/bulb/front.jpg

if nothing else I would be interested to know what type of bulb it is.

Thanks,
Graham

--

.¸¸.·´¯`·.¸¸.·´¯`· Shallow Sea Aquatics .¸¸.·´¯`·.¸¸.·´¯`·
.¸¸.·´¯`·.¸¸.·´¯ http://www.shallowsea.com ¸.·´¯`·.¸¸.·´¯`

In article , doozer
writes
Thanks for the warning about explosions and finger prints. I knew about
both but I didn't realize they exploded with quite that much force. I
will handle it with more care from now on.

If it helps, and someone else asked, I have included a picture of the
front of the bulb here

http://www.crazysquirrel.com/images/bulb/front.jpg

if nothing else I would be interested to know what type of bulb it is.

It is, as someone has said, a short arc discharge lamp. But it appears
to be a custom Philips design.
--
Tim Mitchell

In article ,
doozer writes:
Tim Mitchell wrote:
In article , Martin Angove
writes

In message ,
"BigWallop" wrote:


"Andrew Gabriel" wrote in message
.. .


I don't know what sort of lamp this is, but if it's a short
arc HID tube, it is started with a very high voltage pulse
(many 10's of kV) which is a safety risk. Also the bulb itself
is pressurised even when cold and will not just break, but
will explode if dropped or scratched, and you should be
wearing eye protection whilst handling it. If you damage it
in handling, it can also explode later when running (at even
higher pressure).


Andrew Gabriel


It is under pressure Andy, that's what the UHP stands for on the
lamp. It
is Argon gassed to quite a bit of pressure in fact.


Been there, done that. At the same place where we had all the video
projectors, we also had some theatre-type lamps. The Mac2000s (robotic
lights) had a very bright discharge lamp, but unlike the projectors,
they didn't have an automatic timer-based safety cut out. Result (before
I got into the habit of logging every bulb change) was that a bulb
exploded inside one of the projectors, destroying the ceramic
lampholder, rear reflector and (inch-thick) front lens. Bits of glass
got into the rest of the projector and caused damage to servos, wiring
and electronics. You can imagine the repair cost in parts alone.

The other thing to note with these type of lamps, and with other high
temperature lamps which often have quartz-glass, is not to get
fingerprints on the bulb. I hate to think of the mechanism, but it seems
to soften the glass around the grease mark, causing the envelope to
bulge and thin and eventually break.

It just creates a hot spot because some of the light is absorbed by the
fingerprint. If a lamp does get touched you can clean off the
fingerprint with an alcohol wipe (before firing it up!) to prevent any
problems.

Regarding the original question and having looked at the pictures, the
reflector, lamp and housing look like a custom part. I don't think you
would be able to get the lamp bit separately. Have you tried googling
for the lamp code?

Thanks for the warning about explosions and finger prints. I knew about
both but I didn't realize they exploded with quite that much force. I
will handle it with more care from now on.

If it helps, and someone else asked, I have included a picture of the
front of the bulb here

http://www.crazysquirrel.com/images/bulb/front.jpg

if nothing else I would be interested to know what type of bulb it is.

Now you've posted that, not so sure it's a short arc lamp,
as the arc tube would be expected to have a spherical bulge in
the middle, which I can't see. It may be just a metal halide
lamp, or HMI lamp (probably too small, but no scale in you
photos), or if it didn't require any more than a second or two
warm-up time (before it died), a xenon lamp.

--
Andrew Gabriel

Andrew Gabriel wrote:
In article ,
doozer writes:

Tim Mitchell wrote:

In article , Martin Angove
writes


In message ,
"BigWallop" wrote:


"Andrew Gabriel" wrote in message
.uk...


I don't know what sort of lamp this is, but if it's a short
arc HID tube, it is started with a very high voltage pulse
(many 10's of kV) which is a safety risk. Also the bulb itself
is pressurised even when cold and will not just break, but
will explode if dropped or scratched, and you should be
wearing eye protection whilst handling it. If you damage it
in handling, it can also explode later when running (at even
higher pressure).


