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CIne 8 Onyx Contrast Modulation procedure

Discussion in 'Projectors, Screens & Video Processors' started by wts, Oct 13, 2005.

  1. wts

    wts
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    Hi,

    Does anyone know where I can get the procedure for setting up the Contrast modulation on the Cine 8 Onyx, actually its for the Zenith Pro 1200x but they are basically the same projector.

    Thanks
    Walter
     
  2. crteaman

    crteaman
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    Hi Walter,

    I can help you with this, I used to run a cine 8 onyx, and can tell you how to go about it, I also have the technical white paper on its specs and design.

    James
     
  3. wts

    wts
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    Hi crteaman,

    I didn't realize someone had answered my question, I guess the system failed to send me a notice.

    Hey that would be great, so how can I go about getting this info from you. Also, another question concerning this pj. For setting the grayscale with an colour analyzer, what should the grn gain and bias settings be for a starting reference point, then I'll adjust the R+B around the grn for the proper 6500k grayscale.

    Thanks for your help,

    Walter
     
  4. kalW

    kalW
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    Hi James! Yes, I'd like to know the answer to that last question as well. Just got my brand new (150 hours) Zenith 1200x yesterday and after a full floor mounted setup the thing doesn't have as much low level black detail as my BG800. Dark scenes look very dim and 'flat' from my HTPC.

    Figured I should do some form of greyscale calib. before I go any further...

    Thanks,

    Kal

    EDIT: I fixed the low level black detail problem... it was operator error. :)
     
  5. wts

    wts
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    bump
     
  6. crteaman

    crteaman
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    Hi Guy's, As you now know I had a brand new Onyx just over two years ago, to compare it's black level with a BG800 is like comparing a mini to Porsche? the Onyx being the Porsche of course.

    Htpc is never a good idea for a great perfomance but dont want to get into that at this point.

    The best starting point for Bias and gain is simply to set it back to factory first (D6500) but unless you know 100% what you are doing dont mess with things too much.
    D6500 will alway's get you back to factory, mostly it should not be necessary to adjust Green by more than two or three points,at this point it may be worth mentioning I prepared a Baco 808etc set up guide for the guy's on the "out of sync/evil twin forum" (hard core crt forum), of which 'Tom w' has just popped up on the Mini-event thread....Tom is a moderator for this awesome forum.

    So maybe have a quick read of my 808 set up guide first before you proceed, I have covered everything from Scan coils rotation to Raster width settings.

    Once you work through this let me know when you have got all this surrounded then I can talk you through the contrast modulation etc.

    A properly set up 1200x/onyx should look awesome, in fact I i just recently set up my old unit for the guy who bought it off me, he had just moved again, and this time we hooked up a crystalio to it in place of using it's internal limo pro.

    James
     
  7. wts

    wts
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    Hi James,

    That sounds great but what is the evil twin forum you mentioned.

    Thanks
    Walter
     
  8. kalW

    kalW
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    Hi James! Thanks for info! Yes, as Walter mention, where is this 'evil twin' forum you talk about? Is the 808 setup guide there? Thanks!

    Kal
     
  9. BrianCurran

    BrianCurran
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  10. crteaman

    crteaman
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    That's the one Brian....thanks


    James
     
  11. crteaman

    crteaman
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    post script, Its under which scaler would you choose, page 3 onwards.

    James
     
  12. kalW

    kalW
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    Thanks James. Good concise list... nothing I didn't know already, but it's nice to see the order laid out.

    Kal
     
  13. kalW

    kalW
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    A follow up question if you don't mind:

    I've noticed that a few other well respected forum members with higher end Barco's have increased the horiz width pot (P2 in the SMPS) to go slighly above 48V in order to get the raster width they require for maximized phosphor usage.

    From what I've read, going 2-3 volts above 48V is acceptable. Do you concur?

