Kenwood TK-790 Service Manual

Document Copyrights

form or by any means, electronic, mechanical, photocopying, recording, or otherwise, for any purpose without the prior written permission of Kenwood.

Disclaimer

While every precaution has been taken in the preparation of this manual, Kenwood assumes no responsibility for errors or omissions. Neither is any liability assumed for damages resulting from the use of the information contained herein. Kenwood reserves the right to make changes to any products herein at any time for improvement purposes.

VHF FM TRANSCEIVER

TK -7 90/(B TK-790H(B

SERVICE MANUAL

This service manual applies to products with 30300001 or subsequent serial numbers. (KCH-10 and KCH-11 are applicable to the productions June 2001 and after.) In terms of the products with the serial numbers earier than 30300001, refer to the TK-790/(B)/H(B) service manual as per part No. B51-8438-00 and the TK-790(B) service manual as per part No. B51-8456-00.

TK-790 or TK-790(B) with KCH-10

Cabinet (Upper) (A01-2161-02)

)

REVISED

Panel assy (A62-0606-13)

KCH-11

TK-790H(B)

Cabinet (Lower) (A01-2162-02)

Knob (K29-4664-04) x 2

Panel assy (A62-0607-13)

Cabinet (Upper) (A01-2163-01)

Cabinet (Lower) (A01-2164-01)

TK-790/(B)/H(B

CONTENTS / GENERAL

GENERAL ......................................................................................................................... 2

SYSTEM SET-UP ............................................................................................................. 4

OPERATING FEATURES ................................................................................................. 5

INSTALLATION.............................................................................................................. 16

DISASSEMBLY FOR REPAIR ......................................................................................... 22

CIRCUIT DESCRIPTION ................................................................................................. 26

SEMICONDUCTOR DATA ............................................................................................. 32

DESCRIPTION OF COMPONENTS ............................................................................... 36

PARTS LIST .................................................................................................................... 39

EXPLODED VIEW .......................................................................................................... 57

PACKING ........................................................................................................................ 61

ADJUSTMENT ............................................................................................................... 65

TERMINAL FUNCTION ................................................................................................. 74

WIRING .......................................................................................................................... 77

PC BOARD VIEWS / CIRCUIT DIAGRAMS

DISPLAY UNIT (X54-3190-20) : KCH-10 .................................................................. 79

DISPLAY UNIT (X54-3200-20) : KCH-11 .................................................................. 81

CONTROL UNIT (X57-5610-XX) (B/3) ..................................................................... 87

FINAL UNIT (X57-5610-XX) (C/3) : TK-790/(B) ....................................................... 97

TX-RX UNIT (X57-5610-XX) (A/3) ......................................................................... 101

FINAL UNIT (X45-3560-10) : TK-790H(B) .............................................................. 113

BLOCK DIAGRAM ........................................................................................................ 117

SPECIFICATIONS ......................................................................................................... 119

)

GENERAL

INTRODUCTION

SCOPE OF THIS MANUAL

This manual is intended for use by experienced technicians familiar with similar types of commercial grade communications equipment. It contains all required service information for the equipment and is current as of this publication date. Changes which may occur after publication are covered by either Service Bulletins or Manual Revisions, which are issued as required.

ORDERING REPLACEMENT PARTS

When ordering replacement parts or equipment information, the full part identification number should be included. This applies to all parts : components, kits, and 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 required component, for proper identification.

PERSONNEL SAFETY

The following precautions are recommended for person-

nel safety :

• DO NOT transmit if someone is within two feet (0.6 meter) of the antenna.

• DO NOT transmit until all RF connectors are secure and any open connectors are properly terminated.

• SHUT OFF this equipment when near electrical blasting caps or while in an explosive atmosphere.

• All equipment should be properly grounded before power-up for safe operation.

• This equipment should be serviced by only qualified technicians.

GENERAL

TK-790/(B)/H(B

)

PRE-INSTALLATION CONSIDERATIONS

1. UNPACKING

Unpack the radio from its shipping container and check for accessory items. If any item is missing, please contact KENWOOD immediately.

2. LICENSING REQUIREMENTS

Federal regulations require a station license for each radio installation (mobile or base) be obtained by the equipment owner. The licensee is responsible for ensuring transmitter power, frequency, and deviation are within the limits permitted by the station license.

Transmitter adjustments may be performed only by a licensed technician holding an FCC first, second or general class commercial radiotelephone operator’s license. There is no license required to install or operate the radio.

3. PRE-INSTALLATION CHECKOUT 3-1. Introduction

Each radio is adjusted and tested before shipment. However, it is recommended that receiver and transmitter operation be checked for proper operation before installation.

3-2. Testing

The radio should be tested complete with all cabling and accessories as they will be connected in the final installation. Transmitter frequency, deviation, and power output should be checked, as should receiver sensitivity, squelch operation, and audio output. QT equipment operation should be verified.

4. PLANNING THE INSTALLATION 4-1. General

Inspect the vehicle and determine how and where the radio antenna and accessories will be mounted.

Plan cable runs for protection against pinching or crushing wiring, and radio installation to prevent overheating.

4-2. Antenna

The favored location for an antenna is in the center of a large, flat conductive area, usually at the roof center. The trunk lid is preferred, bond the trunk lid and vehicle chassis using ground straps to ensure the lid is at chassis ground.

4-3. Radio

The universal mount bracket allows the radio to be mounted in a variety of ways. Be sure the mounting surface is adequate to support the radio’s weight. Allow sufficient space around the radio for air cooling. Position the radio close enough to the vehicle operator to permit easy access to the controls when driving.

4-4. DC Power and wiring

1. This radio may be installed in negative ground electrical

systems only. Reverse polarity will cause the cable fuse

to blow. Check the vehicle ground polarity before installa-

tion to prevent wasted time and effort.

2. Connect the positive power lead directly to the vehicle

battery positive terminal. Connecting the Positive lead to

any other positive voltage source in the vehicle is not rec-

ommended.

3. The cable provided with the radio is sufficient to handle

the maximum radio current demand. If the cable must be

extended, be sure the additional wire is sufficient for the

current to be carried and length of the added lead.

5. INSTALLATION PLANNING – CONTROL STATIONS 5-1. Antenna system

Control station. The antenna system selection depends on many factors and is beyond the scope of this manual. Your KENWOOD dealer can help you select an antenna system that will best serve your particular needs.

5-2. Radio location

Select a convenient location for your control station radio which is as close as practical to the antenna cable entry point. Secondly, use your system’s power supply (which supplies the voltage and current required for your system). Make sure sufficient air can flow around the radio and power supply to allow adequate cooling.

SERVICE

This radio is designed for easy servicing. Refer to the schematic diagrams, printed circuit board views, and alignment procedures contained in this manual.

TK-790/(B)/H(B

)

Before Reading About System Set-up

The TK-790(B)/H(B) is a transceiver main unit (without a

panel or speaker) that you complete by adding options.

The options are classified into three types according to

operation and function.

1. Install the front panel kit (controller) directly on a radio to operate it. (Form : Radio + KCH-10/11)

2. Remotely control one radio with one controller. (Form : Radio + KRK-5 + KCH-10/11 + KCT-22M/M2/M3)

SYSTEM SET-UP

3. Remotely control one radio with two controllers. (Form : Radio + KRK-6DH + KCH-10/11 (two) + KCT-22M/M2/ M3 (two))

4. Remotely control two radios with one controller. (Form : Radios (two) + KRK-7DB + KCH-10/11 + KCT-22M/M2/ M3)

5. Remotely control two radios with two controllers. (Form : Radio (two) + KRK-8DBH + KCH-10/11 (two) + KCT22M/M2/M3 (two))

Merchandise received

License and frequency allocated by FCC

Choose the type of transceiver

TK-790/(B), TK-790H(B) (Radio 1)

TK-790(B) or TK-790H(B) is complete by combining

options with only the transceiver body (without panel)

TK-790 : Contain (KCH-10)

Are you using the remote kit?

See page 16

KCH-10 (Basic model)

Front panel kit

Are you using the printed keytops?

See page 16

Supplied accessory knob

See page 16

KCH-11 (Full featured

model) Front panel kit

YES

Are you using the ignition sense cable?

YES *See Remote

kit service manual

Are you using the voice scrambler?

Transceiver programming (option)

Are you using the external speaker?

KCT-23 (DC cable)

Frequency range

148~174MHz 136~156MHz 45W TK-790(B) F2 148~174MHz

Are you using one radio with two controllers?

Are you using one radio

with one controller?

Single control head kit

KCH-10 KCH-11

RF power

45W

110W

Are you using two radios with one controller?

YES

KRK-5

or or

KCT-22M/M2/M3

Control cable

YES

See Installation manual KCT-23 M,M3 : TK-790/(B), KCT-23 M2,M4 : TK-790H(B)

YES

Modified of control unit

See page 13 A personal computer (IBM PC or compatible), programming interface (KPG-43), and programming software (KPG-44D) are required for programming. (The frequency and signalling data are programmed for the transceiver.)

Type

TK-790/(B) F1

TK-790H(B) F1

Are you using two radios with two controllers?

YES

KRK-6DH

Dual control head kit

KCH-10

KES-4 (EXT. SP)

KCT-18

KCH-10

KCH-11

*See Remote kit service manual

See page 17

KCH-11

See page 18

YES

KRK-7DB

Dual band remote kit

KCH-10 KCH-11

YES

KRK-8DBH

Dual band dual control head kit

or or

KCH-10

KCH-11

Delivery

*Service manual parts No. list

Model Parts No.