Andrew Gabriel


It is under pressure Andy, that's what the UHP stands for on the
lamp. It
is Argon gassed to quite a bit of pressure in fact.


Been there, done that. At the same place where we had all the video
projectors, we also had some theatre-type lamps. The Mac2000s (robotic
lights) had a very bright discharge lamp, but unlike the projectors,
they didn't have an automatic timer-based safety cut out. Result (before
I got into the habit of logging every bulb change) was that a bulb
exploded inside one of the projectors, destroying the ceramic
lampholder, rear reflector and (inch-thick) front lens. Bits of glass
got into the rest of the projector and caused damage to servos, wiring
and electronics. You can imagine the repair cost in parts alone.

The other thing to note with these type of lamps, and with other high
temperature lamps which often have quartz-glass, is not to get
fingerprints on the bulb. I hate to think of the mechanism, but it seems
to soften the glass around the grease mark, causing the envelope to
bulge and thin and eventually break.


It just creates a hot spot because some of the light is absorbed by the
fingerprint. If a lamp does get touched you can clean off the
fingerprint with an alcohol wipe (before firing it up!) to prevent any
problems.

Regarding the original question and having looked at the pictures, the
reflector, lamp and housing look like a custom part. I don't think you
would be able to get the lamp bit separately. Have you tried googling
for the lamp code?

Thanks for the warning about explosions and finger prints. I knew about
both but I didn't realize they exploded with quite that much force. I
will handle it with more care from now on.

If it helps, and someone else asked, I have included a picture of the
front of the bulb here

http://www.crazysquirrel.com/images/bulb/front.jpg

if nothing else I would be interested to know what type of bulb it is.


Now you've posted that, not so sure it's a short arc lamp,
as the arc tube would be expected to have a spherical bulge in
the middle, which I can't see. It may be just a metal halide
lamp, or HMI lamp (probably too small, but no scale in you
photos), or if it didn't require any more than a second or two
warm-up time (before it died), a xenon lamp.


It comes on just about straight away and then takes maybe 30 seconds to
get to full power. It's hard to take photos of something that is
mirrored hence the poor quality. Internally it is basically just two
wires that touch together. The bulb is about 75mm x 55mm although I
haven't taken it out of the housing so there is some error in that
measurement. There is certainly no spherical bulge in the middle the
face is perfectly flat.

--

.¸¸.·´¯`·.¸¸.·´¯`· Shallow Sea Aquatics .¸¸.·´¯`·.¸¸.·´¯`·
.¸¸.·´¯`·.¸¸.·´¯ http://www.shallowsea.com ¸.·´¯`·.¸¸.·´¯`

On Wed, 11 May 2005 16:29:45 +0100, doozer
wrote:

I have a Philips cBright XG2 which has just finished it's first lamp
(cuts out after about 10 minutes). I went to buy a new one and nearly
passed out when I saw that it would set me back £450 at least .

Unfortately, the cheapest Ican find it is around the £380+VAT mark.

It'd probably work out cheaper to buy a new projector and sell the old
one on ebay for spares, than to but it a fresh bulb.

It's a bit too late for you but the first rule of buying a projector
is to determine the cost of replacement bulbs.

sponix

"doozer" wrote in message
...
Andrew Gabriel wrote:
In article ,
doozer writes:

Tim Mitchell wrote:

snipped
warm-up time (before it died), a xenon lamp.


It comes on just about straight away and then takes maybe 30 seconds to
get to full power. It's hard to take photos of something that is
mirrored hence the poor quality. Internally it is basically just two
wires that touch together. The bulb is about 75mm x 55mm although I
haven't taken it out of the housing so there is some error in that
measurement. There is certainly no spherical bulge in the middle the
face is perfectly flat.



