BENDIX ADF-T12B Maintenance Manual page 30

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
K E Y I T E M S
( 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
p o s i t i o n ,
(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,
a d j u s t A G C c o n t r o l R 4 3 c l o c k w i s e u n t i l t h e
ADF output voltage at the receiver begins to
l e v e l o f f a s i n d i c a t e d o n t h e V T 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
a n d n o t e t h a t t h e o u t p u t m e t e r i n d i c a 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
o u t p u t m e t e r t o 5 0 0 o h m l o a d .
F . A U D I O A M P L I F I E R T E S T
( 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
K E Y I T E M S
Connect plus terminal of power
s u p p l y t o p i n 3 o f M o d e l I 0 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) Tu r n o n t e s t e q u i p m e n t a n d a l l o w 1 5
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)
T h e a u d i o i n p u t s h a l l n o t e x c e e d
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.
A p r i l 1 9 6 5
(Revised January 1968)
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