Cryotomy Troubleshooting

Possible sources of error, causes and remedies [1]

Problem Cause Remedy
Frost on cryochamber walls and
microtome.
• The cryostat is exposed to air currents (open windows, doors, air conditioning).
• Sliding window was open too long at a very low cryochamber temperature.
• Frost built up by breathing into the cryochamber.
• Eliminate cause or relocate
instrument.
• Close the sliding window
correctly.
Wear a mask if necessary.
Ice formation on the bottom of the cryochamber. • Draining of condensation water of the quick freeze shelf
defrosting system obstructed.
• Level the instrument.
Lubricate sections. • Specimen not cold enough.
• Knife and/or anti-roll plate not yet cold enough – the section melts as a result.
• Select lower temperature.
• Wait until knife and/or anti-
roll plate have reached cryochamber temperature.
Sections splinter, cracks in the
section.
• Specimen too cold. • Select higher temperature.
Sections not properly flattened. • Static electricity/air currents.
• Specimen not cold enough.
• Large scale specimen.
• Anti-roll plate poorly
positioned.
• Anti-roll plate poorly aligned with knife edge.
• Incorrect clearance angle.
• Knife dull or jagged.
• Eliminate cause.
• Select lower temperature.
• Trim the specimen parallel;
increase section thickness.
• Reposition anti-roll plate.
• Align correctly.
• Set the correct clearance
angle.
• Use a different part of the
knife.
Sections not properly flattened despite correct temperature and correctly aligned anti-roll plate. • Dirt on knife and/or anti-roll
plate.
• Edge of anti-roll plate damaged.
• Dull knife.
• Clean with dry cloth or brush.
• Replace anti-roll plate.
• Use a different part of the
knife.
Sections curl on anti-roll plate. • Align anti-roll plate correctly.
Scraping noise during sectioning and specimen head return stroke. • Align anti-roll plate correctly.
Uneven Sections • Knife damaged
• Edge of anti-roll plate damaged.
• Use a different part of the knife.
• Replace anti-roll plate.
Chatter during sectioning. • Specimen insufficiently frozen onto the specimen disc.
• Specimen disc not clamped
tightly.
• Ball-and-socket joint of the
holder not clamped into place
tightly.
• Knife not clamped tightly
enough.
• Specimen has been sectioned too thickly
and has detached from the disc.
• Very hard, inhomogeneous
specimen.
• Dull knife.
• Knife profile inappropriate for this specimen used.
• Incorrect clearance angle.
• Refreeze specimen onto the disc.
• Check clamping.
• Check clamping of the ball-and-socket joint.
• Check knife clamping.
• Refreeze specimen onto the disc.
• Increase section thickness;
reduce specimen surface area if necessary.
• Use a different part of the knife.
• Use knife with different profile.
• Use knife with different profile.
Condensation on anti-roll plate
and knife during cleaning.
• Brush, forceps, cloth or other
cleaning materials too warm.
• Use only cooled components and cleaning materials.
Store all tools on storage shelf in the cryochamber.
Anti-roll plate damaged after
adjustment.
• Anti-roll plate too high above the knife edge.
The adjustment was carried out in the direction of the knife.
• Replace anti-roll plate; then lift it during adjustment.
• Handle anti-roll plate more
carefully!

  1. Reproduced from pages 62-63 in Lecia Biosystems Leica CM1520 Cryosta Instructions for Use [14 0491 81101].thttps://www.leicabiosystems.com/sites/default/files/media_product-download/2022-01/Leica_CM1520_IFU_2v4O_en.pdf

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