Section V
TM 11-6625-2781-14&P-2
ADJUSTMENT PROCEDURES (cont'd)
5-22. First Local Oscillator Adjustment (cont'd)
13. Repeat the alignment procedure at each of the adjustment points listed in Table 5-3 below. At each adjustment
point, set FREQUENCY so that comb signal appears at the left edge of the graticule. Adjust the potentiometers
so that the signal on the right-hand edge is half visible. Use FINE TUNE to keep the left-hand signal half visible
during the adjustment.
14. Repeat the adjustment until the left-hand signal is half visible and the right-hand edge is half visible.
Table 5-3. First Local Oscillator Adjustments
Approximate
Approximate First Local
Dial Frequency
Oscillator Frequency
Adjust
0 MHz
200 MHz
A7A1R3 (LOW FREQ ADJ)
110 MHz
310 MHz
5 MHz
205 MHz
A5A1R32
10
15 MHz
215 MHz
A5A1R38
20
25 MHz
225 MHz
A5A1R41
30
35 MHz
235 MHz
A5A1R44
40
45 MHz
245 MHz
A5A1R47
50
55 MHz
255 MHz
A5A1R50
60
65 MHz
265 MHz
A5A1R53
70
75 MHz
275 MHz
A5A1R56
80
85 MHz
285 MHz
A5A1R59
90
95 MHz
295 MHz
A5A1R62
100
105 MHz
305 MHz
A5A1R65
110
15. Switch RANGE MHz to 0-11 with FINE TUNE control centered and repeat steps 2 and 3 above.
16. Change the comb generator to 1 MC and adjust A13R5 11 MHz low freq adj for maximum base line lift.
17. Turn FREQUENCY to 11 MHz and adjust A13R2 for maximum base line lift.
18. Turn FREQUENCY to 0 MHz and repeat adjustments in steps 16 and 17.
19. Select 1 MHz SCAN WIDTH PER DIVISION. The comb spectrum should be evenly distributed across the CRT
with a 1 MHz marker within +0.2 divisions (200 kHz) of each vertical graticule line.
5-7