KRK-5/6DH B51-8445-00

KRK-7DB/8DBH B51-8452-00

TK-790/(B)/H(B

OPERATING FEATURES

)

1. Controls and Functions

1-1. Basic Function Panel

(20)

CALL

(19)(7)

(24)

(25)

(32) (30)

SCAN OPT OSTA B CMON

(32)

(26)

(27)

MON

SCN

(28)

(26)

(27) (28) (30)

(6)

(1)

POWER

GRP

BUSY

VOL

(2)

(3)

(4) (5) (10) (11) (12) (13) (14)

(29)

(31) (21) (22)(23)

1-2. Full Function Panel

(1)

(6) (7) (19) (9)(8)(17) (15) (16) (18)

POWER

GRP

BUSY

VOL

(2) (3) (4) (5) (10) (11) (12) (13) (14)

(29) (31) (20) (21) (22) (23) (24) (25)

CALL

(1) POWER Switch

Press to turn the power ON and OFF.

(2) TX/BUSY Indicator

The TX Indicator (Red LED) shows that you are transmitting. The BUSY Indicator (Green LED) shows that the channel

is in use. (3) Microphone Connector (4) Volume Knob

To increase the volume level, turn clockwise (CW).

To decrease the volume level, turn counterclockwise

(CCW). (5) UP/DOWN Knob

The function of this Knob can be programmed by the

FPU.

Function Description Note

Channel Channel selector. Default

UP/DOWN To increase the channel, turn CW. setting.

To decrease the channel, turn CCW.

Group Group selector.

UP/DOWN To increase the group, turn CW.

To decrease the group, turn CCW.

(6) GR UP Key, (7) GR DW Key, (8) MON Key, (9) SCN Key, (10)~(18) PF1-9 Key

The function of these Keys can be programmed by the

FPU.

Function Description Note

[ ] : Key top name

No No function.

Function of PF1~9.

Monitor If [MON] is pressed once while

[MON]

Scan Start and stop the scanning

[SCN] sequence. of SCN. (Full

Public The RADIO works as a PUBLIC

Address [PA]

Horn Alert When the RADIO receives a

[HA] the optional signalling calls that

Talk Around

[TA] with other operators directry,

Intercom

[IC]

the RADIO is waiting for reception,

all signalling* squelch is canceled.

If [MON] is held down for 2 seconds,

noise squelch is canceled and the

audio is unmuted.

ADDRESS amplifier.

are assigned to the channel, the

HA relay turns on.

Use this function to communicate

without using a repeater.

Use this function to communicate

between the HEAD1 and HEAD2

operator without transmitting. only.

Default setting

of MON. (Full

function panel)

all singalling;

QT/DQT &

2 TONE/DTMF

Default setting

function panel)

Dual HEAD

configuration

TK-790/(B)/H(B

OPERATING FEATURES

)

Function Description Note

[ ] : Key top name

Channel Switches the display between

Name [AN] Group-Channel No. and Group

channel name.

Speaker

Internal/ Internal speaker and PA speaker.

External [SP]

Delete/ Changes the Scan DELETE/ADD

Add [D/A] setting of each channel or group.

Squelch

Level Mode. The Squelch level can be

[SQL]

Operator Select signalling from the pre-

Selectable programmed QT/DQT list.

Tone [OST]

Scrambler The optional board on and off. Install the

[OPT]

AUX A [AUXA]

AUX B [AUXB]

AUX C [AUXC]

Home Channel

(Fixed) [HC]

Home Channel

(Toggle) [HC]

CH1 Direct

[CH1]

CH2 Direct

[CH2]

CH3 Direct

[CH3]

CH4 Direct

[CH4]

CH5 Direct

[CH5]

Channel

Recall [RCL]

Dimmer

[DIM]

Switch the audio output between

Press and hold

[D/A] for more

than 2 seconds

to toggle a

Group DEL

and ADD.

Press to enter Squelch Level Adjust

adjusted by using the UP/DOWN

Knob, or the preprogrammed

channel Up/Down key or Group

Up/Down key.

Scrambler board.

Turns AUX A port on and off.

Turns AUX B port on and off.

Turns AUX C port on and off.

Switches to the pre-programmed

Home Channel.

When pressed once, switches to

the Home Channel. Press again

to returns to the previous channel.

Switches to the GR1-CH1 directry.

Switches to the GR1-CH2 directry.

Switches to the GR1-CH3 directry

Switches to the GR1-CH4 directry.

Switches to the GR1-CH5 directry.

When pressed once, switches to The [RCL] Key

the last called channel. Press again

to return to the previous channel.

Use this function to adjust the LCD

backlight brightness, Key backlight,

TX/BUSY LED, and DTMF Mic Key

backlight ON/OFF.

works in Scan

Mode only.

Function Description Note

[ ] : Key top name

Speaker 1-2

Mute [SPM]

Channel UP

[ ] increases by one step.

Channel

DOWN

Group UP

[ ] increases by one step.

Group

DOWN

Mobile Relay

Station [RPT]

Emergency To start an Emergency Call, This function

Call [EMG] press [EMG].

Each speaker audio can be Dual HEAD

manually disabled from the configuration

other control head. only.

If [ ] is pressed once, the channel

If [ ] is held down for 1 second,

the channel increases continuously.

If [ ] is pressed once, the channel

[ ] decreases by one step.

If [ ] is held down for 1 second,

the channel decreases continuously.

If [ ] is pressed once, the group

If [ ] is held down for 1 second,

the group increases continuously.

If [ ] is pressed once, the group

[ ] decreases by one step.

If [ ] is held down for 1 second,

the group decreases continuously.

The RADIO works as a repeater. Dual BAND

configuration

only.

needs the ANI

board.

(19) LCD Display

Description Note

(20) CALL

(21) MON Lights when [MON] is pressed.

(22) SCN Indicates when scan mode is

(23) SP Lights when “PA speaker” is

(24) OPT Lights when the optional board*, Optional

(25) A Lights when [AUXA] is pressed.

(26) B Lights when [AUXB] is pressed.

Flashes when the RADIO is called

by proper Optional Signalling has been set

(DTMF or 2Tone).

Signalling squelch is disabled.

enabled.

selected for audio output.

that is installed inside the RADIO,

is enabled. · Scrambler

The PF Port that is programmed

with “AUX A” is ON.

The PF Port that is programmed

with “AUX B” is ON.

If Signalling

“AND”, CALL

lights after

transmitting.

Board :

TK-790/(B)/H(B

OPERATING FEATURES

)

Description Note

(27) C Lights when [AUXC] is pressed.

The PF Port that is programmed

with “AUX C” is ON.

(28) OST Lights when [OST] is pressed,

Operator Selectable Tone is

enabled.

(29) ▼ If the selected group is in the

(Group multi group scan sequence,

Add Status) the indicator appears at the

group.

(30) ▼ If the selected channel is in the

(Channel scan sequence, the indicator

Add Status) appears at the channel.

(31) Displays the channel status.

• BASIC P1 : Lights when a PRIORITY 1

FUNCTION

PANEL 7 P2 : Lights when a PRIORITY 2

SEGMENT

display PP : Lights when a PRIORITY 1

• FULL

FUNCTION

PANEL Channel is selected by [HC] key.

DOT TA : Lights when the RADIO is

MATRIX (S)

display RCL : Lights when recall

(32) Displays the operating Group-

• BASIC

FUNCTION

PANEL 13

SEGMENT

display features.

• FULL

FUNCTION

PANEL DOT

MATRIX (L)

display

channel is shown on the display.

& 2 channel is shown on the display.

HC : Lights when a Home

in Talk Around mode.

channel is selected by [RCL] key.

R1-R15 : Lights when remote

channel is selected by PF port.

Channel number (Channel display),

or name (Alphanumeric display)

programmed by the FPU. Also

displays the status of some

1-3. Microphone

Press PTT (Push To Talk) to transmit, then speak into the microphone.

2. Receive

(1) To turn on the RADIO:

Press the Power Switch. The display and graphics illumi-

nate to indicate the RADIO is ON. (2) To adjust the volume level:

Turn the Volume Knob CW to increase the volume level.

Turn the Volume Knob CCW to decrease the volume

level. (3) To select a Group:

Select a Group by rotating the UP/DOWN Knob which

has been programmed with “Group UP/DOWN” or by

pressing the Keys which have been programmed with

“Group UP” and “Group DOWN”.

If the “Channel Tracking Function” is enabled, the chan-

nel number will not change. (4) To Select a Channel:

Select a Channel by rotaing the UP/DOWN Knob which

has been programmed with “Channel UP/DOWN” or by

pressing the keys which have been programmed with

“Channel UP” and “Channel DOWN”. (5) To enter carrier squelch mode:

If you want to monitor a channel, press [MON] Key. If the

“OFF HOOK Decode” function has been disabled, you

can also enter monitor mode by taking the microphone

off HOOK.

3. Transmit

(1) Normal ON HOOK Scan Mode

First, lift the microphone from the HOOK. The scanning

stops temporarily and the OFF HOOK revert channel is

displayed. Listen for a few seconds to make certain the

channel is not being used.

OFF HOOK Scan MODE

If scanning, pressing the PTT switch will stop the RADIO

on the OFF HOOK revert channel and begin transmis-

sion immediately.

Not Scan Mode

Pressing PTT starts transmission at the selected channel. (2) Press PTT and start speaking. For best results, hold the

microphone 1 to 1.5 inches from your mouth. Release

PTT when your message is complete. Listen for a re-

sponse. (3) When your conversation is finished, replace the micro-

phone on its hook.

4. Scan Operation

4-1. General

There are two “Mic HOOK” scan modes in which the RADIO can be programmed to operate.

