Frequency Display Circuit; Adjustment Of Frequency Display - Pioneer SX-3900 Service Manual

Frequency Display Circuit
o The counter IC (PD5009) has been designed to
match FM ceramic filter IF offset (caused by
displacement of
the central frequency) by
combination of the inputs (of H or L level)
applied to pin nos.3 & 4. The matching IF offset
in the SX-3900 is determined according to the
combinations of connections and disconnections
between the JP14 and JP15 jumper wires in the
equalizer assembly (AWM-226). Check that the
combinations shown in the table below have
been followed for the corresponding grades of
FM ceramic filters F1-F3
(5 ranks -
color
coded).
If
the
SX-3900 frequency display reads
97.95MHz or 98.05MH2 when a 98.00MH2
signal is applied to the receiver, adjust TC1 so
that the display reads 98.00MH2 correctly.
If an accurate 98.00MH2 input signal source is
not available, tune the receiver to the nearest
known broadcasting station in the 98MHz re-
gion, and check that the station's frequency is
correctly displayed, adjusting TC1 if necessary.
L = O V
F M c e r a m i c f i l t e r s
( F 1 - F 3 )
PD5009
AWM-226
P i n n o . 3 P i n n o . 4 J P 1 4 J P 1 5
R e d
B l u e
G r a y
O r a n g e
B r o w n
;
H
H
H
H
H
L
L
H
C u t
C u t
C o n n e c l
C o n n e c t
C u t
Co
C u
C u
C u
C u
1 n e c t
T;rl
B
-rn I
I n d i c a t o r a s s e m b l y
J P
_ /
.T_T
:\
J P
E q u a l i z e r
a s s e m b l y
@
@
o
o
g
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F i g . 8 - 4 A d j u s t m e n t o f f r e q u e n c y d i s p l a y