Advanced Instruments 3900, User Manual

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88
The Advanced
®
Osmometer Model 3900 User’s Guide
“Sample Pre-
Freeze”
1. Were the sample probe
and tube clean? Are the
probe wipers dirty?
2. Is the probe configura-
tion correct?
3. Check the stir/freeze
wire alignment and
adjustment.
4. Is the sample frozen?
5. Does the clapper and/or
the stir wire coil show
excessive wear?
Symptom Check
Suggested Action
1. Replace the probe wipers
and test another aliquot
of that sample in a clean
sample tube. Check/
correct the probe bin
numbers.
2. Correct the stir/freeze
wire alignment and
adjustment as necessary.
3. Try to minimize the
effects of materials that
tend to cause premature
crystallization.
4. False pre-freeze errors
may be reported if the
instrument cannot main-
tain a cooling sample rate
of greater than 20 mOsm
per 7 seconds.
5. See Chapter 5 for further
assistance and possible
replacement of the yoke,
clapper and coil by a
qualified service techni-
cian.