    One of my reasons for wanting to do this is that I have some 'ringing' in the left side of my raster (supposedly a common problem). Only noticeable on bright even scenes though. I'd like to shift the active image area a bit to right in the raster and then shift the entire raster left to compensate, thus giving the raster some more 'settle down time' before the image is displayed. So I need a slightly larger raster which would be shifted off the tube face (but blacked with blanking of course).

    Kal
     
  14. kalW

    kalW
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    Another follow up if you don't mind!

    How exactly do you measure this 48v? The Zenith 1200 service manual doesn't get it right it seems. They say to measure the collector voltage of Q13 on the horiz deflection board at width=99. It only measures 15VDC!

    On most Barco's you measure the tab of Q3 instead. I tried that and all 3 pins of Q3 and they were all in the 150VDC range.

    I don't get it.

    Kal
     
  15. crteaman

    crteaman
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    Hi Kal,

    It's not uncommon to have to raise the 48v a little on some Barco's mainly the 1209 in order to get a little more width, however both raster ringing and greater width/raster size can and should be achieved with timing specs.

    You need to create a much larger Raster area than the active image size, in order to be abe to move the raster over to one side against phase to rid yourself of the ringing, we know certain units need certain timing specs to do it.

    Hence our playing with crystalio's timing specs, many scaler companies adhere to the Vesa timings which may be quite different to a company which does not adhere, no right or wrong here actually.

    On the crystalio 1440x 768 gives a huge raster area and lots of available width.

    Its all about how an individual unit clamps and deals with the timing/signal.

    James
     
  16. kalW

    kalW
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    Thanks James! I use an HTPC so I was able to play with the timing specs in quite some detail in order to reduce the horiz front and back porches as needed. The raster wasn't quite wide enough however even at H-width=99 so I increased the P2 pot just slightly.

    (Timings do nothing to the raster - they only affect the active image area within the raster).

    Kal
     
  17. crteaman

    crteaman
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    correct, you can then shift the raster out totally and blank off, all pj's deal with these things differently, Marquee and Barco being just two examples as you will know Kal, I think you may have mis-understood my wording on raster sizing, my fault at how I explained it.

    The Vesa specs are often a good place to start, but are only a rudimentry starting point.

    Just as you have found out, play with front and back porch etc until you get what you need, kind of fun eh all this tweaking we can do with the wonderfull crt....and we just keep finding new way's of making them better.

    James
     
  18. kalW

    kalW
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    Yup - I've got it all set up perfectly now. Had to increase the back porch a bit to reduce some ringing in the left side of the image, then increased the P2 pot just slightly to get the right raster width. Perfect. The image area is now (more or less) 1/8" from the edge of phosphor at the closest point.

    The only strange thing I've found is measuring the 48V on the horiz defl board. The service manual for the Zenith 1200 gets it wrong I think. They say to measure the collector on Q13, while most service manuals mention to measure the tab on Q3. I did both anyway, and they're nowhere near 48V (Q13 was around 14V, Q3 was around 150V).

    I know that this voltage isn't all that critical, but I'd like to know how far above 48V I've gone.

    Kal
     
  19. wts

    wts
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    Hi James,

    Still waiting for the white paper/setup procedure for the contrast modulation, have you been alittle too busy these days.

    Thanks
    Walter
     
  20. crteaman

    crteaman
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    Hi Guy's

    Sorry, you guessed it things are manic at the moment, with two jobs coming in last night alone...on top of a long list..gulp.

    Basic advice regarding CM (R9828145) module is just don't over apply it.

    The laws of physics applied to crt and optics dictates that the center of the projected image will be brighter than the corners (of course) this phenomenon is normally referreed to as 'corner fall off'.

    Also due to the normal off-axis projection of the red and blue images they will show colour shift.

    For contrast modulation use an external white or grey field, make sure the image is centered on the Raster using the H phase otherwise it isn't possible to adjust the CM correctly.

    The first three adjustments Horizontal R.G.B are used to compensate the error due to the position of the tubes,(clour shift)

    The vertival corrects the error in light output due to the projected ange on Barco's of 10.5 degrees, apart from the onyx which has much less of an angle.

