Geometry question: Center of screen is pinched? - AVS Forum
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post #1 of 6 Old 07-21-2014, 03:31 PM - Thread Starter
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Question Geometry question: Center of screen is pinched?

Hi guys, I'm trying to figure out the proper terminology of this issue I have on a Sanyo CRT (flat screen HT27547) so that I can research any service mode options that could possibly help. The center of the screen appears quite squished and as objects move towards the edges they stretch out. It is especially noticeable when playing sidescrolling games like Mario. The service manual only discusses three pincushion-related parameters and those don't seem to relate to this particular issue.





There is a massive number of service mode settings but I don't know what this issue is called to determine which settings could impact the center out. I had hoped to resolve many distortion issues by getting a flat screen CRT.
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post #2 of 6 Old 07-21-2014, 05:33 PM
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Quote:
Originally Posted by Nexious View Post
The service manual only discusses three pincushion-related parameters and those don't seem to relate to this particular issue.
This distortion should have nothing to do with pincushion (i.e. curvature).
You seem to be describing a (horizontal) linearity issue.

Regards

Last edited by blue_z; 07-21-2014 at 05:39 PM.
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post #3 of 6 Old 07-22-2014, 02:50 PM
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Quote:
Originally Posted by Nexious View Post
Hi guys, I'm trying to figure out the proper terminology of this issue I have on a Sanyo CRT (flat screen HT27547) so that I can research any service mode options that could possibly help.
You know that looks suspiciously like a special aspect mode. As an example here's a description from my Panny manual (unfortunately I was unable to copy the image from the PDF):

"JUST mode will display a 4:3 picture at maximum size
but with aspect correction applied to the center of the
screen so that elongation is only apparent at the left
and right edges of the screen. The size of the picture
will depend on the original signal."

This is for folks that like to watch their 4:3 material in 16:9 aspect but without distorting the center material. Not me, I'll just watch in good ol' 4:3.

Anyhow on my Panny it's selectable via the Aspect button on the remote, although unavailable in 480p and 1080i on component inputs. This TV doesn't have Aspect in the menu either.

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post #4 of 6 Old 07-22-2014, 02:54 PM
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I'd be very surprised if this were his issue, considering that it appears this television actually is in a 4.3 ratio.
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post #5 of 6 Old 07-23-2014, 05:12 PM
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True but I just checked and it's one of those last CRTs circa 2007 with a built-in digital tuner. I just thought at the time it might be 'fresher' based on the model number.

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post #6 of 6 Old 07-26-2014, 07:48 AM
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The threadstarter was last online yesterday, but until he replies to what has been posted, I don't think it will be possible to help him further.
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