Originally Posted by JHouse
As you may know, I have replaced a BUNCH of bulbs over the past 4 years. I have kept and examined the bulbs and this is what I have found:
The filament is NOT burning out from having its lifetime used up.
An internal part of the bulb is melting and destroying the geometry, causing a failure.
I think this is a design defect and its behavior matches what Steve (original poster) has described.
The scenario is you are rocking along for months and suddenly one day right after you fire it up, you notice that the image is dimmer. It seemed fine the last time you watched it, and now it is a lot dimmer. You immediately start to doubt yourself, thinking it was happening gradually and you didn't notice, and this is just normal bulb deterioration. I don't think that's it at all.
My bulbs have a piece of glass tubing in the center that holds one end of the filament which comes from the side. If it was a flower, you would call it the pistil. That tubing apparently positions the filament so that it will properly reflect off of the parabolic mirror/bulb reflector/whatever.
This is what happens (as it has happened to me every time): the pistil develops a bubble near it's base. It looks like a little glass blower went in there and tried to make a vase with the middle of your pistil/filament support. Sometimes it is clear and sometimes it looks brown and little burnt. The result is the glass tube essentially falls over a little and moves the filament out of position. This pistil support has a new elbow in it now (where the bubbling evidence of melting is).
Take a look at your failed bulb and see if you can see this. If you are looking for it, it is easy to spot, as the bubble/failure is usually substantially larger than the original glass pistil/support. Please post or IM me if you can identify the same defect.
My particular bulbs have been Model: POA-LMP38, made in Belgium. They are installed in the Sanyo PLV-70, PLV-75, PLC-XP40, PLC-XP45, as well as the Eiki and Boxlight versions of these Sanyo projectors. They are 200W UHP bulbs.
It is interesting to note that they say the lamp life is 2000 hours but the warranty is 3 months or 500 hours. Its list price appears to be $600.