Kenwood TK-3202 Service Manual page 7

TK-3202
DISASSEMBLY FOR REPAIR / CIRCUIT DESCRIPTION
■ Attaching the antenna receptacle to the chassis
Screw the antenna receptacle to the chassis in the order
shown in the drawing so that the antenna receptacle
comes to the center of the case hole.
Tighten this screw first
■ The nuts of the volume knob and channel knob
Note that the shapes, materials and heights of nuts of the
volume knob and channel knob are different from one an-
other. (The nut of volume knob is stainless steel, and the
nut of channel knob is brass.)
Use the following jig when removing the nuts of the vol-
ume knob and channel knob.
Jig (Part No.: W05-1012-00)
Volume Knob
(Stainless steel)
■ Screw sequence for mounting the TX-RX unit to
the chassis
Attach the TX-RX unit to the chassis using the screws in
the order shown in the drawing below.
i
o
!0
6
Tighten this screw second
Channel Knob
(Brass)
u
t
y
q r
w e
TX-RX UNIT
Component side view
!1
1. Frequency Configuration
The receiver utilizes double conversion. The first IF is
38.85MHz and the second IF is 450kHz. The first local oscil-
lator signal is supplied from the PLL circuit.
The PLL circuit in the transmitter generates the necessary
frequencies. Fig. 1 shows the frequencies.
TX/RX : 440~470MHz (E)
400~430MHz (E3)
ANT
1st MIX
MCF
ANT RF
SW AMP
38.85MHz
RX:
401.15~
431.15MHz (E)
361.15~
391.15MHz (E3)
TX
AMP
TX: 440~470MHz (E)
400~430MHz (E3)
Fig. 1 Frequency configuration
2. Receiver
The frequency configuration of the receiver is shown in
Fig. 2.
ANT RF AMP
BPF Q205
ANT
SW
PCTV
CF201
IC201
IF, MIX, DET
Q1
X3 multiply
2nd Local 12.8MHz
Fig. 2 Receiver section
■ Front End (RF AMP)
The signal coming from the antenna passes through the
transmit/receive switching diode circuit (D103, D104, D106
and D122), passes through a BPF (L229 and L228), and is
amplified by the RF amplifier (Q205).
The resulting signal passes through a BPF (L214, L212 and
L211) and goes to the mixer. These BPFs are adjusted by
variable capacitors (D203, D204, D205, D206 and D210). The
input voltage to the variable capacitor is regulated by voltage
output from the microprocessor (IC405).
CF
450kHz
IF AF
SYSTEM AMP
38.4MHz
X3
TCXO 12.8MHz
multiply
MIC
RF PLL
MIC
AMP VCO AMP
MIXER MCF IF AMP
BPF Q204 XF201 Q203
PCTV 1st Local
IC302
AF VOL AF PA
IC301
AQUA-L
X1
TXCO
SP
SP