M A I N T E N A N C E P R A C T I C E S
( 4 ) A G C A d j u s t m e n t
D E T A I L S T E P S / W O R K I T E M S KEY ITEMS
( a ) S e t t h e r e c e i v e r f u n c t i o n s w i t c h t o R E C
position,
(b) Adjust the signal generator and the
r e c e i v e r t o 2 0 0 k c .
(c) Modulate the generator 30% at 400 cps
and adjust for alevel of 25 pv/mfield strength,
(d) Starting at full counterclockwise position,
adjust AGC control R43 clockwise until the
ADF output voltage at the receiver begins to
l e v e l off a s i n d i c a te d o n t h e VT V M .
( e ) A d j u s t R 4 3 c o u n t e r c l o c k w i s e f o r 1 d b
reduction at ADF output.
( 5 ) A u d i o L e v e l A d j u s t m e n t
(a) Re-adjust signal generator for 8pv/m field
Strength, with frequency and function in step 4.
(b) With VOL control adjusted for maximum
output (fully clockwise), set audio trimmer
potentiometer R51 for an output of 70 mw
±5% as indicated on the output meter,
( c ) T u r n t h e F u n c t i o n S e l e c t o r s w i t c h t o O F F
an d n ot e t ha t t he o u tp u t met e r in d i ca t e s z e r o.
P o s i t i o n I M P E D A N C E s w i t c h o f
outpu t m e t e r t o 5 00 ohm load.
F. AUD IO AMP LIF I ER T E ST
( 1 ) A u d i o G a i n
D E T A I L S T E P S / W O R K I T E M S
KEY ITEMS
Connect plus terminal of power
su p p l y t o pi n 3o f M o d e l I0 2 A o r t o
pin 6of Model 102B.
(a) Connect the test equipment to the audio
amplifier as illustrated in Figure 103.
(b) Turn on test equipment and allow 15
m i n u t e s w a r m - u p t i m e .
Position IMPEDANCE switch on the output
m e t e r t o 3 o h m s .
Adjust the audio generator to 1000 cps and
an audio amplifier output of 1watt.
M a x i m u m P o w e r O u t p u t
Adjust the audio generator to 1000 cps and an
audio amplifier output of 3.5 watts (102A).or
10 watts (102B)
F r e q u e n c y R e s p o n s e
Adj,ust the audio generator to 1000 cps and
a n a u d i o a m p l i fi e r o u t p u t o f 1 w a t t .
Adjust the audio generator to 350 cps, 750 cps
1500 cps, 2000 cps and 2500 cps (in that order).
(c)
(d)
The audio input shall not exceed
1 0 v o l t s r m s .
(2)
(a)
The voltage input indicated on the vtvm
s h o u l d b e l e s s t h a n 1 7 . 5 v o l t s r m s .
(3)
(a)
(b)
The output level indicated on the output
meter should be no greater than +1 db
or -4 db from the 1000 cycle reference
for the five frequency positions tested.
April 1965
(Revised January 1968)
Page 107
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