• ON HOOK Scan

Normal method of scanning that requires the microphone

to be ON HOOK (hanged on the Mic Hanger) to initiate

scan.

• OFF HOOK Scan

The microphone does not have to be ON HOOK to initiate

scan or to scan channels.

TK-790/(B)/H(B

OPERATING FEATURES

)

(1) The scan feature is initiated by pressing the [SCN] Key. (2) A single confirmation tone sounds, and scanning starts. If

there is only one or no added channels, an error tone will sound and scanning will not start.

(3) The display shows “SCN” icon, and “SCAN” or the OFF

HOOK Revert Channel Number (FPU setting).

(4) If the RADIO receives a proper signal while scanning,

scanning stops temporarily, audio is unmuted, and the channel number or name is displayed. If either “Priority1” or “Priority2” is programmed and scanning stops at a Normal Channel by receiving a signal, the RADIO watches for a signal on the Priority Channel periodically. When a signal exists on the Priority Channel, the channel will change from the Normal Channel to Priority Channel. If both “Priority1” and “Priority2” are programmed and scanning stops at the Priority2 Channel by receiving a signal, the RADIO watches a signal on the Priority1 Channel periodically. When a signal exists on the Priority1 Channel, the channel will change from the Priority2 Channel to the Priority1 Channel. If there is no Priority Channel programmed, the scanning stops at a channel and receives only that channel.

(5) If the [SCN] Key pressed again, Scan Mode ends at the

revert channel, and two confirmation tones sound.

4-2. To Delete Undesired Channels

To temporarily delete undesirable channels, press [D/A] Key while the channel is displayed, and scanning resumes. (To temporarily delete Priority Channel 1 or 2, set the “Priority Temporary D/A” function to “YES”.)

You can’t delete a channel in Scan Mode under the following conditions:

• Priority Scan

There is only channel beside the Priority Channel in the

scan sequence.

• Non-priority Scan

There are only 2 channels in the scan sequence. To re-

store the original scan sequence, either turn scan off and

on or turn the RADIO off and on.

6. Deleting Channels and Groups from the Scan Sequence

(1) Channels

To delete a channel from the scan sequence press [D/A]

Key. The CH ADD indicator (▼) goes off, and the channel

is deleted from the scan sequence.

(2) Groups

To delete the currently displayed group of channels from the scan sequence, hold down [D/A] Key for 2 seconds.

The GR ADD indicator (▼) goes off, and all the channels

in the group are deleted from the multi group scan sequence.

7. Operator Selectable Priority

(1) Operator Selectable Priority1

If Priority1 has been set to “Operator Selectable”, you can set the currently displayed channel as Priority1. To set the currently displayed channel as Priority1, hold down the [SCN] Key and press the [MON] Key three times.

(2) Operator Selectable Priority2

If Priority2 has been set to “Operator Selectable” you can set the currently displayed channel as Priority2. To set the currently displayed channel as Priority2, hold down the [SCN] Key and press the [MON] Key twice.

8. Talk Around (TA)

Talk Around is useful when you are close to other mo-

biles you want to talk to, or are outside the range of your repeater system.

Press the [TA] Key. A confirmation tone sounds, and

“TA” (BASIC Panel : 7 segment, FULL Panel : DOT MATRIX (S)) is displayed. You can communicate without using a repeater.

To use a repeater, press [TA] again. A confirmation tone

sounds, and “TA” goes off.

4-3. To Enter Carrier Squelch Scan While Scan is On

If you have pressed the [MON] Key, the MON indicator is

turned on and the RADIO operates in carrier squelch scan.

5. Adding Channels and Groups to the Scan Sequence

(1) Channels

To add the currently displayed channel to the scan se-

quence, press [D/A] Key. The CH ADD indicator (▼)

lights, and the channel is added to the scan sequence.

(2) Groups

To add the currently displayed group of channels to the scan sequence, hold down the [D/A] Key for 2 seconds.

The GR ADD indicator (▼) lights, and the group is added

to the scan sequence.

9. Horn Alert (HA)

If you are called from the base station using 2Tone/DTMF while you are away from your transceiver, you will be alerted by the vehicle horn or some other type of external alert. To turn the horn alert function on, press the [HA] Key. A confirmation tone sounds, and the display shows HORN ALERT (or HA).

If [HA] is pressed again, the horn alert function is turned off.

TK-790/(B)/H(B

OPERATING FEATURES

)

10. Public Address (PA)

Public Address amplifies the microphone audio, and outputs it through a PA speaker. PA is activated by pressing the [PA] Key. A confirmation tone sounds, and the display shows PUBLIC ADDRESS (or PA). PA can be activated at anytime (scanning or non-scanning).

The RADIO continues to scan & receive calls while in PA mode. Pressing PTT activates PA, and will override an incoming call at anytime ; however, no RADIO transmission takes place. If [PA] is pressed again, a confirmation tone will sound, the display will return to the normal channel or SCAN display, and the PA function will turn off.

11. Speaker Internal/External (SP)

SP amplifies the received audio from the RADIO and outputs it through a PA speaker. SP is activated by pressing the [SP] Key. A confirmation tone sounds and the SP icon is displayed. SP can be activated at anytime (scanning or nonscanning).

The RADIO transmits and operates normally while SP is activated, but all received calls will be output through the PA speaker. If [SP] is pressed again, a confirmation tone sounds, the SP icon goes off and the SP function will turn off.

12. Channel Name (AN)

This function switches the 13-segment display (BASIC Panel) or DOT MATRIX (L) display (FULL Panel) between alphanumeric and Group-Channel number.

If you want to change from alphanumeric display to channel display, press [AN] Key. A confirmation tone sounds, and the alphanumeric display changes to the channel display.

If [AN] is pressed again, a confirmation tone sounds, and the channel display changes back to the alphanumeric display.

CASE1 : HC has been set as “HC (Fixed)”

Non-Scan Scanning Scan

Mode temporary

stopping

press [HC] once Change to Home Channel

press [HC] again No effect

CASE2 : HC has been set as “HC (Toggle)”

Non-Scan Scanning Scan

Mode temporary

stopping

press [HC] once Change to Home Channel

press [HC] again Return to Change to Return to

current channelRevert Channel current channel

15. Squelch Level (SQL)

This function allows the radio operator to manually adjust the squelch threshold in 16 steps (Level 0~15) via the front panel controls. To adjust the squelch level:

(1) Press the [SQL] Key. A confirmation tone sounds, and

the RADIO enters Squelch Level Adjust Mode. In this

mode, all signallings are canceled and audio is unmuted.

The display shows SQUELCH XX (or SQL XX). (XX=

squelch level) (2) Change the squelch level by pressing [ ] and [ ] Keys,

or rotating the UP/DOWN Knob. (3) Press [SQL] again. A confirmation tone sounds, the dis-

play returns to the normal channel, the level setting is

memorized, and Squelch Level Adjust Mode will turn off.

* This feature can be initiated when the RADIO is not in

scanning mode.

13. Intercom (IC) ; Dual Head Configuration only

Intercom (IC) allows one control head operator to talk to the another control head operator. IC mode is activated by pressing the [IC] Key. A confirmation tone sounds and the display shows INTERCOM. IC can be activated at anytime (scanning or non-scanning).

The RADIO continues to scan & receive calls while in IC mode. Pressing PTT activates IC and will override an incoming call at anytime ; however, no RADIO transmission takes place. If [IC] is pressed again, a confirmation tone sounds, the display returns to the normal channel or SCAN display, and the IC function will turn off.

14. Home Channel (HC)

This feature allows the radio operator to immediately select a pre-determined “Home Channel” by pressing the [HC] Key. HC can be activated as follows.

16. Operator Selectable Tone (OST)

This function allows the radio operator to change the preset decode QT/DQT, encode QT/DQT. You can select Dec/ Enc OFF or from up to 16 decode/encode pairs (Pair No. 1~16) programmed by the FPU. To select the Dec/Enc pairs:

(1) Press the [OST] Key. A confirmation tone sounds, and

the display shows the OST Name which is memorized in

the channel for 2 seconds. The “OST” icon lights, and

OST is enabled.

Press [OST] again, and the OST icon goes off and OST is

disabled. (2) When the [OST] Key is held down, a confirmation tone

sounds and the RADIO enters OST Select Mode. (3)Select the Dec/Enc pair by pressing the [ ] and [ ]

Keys, or rotating the UP/DOWN Knob. The display shows

TONE XX (XX=Dec/Enc pair number) or the OST Name. (4) Press [OST] again, a confirmation tone sounds, the dis-

play returns to the normal channel, the pair is memorized

and OST Mode will turn off.

* You can select a Dec/Enc pair on each channel.

TK-790/(B)/H(B

OPERATING FEATURES

)

17. Option Board (OPT)

If an optional Scrambler board has been installed in the RADIO, Scrambler is activated by pressing the [OPT] Key. A confirmation tone sounds, and the OPT icon is displayed. If [OPT] is pressed again, a confirmation tone sounds, the OPT icon goes off and the Scrambler will turn off.

If [OPT] is held down, the RADIO enters SCR Code Set Mode. A confirmation tone sounds, and the display shows CODE XX (XX=SCR Code). Change the SCR Code by pressing the [ ] and [ ] Keys, or rotating the UP/DOWN Knob.

play returns to channel (SCR is ON), the SCR Code setting is memorized, then SCR Code Set Mode will turn off.

Press [OPT] again, a confirmation tone sounds, the dis-

18. AUX A, AUX B, AUX C

This function switches the accessory PF Output ports which have been programmed with AUX A, AUX B and AUX C.

