Kenwood TK-290 Service Manual

VHF FM TRANSCEIVER

TK-290

SERVICE MANUAL

REVISED

Antenna (KRA-14 : Option)

Knob assy (SEL) (K29-5282-04)

Knob assy (VOL) (K29-5283-04)

Panel assy (A62-0537-53)

Knob assy (Side key) (K29-5441-04)

Cabinet assy (A02-2139-63)

CONTENTS

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

SYSTEM SET-UP ..................................................... 2

OPERATING FEATURES ......................................... 3

REALIGNMENT...................................................... 11

CIRCUIT DESCRIPTION......................................... 17

SEMICONDUCTOR DATA..................................... 25

DESCRIPTION OF COMPONENTS ....................... 26

PARTS LIST ............................................................ 28

EXPLODED VIEW .................................................. 36

PACKING ................................................................ 37

DISASSEMBLY FOR REPAIR ................................ 38

ADJUSTMENT ....................................................... 39

PC BOARD VIEWS

FINAL UNIT (X45-3592-71) ............................... 50

CONTROL UNIT (X53-3930-XX)....................... 51

TX-RX UNIT (X57-5390-10) .............................. 55

SCHEMATIC DIAGRAM ........................................ 61

BLOCK DIAGRAM.................................................. 67

LEVEL DIAGRAM ................................................... 69

TERMINAL FUNCTION .......................................... 70

KNB-17A (Ni-Cd BATTERY) ................................... 71

KMC-25/26 (SPEAKER MICROPHONE) ................ 72

KSC-19 (CHARGER) ................................................ 73

KSC-20 (RAPID CHARGER) .................................... 73

KPG-36 (PROGRAMMING INTERFACE CABLE)

KRA-14 (HELICAL ANTENNA) ............................... 73

SPECIFICATIONS............................... BACK COVER

...... 73

Photo is TK-290 K type. Does not come with antenna. Antenna is available as an option.

CAUTION When using an external power connector, please use with maximum final module protection of 10V

TK-290

GENERAL / SYSTEM SET-UP

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 the publication data. 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 information, 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 required component for proper identification.

PERSONNEL SAFETY

The following precautions are recommended for person-

nel safety :

• DO NOT transmit until all RF connectors are verified secure 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 technician only.

SERVICE

This radio is designed for easy servicing. Refer to the

schematic diagrams, printed circuit board views, and alignment procedures contained within.

NOTE

WE CANNOT guarantee oscillator stability when using

channel element manufactured by other than KENWOOD or its authorized agents.

FCC COMPLIANCE AND TYPE NUMBERS

Model

TK-290 ALH21893110 136~174MHz Parts 22,74,80,90

Type acceptance number

Frequency range

Compliance

Unit

Model & Frequency range Remarks

destination 0-10 0-11 0-12 2-71

TK-290 K ✓✓ ✓136~174MHz 1st IF : 44.85MHz –

K2 ✓✓✓136~174MHz LOC : 45.305MHz ✓

X57-539X-XX X53-393X-XX X45-359X-XX DTMF

SYSTEM SET-UP

Merchandise received

License and frequency allocated by FCC

Choose the type of transceiver

Transceiver programming

Are you using the optional antenna?

Are you using the speaker microphone?

Frequency range (MHz) RF power Type

TX/RX 136~174

A personal computer (IBM PC or compatible), programming interface (KPG-36), and programming software (KPG-38D) are required for programming. (The frequency, and signalling data are programmed for the transceiver.)

YES

YES YES

KRA-14

Helical antenna

(Option)

With

antenna?

KMC-25

KMC-26

TK-290 K,K2

keypad

Delivery

OPERATING FEATURES

TK-290

1. Getting Acquainted

SMA male type antenna connector

ABAB

Display

Microphone

Speaker

Battery pack release latch

DTMF keypad (keypad models only)

Press the keys on the telephone keypad to send DTMF tones.

Universal connector

Connect the external speaker/microphone (optional) here. Otherwise, keep the supplied cover in place.

