TB 9-6625-177-24
f. Set TI range switch to BAT position; if meter pointer is not well within the battery test
region, replace TI battery. Allow an additional 5-minute warm-up after replacing the battery.
8. Wattmeter Linearity Test
a. Performance Check
(1) Connect male end of a BNC T connector to calibration element.
NOTE
Use a 50 Ω cable no longer than 3 feet for steps (2) and (3) below.
(2) Connect one BNC T connector female end to audio analyzer output.
(3) Connect other end of BNC T connector to multimeter (ac mode).
(4) Adjust audio analyzer frequency controls for 1000 Hz.
(5) Set TI range switch to 100.
(6) Adjust audio analyzer amplitude output controls so that meter pointer will rest
at 1 on the uppermost scale. Multimeter will indicate 1.575 and 1.607 V ac. If not, perform
b below.
(7) Repeat technique of step (6) above for the remaining TI range switch settings
listed in table 3 below. Multimeter will indicate within limits indicated. If not, perform b below.
Table 3. Wattmeter Mainframe Calibration.
Multimeter indications (V ac)
Test instrument range
switch settings
Min
Max
Ideal
100
1.575
1.607
1.591
30
0.8861
0.9040
0.8950
10
0.4980
0.5080
0.5030
3
0.2802
0.2858
0.2830
1
0.1575
0.1607
0.1591
0.3
0.0882
0.0908
0.0895
0.1
0.0495
0.0511
0.0503
(8) Repeat paragraph 7 b through f above with TI in the horizontal position.
(9) Perform steps (1) through (7) above.
(10) Remove calibration element from TI.
b. Adjustments
(1) Remove four screws from side of TI and pull back cover straight off.
NOTE
Ensure male end of BNC T connector is connected to
calibration element.
(2) Connect one BNC T connector female end to audio analyzer output.
(3) Connect other end of BNC T connector to frequency counter.