Press [AUXA] Key. A confirmation tone sounds, the A icon is displayed, and the AUX A Port is switched on (Low level). If [AUXA] is pressed again, a confirmation tone sounds, the A icon goes off and the AUX A Port is switched off (open collector).

In the same way, [AUXB] Key controls the AUX B Port, and [AUXC] Key controls the AUX C Port.

19. Direct Channel Access

This feature allows the radio operator to immediately select CHANNELs 1~5 which are contained in GROUP 1. To select GR1-CH1, press [CH1]. To select GR1-CH2~5, press [CH2] ~ [CH5],

20. Channel Recall (RCL)

This feature is enabled in scan mode.

This feature allows the radio operator to immediately access the last called (Unmuted) channel by pressing [RCL]. The 3-digit display shows “RCL”. Press [RCL] again, and the radio returns to the previous channel.

21. Dimmer (DIM)

To adjust the brightness of the display backlight, TX/ BUSY LED, panel Keys backlight and microphone keys backlight, press the [DIM] Key.

[DIM] controls the brightness at the same time as follows.

Display TX/BUSY Panel Keys Microphone

backlight LED backlight

Default High High High High

Press [DIM]

once

Press again

* The brightness setting is memorized.

Medium ↓↓↓

Low ↓↓↓

OFF OFF OFF OFF

return to return to return to return to

High High High High

Keys backlight

22. Speaker 1-2 Mute (SPM)

; Dual Head Configuration only

This feature allows the radio operator to manually disable

the speaker audio of another control head.

Press the [SPM] Key, a confirmation tone sounds, and the other head speaker is muted. Both head displays shows X MUTE (X=Muted HEAD number).

This muted condition is canceled by both head keys without PTT and Mic HOOK which is connected to Un-muted head.

23. Mobile Relay Station (RPT)

; Dual Band Configuration only

This function allows the radio operator to use the RADIO as a repeater.

(1) Both “Repeater Channel 1” and “Repeater Channel 2”

must be pre-programmed by the FPU. Each channels

must be on diferent bands. (2) Press the [RPT] Key, then both the VHF and UHF units

move to the repeater channel, and enter Repeater mode.

Displays of both heads show “REPEATER”. (3) If one unit receives a proper signal, the other unit will

start transmitting (repeating). (4) If the signal stops, the repeat action will stop. If one of

the units detects another signal, the repeat action will re-

start. (5) Press [RPT] again, both units return to their previous

channels, and exit the Repeater mode. However, during

the repeating mode, pressing [RPT] has no effect.

24. Emargency Call (EMG)

If the [EMG] Key is held down, the RADIO enters the Emergency Mode. In the Emergency Mode, the channel changes to the “Emergency Channel (set by the FPU)” internally. The display depends on “Emergency Channel Display” setting, and the Emergency Call (None, DTMF, MSK or ANI board) is transmitted.

If “ANI Board” is selected for the Emergency Type, turn the transceiver off, then turn it on again to recover “Normal Mode”.

If “ANI Board” is not selected for the Emergency Type, press and hold [EMG] key to recover “Normal Mode”.

TK-790/(B)/H(B

OPERATING FEATURES

)

25. Busy Channel Lockout (BCL), BCL Override

The Busy Channel Lockout function prevents interferance with other stations that may be using the same channel.

While the selected channel is in use, pressing PTT causes the RADIO to sound a warning tone, and transmission is inhibited. To stop the warning tone, release PTT.

If BCL Override has been enabled, pressing PTT within 500msec again will cancel BCL, and transmission is enabled.

26. 2Tone Signalling

2Tone signalling opens the squelch only when the RADIO receives a proper 2Tone code that is the same as the pre-programmed 2Tone for the channel. When the RADIO receives a 2Tone code, the CALL icon flashes.

If Transpond has been programmed, the RADIO will return an acknowledgment signal automatically after receiving the 2Tone code.

If Call Alert has been programmed, an Alert Tone sounds after receiving a 2Tone code. You can configure “Normal” (an alert tone beeps once) or “Continuous” (an alert tone beeps every 5 seconds) for the Call Alert. Unmute condition is canceled and the CALL icon goes off when ; (1) pressing the [MON] Key, (2) hanging the microphone on its hook, (3) muting continues for 10 seconds. (If “Auto Reset” has been programmed)

27. DTMF Signalling

DTMF Signalling opens the squelch only when the RADIO receives a proper DTMF code that is the same as the pre-programmed “Primary Code (Individual ; 1~7digits)” or “Secondary Code (Group ; 1~7digits)”. When the RADIO receives a correct code, the CALL icon flashes.

If Transpond has been programmed, the RADIO will return an acknowledgment signal automatically after receiving the DTMF code.

If Call Alert has been programmed, an Alert Tone sounds after receiving a DTMF code. You can configure “Normal” (an alert tone beeps once) or “Continuous” (an alert tone beeps every 5 seconds) for the Call Alert. Unmute condition is canceled and the CALL icon goes off when ; (1) pressing the [MON] Key, (2) hanging the microphone on its hook, (3) muting continues for 10 seconds (If “Auto Reset” has been programmed), and (4) receiving reset code. (Primary code + “#” or secondary code + “#”)

28. Time Out Timer

(Possible to configure to each group)

The Time Out Timer function interrupts continuous transmission after a specified time elapses.

Holding down PTT for longer than the programmed time causes the RADIO to stop transmitting and sound a warning tone. To stop the warning tone, release PTT.

29. Signalling AND/OR

(Possible to configure to each group)

The RADIO will be unmuted with a combination of QT/ DQT and 2Tone/DTMF. The AND/OR setting works as follows.

29-1. AND

The audio is unmuted when the RADIO receives the correct QT/DQT and 2Tone/DTMF. After transmitting, 2Tone/ DTMF will be canceled.

29-2. OR

The audio is unmuted when the RADIO receives the correct QT/DQT. 2Tone/DTMF is used just as an individual call or group call.

30. Off Hook Decode

If the OFF HOOK Decode function has been enabled, removing and replacing the microphone on the HOOK has no effect for decoding QT/DQT and 2Tone/DTMF.

31. TX Audio Monitor

; Dual Head Configuration only

This function allows the radio operator to hear another operator’s voice which is transmitted through another control head.

If the TX Audio Monitor function is set to “w/Talk Interrupt” and one operator is transmitting, the other operator’s control head displays “INTERCOM” and he/she can speak to the transmitting control head by pressing PTT.

32. Roll Over/Dead End

32-1. Roll Over

When [ ] (CH UP) is pressed, or the CH UP/DOWN Knob is turned CW from the Maximum channel, the channel changes to the Minimum channel.

When [ ] (CH DOWN) is pressed, or the CH UP/DOWN Knob is turned CCW from the Minimum channel, the channel changes to the Maximum channel.

32-2. Dead End

When [ ] (GR UP) is pressed, or the GR UP/DOWN Knob is turned CW from the Maximum group, the group doesn’t change.

When [ ] (CH UP) is pressed, or the CH UP/DOWN Knob is turned CW from the Maximum channel, the channel doesn’t change.

When [ ] (GR DOWN) is pressed, or the GR UP/DOWN Knob is turned CCW from the Minimum group, the group doesn’t change.

When [ ] (CH DOWN) is pressed, or the CH UP/DOWN Knob is turned CCW from the Minimum channel, the channel doesn’t change.

TK-790/(B)/H(B

OPERATING FEATURES

)

33. Minimum Volume

When the Volume Knob is adjusted fully counterclockwise, the audio level is set to the Minimum Volume level which is programmed by the FPU.

34. Dead Beat Disable (DBD)

If the RADIO receives a DBD Code (1~7digits), the RADIO returns an acknowledgment signal automatically, and transmission is disabled. This TX INHIBIT condition is memorized.

If the RADIO receives a DBD Reset Code (DBD Code + #), the RADIO returns an acknowledgment signal automatically, and transmission is Enabled.

35. ANI Board

The ANI board contains functions which you can use. To use the function, you select that function on the ANI board.

36. Accessory Programmable Function

Port (PF Port)

The RADIO has 13 PF Ports.

HEAD (12 pin) : PF Input Port 2, PF Output Port 2

DECK (Dsub 25 pin) : PF Input Port 5, PF Output Port 4

Each Port can be programmed with a function from next Table.

36-1. PF Input Port

External HOOK Open → OFF HOOK, Low → ON HOOK

CH Select A The Channel changes to Remote Channel

CH Select B

CH Select C the channel is selected by using the [ ]/[ ]

CH Select D keys or UP/DOWN Knob. (User Channel) External PTT Open → PTT OFF, Low → PTT ON Scan Open → Scan OFF, Low → Scan ON

Home Channel

Light Sense

Repeater SW

External Monitor Open → Monitor OFF, Low → Monitor ON

1~15. If CH Select A~D are set “H” or “Open”,

Open → Current Channel, Low → Home Channel Open → LCD Backlight is controlled by [DIM], Low → LCD Backlight is set “Low” Open → Repeater inactive, Low → Repeater Active

* Dual BAND configuration only

36-2. PF Output Port

AUX A Pressing [AUXA] once → Low, Pressing [A]

[AUXA] again → OPEN-COLLECTOR

AUX B Pressing [AUXB] once → Low, Pressing [B]

[AUXB] again → OPEN-COLLECTOR

AUX C Pressing [AUXC] once → Low, Pressing [C]

[AUXC] again → OPEN-COLLECTOR

TOR

COR

Receiving correct QT/DQT → ing correct QT/DQT → BUSY → Low, Not BUSY → OPEN-COLLECTOR

Low

, Not receiv-

OPEN-COLLECTOR

37. Timed Power Off

This function works as “Automatic Power Switch Off”.

