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Pearl Lamp SUDDEN dimming - Page 2

post #31 of 90
Thread Starter 
Quote:
Originally Posted by JustBKaz View Post

This just happened to me this afternoon at 754 hours (was fine this morning). Some posters in this thread talk like it's just a little dimmer. Mine went dim to the point that you can barely see anything.

If this happens on my next bulb, the Pearl, as much as I have loved it, goes bye bye.

Well, for me it was probably 60-70% of the light output was lost. I could watch, but it was rough.

This is an interesting pattern...

JHouse, I'll be very interested in what you determine.
post #32 of 90
Quote:
Originally Posted by JHouse View Post

I'm trying to figure out if it is the bulbs or the projector. I have someone looking into it. The bulb maker will say it's the projector and vice versa. I'm going to figure it out. Since this problem goes across quite a few projector lines, I'm betting it's the bulb.


Thanks, JHouse.

Are there any alternatives to the LMP-H200?
post #33 of 90
Just from examining these UHP (Ultra High Pressure) bulbs myself, it appears that the filament is not the wires you see when you look in the bulb. The filament is a flat rectangular piece of metal that is contained in that central tube of glass. There is wire connected to each end of it (one crossing in front of the bulb in plain sight and one that connects at the very bottom, coming up through the middle. The two bulbs I have developed a melted/bubbled up spot on that central glass tube at the very base where it seems to connect to the parabolic exterior of the bulb. That might be where one of the connections to the filament is. Perhaps an area of high resistance/impedance that gets hotter than it should because of a poor connection. Just speculation on my part. I will let you know what I find out.

I have no idea whether there are other sources for bulbs for any particular projector. No matter where I order mine from, I always seem to get the same thing.
post #34 of 90
Thread Starter 
Quote:
Originally Posted by JHouse View Post

Just from examining these UHP (Ultra High Pressure) bulbs myself, it appears that the filament is not the wires you see when you look in the bulb. The filament is a flat rectangular piece of metal that is contained in that central tube of glass. There is wire connected to each end of it (one crossing in front of the bulb in plain sight and one that connects at the very bottom, coming up through the middle. The two bulbs I have developed a melted/bubbled up spot on that central glass tube at the very base where it seems to connect to the parabolic exterior of the bulb. That might be where one of the connections to the filament is. Perhaps an area of high resistance/impedance that gets hotter than it should because of a poor connection. Just speculation on my part. I will let you know what I find out.

I have no idea whether there are other sources for bulbs for any particular projector. No matter where I order mine from, I always seem to get the same thing.

Just as a note of clarification, UHP lamps don't have a filament per se. They are arc lamps. There is an electrode attached to each of the external visible wiring points you describe inside a glass housing filled with specific gasses. The electrode material, arc gap, and gas selection determine the spectral characteristics of the light output.

This small plasma "fireball" gets very hot, obviously. It may be that the cooling for these lamps has been inadequately designed, causing the glass housing to fail. Note that the lamp assembly actually has a cooling duct built in to it to receive airflow from the projector cooling fans. It's interesting that the Pearl was designed to be ultra quiet... perhaps the airflow is only marginal for what's needed?

The other possibility is that the gasses in the glass envelope have been contaminated. If you notice the "bottom" wiring point JHouse described, it's embedded in a hard cement type substance that appears to be the sealing point for the lamp. Mine was a little bit cracked... this could have allowed the gas to escape, compromising the bulb. Hard to tell if the cracks led to the failure/overheat... or the overheat led to the cracks.
post #35 of 90
Yes, sorry, still reading up on these bulbs. Yes, all the light (and heat) comes from the 1 mm gap between the tungsten electrodes. That glass tube which holds it all together is melting/bubbling right at the bottom of the bulb. I don't know if that is where the arc is or where the joint is between the wiring and the lower electrode. Still digging.

If it is where the arc is, that central tube certainly ought to be designed to take that heat.
post #36 of 90
Thread Starter 
Quote:
Originally Posted by JHouse View Post

Yes, sorry, still reading up on these bulbs. Yes, all the light (and heat) comes from the 1 mm gap between the tungsten electrodes. That glass tube which holds it all together is melting/bubbling right at the bottom of the bulb. I don't know if that is where the arc is or where the joint is between the wiring and the lower electrode. Still digging.

