[Histonet] HM 500 M cryostat issue

[Andrew Burgeson]

Hello all,

I have recently been using an older model MICROM HM500 M
cryostat and have been experiencing an annoying problem.

When I cut a section I like to leave the top edge of the OCT
anchored by not cutting through it all the way. This way I
can pull tension on the bottom of the section with a paint
brush and flatten it out before picking it up on the slide.

The carriage that holds the chuck "drifts up" slightly when
I cut the section, pulling the tissue and OCT up and away
from the plate. I have never used a cryostat that had a
carriage that drifted up in that position. Over the years,
every cryostat I have used (including doing a lot of Mohs
and other interoperative work)has enabled me to "stop" the
handle at any position in which I need it to remain.

Anyway, this made cutting some rather challenging sections
of mouse kidney very difficult. I actually had someone stand
next to me and hold the crank in place while I took the
section (or else it would drift a bit).

My sense is that the crank mechanism has something wrong
that is causing it to not remain stationary once I take my
hand off the wheel. Recently an equipment repair service
came in and told me that the unit was designed that way and
even that "if I talked to the Germans that made it, they
would say it waas designed that way." (!!) wtf?

At any rate, he took out the lead conterweight and said that
he would have to modify the handle balance "to suit my
needs" by cutting off some of the weight and proceeded to
get out a hack saw and started trying to saw off some lead.
He got nowhere with this and stated he would have to take
the unit into the shop to do this. He was also kind of
insulting in that he told me that what i wanted the thing to
do wasnt what it was designed to do!

Any thoughts? I have asked around a bit and other histology
techs tell me that they see the "drifting" as an abnormal
occurrence and that it shouldnt do it if it's working right.

I think something is off with the coupling inside or with
the calibration or balance of the wheel. Any one have a
comment? First time in 16 years I have had a repair person
tell me I am using the machine the wrong way. This repair
service is not as experienced as the one I have used for
many years and I think he knows what he is doing.

Thanks