Kenwood TS-590S, Service Manual

Page: 13 / 162

TS-590S
13
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. Since the XF301 terminal imped-
ance is 1k
Ω , the impedance is converted using variable coils
(L301, L302).
The MCF can be adjusted by connecting a tracking gen-
erator to the MCF adjustment connector (CN301, CN302),
and then rotating the variable coil (L301, L302). After replac-
ing the MCF (XF301), variable coil (L301, L302), or TX-RX
unit (X57-785 A/2), adjust the MCF in the adjustment mode.
Fig. 7 First mixer circuit of the RX-2 path
LO
73.120~133.095MHz
+14V
Q321 Q323
Q322 Q324
VR321
L326
1st IF
73.095MHz
RF
L323
L324
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
Ω
, the impedance is converted using variable
coils (L326, L374, L375, L376).
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 (X57-785 A/2), adjust the MCF in
the adjustment mode.
L302 XF301 L301
CN301
from 1st Mixer
11.374MHz
Tune connector Tune connector
CN302
to 2nd IF Amp1
11.374MHz
Fig. 8 RX-1 path MCF circuit
L376 XF371 L374 L326
L375
CN303
+8V
from 1st Mixer
73.095MHz
Tune connector Tune connector
CN304
1st IF Amp1
12dB
to 2nd Mixer
73.095MHz
+8V
Fig. 9 RX-2 path MCF circuit
CIRCUIT DESCRIPTION