If it is where the arc is, that central tube certainly ought to be designed to take that heat.

Agreed. Which is why I wonder about the seal on the lower electrode. DO you by chance still have a failed one to examine?
post #37 of 90
I have two.
post #38 of 90
Thread Starter 
Quote:
Originally Posted by JHouse View Post

I have two.

Would you mind examining the "sealing area" (it looks rather like rough porcelain) where the electrode was inserted and the lamp "sealed off" for cracks?

Or maybe even a picture?
post #39 of 90
So has anyone tried using high altitude just to run bulbs cooler?

I suppose that could stop the melting but might lead to more tungsten darkening?

And what should the darkening be vs hours anyways? I know they get darker as they age but have not seen any actual graphs or high vs low lamp mode differences.
post #40 of 90
Found this quote today from a UHP bulb dealer:

"UHP lamps range from 100 to 200 watts, with useful lifespan ranging from 3,000 to 10,000 hours. To prevent reduced light output, small amounts of oxygen and halogen are mixed with the mercury vapor, and these help remove tungsten deposits from the lamp's walls, and redeposit them back on the electrodes. The result is a lamp that regenerate itself and maintains almost all of its initial brightness up until the day it fails."
post #41 of 90
post #42 of 90
Quote:
Originally Posted by JHouse View Post

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.

I have a Optoma H56 bulb right in front of me. It's a new bulb and I've put 300hrs on it. Still puts out 18ft candles which is high. It's had a balloned ball type portion at the base of the of the filament all along. Have you looked at new bulbs and have seen no bubble at the base of the filament?
post #43 of 90
Quote:
Originally Posted by guitarman View Post

I have a Optoma H56 bulb right in front of me. It's a new bulb and I've put 300hrs on it. Still puts out 18ft candles which is high. It's had a balloned ball type portion at the base of the of the filament all along. Have you looked at new bulbs and have seen no bubble at the base of the filament?

"Bubble" at the base of the filament is OK. It is there in the begin with. But when this "bubble" begins to grow, malform and discolor, then you have a problem.
post #44 of 90
Thread Starter 
Quote:
Originally Posted by Big Lebowski View Post

"Bubble" at the base of the filament is OK. It is there in the begin with. But when this "bubble" begins to grow, malform and discolor, then you have a problem.

Based on examining the new vs. old lamps from mine, I tend to agree. The bubble is there on the new bulb, just celar and much smaller.

I think JHouse described it as ballooning to the point of causing the glass "stem" above it to get "pushed" off of it's original vertical orientation.


Perhaps it's this "bubble" envelope that's the weak point...
post #45 of 90
Yes there is a collar of glass at the base of (and I think is intregral to) the central tube (which holds the tungsten electrodes). That's not what I'm talking about as the bubbled up part. The tube starts to bubble like blown glass on one side. Sometimes it remains relatively clear and sometimes it appears to have deposits of burned material in it, sometimes they look vein-like. There is an obvious difference between a new tube and one that is melting if you look closely. Though it is sometimes hard to see at first with all the reflections.
post #46 of 90
Quote:
Originally Posted by Big Lebowski View Post

"Bubble" at the base of the filament is OK. It is there in the begin with. But when this "bubble" begins to grow, malform and discolor, then you have a problem.


Yes, that is what I'm talking about. Because that affects the integrity of the tube that maintains the electrode positions.
post #47 of 90
This is interesting. The JVC RS1/HD1 has a 200W UHP lamp with mercury. However, it still doesn't get past the 2000 hours lifespan after which time it will be at about 50% of initial brightness. There must be more to it!

Quote:
Originally Posted by JHouse View Post

Found this quote today from a UHP bulb dealer:

"UHP lamps range from 100 to 200 watts, with useful lifespan ranging from 3,000 to 10,000 hours. To prevent reduced light output, small amounts of oxygen and halogen are mixed with the mercury vapor, and these help remove tungsten deposits from the lamp's walls, and redeposit them back on the electrodes. The result is a lamp that regenerate itself and maintains almost all of its initial brightness up until the day it fails."
post #48 of 90
Quote:
Originally Posted by JonStatt View Post

This is interesting. The JVC RS1/HD1 has a 200W UHP lamp with mercury. However, it still doesn't get past the 2000 hours lifespan after which time it will be at about 50% of initial brightness. There must be more to it!

