Kenwood TM-731A Service Manual page 22

TM-731A/E
DESCRIPTION OF ELEMENTS
Operation/Condition/Compatibility
Components Use/Function
Second local oscillator, mixer Operation in reception
C1
PLL 8 V ripple filter
First IF input 10.7 MHz (M,W), 16.9 MHz (K,P)
@@® Second local oscillator 10.240 MHz (M,W), 17.355 MHz (k,P)
@® Detector output
IC2 10 V AVR
love]
| wT 13.8V
@ Sub output (non separate: output),
GND,
separate select output
_ . (separate: ''H'' level)
ICS
Speaker-separate select switch
@ Main output (non-separate: output), @ Main output (separate: output),
Main input
@ AF input (only main when separate)
© AF output (only main when separate)
IC4 AF amplifier
@® 13.8 V
AF output (sub when separate, main and sub when non separate)
@ AF input (sub when separate, main and sub when non separate)
01 Radio-frequency amplifier Operation in reception
Operation in reception 127.1~131.095MHz {K,M,P)
133.3~135.295MHz (W)
Q2 First mixer
144~147,.995MHz (K,M) 16.9MHz {K,P)
144~ 145.995MHz (W) 10.7MHz (M,W)
Q3
First IF amplifier
Operation in reception 10-7 MHz (M,W), 16.9 MHz {K,P)
04,5
S-meter amplifier
'
Q6 Main LPF
—|-@7 ~~} -Gub bP Fo > _ ~ a a
a8
8T switching control
Turns ON in transmission
Qg
8T switching. control
Turns OFF in reception
Q10 | 8T switching control PLL lock OFF
Q11
8T switching control
Turns ON in transmission
Q12
8R switching
Turns ON in transmission
8c
013
8R switching control
Turns ON in reception
. Boy
rd tov?
14 tpin
ov
(8.OV)
8c:
5.0V
(ov?
014 Buffer 12.8 MHz
O16 PLL modulation input mute Turns ON in reception
When receiving, turns Q16 ON, and grounds the mic line
22