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© 2001-1 PRINTED IN JAPAN
B51-8556-00 (N) 1435
VHF FM REPEATER
TKR-750
SERVICE MANUAL
Knob (VOL)
(K29-5389-03)
Knob (DC source)
(K29-9106-04)
Key top
(K29-5460-02)
Panel assy
(A62-0934-03)
Panel (Outer)
(A62-0840-03)
Modular jack
(E08-0543-05)
GENERAL .................................................. 2
SYSTEM SET-UP ...................................... 2
OPERATING FEATURES .......................... 3
REALIGNMENT ....................................... 11
INSTALLATION ....................................... 13
MODIFICATION ....................................... 15
DISASSEMBLY FOR REPAIR ................. 16
CIRCUIT DESCRIPTION .......................... 17
SEMICONDUCTOR DATA ...................... 23
DESCRIPTION OF COMPONENTS ........ 25
PARTS LIST ............................................. 27
EXPLODED VIEW .................................... 37
PACKING ................................................. 39
ADJUSTMENT ........................................ 40
TERMINAL FUNCTION ........................... 47
WIRING .................................................... 51
PC BOARD VIEWS
RX PLL/VCO (X58-4780-10) ................ 53
TX PLL/VCO (X58-4790-10) ................ 54
DISPLAY UNIT (X54-3330-20) ............ 55
FINAL UNIT (X45-3620-XX) ................ 59
TX-RX UNIT (X57-6260-XX) (A/2) ...... 65
TX-RX UNIT (X57-6260-XX) (B/2) ...... 71
SCHEMATIC DIAGRAM .......................... 77
BLOCK DIAGRAM ................................... 89
KES-4 (EXTERNAL SPEAKER) ............... 92
SPECIFICATIONS .................................... 93
CONTENTS


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2
TKR-750
GENERAL / SYSTEM SET-UP
INTRODUCTION
SCOPE OF THIS MANUAL
This manual is intended for use by experienced techni-
cians familiar with similar types of commercial grade com-
munications equipment. It contains all required service in-
formation for the equipment and is current as of the publica-
tion date. Changes which may occur after publication are
covered by either Service Bulletins or Manual Revisions.
These are issued as required.
ORDERING REPLACEMENT PARTS
When ordering replacement parts or equipment informa-
tion, the full part identification number should be included.
This applies to all parts : components, kits, or chassis. If the
part number is not known, include the chassis or kit number
of which it is a part, and a sufficient description of the re-
quired component for proper identification.
PERSONNEL SAFETY
The following precautions are recommended for person-
nel safety :
· DO NOT transmit until all RF connectors are verified se-
cure and any open connectors are properly terminated.
· SHUT OFF and DO NOT operate this equipment near
electrical blasting caps or in an explosive atmosphere.
· This equipment should be serviced by a qualified techni-
cian only.
SERVICE
This radio is designed for easy servicing. Refer to the
schematic diagrams, printed circuit board views, and align-
ment procedures contained in this manual.
Merchandise
received
Choose the type
of transceiver
Installation in the
optional space
Frequency range (MHz)
TX/RX 146~174
TX/RX 136~150
RF power
50W
50W
Type
K,E
K2
See page 11.
A personal computer (IBM PC or compatible), programming interface (KPG-46),
and programming software (KPG-66D) are required for programming.
YES
NO
DC power
supply or
duplexer?
KES-4 installation
YES
NO
External speaker?
Repeater
programming & setup
Delivery
SYSTEM SET-UP


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3
TKR-750
OPERATING FEATURES
1. Controls and Functions
1-1. Front Panel
1 Speaker
2 CH/STATUS Display
Two, 7-segment digits display the channel number or sta-
tus.
3 VOLUME control
Rotate to adjust the volume.
4 DC source switch
5 Dc source indicator
Lights green when DC source is applied from the DC
13.6V jack (DC 13.2V jack on E type versions). Lights red
when DC source is applied from the BACK UP battery
terminal.
6 MIC jack
Connect a microphone to this 8-pin modular jack.
1
9
8
7
6
3
4
5
2
1 TX OUT jack
Connect a TX antenna or a duplexer to this receptacle.
2 CONTROL I/O jack
Connect an external programming device or repeater
controller to this DB-25 interface.
3 FUSE
Insert 15 A blade fuses into these fuse holders.
4 RX IN jack
Connect a RX antenna or a duplexer to this BNC recep-
tacle.
7 Programmable Function keys
Press these keys to activate their programmable func-
tions.
PF1 key (left side)
Default : None (No function)
PF2 key
Default : Repeat disable/enable
PF3 key
Default : TX disable/enable
PF4 key
Default : Take over
PF5 key
Default : Monitor on/off
PF6 key (right side)
Default : Channel up
8 BUSY indicator
Lights green while a signal is being received.
9 TX indicator
Lights red while transmitting.
1
7
6
5
2
8
3
4
9
1-2. Rear Panel
5 DC 13.6V (K type) / DC 13.2V (E type) jack
Connect a 13.6 V (K type) or 13.2 V (E type) DC power
supply to this jack.
6 BACKUP battery terminal
7 TEST/SPKR jack
Test input/output jack. Connect an external speaker to
this jack.
8 Cooling fan
9 Optional space
For external DC power supply, or duplexer, etc.


