I'm experiencing a problem with my current rear projection set. It was ISF'd about a year and half ago if my memory serves (I need to get Gregg back out to recalibrate soon). The set works perfectly fine for the most part, however what I'm experiencing happens only when the set has been powered off for a substantial amount of time. When I turn the power on the picture from about the halfway point of the screen up shifts constantly (as if out of focus and shimmering like mad). The picture will also "jump" momentarily and shift the picture completely and a white line will appear for a second as the shift happens. This entire problem completely clears up after leaving the TV on for about 8-10 minutes. I can then watch whatever I want for hours without it reappearing again. Again, It only happens after the set has been powered off for a few hours. The shimmering and shifting will stop and the picture shift/white line issue will cease entirely. I'm completely dumbfounded as to what the problem could be. It's almost as though the CRT's aren't focusing properly and need to "warm up". I plan to book another ISF calibration near the end of the year, but I don't want to wait long to get this problem fixed and I fear it may get worse. Any ideas or suggestions?