P150 slide projector

[pgs@thillana.lcs.mit.edu (Patrick Sobalvarro)]

My P150 is on the blink again.  The history here is that the
auto-focus mechanism went out about eight months ago, and I had it
repaired under warranty, which took almost three months.  I used an
older projector in the meantime, and only took out the P150 again last
night.  I had verified when I'd gotten it back that the auto-focus was
indeed working, but rather than loading the slide tray I did so with a
single slide, with the traveling arm all the way in, using the
single-slide gate from the top.

This time it's not the autofocus mechanism, but the slide advance,
which seems to be permanently stuck on.  My guess is that in fact they
broke the advance control at the service center, presumably by
shorting it somewhere so it's on all the time.  I opened the hand
control and verified that the problem was not the switch being stuck
closed.  I wanted to look at the other end, to see if there was a bad
soldering job or something, but I can't figure out how to get the
damned projector open!  I don't regard myself as mechanically inept (I
have rebuilt automobile engines, for example), but there were only
four screws I could see, and removing them doesn't free the top cover.

I'm pretty frustrated by this.  I don't want to send the projector
away for another three more months, but I suppose I may have to.  I
called up Leica and asked for a service manual, and they said they
would mail me one, but I have no idea if what I get will actually be a
service manual.

Anyone have any idea how to open up one of these things?

- -Patrick