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4
TKR-750
OPERATING FEATURES
2. Two 7-segment LED displays
· Channel display (1~16) : While operating normally in user
mode.
· When the displayed channel is contained in scan se-
quence, the right side decimal point is displayed.
· When the displayed channel is the priority channel, the
left side decimal point is displayed.
· "PC" is displayed while in PC mode.
· "PG" is displayed while in firmware programming mode.
2 decimal points displayed = 115,200bps
1 decimal point displayed = 57,600bps
No decimal = 38,400bps
· "E1" is displayed when FPU data is not written.
· "E2" is displayed when the channel data is not written.
· "E3" is displayed when PLL is unlocked.
Receiver PLL unlocked = flashing BUSY LED.
Transmitter PLL unlocked = flashing TX LED.
· "E4" is displayed when PTT is attempted on a channel
number that has no frequency data programmed.
· "SC" is displayed while in scan mode.


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5
TKR-750
OPERATING FEATURES
3. Programmable Functions
TKR-750 contains many Programmable Functions tabled below.
Programmable Function
Description
AUX Out 1~5 Off
AUX Out 1 to 5 ports become deactivated, respectively.
AUX I/O 1~6 Off
AUX I/O 1 to 6 ports become deactivated, respectively.
AUX Out 1~5 On
AUX Out 1 to 5 ports become activated, respectively.
AUX I/O 1~6 On
AUX I/O 1 to 6 ports become activated, respectively.
AUX Out 1~5 On/Off
AUX Out 1 to 5 ports are toggled between its active and inactive states, respectively.
AUX I/O 1~6 On/Off
AUX I/O 1 to 6 ports are toggled between its active and inactive states, respectively.
Channel 1~16
Directly select Channel 1 to 16, respectively.
Channel Down
The channel decrements by one.
Channel Up
The channel increments by one.
CW ID On
The CW ID is transmitted.
CW Message 1~8 On
The CW Message 1 to 8 is transmitted, respectively.
Display Off
All panel LEDs are turned off except the Power LED.
Display On
All panel LEDs become active as normal status indicators on the repeater.
Display On/Off
All panel LEDs, with the exception of the Power LED, are toggled between off and their normal status on
the repeater.
Hold Time Enable
The Parameter of Repeat Hold Time is enabled.
Hold Time Disable
The Parameter of Repeat Hold Time is disabled.
Hold Time Disable/Enable
The Parameter of Repeat Hold Time is toggled between disabled and enabled.
Local Tx Disable
The local mic's PTT is disabled.
Local Tx Enable
The local mic's PTT is enabled.
Local Tx Disable/Enable
The local mic's PTT is toggled between disabled and enabled.
Monitor Off
The QT/DQT decoder is disabled.
Monitor On
The QT/DQT decoder is enabled.
Monitor On/Off
The QT/DQT decoder is toggled between disabled and enabled.
Monitor Momentary
The QT/DQT decoder is momentarily disabled.
Multi Table Sub
Multi Table No. Select Signalling changes to the Multi Table Sub.
Multi Table Main
Multi Table No. Select Signalling changes to the Multi Table Main.
Multi Table Main/Sub
Multi Table No. Select Signalling changes between Multi Table Sub and Multi Table Main.
QT/DQT Dec Disable
Disables the QT/DQT decode operation.
QT/DQT Dec Enable
Enables the QT/DQT decode operation.
QT/DQT Dec Disable/Enable
Toggles between disabling and enabling the QT/DQT decode operation.
QT/DQT Enc Disable
Disables the QT/DQT encode operation.
QT/DQT Enc Enable
Enables the QT/DQT encode operation.
QT/DQT Enc Disable/Enable
Toggles between disabling and enabling the QT/DQT encode operation.
Repeat Disable
Disables repeater operation.
Repeat Enable
Enables repeater operation.
Repeat Disable/Enable
Toggles between disabling and enabling repeater operation.
Reset
Resets to default condition set up by FPU.
DC Power Save Off
Activates DC Power Save Mode Off.
DC Power Save On
Activates DC Power Save Mode On.
DC Power Save On/Off
Toggles between DC Power Save Mode On and Off.