I have been reluctant to speak about such problems... as they are similar to the ones in the Marantz units. Entire rows failing.
Well, in the case of the Marantz, the units are a 16x9 PJ panel. The length is longer.
In the PJ's, where the DMD panels are actually electrically addressed, they are held in place, and in contact to, the DMD panel proper by usually 4 pressure points(corners). The DMD is actually free sitting, and is forcibly held in contact. Many times the stressing of the lock down system can be too high, and cause curvature in the board where the contacts are created. Or, one of the steel bars that enact this contact pressure (both horizontal, one top, one bottom.. one screw on each end of each bar) can 'bow' from too much screw tightening. The longer the bar, the greater the bow in the pressure system, the more likely the contacts will fail to be correct.
This could be the failing rows in 16X9 panels. Or, the pressure loosens, as it is done with screws in plastic and metal.. so the pressure can loosen on one end. In most of the more modern machines, they use a full aluminum plate to enact the contact pressure, so as to be sure this problem does not rear it's ugly head.
The Marantz, being new to this game, may not quite have this understanding in place.. and it may have been corrected in the current manufacturing run, or I am off base here.. entirely. My depth of experience in dealing with failing electronics (extensive techichian-repair background), tells me That there is great possibility that I am entirely right. Especially when the symptoms about what the Marantz units are doing, is added into the equation. Most especially, when you add the behavior of heating up,and it goes away... shaking the machine and it goes away etc. It can also be the connectors that bring the signal onto he format ter board,as well(the formatter board is usually the one with the panel on it,if I recall correctly). that is a fairly complex connector junction, and all he mechanical stressing of the junction IS the contact point between the two board's.
So, in essence, there is great chance that your DLP projector merely has to be taken apart, and put back together again. It's worth a shot.