>
> I am currently using a Zeiss LSM510 with an inverted Axiovert 100 M, as well
> as an CCD imaging system build around an Axiovert S100 TV.
> Both systems I use to measure physiological ion concentrations over longer
> periods of time (10-30min), but I have noticed that with both microscopes
> the focus isn't stable and is completely lost over the course of an
> experiment. With the confocal it's about 5mum in 10min, going downwards.

As I have until now received 4-5 replies asking for more details, I will
take the liberty of replying to the list. My apologies to those for
whom this is irrelevant.

The problem we ahd was clearly mechanical, and eventually made the
scope unusable. This is not connected to the more subtle (and probably
more difficult) problem of thermal drift.

The Zeiss Axiovert 135 (and also 100) has a set or reduction
gears. The last gear in this train meshes with vertical bar ( think it
is brass) which has teeth along one of its faces, and which is bolted
to the right side wall (looking from the rear) with screws. That
bar supports the entire weight of the turret. Over time, it slipped
back -- ever so slightly, but it does not take much.

To get at that bar, you must open the scope from the *left* (again,
looking from the rear). This is tricky -- you have to remove the
focussing wheels on the left (mine was modified slightly to accomodate
Bio-Rad's fine focus motor that drives the coarse focus directly, but
this is a different story...). I had to do this without moving the
microscope, and this will probably be the case for anybody who has a
confocal scanhead coupled to the scope. In addition, I found that to
get at this piece, I had to remove the tube lens and the TV side port
(not an issue on the Axiovert 100), and of course the trinocular head.
In short, you have to take out just about all of the guts of the
scope. Since the inside is greasy, do be careful not to touch any
optical surfaces.

After you do this, you can get at the vertical toothed bar (there must
be a better name for it)  and push it back toward the gear. You
should loosen the screws that hold it, push it forward, and then
tighten the screws. In my case one screw was too tight, and I could
not loosen it.  The other was already loose. Anyway, I used a long
steel rod (because this is done from the direction of the trinocular
mount), and positioned it on the bar. Then I gave it a couple of
gentle taps, and then tighted up the loose screw. And it worked.
Don't know how long it will last -- so far it has been a few months.

Reassembling the scope is left as an exercise for the reader...

Hope this information is of use. I assume that this failure mode is
a possibility in any axiovert 100 or 135.

--aryeh
Aryeh Weiss                          | email: [log in to unmask]
Department of Electronics            | URL:   http://optics.jct.ac.il/~aryeh
Jerusalem College of Technology      | phone: 972-2-6751146
POB 16031                            | FAX:   972-2-6751275
Jerusalem, Israel                    | ham radio: 4X1PB/KA1PB