33
Troubleshooting
Cooling fault diagnosis
Ensure that all connections to the stage and Dewar are as described in the specific manual and that the
stage lid and top windows are properly sealed.
1.
The cooling rate is less than programmed.
There can be several causes of this problem, the most likely being that one of the connectors has
become blocked or damaged. Check that each tube is fitted tightly to the connector and that none
of the tubing is twisted or has come lose. The larger diameter tube leading from the LNP95 con-
sists of a tube within a tube, check that the internal tube is connected, it may have come loose. Any
constrictions of either the tubing or the connector will have a drastic effect on the cooling ability of
the LNP95. If the connectors and tubing are OK, check that the capillary tubing to the Dewar flask
is not bent or damaged and that the filter is intact and unblocked. If any damage has occurred to
any of these items then it will be necessary to replace them. If no damage is found, check that the
silver block is not constricted. This can be checked, simply by blowing through one of the steel
cooling tubes using a compressed air line.
2.
Stage will not cool down to
-
196°C.
Check that the stage lid is not touching the silver block when screwed down. Check that the silver
block has not been pushed down so that it touches the base of the stage. Check the sample holder
ramp is not touching the silver block. Any of these faults will cause a substantial loss of cooling
ability.
3.
Condensation and ice forming on the upper side of window
Realign the window gas tube clip to the required position in the stage lid.
4.
Condensation on the sample and/or the underside of lid window
This is due to the stage not being sealed properly and therefore allowing moisture in during purging
or cooling. Check that the lid and bottom window are sealed correctly and that the silicon seals are
in position.
Please visit
www.Linkam.co.uk
for more FAQ for the stage and instruments.
