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Discussion Starter · #1 ·
I'm thinking about masking the unused phospor areas on my crts. Even at lowered contrast/brightness settings, I can see the glow from the edges pretty clearly.


I've seen posts about using cardboard or felt, but I'm wondering about using something simpler like electrical tape.


Any thoughts? Thanks!


Kris
 

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Kris,

These tubes do get warm. I think the adhesive on electrical tape would smear and be one mess to cleanup.
 

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Discussion Starter · #4 ·
The light I want to mask is whats coming around the edges of the raster area. The blanking (at least on my projector) only controls what area of the raster gets used by the image. My lenses are not liquid coupled, so there is a bit of light that bounces around and casts outside the projection area.


Good point about the warmth of the tubes and adhesive... For people who have used felt, or other material - how do you get it to stay exactly in place?
 

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Hi Kris,

One of the things I did when I had my 7" ECP (haven't decided if I want to try it on my Marquee) was line the inside of the lenses with felt. Not for the faint of heart, but definately made a difference.


I had to completely disassemble the lens, keeping everythin in order and pointed in the proper direction. Then I lined the inside of the barrell, which in stock form is somewhat shiny plastic, with a very non-reflective felt.


Some felt has a bit of a sheen when held at the right angle. This stuff was dead as far as light. It wasn't duvetyne, which may have been better yet, but it was still pretty dark.


Seemed to help the contrast on the screen. This isn't exactly the answer to your question, but it may be another thought to try. At least you wouldn't have to worry about heat on the CRT face with this method.
 

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Uh oh Jay, you've another tweak there I need to try. Do you remember where you got the felt and/or how you selected it? Thanks again...


Cary
 

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I got it at Wally World. They had about 3 "grades" of the felt, and I picked the one with the least sheen to it. If I do it on my Marquee, I am going to use that Duvetyne tape I told you about (that I used for my screen frame) or order some actual Duvetyne to use. I just haven't decided whether I want to tackle taking apart these lenses. At least with the ECP I had some backups!
 

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There are some "hi-temp" type tapes on the market that might work to mask the crt's... Of course, you wont know it works until you try it. I was thinking about trying some foil tape (supposed to be good up to ~500 deg F.). Worst case scenario is it will fail, and I spend some time carefully removing the tape/residue with acetone & a razor.


--Eric
 

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It's official...all of you who have posted on this thread...have tweaked too much.


Please sit your butts down in your recliner and watch a movie already.
 

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If only you knew :p
 

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BugMan74


Just think of the last thing you said : Acetone & a razor on your tube faces. Is it just me or does that seem extreme!


Why not build a simple EXTERNAL masking system with felt covered cardboard? If spill-over on the outside of the screen boarders is the problem then why not extend your screen border with felt or other dark material.


Also, if you mask the tube face, what do you do about different aspect ratios?


Jawhn
 

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I guess I should put a disclaimer: I have NO experience with crt glass - just automotive. Acetone and a razor blade is the best thing to use when you need to remove something sticky from glass (IMO). Acetone does a VERY good job removing the residue -- as long as the glass you are using it on has NO tint/anti-reflective coatings/etc on it; my crt glass doesnt have any of these coatings (to the best of my knowledge). On some glass you have to be carefull with the razor - most glass that I've used a razor on had no problems, but once in a while it can scratch. Another method is to scrub for hours on end with a plastic scrubber (so you dont scratch the glass).


>>>>Also, if you mask the tube face, what do you do about different aspect ratios?


Good point, shoulda thought that one through -- The reason why I am thinking of masking is to get rid of a bright vertical band on the left edge of the image (which was introduced when I hook up my transcoder to use my dvd player with the pj(no htpc)) -- I have no budget right now, so it has to stay like it is. I was planning on only masking one side (not top and bottom), to get rid of the band for now... I only run dvd's though the pj, and they will be on a 1.85 screen (not built yet), which should make them all constant width........ I think...........


--Eric
 

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Eric,


Andreas suggestion about blanking should take care of that problem. Also you can usually shift the IMAGE (not the raster) slightly and that line will go away. Blanking would be the best way though. What PJ are you using?
 

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This has already been covered in another post, but heres the quick summary: Shifting the image (Horizontal) is probably the cause of the problem -- if I leave it to 'no move' I get a LOT of horizontal foldover (but no line). I can get rid of the foldover, but then I have to live with the line (which I can get right smack to the edge of the image). Its an ECP4100, so it only has vblank -- (wouldnt I need hblank?); havnt even touched the blanking controll yet.....


Thanks,

--Eric
 

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Interesting, I've seen a couple of PJ's with no APPARENT blanking controls, but never one with only vertical, that stinks! But I guess you know your PJ.


Jawhn
 

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He's right, the ECPs have no H blank circuitry. We looked at trying to add something and never could figure out a cost effective good way to do it.
 

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The reflections are not (at least in my case) because of raster shift. Rather, the lenses appear to reflect the light which bounces off the tube face, which in turn appears to slightly illuminate the screen - IE a dark background with a white square flashing in one corner will allow you to see the overall black shift slightly when the square turns on/off. Masking will not eliminate this 100%, but it will at least keep the change on the screen instead of outside and on the walls...


Ive never thought to line the inside of the lens barrel, but thats next. Now that I look at it, you can see the lens barrel is actually quite reflective for being "as is from Sony."



"Good point about the warmth of the tubes and adhesive... For people who have used felt, or other material - how do you get it to stay exactly in place?"


FWIW- I used black non-reflective paper with some "Goop" - which is available at Home Depot. I found the goop could be peeled away from the glass when ready to remove, yet it held tight enough that I dont think it will ever come loose on its own.


Kieth
 

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How about masking the good area and spraying with flat black automotive hi heat header paint avaiable at any auto store?
 
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