Mcf Adjustment - Kenwood TS-590SG Service Manual

RF
73.120~133.095MHz

MCF Adjustment

There are 2 types of MCFs: for IF frequency 11.374MHz
RX-1 path, and for IF frequency 73.095MHz RX-2 path.
The RX-1 path MCF (XF301) is a fi lter which consists of
a 2-pole MCF, whose center frequency is 11.374MHz and
passband width is 6kHz.
The RX-2 path MCF (XF371) is a fi lter which consists of
a 2-pole MCF, whose center frequency is 73.095MHz and
passband width is 15kHz. Since the XF371 terminal imped-
ance is 2.5k, the impedance is converted using variable
coils (L326, L374, L375, L376).
L326
from 1st Mixer
73.095MHz
CIRCUIT DESCRIPTION
Q321
L323 VR321
Q322
L324
LO
Fig. 7 First mixer circuit of the RX-2 path
Tune connector
CN303
+8V
L374 XF371
L375
Fig. 8 RX-2 path MCF circuit
+14V
Q323
L326
1st IF
73.095MHz
Q324
The MCF can be adjusted by connecting a tracking gen-
erator to the MCF adjustment connector (CN303, CN304),
and then rotating the variable coil (L326, L374, L375, L376).
After replacing the MCF (XF371), variable coil (L326, L374,
L375, L376), or TX-RX unit (XC1-024 A/2), adjust the MCF in
the adjustment mode.
1st IF Amp1
+8V
L376
TS-590SG
Tune connector
CN304
12dB
to 2nd Mixer
73.095MHz
13