Legal lying is called "puffery" under the law.

Illegal lying is called a Deceptive Trade Practice or Fraud or Negligent Misrepresentation.

It is up to the jury to decide whether a particular statement is puffery or one of the others.
post #49 of 90
My projector just went to about 30% brightness with about 950hours on it. I pulled the bulb out and noticed a couple of things.

1. At the base of the bulb where it is rounded there is a bit of white powdery substance that streaks down and around the inside of the bulb. The glass cover has no signs of burning.

2. The reflector has what looks like copper colored lines that rap around it and it doesn't look a silvery as it should. maybe this was just a reflection deseving me

This sucks hopefully the next bulb lasts longer. I guess I'll try to leave the projector on more and not power cycle it so often.
post #50 of 90
Greetings,

I ordered a spare lamp for my Pearl on Monday and it will be here tomorrow. My lamp has 575 hours or so on it and it seems fine.

I like to have a spare lamp on hand in case I need it. Once I receive the new lamp I will install it and keep the old one as a spare.


Regards,
post #51 of 90
My advice is to keep all your old lamps. They might come in very handy.
post #52 of 90
Quote:
Originally Posted by jdamp View Post

1. At the base of the bulb where it is rounded there is a bit of white powdery substance that streaks down and around the inside of the bulb. The glass cover has no signs of burning.

2. The reflector has what looks like copper colored lines that rap around it and it doesn't look a silvery as it should. maybe this was just a reflection deseving me


This is exactly what you will find every time. It happened to you too. Keep the bulb. Mark the hours and dates.
post #53 of 90
I have a very interesting research article on UHP bulbs written by Philips people (Philips is the maker of the bulb in the Pearl) but I cannot upload it because the PDF file is 2.6 MB in size and apparently there is 500 kB limit in place.

The article is comprehensive and is a must reading for those who would like to understand the principles behind the UHP bulbs. If any of you knows how to post such a file here, please do let me know.
post #54 of 90
Interesting topic. This may be a useful link:

http://www.ercservice.com/lamps/phil...sUHPLamps.html

This is pure speculation, but based on some of the information in this link, it could be a line voltage fluctuation or improper cooling (dirty filter). Just a thought.
post #55 of 90
Thanks for that link Chaz, it was very informative.
post #56 of 90
Quote:
Originally Posted by chaz_m View Post

Interesting topic. This may be a useful link:

http://www.ercservice.com/lamps/phil...sUHPLamps.html

This is pure speculation, but based on some of the information in this link, it could be a line voltage fluctuation or improper cooling (dirty filter). Just a thought.


Interesting. One night there was a momentary black out in my area while watching the projector and I had trouble getting a picture back up for a few minutes. Two days later, my dimming problem started.
post #57 of 90
I'm a Sony Pearl owner since December 2006. I have logged 724 hours on my bulb.. and just ordered a new one last night because the image is unwatchable.

I noticed some problems about 50-60 bulb hours ago, and this whole month, I have been making adjustments (brightness and contrast). Now, the bulb must clearly be gone... this past week the Pearl went completely dim and lost a tremendous amount of detail due to lack of light... also a greenish tint to flesh tones.

My replacement bulb ($342 w/ overnight delivery) will arrive tomorrow... and I hope to get my old Pearl back... the image I fell in love with!

I truly hope that I got a defective bulb... If this one only lasts another 600-700 hours (was expecting 1500... I use high lamp setting... better picture)... Sony ought to get an earful about this... Wasn't expecting to spend $350 on a bulb every 6-7 months.

Based on this thread, other projectors with this type of bulb are going out early too. This needs to be researched and resolved!!
post #58 of 90
Man, I feel for you guys. I wouldn't be happy either if my bulb lasted less than 800 hours. I had 1700 on my Panny 900U before I replaced it, and it was still working....
post #59 of 90
Quote:
Originally Posted by JHouse View Post

My advice is to keep all your old lamps. They might come in very handy.

JHouse,

Have you read the journal article I sent you recently on Philips UHP bulbs? What conclusions have you reached?

My Pearl has 350 hours on the bulb and it still looks fine, but stories here are scary.

Michael
post #60 of 90
I'm working on it. Keep the bulb.
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