# How to tell if a lamp is bad?



## Guest

My basic question is: How can I really tell if a projector lamp is ready to be replaced? Does it simply burn out, like a normal light bulb, or are there other failure modes?

Here's the longer version:
I bought an H31 about 20 months ago. I used it for just a little while before putting it into the closet while I finished my basement. A few months ago I brought it back out. At the 60 hour point, I started getting intermittent problems, where the projector would sometimes not power up--I would get a flashing orange "lamp" led. This supposedly meant that the lamp was bad, but I was surprised to be getting the problem with so few hours on the projector. Further, when the projector would power on, I could use it for hours. I tested use for up to 6 consecutive hours, and it NEVER shut off after successfully turning on.

So, I contacted Optoma and they had me send in the PJ for repair. They replaced the main board and the lamp driver, but told me that I needed a new lamp, as mine was going bad. I asked them if the lamp failure wasn't due to the bad lamp driver (perhaps over or under-driving the lamp, or not supplying stable power) and they told me that somehow they had determined that the failure was not due to the driver. I find this highly suspicious. In my experience a bad or unregulated power supply (which is what I'm assuming the lamp driver is) very often leads to component failure.

Anyway, now I have the projector installed again and I am getting the same problem. The PJ will intermittently turn on, and when it does turn on I can use it for hours at a time. For some reason, removing and re-seating the lamp allows the PJ to work properly almost all of the time.

So, how can I tell if the lamp is really bad? I assume that once it's bad it will just not power up at all. Is that correct? I'd like to educate myself a bit more on how exactly the lamp fails, so I have firmer ground to stand on when I call again and ask for a lamp replacement.


----------



## lcaillo

The only way that is even close to practical to know a lamp is bad is to test it on a known good supply in a known good set. That is, unless it is physically broken.


----------



## Anthony

I'm wondering this myself. We have been using a Sanyo Z4 as our daily watcher for over a year now. I think I am noticing the light output going down, but I'm just not sure. Sometimes it competes with ambient light, sometimes not.

I almost want to get a light-meter so I can baseline it and know for sure.

Also, I hear the stories of failures after 100 hours and some that get 10,000 out of a bulb.


----------



## Guest

lcaillo said:


> The only way that is even close to practical to know a lamp is bad is to test it on a known good supply in a known good set. That is, unless it is physically broken.


Well, the system just came back from being repaired, and it passed their "quality assurance" testing. I suppose I could assume that my PJ is good now, but I don't really have any way of being sure.

Is it unreasonable to assume that a bad lamp driver would cause premature lamp failure? They told me that they had determined that the lamp failure was not due to the bad driver, but I'm unsure of how they could actually do that.


----------



## lcaillo

I don't know how they could make that determination unless the lamp had reached the number of hours it was rated for.


----------



## <^..^>Smokey Joe

I believe the bulb life actually should follow the half life curve, so when it is rated at 2000hrs it would in theory be half the light output.

These bulbs actually lack a little Red out of the block, and over time this effect appears to worsen. My bulb is at 1100 hours, I did a calibration on it last Saturday night and light output is a struggle, what I really noticed was how far Red was reduced in certain standard modes.
Visually I noticed faces heading a little green and or pink at times, so as the bulb ages I also think one needs to tickle the adjustments, colour/tint more often.

This aside, you I believe did the right thing to send it back. Here though what they did is weird, to change those components and not change the bulb aswell is weird if the problem still exists. Although they said, replace the bulb, so why not just do that in the process? 
Although you dont mention warranty at all, so I presume you had to pay for the service, if so why again didnt they change the bulb? If it was a warranty job, it is a difficult position for the customer as you have to trust the service people.
What is and what isnt causal can lead to arguments, there I believe the right thing to do would be replace the bulb for customer satisfaction. Even if it wasnt casual, proof is hard to establish, where as satisfaction and return business is assured if the product is returned working.

At this point I would buy a bulb, if it fixes the issue, great, move on.
If the problem continues, return it to the service agent and take the value of the bulb off the bill. Since it was their statement that it would fix the problem.


----------



## Rajesh

I must have installed at least 25 optoma projectors this year. Most of them are home theater projectors.I had come across some problem in 3 projectors.

What i believe is the projector needs to be properly shut down. In India we face power failures , hence we use "UPS" ( uninterrupted power supply ). The projector lamp needs to cool down and that's why even when you switch off the projector with the remote, the fan keeps running even after switching off for 20-50 sec depending on the room temperature and the lamp heat . When ever you ceiling mount a projector make sure the air-conditioner is not too close. So that you don't cool the lamp and kick it on .

I prefer not to switch on the projector immediately after switching off , cause kicking on the lamp when it is too hot must be avoided.

Facts on lamp life:

Every manufacturer claims 2000/3000 hrs . The exact way to achieve is to avoid too many switch on's. Plan for a movie and switch on . If you are going to switch on and off a minimum 10 times a day ,Your lamp life might not even reach half its life.

