Projector image seems to "shift" sometimes - AVS Forum
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post #1 of 3 Old 03-21-2012, 06:57 AM - Thread Starter
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I have noticed sometimes that the image from my SP4805 projector seems to shift from time to time. My screen is the room wall painted with the RS-MMMaxx mixture, with a frame wrapped in black fleece. May not be the best solution but if I recall I couldn't find black velvet locally or something. It was 6 years ago but who knows. Anyway, I made the frame based on the size of the projected image on the wall.

I have the projector mounted on the opposite wall as kind of a large "shelf" setup, with 4 threaded rods and hardware to allow pitch/roll/yaw adjustment of the projector, as shown in this photo:



The issue is that sometimes the 16:9 image appears to bleed into the bottom of the black frame slightly, or sometimes into the top. Sometimes I'll adjust the pitch slightly to get it back in-frame, but then later it might be out one way or the other again.

I can tell you for sure that nothing is "sagging". I checked the level of the upper shelf the other night and it's still perfectly level after 6 years, to the best I can tell with a 2-foot level.

Could the issue just be the house expanding/contracting with temperature changes throughout the days and seasons? This is an exterior wall that the shelf is mounted on. I suppose an interior wall would be better for support, but room layout makes that pretty much impossible.
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post #2 of 3 Old 03-25-2012, 09:04 AM
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Maybe the knobs and linkages in the projector for adjusting the lens shift are not that tight and slip a tad (inherent to the projector).

If you leave the projector as-is, does the image come back to where it should be, perhaps on a daily cycle, or more specifically depending on both outdoor and indoor temperature?

Remember when lines and logos burned the TV screen? I was at a concert where a musical selection made extremely heavy use of about four of the keys of the piano.
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post #3 of 3 Old 03-25-2012, 12:13 PM - Thread Starter
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I just thought about the temperature thing the other day, and I've already replaced the projector so never really had a chance to test that theory. The new version of the mount is extremely solid with no up/down flex whatsoever, so we'll see. The 4805 doesn't have any lens shift features, but the new one (AR100) does so any change in image height would have to be either the wall of the house changing with temperature or the lens shift slipping. Sure hope it doesn't have any problems slipping.
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