TB 9-4931-321-24
7. Equipment Setup
HIGH VOLTAGE is used or exposed during the performance of
this calibration.
DEATH ON CONTACT may result if
personnel fail to observe safety precautions.
REDUCE
OUTPUT(S) to minimum after each step within the
performance check where applicable.
a. Connect TI to autotransformer.
b. Connect autotransformer to a 115 V ac source and adjust for a 115 V output.
c. Position controls as listed in (1) through (7) below:
(1) RANGE-DB switch to 0.
(2) EXPAND switch to NORM.
(3) INPUT (INPUT SELECTOR) switch to 8.7 MA.
(4) GAIN (COARSE GAIN) control fully clockwise.
(5) VERNIER (FINE GAIN) control fully clockwise.
(6) BANDWIDTH control fully clockwise.
(7) POWER switch to LINE ON.
d. Allow at least 30 minutes for equipment to warm-up and stabilize.
e. Set POWER switch to OFF and verify that meter pointer aligns with 2 on 0 (zero) to
2 dB (decibel) scale. If necessary, rotate mechanical zero-adjustment screw clockwise until
pointer is to the left of 2, moving upscale. Stop clockwise adjustment when pointer is
aligned with 2.
f. Set POWER switch to LINE ON.
8. Bolometer Bias
a. Performance Check
(1) Connect resistance standard to TI INPUT and connect multimeter across
resistance standard.
(2) Set resistance standard and TI INPUT (INPUT SELECTOR) switch to settings
listed in table 3. If multimeter does not indicate within specified limits, perform b below.
Table 3. Bolometer Bias
Test instrument
Multimeter indication
INPUT (INPUT) SELECTOR
Resistance standard
(V dc)
setting ( )
switch setting
Min
Max
200
8.7 MA
1.688
1.792
200
4.5 MA
0.873
0.927
1000
BIASED
0.97
1.03