White warmup screen size

Turn the warm up mode off, 99% of owners here turn it off especially if the beam is shooting off to the side of the Tubes..

Cheers..

The warmup mode gets the physical components of the tubes, spacers, etc to their stable operating temperature so that convergence drift is minimized.

If you have good convergence (or can tolerate initial convergence error), there's no harm in leaving it OFF.

I'm on the fence about letting the warm up screen run. You don't want to waste tube hours but it's possible the benifits outway the cost. Letting the warm up screen run may tend to blur the wear line and actually extend the usefull life of a tube. It is my experiance it is not so much the degree of wear but more the pattern of wear that limits a tube's useful life.

BTW: My G90 also displays a full white image outside the image area during warm up, ignoring any user settings.

Even after i let the warm up screen do it's thing...i still find i get a bit of drift after a while, say 5 minutes. I usually have my warm up screen set to 2 minutes. Don't think thats enough for it to be useful. I might just get rid of it for now.

I have always been nervous about the warm up screen running off the tube face on Sony projectors. I don't want to work on a client's machine and then have them later wind up with a possible tube implosion due to the warm up screen. If the warm up screen were to cause an implosion, I don't want a client to think that it was the result of something I did while working on the machine. Because of this, I always turn the warm up screen off on my client's projectors. I also keep the warm up screen off on my own G90.

The point of the warm up screen is two fold however. It does allow the projector to warm up and minimize convergence errors when you sit down to start watching. However, you don't need a white raster for convergence to come back into alignment. If you just run the projector with a black screen, you will find that in 20~25 minutes the convergence will be close to perfect with just a black field.

The other job of the warm up screen is to blast the phosphors with a full 100 IRE bombardment of electrons. It takes the phosphors about ten or more minutes of this before your black level, white level, gray scale, and gamma will be correct. If you look at a black level test pluge right after turning on the projector, you will notice that it will be much too dark compared to a fully warmed up machine. So if you start watching without any warm up, the image will be too dark and the gamma is much too high resulting in loss of detail and a punch-less image.

Full 100 IRE white quickly gets the phosphors ready for reference performance. Just watching a movie for twenty minutes does not do the same thing. Joe Kane used to point out that if you watch a two hour movie without a warm up screen, the phosphor is at its peak performance at the very end of the movie. In other words, there is not enough of a work out with regular viewing, so it takes nearly two hours before the phosphor is ready for reference use. If you use no warm up, you only see what your projector can really do after two full hours of viewing

What I do for myself is to turn on my G90 and let it run with no input and no warm up screen for 15~25 minutes. At that point the convergence is perfect. I then turn on my Lumagen with a full 100 IRE white field and let it run for 5~10 minutes. With this combo I get full performance without the risk of running the warm up screen off the face of the tubes.

craigr

Very interesting topic, I'll have to have a look at my Zenith 1200x and see what options are available for the warmupscreen time. Thanks for the info guys.

I checked my warm-up screen last night and it puts what looks like a 480i white screen up. What does the G90 project for a white screen?

They intentionally use a low frequency for the white warm-up screen. From the factory, they have that mode adjusted to fill the FULL tube face. When people start making raster size adjustments WITHOUT looking at the scanning frequency and mode they're in, they screw up that setup screen. In some cases it winds up not filling the raster.....OR, they wind up setting something else up in that mode and wind up with the raster SO BIG that it goes past the frame, which can be dangerous.

HI Techman707,

Thanks for the info. I had to adjust the vert/hor size in the warmup menu for the warmup screen size (which is normal according to the manual) to just cover the the face, in this case it ended up being set at about 50% of max for each H/V setting.

I never used to use a warmup screen.

But my XG's red tube starts with an elevated black level. Changed all the boards in the projector, it's the tube.

A 5 minute white warmup fixes it.

Hey Mark,

When you take a NEW G70 out of the box, the default is a 20 minute warm-up. However, 5 or 10 minutes is plenty on a broken in projector (although as the projector ages and the caps change value, it might take a little longer for convergence to stabilize).

If you use a lot of 2.35 and 1.85 movies on the projector, running the white screen covering the full raster for 20 minutes and a high contrast/brightness setting once in a while helps to prevent raster burn-in.