Troubleshooting - Leica CM1900 Instruction Manual

14. Troubleshooting

Problem
Frost on chamber walls and microtome
Sections smear
Sections splinter
Sections not properly flattened
Sections not properly flattened despite
correct temperature and correctly
aligned anti-roll plate
Sections curl on anti-roll plate
Scraping noise during sectoning and
specimen return movement
Ridged sections
Chatter during sectioning
Condensation on anti-roll plate and
knife during cleaning
42
Causes
Cryostat is exposed to air currents
(open windows and doors, air
conditioning).
Frost built-up by breathing into the
cryochamber.
Specimen not cold enough.
Anti-roll plate not yet cold enough,
thus warming the section.
Specimen too cold.
Static electricity/air currents.
Specimen not cold enough.
Large area specimen.
Anti-roll plate poorly positioned.
Anti-roll plate poorly aligned with knife
edge.
Incorrect clearance angle.
Blunt knife.
Dirt on knife and/or anti-roll plate.
Top edge of anti-roll plate damaged.
Blunt knife.
Anti-roll plate does not protrude far
enough beyond the knife edge.
Anti-roll plate protrudes too far beyond
the knife edge and is scraping against
the specimen.
Knife damaged.
Edge of anti-roll plate damaged.
Specimen insufficiently frozen onto the
specimen disc.
Specimen disc not clamped tightly.
Knife not clamped tightly enough.
Specimen has been sectioned too
thickly and has detached from disc.
Very hard, inhomogeneous specimen.
Blunt knife.
Knife profile inappropriate for
specimen cut.
Incorrect clearance angle.
Brush, forceps and/or cloth too warm.
Remedies
Change place of installation for the
cryostat.
Wear mouth protection.
Select lower temperature.
Wait until knife and/or anti-roll plate
have reached chamber temperature.
Select higher temperature.
Remove cause.
Select lower temperature.
Trim the specimen parallel, increase
section thickness
Reposition anti-roll plate.
Align correctly.
Set correct angle.
Use different part of the knife or
replace the knife.
Clean with dry cloth or brush.
Replace anti-roll plate.
Use different part of the knife or
replace the knife.
Readjust correctly.
Readjust correctly.
Use different part of the knife or
replace the knife.
Replace anti-roll plate.
Refreeze specimen onto the disc.
Check disc clamping.
Check knife clamping.
Refreeze specimen onto the disc.
Increase section thickness; reduce
specimen surface area if necessary.
Use different part of the knife or
replace knife.
Use knife with differnt profile.
Set correct angle.
Store all tools on storage shelf in the
cryochamber.
Instruction manual V 5.2 – 10/2002