CurtPalme.com Home Theater Forum

[Cube]

I'm finally setting up my used 1272 as a floor mount. The setup is working out okay but I'm not blown away by the sharpness. Got some questions...

-The corner focus is pretty bad but I'm nervous about removing the factory spacers and doing a custom Scheimpflug adjustment. Can you really dial the 1272 that sharp? I don't want to risk cracking the lens casing for nothing. Also it was a big enough pain taking the lenses off once to clean the CRT face.

-Red and green look good to me but the blue is really, really blurry and dim. I think the blue electronic focus needs adjusting but the manual warns you not to do it (it ruins the color balance). Has anyone messed with this and been able to get reasonable gray balance back without a colorimeter?

-The screen is 4:3 and I want to be able to use the whole thing for 4:3 content and a letterboxed image for widescreen. For 720p/1080i memory blocks, I guess this means I should do geometry and convergence with the test pattern projecting into a 16:9 letterboxed space on the screen. (BTW, I was surprised to discover that the test pattern is actually underscanned compared to the actual video signal. Curt's guide suggested it would be the other way around.) However, I was messing with the RGB SIZE adjustment that lets you squeeze the image after convergence, and it seems to actually change the raster space rather than just the video signal. So now I'm wondering if for 16:9 I should do the test pattern geometry setup as 4:3 using the whole screen space and then just RGB SIZE-squeeze the video signal back into 16:9.
(TL/DR: does RGB SIZE change the actual raster scan or will it still scan the unused space after you shrink the image?)

I'd appreciate any tips from somebody who's had experience with a 127x (or maybe even 125x). Thanks.

[ecrabb]

You're not ever going to be blown away by the sharpness of a 1272. It just won't ever be very sharp, and it'll be worse if it's not a pretty minty set. How many hours does your machine have on it?

A 1272 is a nice entry-level CRT that will make a very nice 1080i projector - just don't expect to see 1080i scan lines or resolve much more than about half the 1080i signal. I had a couple of 12xx machines, and used a 1271 in my theater daily for a year or so until I moved to a G70... The sharpness was probably the biggest part of the upgrade. A-B'ing between the two was like getting a new eyeglasses prescription. The G70 isn't digital sharp, but it's a big jump up from the 1271 I used daily before.

From my experience (others have different opinions), the HD-8 and Sony PT-xx lenses on my two 12xx's were the limiting factors. I could easily see 1080i scan lines on the tube faces, but not on the screen. Those lenses were made when 480i NTSC and PAL were the two common video formats and even computers were mostly VGA (640x480), and it showed in the optical performance of those lenses. They suck.

As for the flapping mod, it isn't going to improve corner focus per se - it will improve top/bottom and/or side-side focus, depending on how far off the "stock" install you are compared with the spacers you have installed. So, if when you try to focus the lens, you have to make a compromise between the top/bottom or side/side, then you're a good candidate for the flapping mod. My machine was very close to the spec for throw distance and angle for the spacers I had installed, so I never bothered with the mods.

If the blue is really dim, then your color balance is probably bad anyway, so the risk of messing with the blue focus and G2 (screen) controls. You can pick up a Spyder pretty cheap and use the free HCFR with Kal's guide and get it back in the ballpark, too.

On your last question... I always setup my machine first with the internal pattern (in your case, on the 4:3 screen), saved to all memories, then did tweaks for the external sources. In your case, you'd do tweaks for your external 4:3 source, then tweaks again for your 720p and 1080i memories, and yes - you'd use RGB SIZE to do the vertical squeeze.

Start looking for a G70!

SC

[rosenbush]

To find out if you can get better sharpness of what are you getting right now (We don't know how far are you from the best focus for 12XX), did you see the individual dots of the 'H' on Red and Green?

As ecrabb note, do not expect to get Formidable focus, but you can get a very decent and acceptable image. The point is if you already are on the top of the 12XX focus.

[ecrabb]

[Cube]

I can just barely see dots on the red and green tubes if I turn the contrast way down. Even then it's not razor sharp. I'm thinking the blue is a lost cause... I'm seeing in a lot of archived threads that the blue is left intentionally unfocused to improve light output and color balance. It's not really that noticeable unless you put up the blue test patterns.

Looks like I'm really not going to get that much sharpness out of this, especially if the lenses are as you say. Just have to be satisfied with messing with the raster some more. You're sure I can converge the test pattern at 4:3 and just use RGB SIZE to get 16:9? I thought for sure that was the "wrong" way to do it... seems like I should be adjusting the geometry SIZE control until the test pattern is 16:9 and converge that.

[ecrabb]

[rosenbush]

Don't be afraid to move the focus pot, you need to adjust it in order to get the focus done, the manual refers to the 'SCREEN' pot wich is next to it, not to be touched. Just keep the eye on the screen as you rotate it in order to see the changes. If you only did the optical focus, you're far from real focus.

[AnalogRocks]

Put a piece of tape over the screen controls if your block of plate is missing

[AnalogRocks]

Put a piece of tape over the screen controls if your block of plate is missing

[Cube]

[rosenbush]

My mistake, about the manual "Never adjust the blue electric focus.", you're right. I was reading the manual for the 1270, similar, but not the same.
After you adjust red and green, see how bad is the blue focus, the human eye can not focus very well the blue, if you see there is no much problem with the blue, leave it alone if you feel confortable with that.

The calibration factory has gone already because your tubes are used, and the calibration needs to be done as the tubes change their power. The factory defocus the blue in order to avoid the "Bump"of the blue in the Gamma. But is just a little bit, by now the factory focus has changed as the tube change. This "Defocusing" has to be electronic only, not optical, and at this point I think you have both. What I did, is get the blue the best focus I could get , and then, defocusing a little bit with the pot, until the dots merge each other of the H.
But if you're pleased with the image with out mess with the blue, thats what really matter.

Good luck

[Cube]

Thanks for the advice guys. I've got these issues mostly solved now.