1200MP Projector color is green

When first turned on 1200MP Projector is normal.  After a few minutes, human faces and much else all become noticeably green.  This is not true for the test pattern, but occurs for satellite TV, DVD's, etc.  Test pattern looks great.

Have been working with the OSD for weeks off and on, have read the user manual and been through most if not all the menu options related to lamp temperature (low mid high), RGB, user, red, green and blue adjustments, tint, eco mode, contrast, color saturation, whiteness, etc.  Still have the problem.  Have routinely reset to factory settings and started over.

Model was new May '07 and bulb still has a lot of life and power.  Have tried different projection surfaces.

Wonder what else to check.  Cable length, some other adjustment, upgrade?

Suggestions welcome.