I will be putting a minty blue tube in my 1272 soon and was wondering if anyone knows why the blue tube gets burned way before the green or red shows any wear.
Is there some setting that Sony set too far that causes this ? Any info would be appreciated as I want the nice tube to have a long happy life. Thanks Rich

It is because of the actual phosphor on the tube surface.. blue is inferior in light output on these particular tubes(as far as I have heard- although Barcos with the same tubes seem to wear green faster) and has to be driven harder for proper withe balance. The blue phosphor is also more prone to losing tight spot-size ability. Basically the ability to light a small spot without exiting surrounding phosphor.

To make it last longer, run it slightly defocused as the factory sets them(more light output at same drive levels when slightly defocused-the enlarged spot size lights up more phosphor between dots/scanlines therefore outputting more light, while not hitting the phosphor with as intense a beam area-wise- making the phosphor last longer), and make sure not to run your contrast too high(at least 8-10 clicks below blooming level).

Keep in mind that as the usage hours go by, the guns themselves wear, and the tubes(all 3 colors as they have the same guns) lose focusing ability anyhow. The above technique can't help that. Make sure not to leave your projector running with no input or on pic mute for long periods of time, since the guns are still energized and still wear although no pic is displayed.Turn it on, watch it, then turn it back off as soon as your done is the best rule of thumb. Standby(power off but still plugged in with the main AC switch on) will not hurt the tubes, so thats ok of course.

You can defocus the tube just enough to help, without losing the ability to do 1080i- the highest recommended res. for a 1272.

My grammar is usually better than this lol, but I am kindof tired tonight. Feel free to ask any questions if something above isn't as clear as I mean it to be. :)

Thanks Sonynut I just put a set of pt43s on it and set it up for the first time by myself and the pic is a lot sharper than the revb s I had on it before I also went into the bias and gain controls and the blue was maxed out I then put all of the settings to midpoint (mistake ) and the color looked a little muted I have went back in and readjusted them now the picture is better than when it was set up before by someone ho knows what they are doing. I attribute this to the pt43s not beginners luck. I do have another question If I understand this correctly the blue gets turned up because the eye does not register it as strongly as the other colors and this set of tubes has a weak phosphor for the blue tube . my question is how do contrast and brightness come into play for the tubes life I currently am at 45 on bright and 60 on contrast Thanks again Rich.

The contrast and brightness numbers aren't necessarily meaningful from projector to projector. If it makes you feel any better though, I'm running a 96x54 WilsonArt screen, pretty well maxed rasters, and my brightness and contrast are set at about 45-48 and 60 respectively. At the screen size we're running these machines, and in light controlled environments, you should get years out of your projector. You'll probably want a new projector before the blue tube starts to show significant wear.

SC

Congrats on the PT-43's. :) They are what I have on my 1272. Much better focusing capabilities than HD-8's, and they also seem to help color quality a little also(though some here argue against this, about 5 of my friends that have seen my machine with PT-43, PT-65, and HD-8 lenses agree that the 43's provide better color, along with better focus than the HD-8(same focus as PT-65)).

Again from what I have heard, the blue phosphor used in the 07MSP and 07MP tubes, although the MSP is supposedly a bit better, is inferior in light output to the other two colors. Also, the blue phosphor is less resistant to wear than the green or red, and the fact that it is driven harder from being less efficient worsens the problem. This is why defocusing can help, as a less intense beam hitting more area means more light output(by filling in the gaps between dots a little), and less wear.

Brightness sets your black level, too high and your blacks turn grey. This doesn't wear your phosphor faster if set too high, but may(don't hold me to this), cause the guns to wear faster if set too high.

Contrast on the other hand sets white level, or gun output for the bright part of the image. The higher your contrast is set, the stronger the beam hitting the phosphor and the faster the wear for all three tubes(ESPECIALLY the blue). As Ecrabb said, there is no set number for every machine/setup. Run contrast as low as acceptably possible, but at least 8-10 clicks below the level of blooming on blue.

If you are like most here, Ecrabb is also right that the new blue should outlast your time with the 1272 before you upgrade, but if you are like me, you want your machine to last as long as possible, since upgrading isn't an option for quite a while.

Thanks for helping a newbie understand I was concerned because the blue is pretty toasty and the projector only has about 5000 hours on it .
It will be some time before I will be able to upgrade as the projector I want has went up in price (Marquee 8500) So I purchased extras of every board in the machine . I got the set of tubes when I got the blue and was planning to only change the blue but now I am thinking I should replace them as a set. I am also going to try to put Barco mounts on these tubes as they will add more adjustability.
I think they will be a direct bolt in. :D Thanks Rich

this is why I believe the blue wears faster on 12xx sony's.
most were used with windows NT desktop with blue background
set from factory for high grey scale tracking which pushes blue
as already said. 07mp/msp blue phosphor wears faster than most.

12xx purchased NEW for HT use and were calibrated for flat grey scale I have seen had no wear on red some on green and a little more on blue and all have been in the 6-10k hour range. All I have seen from corporate meeting rooms and such have had much more wear with fewer hours. Blue being much more worn than green.

This is an interesting thread. My 1272 has about 500 hours on the tubes. That seems pretty low, right? If you look through the lenses (not upgraded yet) the blue looks like a 8 or 9 or so, and the green and red are 10s. But...hooked up to my scaler (with maximized raster), there is a brighter crisper blue strip down the left side, and a thin strip on the bottom and right. That means to me that the raster was not maximized before (don't know where this pj has been). Still puzzling since the tubes look so nice.

Regarding color, the eye sees green most efficiently.

Any ideas or suggestions for evening out the blue intensity on this 1272?

Oh yes, I have a Spyder2PRO from work. I need to set it up and see what I can adjust.
Dave

Dave, I think the sony's internal time clocks reset after 9999 hours, so your 500 hour machine might actually be a 10500 hour machine.

Also the timers can be reset.

Even if the 500 hour timer is correct, and hasn't been reset, if the previous owner ran the set too high, the blue could've worn such as yo describe quite easily. Overdriving these sets can kill a tube completely in a matter of a few hundred hours in extreme cases.

Thanks for the comments guys. I sincerely believe the hours are correct on the tubes, this is my 2nd Sony and the first did have worn tubes. But these are really fresh looking. I am betting on the overdrive situation.
If it wasn't such a hassle to get the lenses off (with the pj hanging from the ceiling), I'd take a picture for reference here.
Dave

I did notice my blue tube also will not focus nearly as sharp I am thinking that this is because of the greater amount of wear. I remembered that the blue should be slightly defocused to be sharp mine is a lot out but the picture still looks very good .
I have 2 ehome machines (ecp3500s) that were used for home theater only one has pristine tubes the other has equal wear on all three tubes . Rich

I guess the biggest problem now with my 1272 is the corner focus. Once everything is dialed in, if I display the "H" pattern, the corners are blurry or defocused. I have never been able to get them cleared up - in two different home theaters. Projecting onto an 8' wide 3:2 screen. The picture, skin tones, vibrance, center clarity, etc. is incredible.

From my previous post: I turned down the contrast and brightness using the pluge screen, and man did it make a HUGE difference. I would still like to get the Spyder2PRO set up and see what it has to tell me...
Dave

Don't worry about not being able to focus blue absolutely perfectly. I have my blue electronically defocussed as far as possible in order to boost the light output. It cannot be seen on screen.

Kal

I really cant beleve how sharp the picture is when compared to the image output of the blue tube alone . :eek:
I am going to try to install a set of Barco mounts to get better focus I will post how it comes out, this will give greater adjustment (Kind of like the lens flapping mod) Thanks , Rich