CurtPalme.com Home Theater Forum

rotoscoped · Joined: 08 May 2017 Posts: 34 Location: Virginia

Since setting up my ceiling mounted Electrohome Marquee 9500LC (non-Ultra) in 2018, I've had a "keystone" geometry problem at the top of the picture (and - to a lesser degree - at the right side).

The bottom of the picture is nearly dead level, ditto the left side, but the top right corner is lower than the top left corner (by approx 4%). (And, not as significant, the top right corner extends further to the right than the bottom left corner, a ~2% difference.) The photos should illustrate it more clearly. (The camera wasn't perfectly square relative to the screen, so there's some geometric distortion in the photos -- color distortion too, added by the camera. You'll have to take my word for it that the screen itself, 16:9, has exact right-angled corners -- the movie in the picture is 1.85:1 and there is overscan. I left a light on to illuminate the edges of the screen itself better.) You can click the photos for larger versions -- and here's a link to the gallery.

Browsing the Marquee 9500LC Ultra user manual, I noticed a function called "Top Key". This allows you to raise or lower the top corners of the picture, and it looks like exactly what my situation calls for. Here's a picture from the manual that illustrates this function -- from page 3-16.

The Marquee 9500LC, however, doesn't have this function. "Top" and "Bottom" control only pincushion.

I'm not sure what causes this distortion in the first place. My mechanical set up isn't perfect, though it's as exact as I could get it in the space. It's placed some limits on the projector (the bottom right corner can't be converged, for instance), but it's also not something I can easily change. The projector is mounted to the ceiling and its position is essentially fixed...

Is there a way to improve or correct this distortion? Wishful thinking: is there a way to "upgrade" the geometry functions of the 9500LC to those of the 9500LC Ultra?

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary

Yes, there is a way, to upgrade to ULTRA but it requires to replace the upper motherboard, new firmware on CLM (depending on model number) replacement of FCM to FGM (Focus board), I also think even the VDM (Vertical deflection module) needs to be replaced.
The ULTRA geometry capability is no miracle, in fact it works pretty ugly compared to a NEC's geometry setting of the same kind.
Anyway, why not just adjust green convergence to fit the picture to your screen, then reconverge red and blue?

rotoscoped · Joined: 08 May 2017 Posts: 34 Location: Virginia

dvh99 · Joined: 25 Dec 2009 Posts: 2158 Location: nederland

you should use patterns from the source to converge instead of the marquee patterns for best results.

Tim in Phoenix · Joined: 21 Oct 2006 Posts: 4379 Location: Phoenix

Hello

To start with, your projector isn't level. Get a laser and fix that first.

The other problems are fixable with green convergence. Use Interpolated Green Covergence first, and tweak the small problems with Regular Green. The test grid from the Joe Kane BlueRay Video Essentials is shown. The waveforms used to add the Ultra geometry features are all fed to essentially an earlier design of the convergence amps.

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