TB 11-6625-2932-35
(3) Adjust the audio oscillator until a waveform
(2) Disconnect TI transformer 2 by unsoldering
as shown in figure 1A, appears in TI cathode ray tube.
wire No 11a rt from resistor R13.
(4) The intersection of the stationary sine waves
(3) Remove relay HR and tube V.
must be 11% (for 50Hz power frequency)or 12 % (for
CAUTION
60Hz power frequency) apart. If not, perform b, below.
DANGER of implosion of cathode ray
b. Adjustment.
tube V. Remove the tube from the
(1) Adjust R18 (behind the highvoltage warning
socket by inserting a flat screwdriver
plate on TI control panel until sinewave in figure 1B is
between the base of the tube and the
obtained. (R)
socket and gently pry the tube loose
around the circumference of the base.
NOTE
Do not force or apply pressure to the
Variations of power frequency of up
glass. Safety glasses should be worn
to1 % are permissible, but cause a
while removing the tube and while
drift of the display.
reinserting it after the test is com-pleted.
(2) Retune the audio oscillator if drift is apparent,
and then repeat a(4), above readjusting R18 as
(4) Connect TI to variable transformer (A5) and
necessary for the proper sinewave and intersection
adjust for 220 Vac.
points.
9. Frequency Divider Circuit. a. Performance Check.
NOTE
(1) Deenergize TI and remove the chassis from
Use 220 Volts from wall receptical if a
the protective case.
220 Volt transformer is not available.
(2) Place chassis on a nonmetalic working
(5) Measure voltages as follows using volt-meter
surface, energize and allow for warmup and stabilization.
(A2):
(3) Connect oscilloscope (A3) channel 1 input
At terminals b3-c2 of:
to TI point (A) at the junction of capacitors C3and C4,
transformer Trl
660 to 700 V
and channel 2 input to TI point (B) at the junction of
At capacitor C1
840 to 880 V
capacitor C3 and resistor R1.
At capacitor C2
645 to 685 V
(4) Connect the oscilloscope ground to TI
At terminals bl-b4 of
transformer terminal c1.
transformer Trl
6.3 to 6.9 V
(5) Observe the presents of voltage of TI
(6) If the correct measurements were obtained,
frequency divider circuit as shown by the upper trace in
resolder the wire removed in (2), above. If the correct
figure 2D.
measurements were not obtained, further maintenance
(6) Observe the waveshape of the current of the
and troubleshooting is necessary.
frequency divider circuit as shown by the lower trace in
b. Adjustments. No adjustments can be made.
figure 2D. If traces are not as shown in the figure,
11. Final Procedure. a. Deenergize and disconnect all
perform b, below.
b. Adjustments.
the equipment, and reinstall the chassis in the TI case.
b. In accordance with TM 38-750, annotate and
(1) Adjust R22 to obtain the waveshapes shown
affix DA Label 80 (US Army Calibrated
in figure 2D. (R)
Instrument). When the TI receives limited or
(2) If the adjustment of R22 does not correct the
special calibration, annotate and affix DA Label
waveshapes, resistor R1, and capacitors
163 (US Army Limited or Special Calibration).
C5a,C5b, C5c, and C5d have to be
When the TI cannot be adjusted within
unsoldered, changed or adjusted in
tolerance, annotate and affix DA Form 2417 (US
accordance with the TI maintenance
Army Calibration System Rejected Instrument).
manual.
NOTE
Some instruments do not have trim-
mer capacitors C5c and C5d. These
two trimmer capacitors may have to
be inserted in the circuit to correct the
10. Power Voltages and Current. a. Performance
Check.
(1) Remove the TI chassis from the case by first
removing the four screws on the front panel.
4
