Leica Biosystems CM1950 - Manual (Page 42)

42 Instructions for Use V 1.5 RevF - 08/2014
8. Working with the Instrument
Programming the defrost cycle
• Set the beginning of the automatic defrost cycle.
The automatic defrost cycle takes place once within 24 hours.
It is set with the "+"/"-" buttons on the right of the panel with the clock
symbol. The two buttons are marked by a melting snowflake .
• Briefly press the "+" or "-" button for indication of the beginning of the
defrost cycle which has actually been set. At the same time, the LEDs
between the indication of hours and minutes are flashing.
• To change the beginning of the defrost cycle in steps of 15 minutes, push
the "+" or "-" key. When the "+" or "-" button is pushed for more than 1 sec.,
the defrost time value increases or decreases continuously.
Manual defrost for the freeze shelf (including Peltier element)
• Press the
key for manual defrost, then press the key.
The manual defrost takes 12 min.
• Press the
button again, then the button to stop manual defrosting
again.
Fig. 46
After defrosting the freeze shelf, carefully wipe it out, as otherwise a lot of water collects
in the channel. Ice does not melt during normal defrosting.
Before starting the defrost cycle remove all samples from the cryochamber!
• When the automatic defrost cycle begins, the specimen head temperature adjusts to a tem-
perature between -10 °C and -5 °C (reduction of ice formation). The specimen head cooling
turns off . This is confirmed by the flashing of the decimal points on the panel for the speci-
men cooling. The specimen cooling (controlled to set value) automatically turns back on after
4 hours, once the chamber temperature varies by less than 5 K from the target temperature.
• If you want to turn the specimen cooling back on manually before the automatic activation
sets in, push the "+" or "-" button on the control panel field for the specimen cooling and then
the key button.
• The temperature of the specimen cooling first raises to +10 °C and then adjusts to the pro-
grammed specimen temperature.