SECTION 5
MAINTENANCE
5.1 SCHEDULED MAINTENANCE
The cold head and vacuum shroud assembly requires no regularly scheduled
maintenance. The compressor adsorber should be replaced according to the schedule set
forth in the CTI manual.
5.2 UNSCHEDULED MAINTENANCE
Unscheduled maintenance may occasionally be required to repair problems arising during
the course of operation. These problems may be related to vacuum leaks, wiring failure,
or refrigerator/compressor failure.
5.3 VACUUM LEAKS
Condensation on the outside of the vacuum jacket and inability of the sample mount to
reach 10 K are indications of a vacuum problem. If these symptoms appear, re-evacuate
the shroud as described in the evacuation paragraph above. If the symptoms disappear,
no further action may be required. If the symptoms remain, or reappear quickly, a
vacuum leak may be present. Contact Janis Research to obtain further direction in this
case.
5.4 WIRING
Occasionally a heater or thermometer wire may be broken during sample removal or
installation. If this occurs, reconnect the broken wire using 60/40 rosin core solder. Be
sure to insulate the joint with shrinkable PVC tubing or Teflon insulation. The heater
located at the sample mount is designed to accept the normal output of most temperature
controllers. Occasionally, however, a heater may bum out. Replacement heater kits are
available from Janis, and include all materials and instructions necessary for replacement.
5.5 REFRIGERATOR/COMPRESSOR FAILURE
Compressor and refrigerator failures are characterized either by an inability to operate, or
by an increase in the minimum achievable temperature. In either case, refer to the
troubleshooting section in the CTI operating manual for suggested corrective actions. If
satisfactory operation is still not achieved, contact Janis Research for further
recommendations.
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