Kenwood TM-V708A Service Manual page 5

2-3. Sub VHF Receiver
The signal distributed from the RF amplifier (Q205) at the
main VHF receiver circuit passes through a filter circuit. Then
it enters the RF amplifier (Q507). The amplified signal goes to
the single balanced mixer (Q501, Q502). The frequency of
the signal is converted by the first local oscillator generated
by half of the UHF VCO oscillator frequency, using the
prescaler (IC303). It convents to the upper heterodyne
ANT
RF AMP
LPF
Q205
3SK239A
2-4. Sub UHF Receiver
The signal distributed from the RF amplifier (Q508) at the
main UHF receiver circuit passes through a lifter circuit. Then
it enters the single balanced mixer (Q200, Q201). The signal
frequency is converted by the first local oscillator, generated
by doubling the VHF VCO oscillator frequency (Lower
heterodyne) by Q7, to generate a 38.85MHz first IF signal.
ANT
HPF LPF
CIRCUIT DESCRIPTION
SINGLE BALANCED
RF AMP
LPF
HPF
Q507
3SK239A
Fig. 4 Sub VHF Receiver circuit
SINGLE BALANCED
RF AMP
MIXER
HPF
Q508 Q200,201
3SK239A 2SK302
(GR)
Q7
2SC5108
(Y)
Fig. 5 Sub UHF Receiver circuit
frequency to generate a 45.05MHz first IF signal. The signal
passes through the MCF (XF400). Then it is amplified by the
IF amplifier (Q406), and enters the IF IC (IC400). The signal is
converted to the 455kHz second IF signal, using the second
local oscillator (Upper heterodyne). Then the signal is
detected to generate an audio signal.
MIXER IF AMP
MCF
Q406
Q501,502
2SC5108
2SK302
(Y)
(GR)
XF400
IC303
1/2
UPB
45.505MHz
1509GV
LO
The signal passes through the MCF (XF100). Then it is
amplified by the IF amplifier (Q112), and enters the IF IC
(IC100). The signal is converted to the 450kHz second IF
signal by the second local oscillator generated by tripling the
12.8MHz reference oscillator frequency (Lower heterodyne).
Then the signal is detected to generate an audio signal.
IF AMP
MCF
Q112
2SC5108
(Y)
XF100
38.4MHz
X2
Q102
2SC4649
(N.P)
12.8MHz
TM-V708A
IF IC
IC400 AF
CF
IF IC
IC100
AF
CF
X3
5