1-2. Display

Alphanumeric display

Displays the operating group or channel number, or the group or channel name. When making a DTMF or 2 Tone call, the display will alternate between CALL and the channel. Also displays various menu functions.

1-1. Key Descriptions

TX/Busy/Battery low indicator

Lights red while transmitting. Lights green while receiving. Flashes red when the battery power is low while transmitting; replace or recharge the battery.

Note : This indicator can be disabled by your dealer.

Power switch/Volume control

Turn clockwise to switch ON the transceiver. Turn counterclockwise, until a click sounds, to switch OFF the transceiver. Rotate to adjust the volume level.

Selector

Rotate this control to activate its programmable function (Page 8).

Toggle switch

Switch the toggle position to activate its programmable function (Page 8).

Top 1 Top 2 Orange Side 1

Press these PF (programmable function) keys to activate their programmable functions (Page 8)

Side 2

PTT (Push-To-Talk) switch

Press this switch, then speak into the microphone to call a station.

7 Segment display

Displays the operating group or channel number. Also displays tA (Talk Around), P1 (Priority1), P2 (Priority2), PP (Priority1 and Priority2), or HC (Home Channel); depending on the function being used.

A (Add) indicator

Appears when a channel is added to the scanning sequence.

SCN (Scan) indicator

Appears when Scan mode is active.

MON (Monitor) indicator

Appears when the monitor function is active.

LO (Low) indicator

Appears when low power is selected.

OPT indicator

Appears when Operator Selectable Tone is enabled.

AUX (Auxiliary) indicator

Appears when Aux is ON. Appears and blinks when the optional scrambler board is enabled.

Note : The alphanumeric and 7 segment displays can be inverted if a PF key or the toggle switch is programmed with Invert Display (Page 8).

TK-290

OPERATING FEATURES

2. Scan Operating

2-1. Scan Types

• Single Group Scan

You can scan all valid (ADD) channels in the displayed

group that can be selected with the group selector.

• Multiple Group Scan

You can scan all valid (ADD) channels in the all valid

(ADD) group.

2-2. Scan Start Condition

One or more non-priority channels must be added to all channels that can be scanned. The transceiver must be in normal receive mode (PTT off).

When you activate the key or the toggle switch (to right position) programmed to the scan function, the scan starts. The scan icon “SCN” lights and “SCAN” or revert channel (programmable) is indicated on 7-digit alphanumeric display.

2-3. Scan Stop Condition

The scan stops temporarily if the following conditions are satisfied.

1) A carrier is detected, then signalling matches on chan-

nels for which receive the signalling is set by the pro-

gramming software.

2) A carrier is detected on the channel for which receiving

signalling is not set by the programming software or

when the monitor (signalling cancel) function is activated.

2-4. Scan Channel Types

1) Priority channel 1 is the most important channel for the

scan, and always detects a signal during scan and when

the scan stops temporarily.

2) Priority channel 2 is the next important channel for the

scan, and always detects a signal during scan and when

the scan stops temporarily at a channel other than priority

channel 1.

3) Non-priority channels detects a signal during scan. For

the channels that can be selected with the group or chan-

nel selector when the scan does not occur, adds an indi-

cator “A” lights.

2-5. Priority Channel Setting

Priority channels 1 or 2 can be set as follows with the programming software (KPG-38D).

1) Specify priority channels 1 or 2 as fixed priority channels.

2) Make selected channels, priority channels.

3) Operator delectable

Specify the initial channel before the operator changes it.

2-6. Scan Type According to the Priority Channel

1) When no priority channels are set : Only the non-priority

channels are scanned.

If a non-priority channel stops temporarily, it stops until

there is no signal on the channel.

2) When one priority channel is set : Either priority channel 1 or 2 is scanned. If a non-priority channel stops temporarily, a priority channel signal is detected at certain intervals. If a priority channel stops temporarily, it stops until there is no signal on the priority channel.

