Cleaned my rptv's crts, don't need new set after all.

Discussion in 'Displays' started by Steve Schaffer, Mar 7, 2004.

  1. Steve Schaffer

    Steve Schaffer Producer

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    In recent weeks I've noticed what seemed to be really excessive effects from internal reflections on my Sony KP57HW-40. Black bars on 2:35 films looked grayish or took on the predominant picture color during bright scenes, and the blacks in pictures with large bright areas looked washed out, and colors seemed just a bit less vivid than they should be. Repeated sessions with AVIA had no effect.

    This is my 3rd rptv, and when I first got it I was very happy about it's apparent lack of ill effects from internal reflections--black bars stayed black in bright scenes better than on the previous 2 sets, and the overall picture very closely resembled direct view as far as lack of color bleed and great blacks.

    I could not account for the apparent deterioration and was thinking maybe the crts were tired and it was time to shop for a plasma or big direct view.

    On a whim I overcame my reluctance to open up the set and removed the back fibreboard panel after unplugging the set. I saw a lot of dust on the crt lenses along with what looked like a few tiny insect parts (I've occasionally had bugs inside the set).

    I gently cleaned the lenses with paper towels moistened slightly with Sprayway Glass Cleaner, an ammonia free cleaner in a blue and white can that works great on the screen outer surface, put the back panel back on and waited half an hour before turning on the set. I did not have the courage to try to remove the screen, so left the inside of the screen and the mirror alone.

    The results were incredible--my blacks are back, the apparent internal reflection problems are virtually gone, shadow detail is back and colors are much more vivid-- the set looks better than it did when it was brand new. Apparently the dust on the crt lens surfaces was diffusing the light coming from the crts in a way that mimicked the effects of excessive internal reflections in the set.

    I know this cleaning has been highly recommended here before but didn't really believe it would help that much and was very reluctant to open up the back of the set, but after doing this relatively simple procedure and getting such great results felt like I had to share my experience.

    One caution, while the cleaner I used didn't harm my set's lenses I could not say for sure whether it would harm those of another make of set. The water in my area leaves streaks which is why I did not use just plain water to moisten the paper towels. I was also extremely careful not to touch any metal parts inside the set.
     
  2. Guy Kuo

    Guy Kuo Supporting Actor

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    Gentle dusting with an air can (kept upright to avoid spraying of fluid!) or the safer, air bulb is the least likely to scratch. Canned air needs to be tested to know it won't sprits fluid. Practice on something other than the lens first. Tilting a can usually is disastrous. If you get liquid from a can onto a lens you create a much worse cleaning problem. If air isn't enough, a clean soft brush can be used to gently remove dust. Don't reuse a previously soiled brush. The grit from previous cleanings will scratch the soft plastic lenses.

    If more serious cleaning is needed, use a suitable solution. One which is useful on RPTV lenses is the one developed by William Phelps.


    1 drop dishwashing detergent (not soap!)
    (or Kodak Photoflo if you have it)
    1/3 cup 99% Isopropyl alcohol
    1 2/3 cup distilled water

    This leaves very little residue and is safe for optical coatings. The key is to never go over the lens with the same portion of cleaning tissue more than once. Plan on "wasting" a lot of cleaning tissue. Lens Crafters sells them in large Kleenex box sized containers. Get one or two boxes and use a lot of them. Dampen a tissue and start at the lens center. Wipe towards the periphery of the lens. With each wipe, roll your hands so the swipe continually changes to a clean portion of the tissue. The Phelps solution needs to be wiped until dry for minimal streaking. (BTW, don't substitute tap water for the distilled). This solution also works amazing wonders on your car windshield!

    For front projection lenses, the degree of residue on the lens needs to be dropped to astonishingly low levels or the lens will continue to appear dirty. The Phelps solution isn't quite as useful for digital front projection. Formula MC (available from www.2filter.com) is about the only thing I've found which will leave low enough residue to use on a projection lens or clean a DLP chip's quartz windown.

    Again, first use an air bulb to remove all dust. Then a clean, soft brush to very gently remove any remaining dust. Don't reuse a dirty brush. You'll scratch the lens. A few drops of Formula MC onto a wad of tissue is then used to clean the lens. Wipe gently and NEVER go back over an area of lens with the same portion of tissue. The Formula MC will create an alarming looking foggy appearance on the lens as it first dries. Don't worry. Very gentle buffing with more clean, dry lens tissue will remove that fog and leave the lens as clean as you'll be able to achieve. Finally, blow away any lint with the air bulb.

    Mind you, a lens cleaned this will will still never be as clean and scratch free as a factory fresh lens. The less cleaning you do the better off you will be, but eventually there comes a time when a lens is so dirty that a few scratches are better than the dirty lens.

    While you are in the RPTV, don't get too carried away and automatically clean the mirror. Many mirrors are now front surface mirrors and any attempt to clean those will make a bigger mess than you ever want to see. A second surface mirror you can clean. A front surface mirror you don't.
     
  3. Robert*S

    Robert*S Stunt Coordinator

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    Excellent! You have overcome the hardest part: Opening up your tv. Fun stuff if you like to tweak. [​IMG]
     
  4. ChrisYK

    ChrisYK Stunt Coordinator

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    Steve,

    Glad to hear you had good results with your CRT cleaning.
    I am now a little less nervous about opening up my set as I know we shared similar concerns about that particular aspect of tweaking our TVs. [​IMG]
     
  5. Steve Schaffer

    Steve Schaffer Producer

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    Guy,

    thanks so much for the information on cleaning-I've printed it out for future reference. My set does have a front surface mirror so I'm really glad I didn't mess with it. I just checked the ingredients on the cleaner I used and it has only Alcohol, de-ionized water, and liquefied petroleum gas (I assume that's the propellant), so hopefully it didn't do any harm.

    Chris,

    My set was delivered in October of 01 and it's only in the last few weeks that I noticed the picture quality degradation. Since my original post I've watched quite a bit more HD and dvd on the set and it really does look so much better. I'd say it now looks at least as good as any of the new sets I've seen in the stores lately. Although I've had 2 other rptvs I've never kept one in use this long before, longest was 18 months on an Hitachi Ultravision analog set.

    I saw those focus rings and the little wingnuts that hold them, but needless to say did not touch them--maybe it's gonna take me another 2 years to work up the nerve for that!
     

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