M A I N T E N A N C E P R A C T I C E S
D E T A I L S T E P S / W O R K I T E M S
KEY ITEMS
(a)
Assemble the ADF-T-12B.C System as indicated
in Figure 102, using R-F generator No.l.
Inject signal at mixer coil L7
pin 4.
NOTE
M a k e c e r t a i n t h e 1 4 / 2 8 v d c s e l e c t o r s w i t c h l o c a t e d
at rear of receiver corresponds to the selected input
voltage from the power supply.
(b)
Apply power to all equipment and allow 15
minutes for test equipment to warm-up.
Verify with multimeter that the d-c voltage
between pins 15 and 9of c o nnector J 1 i s 1 3 . 7 5
±2% vdc (for 14 Voperation) or 27.5 ±2% vdc
( f o r 2 8 Vo p e r a t i o n ) .
Adjust the r-f signal generator to 142.5 kc,
modulated 30%at 400 cps.
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 t h e R E C
position.
S e t t h e r e c e i v e r b a n d s e l e c t o r s w i t c h t o t h e
190-440 position.
Adjust the receiver tuning knob for afrequency
of 400 kc.
Adjust the output of the R-F signal generator
u n t i l a m i d - s c a l e d e fl e c t i o n i s o b t a i n e d o n t h e
tuning meter.
(c)
(d)
Signal generator frequency should
be accurate within 1%.
(e)
(f)
(g)
(h)
Tu n i n g m e t e r ( a c c e s s o r y f o r a l l b u t
Models 201C/D) S20001-01, 0-1 ma.
NOTE
Steps (i) and (j) must be performed with extreme
care so that the selectivity requirements of para¬
graph I. (3). (i) can be obtained.
(i) Adjust the tuning cores of the i-f transformers
for maximum indication on the tuning meter.
Adjust in the following order: T5, T4, T3.
Primaries, top-side; secondaries, bottom.
A d j u s t t h e p r i m a r i e s o f e a c h t r a n s ¬
f o r m e r fi r s t ; s e c o n d a r i e s , s e c o n d .
Reduce the generator output as
f o u n d n e c e s s a r y t o m a i n t a i n m i d ¬
scale indication of tuning meter.
Volume control to be set full clock¬
wise. Steps (i) and (j) must be per¬
f o r m e d c a r e f u l l y i f s e l e c t i v i t y s p e c i ¬
fications in paragraph I. (3) (i)
(page 116) are to be met.
a)
Tune T6 for maximum audio output on the
o u t p u t p o w e r m e t e r .
( 2 ) R - F A l i g n m e n t
Connect the R-F signal generator, through the
"dummy” test antenna to terminal 1of connector Jl.
W i t h t h e r e c e i v e r f u n c t i o n s e l e c t o r s w i t c h s t i l l i n
the REC position, adjust the signal generator to
200 kc, unmodulated.
Adjust the receiver tuning knob for afrequency of
200 kc.
Adjust the output of the signal generator until the
t u n i n g m e t e r r e a d s a b o u t m i d - s c a l e .
April 1965
(Revised January 1968)
(a)
See Figure 102, using R-F
ge n e r at o r N o . 2 .
(b)
(c)
(d)
Page 103
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