Description Of Components - Kenwood TK-785 Service Manual

TK-785
TX-RX Unit (X57-6142-71) (A/2) : K,E
Ref. No. Use / Function
IC1 DC amp
IC2 DET amp
IC3 Amp/Summing amp
IC4 Analog switch
IC5 A/D converter
IC6 DC amp
IC7 Shift register
IC8 Shift register
IC9 5V AVR
IC10 AF power amp
IC11 FM IF DET
IC12 5V AVR
IC13 9V AVR
IC14 8V AVR
IC15 Flip-flop
IC201 DC amp
IC202 Mixer
IC300 PLL
IC400 Power module
IC401 Short protection
Q1 DC switch
Q2 Ripple filter
Q3 Ripple filter
Q4 HOR switch
Q5 HOR SW control
Q6 HOR SW control
Q7 Buffer amp
Q8 AF mute
Q9 AF mute
Q10 8R SW control
Q11 8R switch
Q12 8T switch
Q13 8T SW control
Q15 IF amp
Q16 DET output level switch
Q17 PC switch
Q18 DET mute
Q19 APC
Q20 APC
Q21 APC control
Q22 TOF switch
22

DESCRIPTION OF COMPONENTS

Operation / Condition
FC, TCXO control
External DEO, internal DEO
DI / DI and MO addtion
DI switch
PC, TV, FC, AFO, BEEP, TO, MO control
PC
HNC, H/L, TOF, CODE3, CODE4,
PA control
AM, LOK, STR, DM, OPT, CODE1,
CODE2 control
External 5C
Quadrature detector, 2nd mixer,
OSC, IF amplifier, RSSI
5C
9C
8C
Power on/off control
TV
DBM
Reference 16.8MHz.
PLL lock : LD "H"
RF power 10W (K), 15W (E)
When PTT on CN1 is "H",
DI on CN1 is muted
8CL
9CL
IGN
IGN
Active while HNC is "H"
HT
Avtive while AM1 is "H"
Active while power switch is off
Active while T/R is "H"
Active while Q10 is active
Active while Q13 is active
Active while KEY is "H"
44.85MHz
No function
Active while TX
Active while KEY is "H"
APC driver
APC predriver
Active while TOF is "H"
Ref. No. Use / Function
Q23 W/N switch
Q24 W/N switch
Q25 TOF switch
Q26 Inverter
Q27 SB switch
Q28 SB SW control
Q29 H/L switch
Q30 SB SW control
Q31 SB SW control
Q32 DET mute
Q202 LNA
Q203 RF amp
Q204 RF amp
Q300 Buffer amp
Q301,302 Active filter
Q401 Short protection
Q402 W/N switch
Q403 W/N switch
D1~6 Protection
D7 HOR protection
D8,9 Protection
D11 OR gate
D12~14 Protection
D15 HT switch
D16 Reverse protection
D17 Protection
D20 Reverse protection
D21 Protection
D22,23 W/N switch
D24 Over current
protection
D26 Reverse protection
D27 Power detection
D28 Protection
D30 Power detection
D31 Reverse protection
D32 Surge absorption
D34 Protection
D35 Charge
D37 Reverse protection
D206~208 BPF tune
D209,210 Usable temperature
range
D211 ANT swtich
D212 ANT switch
Operation / Condition
No function
No function
Active while Q22 is on
Active while power switch is "L"
Active while Q28 is on
Active while Q30 is on, and Q31 is off
Active while RF power is High
Active while power switch is on
Active while power supply voltage
is more than 20V
Active while TX
Power module predrive
Power module drive
PLL
Power module protection
No function
No function
AF mute
IGN
5V (IGN)
No function
B
Active while power supply voltage
is more than 20V
DEO
Active while TX