Advanced Instruments 3250 User Guide

79
Troubleshooting and Service
Alternate method—using a sample tube containing 0.2mL of
water
Proper alignment and adjustment of the mandrel, probe and stir/freeze
wire are of utmost importance to assure accuracy, precision and proper
operation of the instrument.
Note After making any probe and/or stir/freeze wire adjustments, the
instrument calibration must be checked and adjusted as
necessary.
1. Pipette a 0.2-mL sample of HO or any of the standards into a
sample tube. Then hold the tube up on the mandrel in the position
shown in Figure 9. Note in which direction the tip of the probe
must be moved (if any) to perfectly center its black sensor bead in
the sample volume. Remove the sample tube.
2. If vertical adjustment of the probe tip is necessary to center
the black bead in the 0.2-mL sample volume, loosen the probe
setscrew (Figure 7, Item 6), then manually raise or lower the probe
within the mandrel. Retighten the setscrew gently (overtightening
will crack or distort the thin plastic wall of the mandrel). Recheck
as described in step 1 above.
3. If horizontal adjustment is necessary to center the black bead in the
sample volume, bend the metal probe stem gently in the required
direction by hand. Recheck as described in step 1, above.
4. Check and adjust the stir/freeze wire position according to the
recommendations in Figure 9.
5. After any stir/freeze wire position adjustment, check and adjust the
stir/freeze amplitude, as necessary, as recommended in the next
section, Stir/freeze amplitude adjustment.

Advanced Instruments 3250 Specifications

General

Brand	Advanced Instruments
Model	3250
Category	Measuring Instruments
Language	English