Originally Posted by pjneder
When mine is first starting up, before the "D-ILA" image there is a whine/ringing noise, but then it goes away at exactly the same time as the logo image appears. I have always assumed this was some form of start up circuit bringing the lamp up to temp. High power lights (i.e. car xenon lights) have power modulated circuits that dump higher voltages into gas based bulbs. As the gas heats and conducts the voltage is modulated down.
Yeah it's the bulbs heating up once turned on, I'd imagine the vast majority of projectors of all brands go through it.
Originally Posted by pjneder
Does your house flex or move or something? Do you have 20-0 Hawkeye vision? I cannot imagine adjusting my focus every few days. I have my projector ceiling mounted on 2.5" galvanized pipe with the flange screwed into a ceiling joist. My fixed frame screen is suspended from an angled knee wall from only plastic anchor drywall screws. Once focus is adjusted I use the lens memory function to change from 1.76:1 to 2.35:1 viewing and back with no issues.
Haha, nothing abnormal about my environment, I live in a brick house and my projector is mounted on a very sturdy wall-mounted shelf (rated to above 100kg load) that reads dead level if you place a spirit level on it.
All the projectors I've owned have exhibited some form of focal & positioning drift over time, but then I've only really owned two projectors. My first projector was a Sony VPL-HW10, you'd turn it on and it would be in focus perfectly on the left side of the screen, but be out of focus on the right. So you adjust the focus and watch your film, but by the end of the film you'd notice that the image was now in focus on the right hand side, but out of focus on the left hand side! Basically it took about 60-90mins for the focus to settle, so if you change the focus within that settling time it would be out of focus after it had settled. There was also an issue with the lens position going up and down. I'd start the day and the image would be about an inch or two lower than my screen's position (on the wall), so I would adjust the vertical alignment, then by the end of the day the image would be an inch or two higher than my screen's position. It was the exact same situation as with the focus.
The JVC DLA-X35 I've found to be much more solid lens-wise. I always check the focus before I play a film to ensure it's at its optimal focus, and while I find that it remains in focus once you've set it (much unlike my old Sony), it does drift a little out after so many hours use (and in a couple of days I've been known to rack up 10hrs use or more!). Image position on the other hand does tend to wander, I've had my screen dip a centimeter or two over the course of 24hrs many a time in the brief period I've owned it. None of this is any problem to adjust for of course when you have a motorised lens and a pretty nifty lens-memory feature.