Hello Sandra,
	I have that cryostat with a Bright rotary retracting microtome inside. It 
sounds like you ran out of travel on the lead screw and the solution is 
simple. You rewind the wheel at the top of the microtome (anticlockwise) 
and then move the knife and holder forwards to the tissue and trim and cut 
your section.
	Next time you decontaminate take the microtome out and have a good look at 
the mechanics of it. See what happens when you go too far winding, the 
thing can actually detach and you must train all the staff about this 
because it is a disaster if it happens during a frozen to someone 
unfamiliar with it.
	 When I have  a frozen the first thing I do is reset the wheel. Hope this 
helps. Bright Instruments can probably get you a manual as they are very 
much still in business and on histonet.

Annette Ryan FAMLS
Medical Laboratory Technologist,
Histology laboratory,
Our Lady of Lourdes Hospital
Drogheda
Co Louth.
Ireland