Timed Power Off timer starts from the ignition-off. After the timer expires, the RADIO will automatically turn off. The timer will be reset if the ignition is turned on and off.

This function requires ignition-sense. Connect the ignition-line to the 9-pin connector which is located at the rear of the RADIO.

After the timer expires, you can turn the transceiver on again with 2 methods below.

1) Timed power off function (Default) Press the power switch.

2) Ignition function & Timed power off function Turn the ignition on.

38. Emergency

• Active tome

Automatic transmission period in the emergency mode.

• Interval Time

Interval time between the automatic tansmissions.

• Duration of Locator Tone 1

Duration of an alert tone before the automatic transmis-

sion is performed.

• Duration of Locator Tone 2

Duration of an alert tone after the automatic transmission

is performed.

• Emergency Channel Display

Setting for the display in the emergency mode. The transceiver can be programmed to display “EMER-

GENCY” channel name when it is in emergency mode.

If you set to “off” by KPG-44D the transceiver shows selected group/channel/status before entering to the emergency mode however the transceiver is in an emergency mode.

TK-790/(B)/H(B

User mode

PC mode

PC programming mode

PC test mode

PC tuning mode

Panel test mode

Panel tune mode

Clone mode All clone mode

Group clone mode

Firmware programming mode

19200 bps

38400 bps

57600 bps

115200 bps

[PF4]

OPERATING FEATURES

)

• Emergency Mode Type

Speaker mute on or off in the emergency mode.

• Emergency Type

Select an Emergency code format from DTMF, MSK, ANI

board or OFF (Disabled).

• Emergency DTMF ID

The emergency DTMF ID code when you select DTMF in

the emergency type.

• Emergency Call Fleet

The emergency fleet number when you select MSK in

the emergency type.

• Emergency Call ID

The ID number when you select MSK in the above emer-

gency type.

39. MSK PTT ID

• Side Tone

A tone to notify the voice transmission is allowed after

sending the MSK PTT ID (Connect ID).

• Fleet (Own)

• ID (Own)

Configure the Fleet/ID of the MSK PTT ID (Fleet Sync

Format).

41-2.

Programming Interface Cable KPG-43 Description

The KPG-43 is required to interface TK-790 to the computer. It has a circuit in its D-sub 25 pin connector case that converts RS-232C logic level to TTL level.

KPG-43 is used to connect between TK-790 microphone connector and RS-232C serial port of computer.

41-3. Programming Software KPG-44D Description

KPG-44D is the programming software for TK-790 supplied on a 3.5" floppy disk. This software runs under MSDOS version 3.1 or later on an IBM-PC/XT, AT, or PS2 or compatible machine.

The data can be input to or read from TK-790 and edited on the screen. The programmed or edited data can be printed out. It is also possible to tune the transceiver.

We recommend that install KPG-44D for example to harddisk first then use it.

KPG-44D instruction manual part No. : B62-1011-XX.

IBM-PC

KPG-43

• Data TX Mod. Delay

Delay time of transmitting the MSK ID after the trans-

ceiver enters the transmission mode.

40. Power On Text

To display the Power on text for approximately 2 seconds

when the transceiver is turned on.

41. Data Programming (PC Mode)

41-1. Preparation and Connection

TK-790 transceiver is programmed by using a personal computer, programming interface cable KPG-43, and programming software KPG-44D.

The programming software can be used with an IBM-PC or compatible machine. Figure 1 shows the setup for programming.

KPG-44D

Fig. 1

42. Mode

: Single band only

TK-790/(B)/H(B

MIC

IC1

GND

TRD

MAXIM

MAX232C

OPERATING FEATURES

)

Mode Function

User mode Customer use this mode

PC mode Communication between the radio and

PC (IBM compatiible). It requires the

KPG-44D.

Panel test mode Dealer uses to check the fundamental

(Refer to ADJUSTMENT)

Panel tune mode Dealer uses to tune the radio.

(Refer to ADJUSTMENT)

Clone mode Programmed data is transferred from

Firmware program- Re-write the firmware of the flash ROM.

ming mode Note : When programming the firmware,

characteristics.

one transceiver to another by using a

cloning cable.

it is best to copy the data from the

floppy disk to your hard disk, then from

the hard disk to the CPU.

Directly copying from the floppy disk to

the CPU may not work because the

access speed is too slow.

43. PC Tuning Mode

When making adjustment while in PC tuning mode, modify the KPG-43 programming interface cable as described below.

1. Remove the two screws from the plug cover, then lift the

cover from the plug.

2. Solder the lead wire onto the MIC tab on the PCB, and

the ground wire onto the ME tab.

42-1. How to Enter Each Mode

Mode Operation

User mode Power on

PC mode Connect the PC and turn the power on.

Then the radio can be controlled by the FPU.

Panel test mode Hold down the [PF1] key, turn the radio

power on.

Panel tune mode Press the [GR ] key from the panel test

mode.

Clone mode Hold down the [PF5] key, turn the radio

power on.

Firmware Hold down the [PF2] key, turn the radio

programming mode

power on.

3. Create a hole in the casing (as shown in the illustration)

then fit the cable into the hole. Replace the cover and

secure it using the two screws.

Create a hole

MIC

Cable

OPERATING FEATURES

A CLONE / ALL CLONE

Master side display

TX LED on

TX LED off

END

Slave side display

– PC –

Busy LED on

Busy LED off

User mode

Data cloning

[PF5]

Master side display

TX LED on

TX LED off

END

Slave side display

– PC –

G CLONE / GROUP CLONE

GRP 1M / GROUP 1M

GRP 160M / GROUP 160M

GRP 1S / GROUP 1S

GRP 100S / GROUP 100S

User mode

Busy LED on

Busy LED off

User mode

Data cloning

[PF5]

[Up/Down]

[PF5]

TK-790/(B)/H(B

)

44. Clone Modes

There are two clone modes : "All Clone Mode", in which all data programmed in one transceiver with the "FPU" is copied to another transceiver, and "Group Clone Mode", in which group data in one transceiver is copied to a group in another transceiver.

The cloning operation is performed from the master side transceiver.

[PF5] + Power on

All clone/Group clone selection

All clone mode

[PF5]

[Up/Down]

Cloning

END

Power off

Group clone mode

[PF5]

Master group selection

[PF5] [Up/Down]

Slave group selection

[UP/Down]

[PF5][PF5]

44-3. Group Clone

1. Enter the group clone mode from the clone mode with [Up/Down] knob.

2. Press the [PF5] key to enter the master group select mode. Select the master group with [Up/Down] knob.

3. Press the [PF5] key to enter the slave group select mode. Select the slave group with [Up/Down] knob.

4. Press the [PF5] key to start cloning.

Note : The transceiver does not enter the clone mode if it is disabled with the FPU. To clone the transceiver both transceivers must be same. If the panels, frequency ranges, optional board are different, they cannot be cloned.

44-1. To Enter the Clone Mode and Connect

Transceivers

(1) Hold down the [PF5] key and turn on the power switch on

the master side transceiver. Turn on the power switch on the slave side transceiver as usual.

(2) Connect the master and slave side transceivers with a

cloning cable.

44-2. All Clone

1. Enter the All Clone Mode from the clone mode with the [Up/down] knob.

2. Press the [PF5] key to start cloning.

Cloning cable (Part No. E30-3370-05)

Fig. 2

TK-790/(B)/H(B

GRP

VOL

POWER

BUSY

PF1 PF2 PF3 PF4 PF5

GRP

POWER

VOL

BUSY

SCAN OPT OSTA B CMON

CALL

MON

SCN

PF1 PF2 PF3 PF4 PF5

PF8 PF9

PF6 PF7

)

INSTALLATION

1. Contents

• Front panel kit (KCH-10, KCH-11) Description and use of the knob supplied with the KCH10/11

• Optional voice scrambler function Voice scrambler use and connection

• Optional ANI function ANI board connection

• Ignition sense cable (KCT-18) Description of the ignition function and timed power off function and connection

• External speaker (KES-4) KES-4 connection method and modification for increasing the speaker output of the control head

• Horn alert function Modification for changing the function of the ACC terminal for horn alert

• Accessory terminal function Description and use of D-SUB 25-pin ACC terminals, “MI/ DI” and “SB”

• Connection with remote kit Modification of the radio to use KRK-5, KRK-6DH, KRK7DB, or KRK-8DBH

2. Front Panel Kit (KCH-10, KCH-11)

2-2. Connection with TK-790(B)/H(B)

1. Remove the upper and lower halves of the case of the TK-790(B)/H(B).

2. Connect the lead (W501) with a connector of the control unit (X57-561 B/3) to CN1 of the KCH-10 or KCH-11.

3. Install the KCH-10 or KCH-11 on the radio using the screws (N32-3006-46) ( kit. Take care not to get the lead between the KCH-10 or KCH-11 and an edge of the case. (You can install the panel upside down if necessary to install the radio.)

4. Reinstall the upper and lower halves of the case.

5. Connection the short plug for the accessory connector (9-pins) on the rear of the radio.

) supplied with the front panel

2-3. Install the accessory knobs

When a function is set by the programming software (KPG-44D), the key legend can be changed by inserting the accessory knobs into PF1 to PF9 of the KCH-11 (PF1 to PF5 : KCH-10). The accessory contains a set of 30 knobs : AN, D/ A, DIM, HA, HC, IC, MON, OPT, OST, PA, RCL, RPT, SCN,

SP, SPM, SQ, TA, , , CH1, CH2, CH3, CH4, CH5, AUX A,

AUX B, AUX C, EMG, and blank.

