Advanced Instruments 3900, User Manual

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distort the thin plastic of the mandrel). Recheck and readjust the
probe position as necessary.
e. The probe bead must also be axially centered in the sample. If
horizontal adjustment is necessary, bend the metal probe stem
gently by hand in the required direction to align it with the raised
V centerline on the footed face of the alignment tool (see figure
10). Recheck and readjust the bead position as necessary.
f. The bottom of the stir/freeze wire should be even with alignment
tool STEP or up to 1/32” or 1 mm higher than the tip of the
probe. As necessary, loosen the stir/freeze wire setscrews in the
clapper and reset the stir/freeze wire. Retighten the stir/freeze
wire setscrews. After retightening the setscrews, bend the
stir/freeze wire, as necessary, so that the wire surface nearest the
probe is next to the vertical edge of STEP, as shown in figure 10.
g. Reverse the steps described in Sample Probe Checks, item 3.a
through 3.c to restore the instrument to operating condition. Each
time the 3900 is turned on, it follows the power-up sequence
described in Installation & Setup to the point where “ Press
START to Continue ” scrolls across the display.
h. Always check and readjust the stir/freeze amplitude, as necessary,
after aligning the probe and/or stir/freeze wire (see item 6
below).
6. Stir/Freeze Amplitude Adjustment
The stir and freeze vibration amplitudes are affected by the probe,
stir/freeze wire and mandrel positions. Always realign the stir/freeze
wire according to the recommendations in item 5 before checking
and adjusting the freeze and stir vibration amplitudes, as follows:
a. With the 3900 power turned on and “
Press START to
Continue ”, “ Osmometer Ready ” or the date and time on the
display, open the cassette deck cover (see figure 2) and observe
the position of the operating head, which should be in standby
72
The Advanced
®
Osmometer Model 3900 User’s Guide