    Left and right H and V improves the hot spotting in the centre of the screen, the module will receive the incoming signal and adjust it as it draws it scan along the tube face (clever eh?) RGB Horizontal is used to match the two edges (west/east) and Vertical does the same in North south plane, of course its a bit easier to use a light meter here.

    With edge corection remember two things, the more you apply CE the more you reduce the light output of your unit, and the more you introduce colour shift, the latter can be corrected by re-doing your colour balance again afterwards, remember this unit is an analogue device, Barco also do a Digital CM unit which is very expensive...but better.

    Barco suggest limiting Edge correction H+V to 10-15 points, I would say around 9 for the H and 5 for the v.

    Hope this helps?

    James
     
  21. wts

    wts
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    Hi James,

    I did alittle playing around with the adjustments before you replyed with this procedure. The first adjustments on the menu when selected turn off the other 2 tubes. Like if you select R Hor, the B & G tubes are turned off, it didn't really seem to do much when it was adjusted from one extreme to the other. I would have thought that in order to correct for colour shift it would have left all the tubes on and then you'd use a colour analyzer on the red side to adjust the grayscale to D65, then check the center and back and forth until they were balanced and then do the same for the blue side.

    The last 2 items in the menu, don't recall what they were called, but adjusting them from min to max just seemed to make the sides darker gradually working towards the center. How does that take care of hotspotting, I would have thought it would have started at the center and work out to the edges - L R T B.

    So on the first selections in the menu, the Hor RGB, how do you adjust it. Lets just do for ex. the red side. Select it then adjust it then exit menu and see how of a difference it made, then go back and repeat until its right. Hmmm, I know I'm missing something here in the method/procedure because that doesn't seem right.

    Something alittle off the topic. Would you happen to know where the center balance point would be for these 1200's. What I'm getting at is I want to hang it from the ceiling by using a single rod, so I need to know where the balance point is front to back so the weight is distributed evenly frt/bck on the rod. Kinda like a perfectly balanced knife's balance point is where the blade meets the handle. I would tend to think it might be at about the 35% to 40% mark(lenses tip being 0%) but I'm not sure thus the reason for the question.

    Thanks James, maybe if you have some time you can go over this again. Can you post the white paper you mentioned too, I like to read the theory behind it( I assume thats what the white paper is about).

    Thanks

    Walter
     
  22. wts

    wts
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    Hi James,

    Another problem I've noticed is there seems to be alot of colour shift. Its almost like a divider line was drawn right down the middle(vert)and on the left we have red and on the right we have blue. No gradually blending from white to redish or from white to bluish, its redish tinted from center to left edge and bluish from center to the right edge, maybe the center 12" is pure white(84" wide screen). It bright bluish in the lower right middle section like its hotspoting.

    Can the contrast mod board be removed and not interfer with normal operation.

    Thanks
    Walter

    Any help would be much appreciated on this one.
     
  23. Person99

    Person99
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    Hey, sorry, I'm late to the game. Add me to the Zenith 1200 owners looking for this info!

    Dave
     
  24. Gary Lightfoot

    Gary Lightfoot
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    Walter,

    Not sure how easy it will be to do this, but if you can safely slide a pole under the pj, you can possibly move it along until you find the front to back balance point, and then you'll have a good idea where the center of gravity is. If the pj is unbalanced left to right you might be able to do the same thing there sliding the pole from one side to the other. Don't forget to mark the pj so that you know where the balance point is.

    HTH

    Gary.
     
  25. wts

    wts
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    Hi Gary,
    Thanks for your suggestion but I think it would be easier to just use a rope and sling it under the pj to determine where the balance point is. The pole idea sounds a little iffe.
     
  26. wts

    wts
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    Hi James,

    Still waiting here for that white paper you were going to post on contrast modulation. It would be nice to know just exactly what to expect from each setting when its changed instead of trying to guess what it might be doing or is suppose to be doing.

    Thanks
    Walter
     

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