Thermo Scientific PARTISOL 2000 Service Manual page 44

Service Manual, Partisol Model 2000 Air Sampler
S 3: S P
ECTION ERVICE ROCEDURES
7) Locate the test point labelled "PWM1" (green) on the middle-right
side of the interface board (Figure 3-11). Attach the positive lead
from the multimeter on the PWM1 test point.
8) Locate the ground test point labeled "AGND" (black) near the front
right corner of the interface board. Place the ground lead on the
AGND test point.
9) Using the arrow key, position the cursor so that it is in the location
labelled "A/O" on the Calibration screen.
10) Press <F1:Edit> to enter the Edit Mode. Type in a number between
0.050 and 0.150 volts and press <ENTER>.
11) Observe the number displayed in the row labelled "A/I" in the
column labelled "Calc." Ensure that this number does not vary
more than ±0.005 volts after watching it for 5 seconds. If this
number is not stable, choose a new number for "A/O" between
0.050 and 0.150 volts.
12) Read the voltage displayed on the multimeter.
13) Using the arrow keys, position the cursor so that it is in the row
labelled "A/I" and the column labelled "Act" (actual).
14) Press <F1:Edit> to enter the Edit Mode. Type the voltage read
from the multimeter (to a 3-digit accuracy; i.e., "0.xxx") in this
position and press <ENTER>. This calculates the "Offset."
15) Ensure that the number now displayed in the row labelled "A/I"
and the column labelled "Calc" matches the number displayed on
the multimeter within ±0.005 volts.
16) Using the arrow key, position the cursor so that it is in the location
labelled "A/O."
17) Press <F1: Edit> to enter the Edit Mode. Type in a number be-
tween 4.800 and 4.900 volts and press <ENTER>.
18) Observe the number displayed in the row labelled "A/I" in the
column labelled "Calc." Ensure that this number does not vary
more than ±0.005 volts after watching it for 5 seconds. If this
number is not stable, choose a new number for "A/O" between
4.800 and 4.900 volts.
19) Read the voltage displayed on the multimeter.
20) Using the arrow keys, position the cursor so that it is in the row
labelled "A/I" and the column labelled "Act."
Revision B.000
P 3-16
AGE