We recently had a similar problem, which turned out to be related to the
"uv upgradability" of ourMRC600.  It was solved by having the modified
adapter (for lack of the precise term) installed instead of the one ours
was originally supplied with.  At the time this was taken care of, we
were told that BioRad knows the original piece doesn't work properly, but
that they haven't been changing them over until the customers scream &
yell...this seems to be consistent with ongoing discussions, although
our new service rep was quick to identify the problem once he
came on board.
 
On Mon, 9 Jan 1995, Martin Th. A. Bos wrote:
 
> We are studying dairy systems with fluorescence-CSLM, using rhodamine as
> dye, YHS filter block, but find that the intensity near the edges of the
> picture is considerably less than near the center. At high zoom factors
> this is not such a problem, but at lower zoom factors it gets worse. Does
> anyone know a simple explanation behind this? Could this be helped by a
> better alignment of the microscope? Though experienced with operating the
> MRC600, we are novices to aligning it. The operator at our department does
> not seem very concerned, so we would appreciate some outside help.
>
> Thanks,
>
> Martin Bos and Marieke van Marle
> Wageningen Agricultural University, The Netherlands.
>