FAQ Leica SM2400

Problem: Upper feed limit reached

Turn the coarse feed wheel clockwise to lower the specimen.

Problem: User may accidentally be holding coarse feed wheel while sectioning.

Stop holding the coarse feed wheel.

Problem: The coarse feed wheel cannot rotate freely.

Remove any obstruction.

Problem: Internal mechanism (gear) might be defective.

Contact your service representative for replacement of coarse advance mechanism.

Problem: Insufficient clamping of specimen and/or knife

Check that all levers are locked and screws are tightened.

Ensure the cassette isn't under filled or over filled (excess of paraffin on the outside of the cassette has to be removed before clamping).

Ensure the correct clamping system is used (standard clamp/UCC).

Problem: The clearance  angle is too small/big.

Systematically decrease/increase the clearance angle until the optimum angle is found.

Problem: Blunt knife/blade

Use a different part of the knife or blade edge.

Use a new knife or blade.

Problem: Excess oil on the knife

Remove the oil with soft paper or Q-tip.

Problem: The specimen block is too large or too hard

If possible trim the specimen.

Soften the block by using Osteosoft® or soak the block with iced water.

Try a knife with a different profile (d-profile instead of c-profile).

Problem: Clearance angle is too big

Systematically decrease the clearance angle until the optimum adjustment is obtained.

Problem: Unsuitable knife/blade profile

Try a knife with a different profile.

The high profile blade might be too big, try using a low profile blade or use a different brand.

The blade might be too thin, try using a high profile blade or use a different brand.

Problem: Blade holder pressure plate is damaged or wax is built-up

Try a new blade holder or use a different part of the blade holder.

Remove and clean the rear of the pressure plate.

Problem: Insufficient clamping of specimen and/or knife

Check if all levers are locked and screws are tightened.

Note: The reason might be an application issue, not a microtome problem

Consider the following factors that can influence sectioning:

Infiltration

Dehydration

Decalcification

Paraffin age

Paraffin purity

Problem: Table-top stability

Try to steady the microtome or replace the table if it is not sufficiently sturdy.

Problem: Sectioning speed too high

Work at a slower sectioning speed. Thin sections require a slow cutting speed.