Fig. 2

No. K29-5276-*3 K29-5277-*3 K29-5305-*3

1 AN RCL CH1

2 D/A RPT CH2

3 DIM SCN CH3

4 HA SP CH4

5 HC SPM CH5

6 IC SQ AUX A

7 MON TA AUX B

8 OPT AUX C

9 OST EMG

10 PA No printing

KCH-10

KCH-11

KCH-10 or KCH-11

Fig. 1

Fig. 3

Fig. 4-1 Knob insertion

CN508

Voice

scrambler

MCI (MIC signal input)

MCO (MIC signal output)

DEI (Detection signal input)

AC (Audio control signal output)

BC1 (Scramble code output 1) BC2 (Scramble code output 2) BC3 (Scramble code output 3) BC4 (Scramble code output 4)

TXD2 RXD2

DEO (Detection signal output)

PTO (PTT signal output)

8C (8V output)

E (Earth)

CN507

ANI board

10 14

SQ (Squelch signal output)

EMG (Emergency signal output)

EPT (External PTT signal input)

I/O (Auxiliary input/output)

SEL (Non connection)

AS2 (Audio mute input)

MCM (MIC mute input)

TON (Side tone input)

TCN (Speaker mute input)

DTI (Data input)

E (Earth)

8C (Common 8V output)

PTO (PTT signal output)

DEO (Detection signal output)

CN508

INSTALLATION

3-2. Voice scrambler board connection

• Modification

1. Remove the upper half of the case of the TK-790.

2. Remove R515 and R604 on the control unit (X57-561 B/

3) (Refer to page 21).

• Connection

The functions of pins of CN508 on the control unit (X57-

561 B/3) are shown in the figure.

Join the CN508 connector to the voice scrambler board

via the E37-0808-05 connector cable.

TK-790/(B)/H(B

)

3. Optional Voice Scrambler Function

The optional voice scrambler function can be used by two

methods.

1. Assign this function to the OPT key by using the programming software (KPG-44D). When the OPT key is pressed, the on, and the optional (scrambler) function is enabled. When the key is pressed again, the off and the function is disabled.

2. Assign the optional scrambler function to each channel by using the programming software (KPG-44D). The optional scrambler function can be used without pressing the OPT key.

3-1. Code setting

The code can be set by two methods.

1. Hold down the OPT key to enter the code setting mode. Codes 1 to 16 will be displayed. Set a code by turning the [Up/Down] knob. When the OPT key is pressed again, the code setting mode terminates.

2. Set a code for each channel by using the programming software (KPG-44D).

Fig. 4-2 Knob removal

Fig. 5

4. Optional ANI Function

• Connection

Join the CN507 connector to the ANI board via the E370809-05 connector cable, and the CN508 connector to the ANI board via the E37-0808-05 connector cable.

OPT indicator comes

OPT indicator goes

Fig. 6

TK-790/(B)/H(B

Rubber cap

Tie wrap

KCT-18

Cut

Accessory connector (12P)

)

INSTALLATION

5. Ignition Sense Cable (KCT-18)

The KCT-18 is an optional cable to use the following func-

tions:

5-1. Ignition function

The ignition function allows you to turn the transceiver's power on and off with the ignition key of your car. When you are driving with the ignition key on, the horn alert function is disabled.

5-2. Timed power off function

The timed power off function turns the transceiver's power off the time specified with the programming software (KPG-44D) after the ignition key is turned off. When you are driving with the ignition key on, the horn alert function is disabled.

The ignition sense function and the timed power off function can be used at the same time.

5-3. Modification

• If the TK-790 and KCH-10 or KCH-11 are used

1. Remove the short plug from the accessory connector (9

pins) on the back of the transceiver.

2. Insert the KCT-18 into pin 1 (IGN).

3. Remove the upper half of the case of the TK-790.

4. Set jumper resistors (0 ohm), R504, R506, R742 and

R743, on the control unit (X57-561 B/3) as shown in

Table 1 (Refer to page 21).

5. Reinstall the upper half of the case.

• When the remote kit is used

If the accessory connector (9 pins) on the rear of the transceiver is available, use the method described above. (If the KRK-7DB or KRK-8DBH is used, use the accessory connector (9 pins) on the back of radio 1.)

If the accessory connector (12 pins) on the back of the control head is used:

1. Remove the plug from the accessory connector (12 pins)

on the back of the control head.

2. Cut off the end of the rubber cap (accessory), insert the

KCT-18 into the cap, and insert it into pin 1 (IGN) of the

short plug.

3. Install the short plug and rubber cap on the connector on

the rear of the control head, then clamp the bottom of the

rubber cap with the supplied tie wrap.

4. Remove the upper half of the case of the TK-790.

5. Set jumper resistors (0 ohm), R504, R506, R742 and

R743, on the control unit (X57-561 B/3) as shown in

Table 1 (Refer to page 21).

6. Reinstall the upper half of the case.

Available function when KCT-18 is

connected

Horn alert function OFF during

driving, Timed power off function

(Default)

Horn alert function OFF during

driving, Ignition function

None (The transceiver cannot be

turned on.)

HA function OFF during driving,

Ignition function & Timed power

off function

R504 R506 R742 R743

Present Absent Present Absent

Absent Present Present Absent

Absent Absent Present Absent

Present Absent Absent Present

Table 1 R504, R506, R742 and R743 setup chart

(Refer to page 21)

Accessory connector (9P)

KCT-18

Fig. 7

6. External Speaker (KES-4)

The speaker output from the TK-790 is as follows:

1. The KCH-10 has a built-in speaker (3W/8 ohms).

2. The KCH-11 does not have a built-in speaker.

3. The external speaker output from the accessory connector (9 pins) on the back of the transceiver is 13W/4 ohms. Use the KES-4.

4. The speaker output from the accessory connector (12 pins) on the back of the control head is 2W/4 ohms. If the remote kit (KRK-5, KRK-6DH, KRK-7DB or KRK-8DBH) is used, use the KSP-1A or KES-4. If the KSP-1A is used, do not attempt to modify the transceiver to increase the audio output.

Note : If the KCT-18 is used for the KRK-8DBH, use the 9-pin plug on the back of radio 1 or the 12-pin plug on the back of head 1. The plugs on radio 2 and head 2 cannot be used. If the KCT-18 is used for the KRK-7DB, use the 9-pin plug on the back of radio 1 or the 12-pin plug on the back of the head. The plug on radio 2 cannot be used.

Note : Since the TK-790 uses a BTL audio amplifier, do not

ground the speaker output pin.

INSTALLATION

TK-790/(B)/H(B

)

6-1. Connection for the KES-4 with the TK-790

• When taking the AF output from the accessory connector (9-pin) on the rear of the radio

The following tools are required for changing the connec-

tor.

Extracting tool

the following extracting tool is recommended : Molex Inc. Order No. : 11-03-0002

1. Remove the connector with jumper from the external speaker connector on the rear panel of the radio (Fig. 8-

1). Note : Save the jumper, which is required when the radio is used without the external speaker.

2. Remove the terminals with the jumper from the connector housing holes number 3 and 6 using the extracting tool.

Removing the jumper lead (Fig. 8-2)

1) Insert the extracting tool (11-03-0002) into the connector while pushing the jumper lead in the direction of (a).

2) Push the extracting tool into collapse the barbs of the crimp terminal.

3) Pull out the lead while continuing to push the extracting tool in the direction (b).

3. Reinsert the terminal with the black and white stripe lead into hole number 2, and the terminal with the black lead into hole number 6 (Fig. 8-3).

4. Attach the connector to the external speaker connector on the radio.

(a)

(b)

Square-type plug (E37-0733-05)

Extracting tool (11-03-0002)

Jumper lead

6-2. Connection for the KES-4 with the remote kit

(KRK-5, KRK-6DH, KRK-7DB, KRK-8DBH) (When output is from the 12-pin accessory connector on the rear of the control head : remote operation)

• Modification of plug (12-pin)

1. Remove the plug from the accessory connector (12-pins) on the rear of the control head.

2. Cut off the end of the rubber cap, insert the KES-4 speaker cable into the cap, and insert it into pins 10 and

11.

3. Install the plug and rubber cap on the accessory connector on the rear of the control head, then clamp the bottom of the rubber cap with the supplied tie wrap.

Plug (12P)

Rubber cap

Tie wrap

Cut

Speaker cable (To KES-4)

Fig. 9

• If the KCH-10 is used

If the KSP-1A or KES-4 is connected to the 12-pin acces-

sory connector, cut the internal speaker wire at the base of the speaker.

If the internal speaker is used, cut the wire connected to

pins 10 and 11 of the 12-pins accessory connector at the base of the connector (Fig. 10).

Fig. 8-1 Fig. 8-2

Black lead

Black/White lead

Fig. 8-3

Barbs

Crimp terminal

KCH-10

Rear of the control head

Fig. 10

CN3

CN1

CN2

TK-790/(B)/H(B

)

INSTALLATION

6-3. Modification to increase the audio output of

the control head

The speaker output can be increased to 13W by moving jumper resistor (0 ohm) R628 on the control unit (X57-561 B/3) to R627. In this case, the KCH-10 internal speaker cannot be used because the maximum input (3W) of the internal speaker is exceeded. Therefore, use the KES-4.

Note : Even if the KRK-6DH is modified in this way, the audio output of head 2 cannot be increased. To increase the audio output of head 2 of the KRK-8DBH, modify radio 2 in the same manner.

6-4. Use as public address speaker

1. Remove the short plug from the 9-pin accessory connec-

tor on the rear of the radio. (Remove the jumpers as de-

scribed in Section 5-1.)