I knew I'd seen it somewhere, and here it is:

http://www.research.philips.com/prof...chers/uhp.html

Well worth watching the video stream.

doozer wrote:
Yeah I agree. We bought the PJ about 2.5 ago and I thought about getting
a spare bulb then but was put off because they were about 250 of my hard
earned pounds, which I thought was quite a lot, and that they would
probably come down a bit. I am really kicking myself now because they
have done nothing but go up in price. Doh.

The projector manufacturer now has a captive market of owners who don't
want to shell out ££££ on a replacement projector and are now tied to
paying £££ for replacement lamps instead.

Also older model projectors are not going to be reviewed in magazines
etc, so nothing to draw attention to replacement lamp costs. I wouldn't
put it past some manufacturers to keep replacement lamp costs
artificially low for the first six months of a model's lifespan because
of this.

Owain

BigWallop wrote:

I knew I'd seen it somewhere, and here it is:

http://www.research.philips.com/prof...chers/uhp.html

Well worth watching the video stream.

Where? I couldnt see any.

NT

Owain wrote:
doozer wrote:

Yeah I agree. We bought the PJ about 2.5 ago and I thought about
getting a spare bulb then but was put off because they were about 250
of my hard earned pounds, which I thought was quite a lot, and that
they would probably come down a bit. I am really kicking myself now
because they have done nothing but go up in price. Doh.


The projector manufacturer now has a captive market of owners who don't
want to shell out ££££ on a replacement projector and are now tied to
paying £££ for replacement lamps instead.

Also older model projectors are not going to be reviewed in magazines
etc, so nothing to draw attention to replacement lamp costs. I wouldn't
put it past some manufacturers to keep replacement lamp costs
artificially low for the first six months of a model's lifespan because
of this.

Owain


You are certainly coming through on FM there.

I'm surprised that you can't get cheepo Chinese knockoffs though. I
would have thought it would would be well worth the time. I presume that
these lamps have patents on them or something.

--

.¸¸.·´¯`·.¸¸.·´¯`· Shallow Sea Aquatics .¸¸.·´¯`·.¸¸.·´¯`·
.¸¸.·´¯`·.¸¸.·´¯ http://www.shallowsea.com ¸.·´¯`·.¸¸.·´¯`

doozer wrote:
Adrian C wrote:
Martin Angove wrote:

Have you ever *seen* the light from a discharge lamp?

One would not forget it.


Just thinking. Do white LED's yet come anywhere close (even in an
array?)

no


I think the cheapest solution is short florescent tubes. I
could probably pack quite a few into a small area.

But how are you going to turn that into a high intensity point source?
Wrap in tin foil and poke a hole? I'm doubtful.


Another possibility
is just powering up the cheapest projector bulb money can buy.

I'd still try a halogen, of as much power as you can fit in there. Low
v, not 240v, rnu it off a transformer. Likely it will be a below par
sub, but a small low v 3000K filament might be runnable.


I haven't
really decided because until I know how to get the projector to come
on
without a bulb in place the whole things a bit moot.

Thats simple, dummy load. If youre lucky and the thing is unfussy
enough it might even run a filament bulb.


NT

I think the cheapest solution is short florescent tubes. I
could probably pack quite a few into a small area.


But how are you going to turn that into a high intensity point source?
Wrap in tin foil and poke a hole? I'm doubtful.


The box containing the tubes would be mirrored on all sides at one end
on the top would be a hole to let the light out (roughly 3cm by 3cm
probably) to which I would fit a glass lense to focus the light to a
point. Inside the projector body would be a flat mirror placed at or
close to the place where the point forms and simply reflects the light
into the machine.

I think this solution would probably scale sufficiently to provide
enough light and the lense makes the light into a point source. I
realize that there would be tremendous losses with the light bouncing
all over the place in the box but it's so cheap...



Another possibility
is just powering up the cheapest projector bulb money can buy.


I'd still try a halogen, of as much power as you can fit in there. Low
v, not 240v, rnu it off a transformer. Likely it will be a below par
sub, but a small low v 3000K filament might be runnable.


It's certainly worth a go. Mounting it might be tricky though.



