I did a fair bit of research and troubleshooting and listening to give as many details as possible.
This projector has served me well for over 2 years, always in table mode/right side up.
I was tired of perching the PJ on a tall shelf, because the shelf took up too much living room space, so I bought a ceiling mount assembly from monoprice: linky
I had the assembly attached to underside of PJ, and PJ inverted so I could test how the image looked while lining up ceiling positioning. This is the turning point.
While upright, here's the boot order: press power button, lamp has dim glow indicating it is powering on. Fan kicks on. Lamp briefly turns off, then gives a mechanical whirr, then kicks the lamp into regular bright mode and displays whatever input is selected.
While inverted, boot order: press power button, lamp has dim glow indicating it is powering on. Fan kicks on. Lamp briefly turns off, then visibly goes bright, then immediately goes off
. Lamp goes to dim for a few seconds, switches to bright, them immediately goes off. Repeat same a third time, then kicks fan into high speed, and blinks red light on lamp indicator on and off (troubleshooting instructions matching this symptom in manual claim that the lamp needs replaced. This lamp has under 100 hours of use, so I'm leaning away from that conclusion.)
More important findings: I started PJ upright, then very slowly and steadily rotated 180 degrees. After passing to the 110 to 120 degrees of rotation, I hear a quiet, but very distinct sound of something sliding, then a gentle clink of metal on metal. Right when that sound and internal impact occurs, PJ IMMEDIATELY
does the same error described in the above paragraph. I am guessing that something internal is loose, and is triggering a faulty-lamp-installation failsafe.
This projector does not feature an auto-inversion detector.
Lamp is securely installed, and does not shift when I tug on the handle.
I have also tried this slow 180 degree rotation while PJ is set for "right side up image" and "upside down image" (while projecting an inverted image, the PJ fan accelerates, but it does not trigger
the lamp error described above). I get identical results during rotation.