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
Thanks, Graham
In article , doozer writes
It is, as someone has said, a short arc discharge lamp. But it appears to be a custom Philips design.
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.
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
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.
Could you let me know where you found it for that price though please?
Cheers, Graham
I knew I'd seen it somewhere, and here it is:
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
Where? I couldnt see any.
NT
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.
One would not forget it.
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.
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.
Thats simple, dummy load. If youre lucky and the thing is unfussy enough it might even run a filament bulb.
NT
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...
It's certainly worth a go. Mounting it might be tricky though.
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)
Try pasting this link in to your media player:
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
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?
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.
In article , Grumps writes
Operational life, in absolutely ideal conditions, which you will never achieve in real life.
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