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Overscan Question re: Toshiba TP48E50 RPTV

Discussion in 'Displays' started by Jay Mitchosky, Nov 27, 2005.

  1. Jay Mitchosky

    Jay Mitchosky Producer

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    Hey All

    I have a Toshiba TP48E50 4:3 RPTV that is a few years old. I have been trying to readjust the 1080i compressed geometry and have run into a snag. The 16:9 raster area was too short so I adjusted it to proper 1.78:1 ratio using the HIT function in the service menu. Previously the geometry was properly adjusted within that raster area so now it's slightly off on the vertical plane following the HIT change.

    Here's where my question lies: what parameter do I select to adjust the image overscan, centering, and geometry within the 16:9 raster area? For whatever reason the image is off-center vertically, showing about 4% overscan on the bottom but 8% on the top. When I try VPOS and VCEN parameters the entire raster moves, not the image within the compressed raster. I have also tried VPS but with similar results.

    I need to a) center the image vertically, then b) adjust the height within the raster to restore proper geometry. Any assistance would be appreciated.
     
  2. ChrisWiggles

    ChrisWiggles Producer

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    Say jay: sorry in a rush, but have you tried v-phase? I don't know if there is an adjustment for this on this set, but if one scanrate is off center(eithr way v or h), but the raster is correct, phase (v or h) should be what you'd want to adjust. hope the leads you in the right direction!
     
  3. Jay Mitchosky

    Jay Mitchosky Producer

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    Hey Chris

    Thanks for the input. There is an "HPHA" parameter (I have a list with me, not referring to the actual set which I'll do later) but no indication of "VPHA" or the like. Here are the other parameters available relating to vertical adjustment (or at least seem to relate):
    • VLIN - linearity, not movement
    • VSC - V-S Correction, no clue
    • VPS - Vertical Position Shift, thought this would be right but moves the entire raster and jumps back to the top once it reaches end of range
    • VCP - Vertical Compensation, again no clue, but didn't seem to change at all with adjustment
    • VFC - V-F Correction, again no clue, vertical "frequency" correction perhaps?
    • VPOS - vertical position of the entire raster, not the image within
    • VBKH, VBKL - the list I have doesn't indicate what either of these do, but presumably further vertical adjustment as part of the same geometry section
     
  4. ChrisWiggles

    ChrisWiggles Producer

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    i don't really know i'm clueless when it comes to consumer sets and service menu options, but phase is what i'd look for, or maybe you can fiddle with the timing options in your source? maybe one of the other guys who knows will chime in.
     
  5. Michael TLV

    Michael TLV THX Video Instructor/Calibrator

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    Greetings

    Jay, the TP48E50 is not an HD set. It's interlaced analog.

    HD was first introduced in the H series ... E-F-G ... Then H.

    Me thinks you are talking about the 50H70 set or there abouts introduced in 2000-2001 time frame. The first 4:3 sets with the 16:9 HD squeeze mode.

    But no 16:9 mode for 480i/p DVDs.

    I recall that these sets had 3 convergence memories ... 480 ... 1080 4:3 and 1080 16:9 ...

    Must have HD signal in background to affect changes in the HD modes.

    See if you can make your changes in the 4:3 1080 mode and observe the changes in the 16:9 collapsed raster mode. There is nothing above or below the image in the squeeze mode.

    The blanking may simply be set wrong and it is nothing to do with rasters. If it is the blanking ... you are out of luck. Those things are in the ADDR somewhere among the 1000's of parameters in there.

    REgards
     
  6. Jay Mitchosky

    Jay Mitchosky Producer

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    Ooops. You're exactly right. I just read it off my old service manual but it is in fact the H70 HD ready. This was 2nd gen. You're also right re: DVD anamorphic squeeze. No dice unless you're feeding it a 1080i signal, which I am from a LITE-ON DVD player which outputs 1080i through component. That's a great idea re: adjusting in 1080i 4:3 first. Will try it when I get home. One goofy thing I recall with that set is that, while the three convergence memories are supposed to be discrete, there is in fact some interaction between them. I recall that if I adjust 1080i 4:3 convergence then 16:9 changes and vice versa. Been a long time since I used 4:3 mode.
     
  7. Jay Mitchosky

    Jay Mitchosky Producer

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    Tried it and didn't seem to work. Was able to center and adjust the image in 4:3 mode but didn't seem to translate when compressed to 16:9. Which brings me to another question: what is the difference between VPOS and VCEN? What parameter(s) do you use to center the image within the raster in 4:3 mode? I might be working with the wrong variables.
     

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