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Discussion Starter · #1 ·
I'm just buy my first CRT. To adjust the blue focus, I play with 2 screws on the gun for the center and 4 corners. The "H" of center is acceptable but the "H" at corners are very fuzzy. The manual say NEVER make electronic adjustment. It is not the case for Red and Green tube.

1) is-it normal for the blue tube ?

2) Any problem if i make an electronic adjustment for the blue ?

3) Any suggestion please.

Thank for your time and help.:)
 

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As I understand it, the blue tube is supposed to be slightly "soft" in focus in general. The blue tube has to do most of the work for the picture and as I understand it, the slight softness saves the wear on the tube. This is set at the factory like this.


Don't fool with the blue electronic focus. I have heard this is a major no-no. Of course I am new to the Sony FP's so I bow to any expert opinion that may correct this.


-Alex-
 

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lemt,


First thing to do is pull off the blue lens and clean the dirt off the back (Soft damp cloth to wipe, even softer to dry) You are setting the mechanical focus at this point with the wing nuts on the lenses.


If you are technically inclined you can do a search here and find how to do the astig adjustment (2/4 pole magnets) on the tube necks. This greatly effects beam size and shape to allow sharpest focus.


To move the blue electronic focus (which must be done during astig adjust) will change the grey scale setting (bias and gain)


Do a search here for blue crt defocus and read the explanations about why it is done to allow for a slightly brighter picture>
 

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Lemt,

I cleaned the len's of all your tubes prior to shipping the 1271 to you. I do that on all the 12xx projectors (expecially the blue tube) prior to shipping. After a few thousand hours they get a black coating on them that can really reduce the light output. So you don't need to do that.

The Blue is deliberately de-focused by Sony for saturation reasons and so that you don't have to drive the blue gun as hard to achieve a white balance. It's interesting to note that on the newer projectors like the G-70, you have the ability to "defocus" the blue electronically.

As stated by others here, you probibly want to stay away from the blue electronic focus (although the temptation is to focus it) as doing that electronis focus will screw up your white.

Use the manual focus and go for the best "H" overall you can get. Don't worry if the H is not as sharp as the red and green. This is normal.
 

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Discussion Starter · #6 ·
Thanks for quick replies,

- I will do some search for my knowledge.

- YES, i bought this CRT from Terry (ChuChuf). It arrive in good condition in time like promise. He has many used CRT with low hours and his price is very competitive. It is a pleasure to deal with him. If someone want a CRT , i recommand him without hesitation.

- Someone warn me about to do astig adjustment due to 20000 Volts in cathodic tube. Are there someone have courage to do that ?????
 

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Just grab one crt neck with each hand and ride the lightening! Don't hold me responsible for the consequences, but please have someone take a picture!


Just kidding of course, couldn't resist. If you do the astig, follow an old rule of keeping one hand in your pocket while using the other to make the adjustment. That way you can't ever close the circuit with your body and shouldn't get hurt too bad if you accidentally touch something.


I too just bought a 1271 from Terry and highly recommend him.


- Brian
 

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And I cleaned your lens's to Brian, even though they didn't need it. LOL

But seriously, thanks guys, hope you enjoy your projectors as much as I did my 1272 for the few years I had it.


Terry
 
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