Pioneer KEX-70 Service Manual page 13

468 kHz signal is taken from T6's secondary winding, lead to
scan sensitivity adjustor VR1, amplified by O8, positively recti-
fied by D8 and become the output of MW scan stop.
Th signal is negatively rectified by D9, mixed by C26 and the
+ side of the AM envelope, the rippie (audio) component in
the rectified output is minimized and the difference in the
scanning sensitivity due to the AM modulation degree is
MW mode
LW mode
al
Tuning Voltage
cé
04 05
Tc2
>
Tuning Voitage
RI
4 =>, Cy 48 Viv 4)
reduced.
Scan stop output is applied to R34. When an MW ANT input
signal is available, a positive voltage is produced at R34, it
passes through R177, it is applied to the Q35 base, 035 is
turned ON, PD7004 D6/K2 is closed just as with FM reception
and the scanning is terminated.
Fig. 16
Fig. 17
Ks
Q4
int
[owen [BI oom
Tuning Voltage
Fig. 18
11