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Toshiba 32HFX71 Geometry

Discussion in 'Archived Threads 2001-2004' started by SeanPg, Jan 31, 2002.

  1. SeanPg

    SeanPg Auditioning

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    Calling all Toshiba 32HFX71/36HFX71 owners!

    I need to find out how out of spec my 32HFX71 is. It has the following problems:

    1. Inward bowing of vertical lines at right and left edges of screen (pincushion)

    2. Horizontal non-linearity (when I display the Avia crosshatch pattern the squares on the right hand side are horizontally squished compared to those in the centre and left hand side)

    3. Defocussing + mis-convergence in corners

    4. Extreme right hand edge of picture is brighter than rest of image. This is OK at 5% overscan, but if I reduce the overscan I get a very noticeable vertical band that is lighter than the rest of the picture.

    I had a technician come out and he was able to mostly fix 1., but there is no horizontal linearity control so no fix for 2. 3. is a tradeoff between focus in the centre and focus in the corners. 4. is also unfixable, except to keep overscan at 5% or more.

    So, my question is do I return it for another set? These things are always a crap shoot. The tech told me that he heard from a Toshiba tech that Toshiba sets vary as much as 20%. I would like to know what other owners have experienced with their sets. Throw up a grid pattern and tell me what you see.

    Another thing I notice with this set is the deinterlacing artifacts. Any portion of an image that is a fairly saturated red will have nasty comb type pattern on it's edges. I only see this on red objects. Now that I have seen it, it drives me wild! Anyone else notice this?

    I know that no set is perfect, but it still hurts to pay $2000 (CDN) for a set with such imperfections!

    Thanks,

    Sean
     
  2. Doug_Bbn

    Doug_Bbn Auditioning

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    I just got a 36HF71... your $2K CDN is way cheaper than the $1900US I paid... I could have paid less from an internet source, but I decided that having the store local for a large item prone to delivery problems was the right thing to do.

    When they delivered my set, I watched them, while on my front porch, roll the box onto one side, then onto the top. They then opened the bottom of the box, rolled the set back over so that it was upright again, then removed the box. This is IMMEDIATE DEATH to a set this large... at least as far as picture quality goes. Shadow masks are not designed (though they probably should be, if they could be) to survive 90 or 180 degree rotations. I kept my mouth shut, hoping against hope that somehow this set had a more durable shadow mask. NOT!

    The set was terribly screwed up with these problems:

    - Left and right edges more than 2X as bright as the center 1.2 of the screen - unfixable according to the local authorized Toshiba service center, an artifact of a damaged shadow mask

    - Vertical lines pincushioned on both sides, relatively straight in the center 1/3 of the image - fixable by a technician using the service menu - but the guy has to know what he's doing and they may not be perfect, but better than what was delivered is possible.

    - When the screen goes black, the raster is royally screwed up - the screen is really just gray and you can see pink angled raster re-trace lines through it... this is visible in even darkly lit scenes.

    - The purity is whacked... there are pastel shades of color all over the screen when viewing white or gray patterns. Degaussing does not help. Probable artifact of the shadow mask being screwed up.

    - 2 to 4 times per hour, the screen goes very bright, not quite completely white, then over about 5 seconds, slowly settles back to "normal" (as screwed up as normal is).

    - Dark images get lighter when a white object appears on-screen, even if the dark areas of the screen are 80% of the image.

    - The set looks relatively normal on well saturated and brightly lit scenes - in fact, it can look incredibly good. With a progressive scan DVD player and vertical compression turned on, some of the images are stunning - as long as they don't reveal this set's damage. That's the only reason I agreed to swap for the same model - will have one more go at it before giving up.

    The horizontal lines on this set are straight as arrows - only the vertical lines are screwed up.

    I can't comment on convergence & focus as the shadow mask problems screw with that pretty badly.

    Based on what the Toshiba service center told me about the right and left edges being way brighter than the center... you may also have a shadow mask problem - my images look less sharp when they are dark and pretty amazingly sharp in brightly lit scenes in spite of the color fringing on crosshatch patterns - again, this is said to be part of the shadow mask problem.
     
  3. Doug_Bbn

    Doug_Bbn Auditioning

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    I got the second 36HF71 set to replace the first one that was ruined by the delivery people turning the set upside down to take it out of the box.

    This one is nearly perfect. Horizontal lines are straight as arrows and not tilted. Vertical lines are pincushioned just a bit at the outsides of the screen. Red convergence is off on the left side of the screen a bit. All easy enough to fix. I'll have Toshiba service do this shortly - service manual is on order, but backordered and I'd rather have someone else do this the first time so I can watch anyway. The image quality even with the red convergence problem is quite excellent after setup with any of the setup DVDs. Fed by a Panasonic RP56 with the Faroudja/Sage chip with the set in vertical squeeze mode is stunning... just as good as the 16:9 version of the same set which is the same width... it has a shorter tube and costs $500 more. Couldn't figure out why... the chassis driving both sets appear to be identical - the features are identical, the menus are identical. Only difference is you get a much bigger 4:3 image on the $500 cheaper set - anamorphic DVDs look identical on the 34 16:9 set and the 36 4:3 set.
     
  4. Allan Jayne

    Allan Jayne Cinematographer

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    The sets with the problems may have been dropped or otherwise physically mishandled. The shadow mask would probably not be damaged without a significant jolt or a large nearby magnet.
    The yoke and other fittings on the picture tube neck may have been jarred out of position to cause pincushion and geometric distortion.
    It is possible that parts inside the picture tube neck were also jarred out of position which means you need a new picture tube. This is less likely because force that is enough to do this would probably have broken the neck and killed the picture tube completely.
    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     

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