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Discussion Starter #1
Which ones do I turn for mechanical and electrostatic focus?


Here are pix of my 57S700's guts


Front mini panel removed
http://pages.sbcglobal.net/jcuadra/H...%20removed.JPG


Look at the 3 guns
http://pages.sbcglobal.net/jcuadra/HDTV/3guns.JPG


another view:
http://pages.sbcglobal.net/jcuadra/HDTV/3guns2.JPG


Closeup of board with focus (electrostatic?) pots
http://pages.sbcglobal.net/jcuadra/H...us%20block.JPG



Now for the Q's:

- Do I have to turn all 4 silvery screws with springs in them? (that's 4 for each gun) The far ones look like I'll electrocute myself turning them with the TV on.


- Which set of trimpots is the electrostatic focus in the last picture above? The lower 3 labelled focus?


- If so, what do the upper 3 knobs labelled "screen" do?


TIA
 

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Not to sound rude, but based on your questions you are way over your head. I strongly suggest you either download the service manual and study it. If not have your set ISF'd by a competent professional.
 

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Discussion Starter #3
Just so I don't seem too newbie-ish :), I have already spent several hours tweaking:

- the different sharpness and edge enhancement parameters in the ISF and FLEX menu

- eyeballed and tweaked the grayscale, and color decoder parameters using AVIA


And I'm an Electronics Engineer that specializes in Power Electronics, so being up close and personal with high voltages isn't new to me. I just want to know how people adjusted the rear (far) screws, and stayed alive. I also want to know if 3 or all of those trimpots are the "DO NOT TOUCH THEM" VR trimpots.


I was surprised myself I got a noticeable improvement in color by eyeballing grayscale; The sharpness tweaks had a huge impact on DVD.


So... I've read several threads on doing focus, including the blue focus debate. Now I want to try it myself. :)
 

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If look in the screen side of the unit (other side of the lens assembly) you will find the adjustment for the focus on the lens. What your picture shows is the adjustments for the crt's. You also focus the lens.
 

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The focus trimpots are the bottom three. I did the manual focus by opening up the back of the unit. Once you do that there is a tray/shelve that is preventing you from getting to the CRT's. I removed that (4 screws from top). Then I was able to manual focus the lenese. The wing nuts are on the front of the lenses just reach around and losen them.


chris
 

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Discussion Starter #7
Ah, thanks all. It was pretty easy.


My 57S700 indeed lets you access the manual LENS focusing knobs from the front, by removing the panel with the buttons. I'd mistakenly assumed that the same panel for accessing the electrostatic focus would let you access the manual focusing knobs.



For posterity's sake, loosen the wingnuts, then slide them left-right.


My green manual focus was a wee bit out, and my red and green electrostatic focus were also a wee bit out.


Adjusting the blue manual focus indeed produced a purple halo when I tried sharpening it, and I followed the recommended procedure of defocusing it (in one direction) until the purple halo just starts to be invisible. The "correct" blue focus point was kind of vague. I checked the AVIA gray bars and grayscale wasn't noticeably affected.


The electrostatic trimpots are indeed very sensitive. It required a deft touch, and I had to hold my breath, and it was easier to do it by hand than screwdriver.


DVD was slightly improved, but the 1080i football game on CBS was eye-poppingly sharper! Holy mad cow, I thought it was sharp before, but this is ridiculous! :) :cool:



TIP: if you have cats, they will treat the opening in front of the TV as a new place to explore. Hang the panel back on. I got a good scare when one of them was sniffing at the high voltages when I got up to answer the phone!
 

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Discussion Starter #8
Just an epilogue.


I tried focusing blue again, this time for best apparent sharpness, both with the manual adjuster and the electrostatic knob. I checked the graybars and to my eye grayscale wasn't affected.


I then went and retuned YDTL-0, APRTRxx, and SRTGA-0. Optimum settings changed: YDTL-0 = 08 (was 07), SRTGA-0 = 06 (was 0A), and APRTRxx=01 IIRC. DVD picture is more natural and sharper than ever, with less ringing on test patterns.


:)
 

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Yes I refocused mine last night by going in the front of the unit like you suggested. thanks. Did not get much time to go back and check out the sharpness test pattens. Hopefully get a chance tonight.


chris
 

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Discussion Starter #11
Quote:
Originally posted by rcwalters
So I take it the "MagicFocus" feature isn't so magic after all?
Magic Focus is really "Magic Convergence", and it's useful for when your convergence is way out, such as after I did my mechanical blue focus. It at least improves your starting point for when you do manual convergence. :)
 

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So on the 57 all I have to do is take the front control panel fascia off and I can adjust the focus lenses right from there? I don't have to take the screen off like my 51 inch?...Frenchy
 

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that is the way my 51s700 is. I am assuming the 57 and 65 would be the same design. Can not imagine why they would not be.


chris
 

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Discussion Starter #14
french, to reach the lenses you have to remove the panel with the power switch and other buttons. Just let it hang.


TIP: Before taking it off, observe how the wires for the button panel are routed, so that when putting it back together, you won't pinch them when you cinch down the screws.
 

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Quote:
Originally posted by Jason EC
Magic Focus is really "Magic Convergence", and it's useful for when your convergence is way out, such as after I did my mechanical blue focus. It at least improves your starting point for when you do manual convergence. :)
Actually, Magic Focus attempts to return to a service level (DCAM) manual convergence. So there really is nothing magical about it.
 

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Thanks, I did my 51 inch taking the screen off, was going to do my mom's 57 inch too, great to know I don't have to mess with that big screen this time...wheres my phillips screwdriver.... : ) Frenchy
 
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