I haven't
really decided because until I know how to get the projector to come

on

without a bulb in place the whole things a bit moot.


Thats simple, dummy load. If youre lucky and the thing is unfussy
enough it might even run a filament bulb.


What would you use as a dummy load though? I think that I would have to
mimic the real bulb quite accurately since the behaviour upon failure
seems to indicate that it is sensing the current and or voltage as it
cuts out about 10 minutes after it has fired up the bulb - that would
mean having to dissipate 200W! If, as another poster mentioned, it also
uses several KV as a start up voltage I'm not sure I should be playing
with it at all :o)


NT



--

.¸¸.·´¯`·.¸¸.·´¯`· Shallow Sea Aquatics .¸¸.·´¯`·.¸¸.·´¯`·
.¸¸.·´¯`·.¸¸.·´¯ http://www.shallowsea.com ¸.·´¯`·.¸¸.·´¯`

wrote in message
oups.com...
BigWallop wrote:

I knew I'd seen it somewhere, and here it is:

http://www.research.philips.com/prof...chers/uhp.html

Well worth watching the video stream.

Where? I couldnt see any.

NT


Try pasting this link in to your media player:

mms://ntstream2.ddns.ehv.campus.philips.com/efi/86090/meet_philips_research
/uhp.wmv

"BigWallop" wrote in message
. uk...

"doozer" wrote in message
...
Andrew Gabriel wrote:
In article ,
doozer writes:

Tim Mitchell wrote:

snipped
warm-up time (before it died), a xenon lamp.


It comes on just about straight away and then takes maybe 30 seconds to
get to full power. It's hard to take photos of something that is
mirrored hence the poor quality. Internally it is basically just two
wires that touch together. The bulb is about 75mm x 55mm although I
haven't taken it out of the housing so there is some error in that
measurement. There is certainly no spherical bulge in the middle the
face is perfectly flat.



I knew I'd seen it somewhere, and here it is:

http://www.research.philips.com/prof...chers/uhp.html

Well worth watching the video stream.

I like the bit "... we extend the lifetime up to 20.000 hours making
consumer products realistic."
I know he says twenty thousand hours in the wmv, but maybe they really meant
20.0 as per the text.

Grumps wrote:
I like the bit "... we extend the lifetime up to 20.000 hours making
consumer products realistic."
I know he says twenty thousand hours in the wmv, but maybe they really meant
20.0 as per the text.

Philips are a Dutch company and along with many Europeans confuse the
decimal point and thousands separator.

Owain

"Owain" wrote in message
...
Grumps wrote:
I like the bit "... we extend the lifetime up to 20.000 hours making
consumer products realistic."
I know he says twenty thousand hours in the wmv, but maybe they really
meant
20.0 as per the text.

Philips are a Dutch company and along with many Europeans confuse the
decimal point and thousands separator.

Not wanting to get into a discussion about European and British (I know
we're European too) use of the decimal point and comma for number
separation, I just thought it was a bit of a cheek to say that they have
realistic consumer products with a lifespan of 20,000 hours. Whereas in
reality, a projector bulb (as per the OP) has a lifetime far, far shorter
than this.

In article , Grumps
writes
"Owain" wrote in message
...
Grumps wrote:
I like the bit "... we extend the lifetime up to 20.000 hours making
consumer products realistic."
I know he says twenty thousand hours in the wmv, but maybe they really
meant
20.0 as per the text.

Philips are a Dutch company and along with many Europeans confuse the
decimal point and thousands separator.

Not wanting to get into a discussion about European and British (I know
we're European too) use of the decimal point and comma for number
separation, I just thought it was a bit of a cheek to say that they have
realistic consumer products with a lifespan of 20,000 hours. Whereas in
reality, a projector bulb (as per the OP) has a lifetime far, far shorter
than this.