2. Insert the KES-4 speaker leads into pins 7 and 8.

3. If you remove jumper shorting pins 3 and 6, the 20W PA

(public address) voice signal is output from pins 7 and 8.

(Only when the PA or SP switch is on.)

4. If you use the radio with pins 3 and 6 shorted, the internal

speaker is available (when the KCH-10 is used). The KCH-

11 does not contain a speaker.

Note : Relation ship between accessory connector (9-pins) connection and speaker output. When pins 3 and 6 are shorted ; The 3W internal speaker is used (KCH-10 only). When pins 3 and 6 are open and output is from pins 7 and 8 ; The 20W external speaker is used.

Plug (9P)

Crimp terminal (E23-0613-05)

To KES-4

Black lead

Black/White lead

Fig. 11

Default Modification 1 Modification 2

R690 Present Present Absent

R691 Present Absent Absent

R692 Absent Present Present

State

HR1

HR2

HR1

HR2

Table 2 (Refer to page 21)

8. Accessory Terminal Function

8-1. 25-pin accessory terminal

• Pin 13

MI/DI (MIC Signal Input/Output or Data Audio Input) This pin has one of the two functions listed in Table 3 by setting jumper resistors (0 ohm) R640 and R641 on the control unit (X57-561 B/3) (Refer to page 21).

1) MIC signal input/output

This pin is directly connected to the MIC input pin of the transceiver, so it has the same function as the MIC input pin. When the input is 5mV/3 kHz, DEV (600 ohms) modulation is obtained. The MIC input is output from the transceiver panel as it is.

2) Data audio input

The signal from this pin passes through the LPF (fc: about 10kHz), is summed with the MIC AMP output, and goes to the modulator. Therefore, it is not preemphasized.

• Pin 14

SB (DC Power Output After Power Switch) The maximum output (13.6V : TK-790/(B), 13.4V : TK790H(B) / 0.5A) can be obtained by modifying the control unit as follows: Short the land of the print pattern near CN505 of the control unit (X57-561 B/3).

R640 R641 Function

Present Absent MIC signal input/output

Absent Present DATA audio input : Default

Table3 (Refer to page 21)

HR1

HR2

7. Horn Alert Function

The HR1 pin of the accessory connector (9-pin) on the rear of the transceiver is an open collector and the maximum current is 100mA. The maximum available current can be increased to 1A by installing a relay.

1. Remove the upper half of the case of the TK-790.

2. Move jumper resistor (0 ohm) R691 on the control unit

(X57-561 B/3) to R692. To make the HR2 pin, remove

R692 (Refer to page 21).

3. Remove screws and erect the PC board. Install and sol-

der relay K501 (Part No. : S76-0407-05).

4. Reinstall the PC board and the upper half of the case.

9. Connection with the Remote Kit

When the KRK-5, KRK-6DH, KRK-7DB or KRK-8DBH is used, set chip resistors and transistors as shown in the table below.

KRK-5 KRK-6DH KRK-7DB KRK-8DBH

Radio 1 Unnecessary

Radio 2 – Remove R546 and R661

Move R602 to R705.

Table 4 (Refer to page 21)

TK-790/(B)/H(B

)

INSTALLATION

CONTROL UNIT (X57 B/3)

Component side view

Accessory terminal function (Page 20)

R604

R705

R602

Connection with the remote kit (Page 20)

R640

R515

R641

Horn alert (Page 20)

R690

R691

R692

Connection with the remote kit (Page 20)

Ignition sense cable (KCT-18) (Page 18)

R627

R628

K501

R661

R504

R506

R546

Connection with the remote kit (Page 20)

External speaker (Page 18)

R743

Ignition sense cable (KCT-18) (Page 18)

R742

Voice Scrambler (Page 17)

R515 : Voice Scrambler (Page 17)

R640,641 : Accessory terminal function (Page 20)

TK-790/(B)/H(B

DISASSEMBLY FOR REPAIR (TK-790/(B))

)

1. Removing the Case and Shield Cover

1. Remove the 9 screws ( 1 ), and remove the upper and lower halves of the case. (Remove the 4 screws holding the upper half and the 5 screws holding the lower half.)

2. Remove the shield cover (

2. Removing the TX-RX Unit (X57-561 A/3)

1. Remove the 7 screws ( 3 ), and remove the PLL shield case.

2. Remove the connector (CN201) and coaxial plugs (CN104, CN203) from the final unit, and remove the flat cable (CN202) upwards from the control unit (CN502).

3. Remove the 5 screws (

CN203

CN201

TX-RX unit

3. Removing the Final Unit (X57-561 C/3)

1. Remove the 2 screws ( 5 ) holding the power module to the frame.

2. With a screwdriver, remove the leaf spring ( the Q2 to the frame.

3. Desolder the power module.

4. Remove the 2 screws holding the lead terminal from DC connector (2P) on the rear.

5. Remove the 8 screws (

6. Desolder CN4 on the antenna connector.

CN104

Final unit

) holding the PC board.

) holding

Control unit

TK-790/(B)/H(B

DISASSEMBLY FOR REPAIR (TK-790H(B))

)

1. Removing the Case and Shield Cover

1. Remove the 12 screws ( 1 ), and remove the upper and lower halves of the case. (Remove the 6 screws holding the upper half and the 6 screws holding the lower half.)

2. Remove the 2 screws (

), and remove the shield cover.

2. Removing the TX-RX Unit (X57-561 A/3)

1. Remove the 7 screws ( 3 ), and remove the PLL shield case.

2. Remove the connector (CN201) and coaxial plugs (CN104, CN203) from the final unit, and remove the flat cable (CN202) upwards from the control unit (CN502).

3. Remove the 5 screws (

CN203

TX-RX

unit

3. Removing the Final Unit (X45-356)

1. Remove the 2 hexagonal bosses ( 5 ).

2. Remove the 3 screws ( and transistor to the frame.

3. Desolder the power module.

4. Remove the 1 screw (

5. Remove the 4 screws (

6. Remove the 2 screws ( from DC connector (4P) on the rear.

7. Remove the 13 screws (

8. Desolder W3 on the antenna connector.

CN104

CN201

Final unit

) holding the power module

) holding TH1.

) holding the final transistor.

) holding the lead terminal

) holding the PC board.

Control unit

TK-790/(B)/H(B

DISASSEMBLY FOR REPAIR

)

4. Removing the Control Unit (X57-561 B/3)

1. Remove the 8 screws ( 1 ).

2. With a screwdriver, remove the 2 leaf springs holding the ICs to the frame (

3. Remove the flat cable (CN502).

4. Remove the 2 connectors CN501 and CN506.

5. Remove the connector (CN505) from D-sub connector (25P) on the rear.

CN505

CN502

5. Removing the Accessory Connector on

the Rear

1. Confirm that the screw holding +DC cable (red) and the screw holding –DC cable (black) of the final unit are removed, and that CN506 of the control unit (X57-561 B/3) is disconnected. Remove the 4 screws on the rear (

2. Pull out the connector. (Take the connector terminals out through the opening in the frame.)

CN501

CN506

Leaf spring

Screw-

driver

TK-790/(B)/H(B

DISASSEMBLY FOR REPAIR

)

6. Disassembly of the Display Unit (X54-3190) : KCH-10

1. Pull out the VOL and UP/DOWN knobs ( 1 ).

2. Remove the 2 hexagnal nuts (

3. Disconnect the 2 connectors (CN2 and CN4) of the display unit (X54-3190 A/3). You can remove the UP/ DOWN encoder (

4. Remove the waterproof seal (

5. Remove the 4 screws (

board fitting.

6. Remove the 3 screws (

units (X54-3190 A/3 and C/3) (

7. Remove the 3 screws ( (

) and keytop ( 11 ).

CN2

CN4

A/3

C/3

) holding the speaker and PC

). You can remove the display

and 8 ).

), and remove the sub-panel

B/3

7. Disassembly of the Display Unit (X54-3200) : KCH-11

1. Pull out the VOL and UP/DOWN knobs ( 1 ).

2. Remove the 2 hexagnal nuts (

3. Remove the waterproof seal (

4. Disconnect the connector (CN4) of the display unit (X543200 A/2), and remove the 5 screws ( remove the up/down encoder (

5. Remove the 4 screws ( (

) and keytop ( 8 ).

A/2

CN4

). you can

) and display unit.

), and remove the sub-panel

B/2

TK-790/(B)/H(B

POWER MODULE

AMP

FWD DET

REF DET

LPF

ANT SW

CM coupler

APC DRIVE

DC AMP

Differential

AMP

VR1

FINAL UNIT (X45)

AMP

Rectified

Diode

DC SW

TH1

Q9 Q8

IC1

CIRCUIT DESCRIPTION

)

1. Transmitter Circuit

1-1. Microphone amplifier section (X57 B/3)

The audio input from the microphone is attenuated by VR501 and passes through the active high-pass filter (preemphasis circuit) in IC505, the compressor circuit in IC504, the IDC (limiter circuit) in IC505, the summing amplifier circuit in IC510, the active low-pass filter in IC510, the summing amplifier circuit in IC513, and the D/A converter in IC512, and is output from the CN502 to the CN202. Q504 is used as a microphone mute switch.

to TX VCO

IC512

DAC

IC513 IC510 IC510

SUM AMP

CONTROL UNIT X57 B/3

1-2. Modulation section (X57 A/3)

The signal from the MO terminal of the CN202 goes to D305 in the VCO, and the VCO is directly modulated. The transmit signal output from the VCO passes through switch D306, is amplified by Q201 and Q204, and is output from the CN203 to the CN1.

