TB 9-6625-086-24
7. Equipment Setup
a. Connect autotransformer to the power source and adjust for 115 volts ac.
CAUTION
Throughout this procedure, make sure the TI is deenergized
while connecting or disconnecting a thermistor mount or when
repositioning the MOUNT RES switch.
b. Connect the TI to autotransformer.
c. Adjust the TI mechanical zero setscrew clockwise until the pointer is left of zero,
moving up scale. Stop when the pointer indicates zero.
NOTE
If pointer overshoots zero indication during adjustment, repeat
c above.
d. Adjust the zero setscrew approximately 15 degrees counterclockwise to free the
setscrew from the meter movement.
e. If the pointer moves while freeing the setscrew, repeat c and d above.
f. Connect 200 ohm thermistor mount to the TI, using cable furnished with the TI and
terminate the mount with a 50 ohm termination.
g. Set the CALIB FACTOR PERCENT switch to 100 and leave it in this position for
the remainder of the procedure.
CALIBRATION PROCESS
NOTE
When indications specified in paragraphs 8 through 11 are not
within tolerance, perform the oscillator frequency check in
before making adjustments. Do not perform the procedures in
paragraphs 12 and 13 if all other parameters are within
tolerance.
NOTE
Remove top and side covers from the TI only for adjustment.
When adjustment is completed, reinstall the covers.
8. Coarse Null
a. Performance Check
(1) Position the TI RANGE switch to the .01 MW position.
(2) Adjust the TI ZERO controls for a 25 to 75 percent indication on the TI meter.