CurtPalme.com Home Theater Forum

davebot · Posted: Tue Jun 02, 2009 4:23 pm Post subject: 1252 Blue Focus Probem

Hello all,
I am having a problem focusing my blue tube on my Sony 1252q. I have a feeling that it is something in the settings and not physical setup, but I could be wrong.

Here is the green test pattern...

Here is the blue. I didn't move the camera between shots.

Adjusting the focus on the lens only makes it worse.

Any ideas what is going on? I have been looking around for away to set all the settings back to the factory defaults but I was unable find anything. Does anyone know how to do that?

Thanks for the help!
-Dave

ecrabb · Posted: Tue Jun 02, 2009 4:28 pm Post subject:

Have you played with the electronic focus controls? The blue one is recessed and usually has a sticker over it that says "do not touch" or something along those lines. Usually, you don't want to mess with it, as it should be slightly defocused and if not, will make greyscale difficult (or impossible), but obviously it shouldn't look like your photo.

SC

davebot · Posted: Tue Jun 02, 2009 4:42 pm Post subject:

I played with that a little bit, but there wasn't a huge improvement.

greg_mitch · Joined: 03 May 2006 Posts: 5320

What does it look like on the tube face when the pattern is displayed with the lens off?

How about a screen shot of some material? Is it annoyingly noticeable during movies?

davebot · Posted: Tue Jun 02, 2009 5:59 pm Post subject:

If I look in to the tube, it looks about the same. All the "H"'s have a halo on them. I'll take some pictures of that tonight.

Here are some screen shots... I really need to do a grey scale calibration on this.

Red is a bit off.

Blue is off. Nothing is really sharp. Text is very hard to read.

Blue "Fuzz"...

Thanks for the help!

greg_mitch · Joined: 03 May 2006 Posts: 5320

What resolution are you using? I thought it was set up for 1080i already.

What is your screen size? Did you adjust the lens flapping accordingly?

I would look for a screen that is more uniform instead of a sheet or at least secure the sheet in all four corners to make a solid plane so that the focus distance is equivalent to the entire screen surface.

imprez25 · Joined: 01 May 2007 Posts: 70

If I remember right, the blue is very touchy when it comes to electronic focus. A little ajustment on the knob will make a major change on the screen. It has taken me a while to get blue dialed in on my 1251q, and it's still out a little more than I would like, but it's livable.

This is my method for focusing:

You first need to get the center optical focus as close to "right" as possible. If your optical is out and you try to adjust the electronics you will be chasing focus forever. You can do this by getting the phosphor "grain" to show on the screen. By using this method your electronic focus becomes a non issue. If proper optical focus is acheived the crt's phospher grain will always show through regardless of how the electronics are adjusted. For this you will need to display a "white" feild and have only the tube you are working on turned on. Using just the center focus ring adjust the lense until you can see the phosphor grain. Once you can see the inherent grain of the phosphor on the screen you will know that the optical focus is correct, and can then move on to adjusting the electronic focus. You may need binoculars, another person, or you may have to get up close to the screen inorder to see the grain, but trust me it is there. Smile

Blue is the most difficult to focus and should be left a little electronicly defocused (though on these 12xx's that typically isn't to hard to do). With the optical focus set, you can now display the internal H patern with no signal going to the projector. This is when you use the electronic focus controls using only small twists. Again small adjustment to the pots will make major changes to the focus on the screen. Continue until you get the H's as clear as possible, (with blue they will typically always remain a little out of focus on these projectors). You again may need binoculars, another person, or continious trips to the screen to get this correct.

Once the H's are as clear as possible you can then move back to optical with the H pattern. Make minor adjustments until the dashes are visable on the H's (this may not be possible on your projector, so simply make the h's as sharp as possible optically)

You may have to move back and forth between the electronic and the optical adjustments until it is dialed in perfect, each time making smaller and smaller adjustments. Once the center is dialed in you can then move to the outer focus, which should be done quite quickly once the center is set, but again you might need to make minor adjustments to the center in order to balance out the edges.

This is my method for focusing my 1251q and it has worked quite well, but your milage may vary.
Good luck! Smile

tommo2 · Joined: 03 Jun 2006 Posts: 226 Location: Ireland

Vibe · Joined: 03 Apr 2006 Posts: 164 Location: SoCal

Maybe the coil on the blue is not snug to the bell of the the tube. Loosen the coil and get it as snug to the bell of the tube as possible. It may be hard to move at first but keep twisting and it will move. Make sure you get the picture on the tube face lined up correctly after though as twisting the coil "tilts" the picture on the tube face.

Could this also be an astig issue?

**AnalogRocks** · Posted: Wed Jun 03, 2009 4:36 am Post subject:

Clean the back of the blue lens. It's dirty and causing halo's.

Do NOT use windex!

Here's the link to the proper cleaning fluid:
http://www.curtpalme.com/Lens_Cleaning.shtm

davebot · Posted: Wed Jun 03, 2009 2:49 pm Post subject:

greg_mitch, I am running it at 720p. My old screen actually was a plastic picnic table cloth. Major thanks to AKAJester for the new screen! I don't recommend using a table cloth as a screen...

Ok, I removed the lenses and wiped everything down. Then I switched the lens flapping to Large setting which really improved the image sharpness!

I was able to clear up the blue a bit. I tweaked the electric focus a little and then I went in to the settings and took everything to 128, then remade my adjustments. The blue gain was really high. When I backed it down the halo effect was less noticeable. Its not %100 there yet but its close.

It still needs a gray scale adjustment, but its getting better. Thumbs Up

Thanks for the help!

**Curt Palme** · Posted: Wed Jun 03, 2009 4:50 pm Post subject:

All answers above are correct, but if you see a slight dip in brightness as you adjust focus, that dip is the best electronic focus possible. Once it's set, leave it alone. As Analog says, clean the front of the tube face along with the back of the lens. The HV supply is right next to teh blue tube, and the air gap between the lens and tube attracts dust like crazy, causing halos and poor focus.

If you've cleaned that, and it's still as bad as your image, then the tube is worn, and nothing short of replacement will get you better focus.

greg_mitch · Joined: 03 May 2006 Posts: 5320

Try 1080i...I always found 1080i a bit sharper on that set. I never have used 720p on either CRT setup.

ecrabb · Posted: Wed Jun 03, 2009 10:16 pm Post subject:

tommo2 · Joined: 03 Jun 2006 Posts: 226 Location: Ireland

imprez25 · Joined: 01 May 2007 Posts: 70