1-3. Final amplifier section (X57 C/3) : TK-790/(B)

The signal from the DO terminal of the CN1 is applied to drive the power module and the output is fed through transmit/receive switching diode ; D3,D4, low-pass filter, and CM coupler to the antenna connector.

CM coupler is a line for detecting traveling and reflected waves. Traveling waves are detected by D5 and fed through the APC control to differential amplifiers Q5, which compare the signal level with the reference voltage of PC tuned.

The output is amplified by DC amplifier Q1 to control APC DC amplifier Q2. Q1 controls the power supply voltage for the power module, keeping the transmitter output constant. To protect the transmitter power amplifier stages, there is protection circuit, against abnormal antenna loading.

If an abnormal antenna load is connected the reflected wave level increases. Reflected waves are detected by D6 and the output level is fed to the differential amplifier, leading to the transmitter output power being reduced in the way already described.

LPF

SUM AMP

TX-RX UNIT X57 A/3

Q201 Q204

AMP

TX-VCO

IC505 IC504

IDC

COMP

Fig. 1

D306

Fig. 2

AMP

IC505

HPF

APC

Q504

MUTE SW

VR501

MIC

FINAL UNIT (X57 C/3)

D3,4

ANT

LPF LPF

Differential

AMP

VR1

FWD DET

CM coupler

REF DET

DC AMP

POWER MODULE

APC DRIVE

DC AMP

Fig. 3

1-4. Final amplifier section (X45) : TK-790H(B)

The signal from the DO terminal of the CN1 is applied to drive the power module, and the output is divided into two signals which are amplified by Q6 and Q7. The signals are mixed and the resulting signal is fed through CM coupler, transmit/receive switching relay ; K1, and the low-pass filter to the antenna connector.

CM coupler is a line for detecting traveling and reflected waves. Traveling waves are detected by D1, D3 and fed through the APC control to differential amplifiers Q5, which compare the signal level with the reference voltage of PC tuned.

The output is amplified by DC amplifier Q4 to control APC DC amplifier Q3. Q4 controls the power supply voltage for the power module, keeping the transmitter output constant. To protect the transmitter power amplifier stages, there are two protection circuits which one is against abnormal antenna loading and the other is against overheating.

If an abnormal antenna load is connected, the reflected wave level increases. Reflected waves are detected by D2, D3 and the output level is fed to the differential amplifier Q5, leading to the transmitter output power being reduced in the way already described. If an abnormal high temperature is detected by the thermistor TH1, DC SW Q1 is made to reduce the reference voltage of the PC tuned. This also leads to the transmitter output power being reduced. Antenna switching is done by a relay K1 with 8R.

FIg. 4

TK-790/(B)/H(B

ANT

LPF

L7,5,4

LPF

L9,8,7

D3,4

ANT

BPF

IC101

IC504 IC515

AMP HPF BEF

RF AMP

Q101

RF AMP

Q104

BPF

L110~112

1st MIX

A101 LPF

D306

ANT

T/R

CF103 CF101

Ceramic

filter

WIDE

CF104 CF102

Ceramic

filter

NARROW

X101

45.305 MHz

FM SYSTEM IC

NOISE

AMP

NOISE

DET

RSSI

DET

RSSI

DET

Q109D103

455kHz

1st IF AMP2

Q107

1st IF AMP1

Q102

MCF

XF101

MCF

XF102

WIDE

NARROW

44.85MHz

VCO

RX VCO

fRX+44.85MHz

IC518

(2/2)

IC524

(1/2)

IC524

(2/2)

DE-EMP

EXP

IC512

IC518

(1/2)

IC522

VOL

BUFF

AF PA

VOL

IC516

CPU

27 26

RSSI

ASQ

FINAL UNIT : TK-790H(B)

TX-RX UNIT

CONTROL UNIT DISPLAY UNIT

FINAL UNIT : TK-790/(B)

CIRCUIT DESCRIPTION

)

2. Receiver Circuit

Incoming signals from the antenna pass through a lowpass filter in the final unit of the transmitter system, and are switched to the front-end of the receiver system via a receive/transmit switch (switching diode D3 and D4 : TK-790/ (B), switching relay K1 : TK-790H(B)).

The signal is then passed through an antenna matching coil. After passing through the BPF (L.C filter), it is amplified by the RF amplifier (Q101). The tuned varactor BPF (L110~112) is then passed, and it enters the 1st mixer.

The 1st mixer use a double balanced mixer (A101). The DBM is an excellent IM (intermodulation distortion) and image. The 1st mixer mixes the signal with the 1st local oscillator frequency and converts it to the 1st IF (44.85MHz). The signal is amplified by the 1st IF amplifier 1 (Q102).

The signal then passes through two monolithic crystal filters (XF101 : Wide, XF102 : Narrow) to remove unnecessary nearby frequency components. The signal from the XF101 or XF102 is used as the 1st IF signal.

The 1st IF signal is amplified by 1st IF amplifier 2 (Q107) and fed into IC101 in the FM IF IC. The IF signal is then mixed with the 2nd local oscillator frequency of 45.305MHz to generate the 2nd IF of 455kHz. The 455kHz signal is then passed through a ceramic filter (CF101, CF103 : Wide, CF102, CF104 : Narrow) and fed back into IC101 for additional amplification.

The AF signal output from IC101 then passes through the control unit's HPF and D/A converter IC. After entering the AF power amplifier (IC522), the signal is output from the speaker.

Item Rating

Nominal center frequency 44.85MHz Pass bandwidth ±5.5~7.5kHz or more at 3dB Attenuation bandwidth ±25kHz or less at 40dB

Ripple 1.0dB or less

Insertion loss 3.0dB or less

Guaranteed attenuation

85dB or more at fo+400~+1000kHz

fo–200~–1000kHz

Terminating impedance 3.2kΩ / –1.0pF

Table 1 Crystal filter (L71-0512-05) : Wide

(TX-RX unit XF101)

Item Rating

Nominal center frequency 44.85MHz Pass bandwidth ±3.5kHz or more at 3dB Attenuation bandwidth ±15kHz or less at 40dB

Ripple 1.0dB or less

Insertion loss 4.0dB or less

Guaranteed attenuation

85dB or more at fo+400~+1000kHz

fo–200~–1000kHz

Terminating impedance 3.0kΩ / –0.5pF

Table 2 Crystal filter (L71-0513-05) : Narrow

(TX-RX unit XF102)

GND

GND GND

Fig. 6 Double balanced mixer

456

Fig. 5 Receiver circuit

TK-790/(B)/H(B

8CL

TX VCO

PLL-IC

IC516

µ-com

RX VCO

BUFF AMP

AMP

LPF

8CL

STR

Q306

Q307

Q308

Q309

Q305

IC301

Q311

X301

MB MO

Q310

Q312

D306

TX RX

TX-RX UNIT

CONTROL UNIT

8C 8T

8CL

VCXO

5C9CL

Q303,304

CIRCUIT DESCRIPTION

)

3. Squelch Circuit

The output from IC101 enters FM IC again, then passed

through a band-pass filter. The noise component output from IC101 is amplified by Q109 and rectified by D103 to produce a DC voltage corresponding to the nose level.

The DC voltage is sent to the analog port of the CPU

(IC516/pin 27). And IC101 output a DC voltage (RSSI) corresponding to the input of the IF amplifier. The CPU reads the RSSI signal via pin 26. IC101 determines whether to output sounds from the speaker by comparing the input voltage of pin 27 with the present value.

Only during scan, the RSSI DC voltage is used together

with the noise wave detection pin's DC voltage (pin 27).

SQ voltage

SQ close

Preset value

SQ open

ANT input level

RSSI voltage

Preset value

ANT input level

Fig. 7 Squelch and RSSI voltage vs ANT input level

4. RX BPF (L110~112)

The signals are then fed into band-pass filter that uses

varactor diode tuning to reject unwanted signal components, and is fed to the 1st mixer.

5. VCO/PLL Circuit

The VCO of TK-790 consists of two VCO circuits which one oscillates the transmit signal with Q306 and the other does the first local receive signal with Q305.

Each oscillators are switched by turning the source line for Q307, Q308 and Q309 on and off. The signal output of the VCO is amplified by the buffer amplifier Q310 and divided into two signals which one is amplified by Q312 and the other is done by Q311. The signal from Q312 passes through D306 which is transmit/receive switch, is amplified by Q201 and Q204, and is output from the CN203.

The signal from Q311 passes through the low-pass filter and is applied to IC301 which is PLL frequency synthesizer with VCXO ; X301. The VCXO of which the frequency stabil-

ity is within 2.0ppm (temperature range of –30 to +60°C)

generates 16.8MHz. The PLL-IC consists of three modulus prescaler, fractional divider, reference divider, digital phase comparator with charge pump output.

This PLL-IC is Fractional-N type synthesizer and performs is 40 or 50 or 60kHz reference signal which is eighth of the channel step (5 or 6.25 or 7.5kHz). The input signal from the pins 5 and 8 of the PLL-IC is divided down to the 40 or 50 or 60kHz and compared at digital phase comparator.

The pulsed output signal of the digital phase comparator is applied to the charge pump and transformed into DC signal. The DC signal from the pin 14 of the PLL-IC passes through the active low-pass filter (loop filter), is applied to the VCO and controls to keep the frequency of the VCO.

The serial data (DT, CP, EP) from the microprocessor IC516 is input to the PLL-IC. And PLL lock condition is always monitored by the pin 28 (UL) of IC516.

Fig. 8

Fig. 9 VCO/PLL circuit

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