Dear Angie,
     I have to agree with Welch that the cryostat should be regularly defrosted. As for the plastic screws: Plastic becomes brittle when exposed to cold. Even the cold 
of a cryostat. Ask the service representative to replace them with metal screws. 
    Sincerely,
    Paul Lockwood
2/2/02 10:31:33 PM, Schmang155@aol.com wrote:

>
>
>
>   In just this last year, we purchased a Microm Cryostat from Richard Allan.
>   We love the way it sections the tissue but we are concerned with this
>   constant ice build-up on the back inside of the unit. Even with the
>
>   overnite defrost cycle, we have a waterfall effect on the back panel. The
>   company has tried to fix this once--but a factory service man said that it
>   was our responsibility to manually defrost the unit every couple of
>   months. We feel that this should not be necssary with a brand new unit.
>
>   Also--we have a metal plate with plastic screws that is attached to the
>   cryobar that keeps breaking off. Have any of you experienced this problem
>   with this cryostat?  We almost feel as though our instrument should be
>   replaced .  Thanks ahead of time for your replies 
>
>                                                                  Angie
>   Schmidt      
>                                                                    Tri-Health
>   labs 
>
>                                                                     Cincinnati,
>
>                                                                        513-872-