TM 11-5840-360-14-1-1
5.12.3.6 North Stabilization Circuits Alignment. The
53. Turn EBL front panel knob to position displayed
sweep circuits alignment given in paragraph 5.12.3.5
EBL at 180on relative bearing scale.
must be in effect prior to performance of this procedure.
54. Note error (if any) between EBL VRM dot and
1. At Indicator under test:
VRM range ring; adjust R23 on EBL PCB A2A9 to
a. Remove upper front access cover and
remove one-half the error.
swing A9 assembly down into its service
55. Repeat steps 51 through 54 until no vertical
position.
error is detectable between EBL VRM dot and VRM
b. Set POWER switch(es) as follows:
range ring.
(1) If Indicator under test is a master
56. Turn EBL front panel knob to position displayed
Indicator, set its POWER switch to
EBL at 090on relative bearing scale.
TX ON.
57. Adjust R7 on A2A8 PCB to superimpose the
(2) If Indicator under test is a slave
EBL VRM dot on the VRM range ring.
Indicator, set its POWER switch to
58. Turn EBL front panel knob to position displayed
ST BY and that of associated
EBL at 270on the relative bearing scale.
master Indicator to TX ON.
59. Note error (if any) between EBL VRM dot and
c. Set RANGE SELECT switch to 24 MILES.
VRM range ring; adjust R39 on EBL PCB A2A9 to
d. Turn CONTRAST control fully counter-
remove one-half the error.
clockwise.
60. Repeat steps 56 through 59 until no horizontal
e. Set HDG SET/GYRO STAB/HD UP
error is detectable between EBL VRM dot and VRM
switch to GYRO STAB.
range ring.
f. Adjust BRILLIANCE control counter-
61. Turn EBL front panel knob to slowly rotate
clockwise until range rings are barely
displayed EBL through 360 verify EBL VRM dot
;
visible.
remains within 2 range cells of VRM range ring.
g. Set all remaining controls for normal
62. Adjust R30 on EBL PCB A2A9 to position sixth
operation.
range ring 1/8 inch from edge of the cursor at 0 and
180
.
2. Verify ship's gyro compass system is operating.
63. Adjust R34 on EBL PCB A2A9 to position sixth
3. Disconnect following leads at Indicator terminal
range ring 1/8 inch from edge of the cursor at 090and
boards:
270
.
a. TB3-5 (resolver S1)
64. While alternately setting OFFSET switch on and
b. TB3-7 (resolver C1)
off, adjust R43 on EBL PCB A2A9 to obtain the
4. Connect oscilloscope, set for dc voltage
applicable downward vertical offset as follows:
measurement, at 4/5A9A1J3-2.
a. 12 inch (IP-1282) Indicator: 3.0 inch
5. Adjust R8 on A9A1 PCB for 0.0 Vdc on
offset.
oscilloscope.
b. 16 inch (IP-1283) Indicator: 4.0 inch
6. Connect oscilloscope set for dc.
voltage
offset.
measurement at 4/5A9A1J3-4.
65. Set RANGE SELECT switch to 48, then 64
7. Adjust R7 on A9A1 PCB for 0.0 Vdc on
MILE positions. Verify display is normal for both ranges.
oscilloscope.
NOTE:
8. Reconnect leads disconnected in step 4.
If, on 48 and/or 64 mile ranges,
9. Disconnect lead from terminal 8 (R1 signal) of
portions of the sweep are blanked,
Indicator terminal board TB3.
adjust R54 on Sweep Generator PCB
CAUTION
A2A10 slightly counterclockwise
THE CRT DISPLAY SHOULD NOW
until normal display is observed,
SHOW A HORIZONTAL TRACE.
then select 24 mile range. Verify, on
TURN
BRILLIANCE
CONTROL
24 mile range, that sweep covers
COUNTERCLOCKWISE AS NECES-
entire CRT face with no flat (octagon)
SARY TO PREVENT BURNING OF
edges visible. If octagon edges are
THE CRT FACE.
visible, repeat steps 39 through 65
10. Carefully rotate the knob of A9B2 until the CRT
above.
trace is sweeping between 090and 270
.
66. Set Indicator POWER switch to OFF. Remove
11. Reconnect the lead removed from TB3-8.
A2A9 EBL PCB and extender card. Insert EBL PCB into
12. Adjust R14 on A9A1 PCB to position sixth range
A9 slot of card basket A2.
ring 1/8 inch from edge of the cursor display at 270
.
67. Lower and secure bezel assembly. Replace
stabilizer bar and upper front access cover.
5-63
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