3) When two priority channels are set : The non-priority channel, priority channels 1 and 2 are scanned. If a non-priority channel stops temporarily, priority channel 1 and 2 signals are detected at certain intervals. If priority channel 2 stops temporarily, the priority channel 1 signal is detected at certain intervals. If priority channel 1 stops temporarily, it stops until there is no signal on priority channel 1.

2-7. Revert Channel

The revert channel is used to transmit during scanning

and set by the programming software (KPG-38D).

1) Priority 1 The transceiver reverts to the priority channel 1.

2) Priority 1 with talkback The transceiver reverts to the priority channel 1. If you press PTT during a resume timer (dropout delay time, TX dwell time) or calling, you can transmit on current channel to answer to the call however revert channel is set to priority channel 1. After resume time, scan re-starts and transmission channel is return to priority channel 1.

3) Priority 2 The transceiver reverts to the priority channel 2.

4) Priority 2 with talkback The transceiver reverts to the priority channel 2. If you press PTT during resume timer (dropout delay time, TX dwell time) or calling, you can transmit on current channel to answer to the call however revert channel is set to priority channel 2. After resume time, scan re-starts and transmission channel is return to priority channel 2.

5) Selected channel The transceiver reverts to the channel before scanning or the channel that you changed during scan.

6) Last called channel The transceiver reverts to the last called channel during the scan.

7) Last used channel The transceiver reverts to the last used (transmitted) channel during scan. “Last used” revert channel includes talkback function.

8) Selected with talkback The transceiver reverts to the channel before scanning or the channel that you changed during scan.

2-8. Scan End

When you reactivate the key or the toggle switch (to left

position) programmed to the scan function during scan mode, the scan ends.

The scan icon “SCN” and “SCAN” or revert channel (pro-

grammable) display goes off.

OPERATING FEATURES

TK-290

2-9. Temporarily Delete/Add

It is possible to delete or add channel temporarily during scan. When scan stops on unnecessary channel for example by interference of the other party, activate the delete/ add function (for example press the key), then that channel is deleted temporarily and scan re-start immediately.

When you would like to add the deleted channel temporarily to scan sequence, select the desired (deleted) channel during scan, activate the delete/add function (for example press the key) before scan re-start.

That channel is added temporarily to scan sequence. The temporary deleted or added channels are returns to pre-set delete/add, when the transceiver exits from scan mode.

3. Optional Features

You can use these features using the programming software (KPG-38D).

3-1. Alphanumeric Display (Group/Channel Name)

The programming software (KPG-38D) enables you to set the alphanumeric display for group/channel name. The total text size of group and channel name are 7-digits.

For example, If you set 2-digits for group name, then you can use 5-digits for channel name. The characters can be used as shown in Figure 1.

3-4. Squelch Threshold Level

Squelch threshold level value. 0 (Most loose)~15 (Most tight)

3-5. BCL (Busy Channel Lockout) Override

You can transmit in spite of Busy Channel Lockout situa-

tion. For example : To make an emergency voice call.

To transmit under busy channel lockout situation, press

PTT once more within approx. 500ms after the PTT release.

3-6. Selective Call Alert LED

You can select whether or not the LED on the transceiver

flashes in an orange color when Selective call was occurred.

3-7. Battery Warning

This transceiver has battery warning feature. If the low voltage is detected during transmission, the transceiver warns it by flashing red “LED”.

Then more low voltage is detected during transmission, the transceiver stops transmission and warns it by flashing red “LED” and beep.

Please notice “standard” for the battery exchange, charging time by flashing red LED and beep.

3-8. Busy LED

You can program the enable or disable the busy “LED” function when a carrier is detected. “Disable” saves battery life.

ABCDE FGH I

JKLMNOPQR

STUVWXYZ

123456789

All on

Fig. 1

3-2. Beep Tones

The beep tones (power on tone, control tone, warning tone, alert tone) are individually programmable to the fixed level 0 to 31 or follow the mechanical volume position.