Regards
Rajesh


----------



## emarlin

We have two Toshiba TDP-45 projectors that are a couple years old. One bulb burnt out, and so we ordered a new one. After replacing the bulb, the projector fails to do anything. It has no power at all. Is it possible that the new bulb was damaged in shipping? Should putting the old bulb back in at least let the power lights come on?
So you might ask, what about the second projector. Well, we opened it up to test the bulbs, and opening that bottom door turned that projector into a lump of plastic and metal too.
At this point, I thought power supply, open door kill switch, heat switch, etc. So, now having two completely failing projectors and three useless bulbs, I opened one of them up. Using a Volt-OHM meter, and the patience of Job, I checked the heat switch, and the kill switch the best I could, and determined that the switch was working and 110V getting to the inside of the projectors. Tried jumpering the connections on the door switch to see if that was the problem. So far a good 40 hours of thinking and measuring for naught.
Best I can tell is that opening the bottom door, to change the bulb, completely fried two projectors. So, can I tell if it is 3 bad bulbs causing all of this, or determine a course of action in some way?
We have since purchased two new projectors, but this has become a mission.


----------



## Mark Techer

Just my $0.02 worth.

My BenQ W5000 is my fourth projector since 2000. My last three were LCD. What I noticed with them was as the lamps aged, the image got yellowish around the edges. Lamp strike failures are usually due to the electronics that drive the display, not the lamp itself unless the lamp has either exceeded its life or being damaged. The lamps are high pressure vapor (mercury) and do not have a filament, so it is not like a sudden jolt can break that. Acid from your finger prints can damage the glass as it heats up and why you should not touch them with your fingers. Sometimes the socket that the lamp module plugs into can be loose and not make proper contact and the result will be a lamp strike failure.


----------



## sareenaJJ

When you notice picture quality fading then surely its the time for replacing.

If the lamp explodes in the unit and the cage is not designed to properly hold in the glass you can end up with jammed fans or broken color wheels/light pipes.:hsd:


----------



## TestTones

I have an Optoma EP708 with a lamp that has been run for 7,000+ hours well over 5,000 hours passed the 2,000 hour rating and it still works well. 
Should I replace it?

It has been a few years but I am nearly certain it was far more visible in a lit room during the day when it was first purchased. It is around 4 years old.


----------



## lcaillo

It depends on what you consider bad. It surely has much lower output than new and worse color. There is no good/bad test other than whether it lights up and comparing the spectrum to a new lamp.


----------



## Anthony

At that point, I'd start thinking about replacement. No huge rush, but you definitely got your money's worth out of that bulb. Save it though until you have about 100 hours on the new bulb in case it fails early (a common time to fail if the new one is bad)


----------



## TestTones

I notice sometimes after about 20 minutes the color starts to wash out and I have to adjust some settings. Sometimes it can take a couple hours and sometimes it doesn't happen at all. I suspected new bulbs run a risk of early burn out which is one of the main reasons I want to replace this one while it still works. 

I think 3,000 hours is the sensible time for replacement. 
I am currently at 7,040 hours and will replace it when I can. 
I bought this model because multiple reviewers with much more expensive projectors who had this as a backup said it was the only unit under 2 grand that could compete with theirs. 
Something to think about for anyone deciding on an older, used model. 

Hopefully someone starts producing SMD's that can match a 200 watt halogen. I have a couple automotive SMD bulbs that match a 50+ watt halogen and work regularly with LED's as I earn my electronic engineering degree so I know it is possible


----------



## lcaillo

Color washing out generally has little to do with a lamp, other than the brightness increases as the lamp warms. In your case, if you have exceeded the expected life of the lamp so much, it may be that the brightness is actually dropping after warmup.

More likely you are seeing thermal effects on the light path or on other parts in the system. Can you describe what you are seeing that you call washing out the color?


----------



## lcaillo

Let me clarify my comments above.

Washed out color is usually meaning a lack of saturation. In this case, it may mean a lack of contrast, which certainly could be a weakening lamp. The normal output trend is for a lamp to actually increase in output, resulting in greater contrast, as it warms up. Aged lamps can often take a while to reach peak output. A very old lamp like this one may behave differently. 

So it would be unusual for a projector to actually lose saturation as it warms up. This would not be a typical symptom of a bad lamp. What does happen often is that filters in the light path begin to break down, or oils and dust tend to bake due to heat, causing optical properties to change, or electronics heat up and misbehave. Since I now see that this is a DLP, the light path issues are far less common than with LCD projectors (where they are VERY common), and the higher probablility for a true lack of saturation or loss of blacks is with something getting hot, such as the DMD board, or a problem in a power supply such as the very pervasive problems with bad capacitors.

Bottom line here is that the lamp in this latest discussion is far beyond its expected life and may not behave typically. If the problem is that it is getting dimmer after running a while and that is what is meant by colors washing out, changing the lamp is a likely solution. A better description of the symptom would be useful in troubleshooting, however.


----------



## wes

There is no light


----------

