130
Thermo Fisher Scientific
Operation Manual HM550
Possible sources
of errors –
cause and removal
Problem
Cause
ꢀemoval
Cryostat temperature cannot be
achieved
Ambient temperature too high
Lower ambient temperature by fresh air,
climate. Please note the specified temperature
of +22°C!
Cryostat is influenced by near, heat-generating
instruments
Change site of installation
Draught into the cryostat
Change site of installation
Soiled condenser
Open the service door on the left side, clean
the condenser
Defective cooling
Call a service technician
Frost built-up on chamber wall and on
microtome
Draught (open doors, windows)
Change site of installation; close windows,
doors
Retarded freezing-on of the specimen Surface of the fast freezing station is soiled
Remove debris
Lower part of the chuck is soiled or damaged
Remove debris,
remove damage
Chatter while cutting
Unfavorable clearance angle
Readjust clearance angle
Insufficient knife sharpness
Move the knife in the knife carrier
Knife not adequately clamped
Check knife clamping
Chuck inadequately clamped
Check clamping
Specimen inadequately frozen on onto the chuck
Again freeze on the specimen
Specimen grossed too thick – it loosens from the
chuck
Again freeze on the specimen
Specimen very hard and inhomogeneous
Select new section thickness, reduce the
specimen
Sticky sections
Specimen not cold enough
Select a deeper temperature
Knife and/or anti-roll plate are not yet cold
enough – section melts
Wait until the knife and/or the anti-roll plate
have reached the corresponding chamber
temperature
connect foot pedal (optional) or interlock plug
Sections do not stretch, although the
correct temperature has been selec-
ted and the anti-roll plate has been
adjusted correctly
Knife and/or anti-roll plate are not clean
Clean with a dry cloth or brush
Edge of anti-roll plate is damaged
Replace anti-roll plate
Blunt knife
Move the knife
Sections break, fissures in the
sections, sections are not stretched
properly
Specimen too cold
Select a higher temperature
Static charge/draught
Remove the cause
Specimen not cold enough
Select a deeper temperature
Working with the cryostat
Possible sources of errors – cause and removal