TM 11-5840-360-14-1-1
13. Disconnect lead at TB3-8 (see CAUTION above).
11. At Indicator under test, set POWER switch per
step 2 above.
14. Carefully rotate the knob of 4/5A9B2 until the CRT
trace is sweeping between 0and 180
.
12. At master Indicator, turn GAIN control fully
counterclockwise.
At Indicator under test, turn
15. Reconnect the lead removed from TB3-8.
CONTRAST control fully clockwise.
16. Adjust R13 on A9A1 PCB to position sixth range
13. Connect oscilloscope, set for ac input and 5 volts
ring 1/8 inch from edge of the cursor display at 270
.
per division, to TP4 of A2A1 PCB at Indicator under test.
17. Adjust R15 on A9A1 PCB to position sixth range
NOTE:
ring 1/8 inch from edge of the cursor display at 0
.
18. Carefully rotate the knob on 4/5A9B2 so that the
The video signals displayed in the
sweep rotates slowly through 3600 , verify that the sixth
following steps are negative-going
range ring remains circular on the display.
pulses
from
a
baseline
of
19. If the range ring remains circular proceed with
approximately +60 Vdc.
step 20. If the range ring is not circular repeat steps 9
14. At master Indicator, adjust GAIN control clockwise
through 18.
just until negative-going LSB video signals are observed
20. Set POWER switch to OFF. Tighten 4/5A9B1
on oscilloscope.
securing screws. Swing A9 assembly up into its operate
15. At Indicator under test, adjust R8 on A2A1 PCB
position and secure. Replace Indicator upper front access
until LSB video signal amplitude is 25 volts (baseline to
cover.
peak) on oscilloscope.
5.12.3.7 Video Circuits Alignment. - The following steps
16. At Indicator under test, turn CONTRAST control
provide instructions for adjustment of the variable controls
counterclockwise until LSB video signal amplitude is 15
on the A2A1 Video Amplifier and A2A3 Data Storage
volts (baseline to peak) on oscilloscope.
PCBs.
17. At master Indicator, adjust GAIN control slowly
1. At Indicator under test:
clockwise just until two-level (LSB and MSB) video signals
a. Set POWER switch to OFF.
are displayed on the oscilloscope.
b. Remove upper front access cover.
18. At Indicator under test, adjust R9 on A2A1 PCB
c. Remove A2A3 Data Storage PCB and
until MSB video signal amplitude is 35 volts (baseline to
extender card from A2 card basket.
peak) on oscilloscope.
d. Mount A3 PCB on extender card and
19. At Indicator under test, observe LED indicator
insert into A3 slot of card basket.
above TUNE control and adjust R66 on A2A1 PCB for
2. Set POWER switch(es) as follows:
desired indicator brightness.
a. If Indicator under test is a master Indicator,
20. At indicator under test observe heading line on
set its POWER switch to TX ON.
CRT and adjust R20 on A2A1 PCB for desired heading
b. If Indicator under test is a slave Indicator,
line brightness.
set its POWER switch to ST BY and that of
21. At Indicator under test:
associated master Indicator to TX ON.
a. Set POWER switch to OFF.
3. Install Integrated Circuit (IC) clip on U29 of A2A3
b. Remove extender card from A2A1 card slot
PCB.
and disengage A2A1 PCB.
4. Connect
set
for
10
VDC
c. Insert A2A1 PCB and extender card into
measurement, between pin 2 of A2A3U29 (positive lead)
their respective slots in A2 card basket.
and chassis.
d. Replace upper access cover.
5. Adjust R29 (LSB) on A2A3 PCB to obtain 1.0 VDC
5.12.3.8 Reflection Plotter Alignment. - Perform the
reading on multimeter.
following steps to insure proper alignment of the reflection
6. Move multimeter positive lead to pin 11 of
plotter. The Indicator at which the alignment is to be
A2A3U29.
performed is referred to as the Indicator under test.
7. Adjust R30 (MSB) on A2A3 PCB to obtain 3.0
1. Set Indicator POWER switches as follows:
VDC reading on multimeter.
a. If the Indicator under test is a master
8. Set POWER switch to OFF at Indicator under test.
Indicator, set its POWER switch to TX ON.
9. Remove extender card, disengage A3 PCB and
b. If the Indicator under test is a slave
remove IC clip; insert A3 PCB into its slot in card basket
Indicator, set its POWER switch to ST BY
A2.
and that of the associated master Indicator
10. Remove A1 PCB from card basket and mount it
to TX ON.
on the extender card; insert extender card into Al slot of
2. Adjust controls of the Indicator under test for
card basket.
normal operation.
5-64
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