Axiom Home Page Forums General Discussion Home Theater UPS for projector

A couple of years ago there were some interesting arguments about whether running your projector / TV on a UPS made sense in order to protect the bulb from thermal abuse if the power (and hence fan) failed while the unit was running.

This issue became a lot more real for me a couple of days ago; first time we had a power failure while my projector (Sanyo Z4) was running. When the power came back on the projector would cycle on, then after ~20 seconds the "replace bulb" light would come on and the projector would just down. Gave it a day without power and problem still persists, so it seems likely the bulb is now an ex-bulb. I can't see how many hours were on the bulb without a new bulb, of course, but my guess would be 1500-ish.

Now watching BluRay disks in a small area of a 27" CRT TV, connected at 480i via composite RCA. It's... different.

So, what is the thinking these days about UPSes ?

that reminds me, I need a UPS for my RP. Why is there any question about this? I would think that you want to be able to run the fan through a cooldown cycle if the power goes off while you are using your projector.

Last time this came up the general feeling seemed to be that a UPS shouldn't make any difference.

... thinks for a minute...

Maybe I should have asked how many people had UPSes, not how many people thought they would help. I wondering how many of the people who were iffy on the benefit had UPSes anyways

John, if I recall that previous discussion, the point was made that although the fan almost immediately stopped when a power failure occurred, so did the bulb. No additional heat would be added to increase the temperature, and although the bulb would take longer to cool down by convection, it wouldn't get hotter and there'd be relatively little additional wear because of the extended cool down period. There was of course no question that while the bulb was operating the fan also had to run.

Residual heat from the lens assembly could continue to increase the temperature of the bulb, even though it is off. I run a UPS. It's also handy for the cable DVR. Whenever the DVR is powered off, all my recording timers get screwed up. I picked up one of the Belkin units a while back when they were on sale. Cheap insurance as far as I’m concerned.

I don't know about the theory on this one, but I do know that all the commecial projectors I have used run the fan on cooldonwn for a few minutes after the bulb is turned off and give a warning in the instruction manuals not to pull the plug before the fan shuts down or bulb dammage could result.

Yeah, that's what bothers me; most of the time when people skip that cooldown cycle bulb life ends up being very short, at least with business projectors.

Then again, tossing the hot projector into a bag and bumping it down a flight of stairs probably doesn't help either

Bridgeman, sorry to hear of the unfortunate occurance.

As a Mitsub. 73" DLP owner, I'd be curious of the relevance of a UPS in this application. I'll have to pay attention if or how long the fan runs after TV is turned off. I'd agree that the temperature would rise in the bulb chamber if the bulb and fan turned off at the same time. I'd guess the degree of temperature rise would depend on the physical characteristics of each individual devices light box. If the bulb would be adversely affected may also vary somewhat by bulb too, I'd guess.

Yada, Yada, Yada... But the bottom line. What about my damned TV.

John-
I have a Belkin UPS primarily for my TiVo and external hard drive, but have plugged in my DLP into it as well for the reasons above. Works for me... though if it were just for the DLP cool down, I'd likely just have a small computer-style model hidden behind the TV.

Do DVR's (Comcast in my case) lose programming immediately after loss of power, or only after some longer amount of time?

I understand what JohnK is saying, however, if the fan is not running the heat has no way to escape in an efficient manner. The fan runs all the time when using a projector to keep airflow moving, as well as when turned off to cool down correctly.

I bought a cheap UPS for my PJ, same one as for my computer. It didn't work; either the battery was hooped or simply not enough juice. Anyway, I used to deal with relatively frequent power outages (4/yr) and my Epson Home 10 bulb was still good after 4100 hrs. Still, I would have felt happier if my UPS had worked, and I'll certainly be upgrading it when I upgrade the PJ.




By the way, I remember reading over at AVS about there being a reset button near the bulb in some projectors, and that cleared up this very problem.

Probably not enough juice. UPSes can be pretty sensitive to having enough output.