It depends how you use it, and of course they quote the absolute max,
which would be leaving the thing turned on continuously.
--
Tim Mitchell

"Tim Mitchell" wrote in message
...
In article , Grumps
writes
"Owain" wrote in message
...
Grumps wrote:
I like the bit "... we extend the lifetime up to 20.000 hours making
consumer products realistic."
I know he says twenty thousand hours in the wmv, but maybe they
really
meant
20.0 as per the text.

Philips are a Dutch company and along with many Europeans confuse the
decimal point and thousands separator.

Not wanting to get into a discussion about European and British (I know
we're European too) use of the decimal point and comma for number
separation, I just thought it was a bit of a cheek to say that they have
realistic consumer products with a lifespan of 20,000 hours. Whereas in
reality, a projector bulb (as per the OP) has a lifetime far, far shorter
than this.

It depends how you use it, and of course they quote the absolute max,
which would be leaving the thing turned on continuously.

So, do you think the 20,000 figure (whilst it may not apply to this
particular lamp) is a shelf-life or an operational life?

Tim Mitchell wrote:
In article , Grumps
writes

"Owain" wrote in message
...

Grumps wrote:
I like the bit "... we extend the lifetime up to 20.000 hours making
consumer products realistic."
I know he says twenty thousand hours in the wmv, but maybe they really

meant

20.0 as per the text.

Philips are a Dutch company and along with many Europeans confuse the
decimal point and thousands separator.


Not wanting to get into a discussion about European and British (I know
we're European too) use of the decimal point and comma for number
separation, I just thought it was a bit of a cheek to say that they have
realistic consumer products with a lifespan of 20,000 hours. Whereas in
reality, a projector bulb (as per the OP) has a lifetime far, far shorter
than this.

It depends how you use it, and of course they quote the absolute max,
which would be leaving the thing turned on continuously.

It doesn't matter how you use it there just isn't a "portable"*
projector out there that has a bulb life over 5000 hours. There are a
couple of new projectors out there that claim lamp lives in the region
of 6000 hours but that is with "bulb saving" which basically just means
half brightness. If the bulb is run at a sensible brightness it last
about 2000 to 2500 hours.

As for the best lifetime being achieved by not switching it off that is
not necessarily true for all situations. Many of the enthusiasts over at
AV Forums advocate not running the projector for more than about 4 hours
at a time. The thinking being that prolonged on-time can damage the
front window of the bulb and cause premature failure. We basically
followed that pattern with our projector (although that was simply out
usage pattern) and a bulb rated for 1500 hours lasted 1650.

* Portable can be anything up to about 10Kg depending on exactly what
their current definition of portable is. I'm not talking about digital
cinema instalations which may well have lamps that last 20000 hours but
these are way outside the range of 99% of installations.

--

.¸¸.·´¯`·.¸¸.·´¯`· Shallow Sea Aquatics .¸¸.·´¯`·.¸¸.·´¯`·
.¸¸.·´¯`·.¸¸.·´¯ http://www.shallowsea.com ¸.·´¯`·.¸¸.·´¯`

In article , Grumps
writes
"Tim Mitchell" wrote in message
...
In article , Grumps
writes
"Owain" wrote in message
...
Grumps wrote:
I like the bit "... we extend the lifetime up to 20.000 hours making
consumer products realistic."
I know he says twenty thousand hours in the wmv, but maybe they
really
meant
20.0 as per the text.

Philips are a Dutch company and along with many Europeans confuse the
decimal point and thousands separator.

Not wanting to get into a discussion about European and British (I know
we're European too) use of the decimal point and comma for number
separation, I just thought it was a bit of a cheek to say that they have
realistic consumer products with a lifespan of 20,000 hours. Whereas in
reality, a projector bulb (as per the OP) has a lifetime far, far shorter
than this.

It depends how you use it, and of course they quote the absolute max,
which would be leaving the thing turned on continuously.

So, do you think the 20,000 figure (whilst it may not apply to this
particular lamp) is a shelf-life or an operational life?

Operational life, in absolutely ideal conditions, which you will never
achieve in real life.
--
Tim Mitchell