If memory serves, that projector had DT 40's in it. And DT 40's are known to have issues with the poly switch.
Hank: Try reducing your scan angle by half and power it back up. If it's OK, then it's definitely the poly switch. And even if it's still hosed, it could still be the poly switch, although with half the scan angle it should reduce the current draw enough that the switch won't trip...
If the scanners really are toast, you can replace them with a set of PT-40's for less than $300. But I suspect that the scanners are fine. Try the reduced scan angle and report back here.
Adam