M A I N T E N A N C E P R A C T I C E S
KEY ITEMS
D E T A I L S T E P S / W O R K I T E M S
Tu n e f o r a p e a k r e a d i n g o n t u n i n g
meter. Reduce output of signal
generator (if necessary) to maintain
amid-scale reading on tuning meter.
Adjust the receiver tuning knob for a
frequency of 200 kc.
(d)
Adjust the tuning core of coil LI for maximum
ind i c a tion o n VTVM c o n nec t e d to J1 p i n 16.
Adjust the signal generator and the receiver
to 400 kc.
Adjust trimmer capacitor C3 for maximum
indication on VTVM.
Repeat steps (c) through (g) until no further
improvement can be obtained.
(e)
(f)
(g)
In each case, always make the last
adjustment with the trimmer
capacitor.
(h)
Repeat steps (b) through (h) for band 2and 3
a s f o l l o w s :
B a n d 2 ; 5 0 0 k c - A d j u s t L 2
800 kc -Adjust C4
B a n d 3 : 1 0 0 0 k c - A d j u s t L 3
1 6 0 0 k c - A d j u s t C 6
With ascope connected to TPl (see Figure 102
and Figure 308), a47 cps modulated square-
wave is to be expected as shown in Figure 104.
The best modulation percentage is obtained
when the loop stage is properly tuned. Modu¬
lation between 30% to 100% is typical of the low
end of each band and 20% to 100% at the high
end of each band.
(i)
(j)
April 1965
(R e v i se d J a n u a r y 1 9 6 8)
Page 105
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