3-3. Minimum Volume

The minimum volume is programmable (0 to 31). The transceiver remains the minimum volume level however the mechanical volume position is set to zero.

3-9. TX LED

You can program the enable or disable the transmission

“LED” function.

3-10. 2-Digit 7-Segment Display

You can use 2-digit 7-segment the display to display the channel number or group number. It is useful when the main (7-digit 13-segment) display indicates group or channel name.

3-11. Invert Display

Main (7-digit 13-segment) display and sub (2-digit 7-segment) display can be programmed to invert display.

It is easy to read the display when the operator suspended the transceiver on a waste belt. The operator also can change the display between normal and invert using key. Refer the invert display function of key function.

3-12. Clear to Transpond

The transceiver waits the transpond of 2-Tone/DTMF if channel is busy until channel open. This feature prevents the interference to other party.

3-13. External Speaker

It can be selected if the receive sound is made by SP-Mic SP or the main body SP at a SP-Mic mount.

3-14. Noise Cancelling MIC

Enable or disable the noise cancelling function of the internal microphone. It is not valid for the external SP/MIC.

TK-290

OPERATING FEATURES

3-15. Mode (Enable/Disable)

The transceiver has many special modes mainly for main-

tenance.

· Self Programming mode

· Panel Test mode

· Clone mode

· Firmware Programming mode

· Version info.

It is possible to set enable/disable for each mode. We recommend to set these mode to Disable after set up to save contents.

3-16. ID

The transceiver is capable to have ID. The format is DTMF, MSK or ANI board (if installed). The timing that the transceiver sends ID is programmable.

Connect ID : Connect ID is send on beginning of trans-

mission.

Disconnect ID : Disconnect ID is send on end of trans-

mission.

Both : Connect ID is send on beginning of transmission

and disconnect ID is send on end of transmission.

Off : Sending ID function is disabled.

There is also “PTT ID” setting for each channel. Refer “PTT ID” of channel feature.

When you use an ID code for ANI board, the ID code and transmitting timing are configured to the optional ANI board.

3-17. OST (Operator Selectable Tone)

The transceiver is capable to have “OST” function and 16 tone pair (QT/DQT) with max 7-digit name for each tone pair.

•“OST” Back Up

The transceiver is programmable the selected “OST” code is memorized or not. If you set to Disable (no memorized), the “OST” function always starts at “off”.

• Man Down Delay Time

Delay time of entering the emergency mode when the

internal Man Down port becomes active.

• Man Down Pre-alert

Wait time of the alert tone when the internal Man Down port becomes active to enter the emergency mode. (After an alarm sounds, the transceiver waits for the programmed wait time then enter the emergency mode.)

• Emergency Channel Display

Setting for the display in the emergency mode.

The transceiver can be programmed to display “EMERGENCY” channel name when it is in emergency mode.

If you set to “off” by KPG-38D the transceiver shows selected group/channel/status before entering to the emergency mode however the transceiver is in an emergency mode.

• 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 Fleet number 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 emergency DTMF ID code when you select MSK in the above emergency type.

• Direct “OST”

It is possible to call “OST” number directory using keypad. In this case, keypad is used for “OST”, then “DTMF Auto PTT”, “DTMF Auto Dial” functions by keypad are not usable.

3-18. Emergency

• Active Time

Automatic transmission period in the emergency mode.

• Interval Time

Interval time between the automatic transmissions.

• Duration of Locator Tone 1

Duration of an alert tone before the automatic transmission is performed.

• Duration of Locator Tone 2

Duration of an alert tone after the automatic transmission is performed.

3-19. Radio Password (Keypad Model Only)

The radio password prevent unauthorized users operation. Every time the power on, transceiver is locked and unusable until entering correct password.

Enter pre-programmed password by FPU and [#] key causes the transceiver unlocked.

3-20. Data Password

The data password prevents unauthorized reading of the programmed transceiver data by FPU. Enter pre-programmed password in FPU reading process. This password also protects the clone.

Enter pre-programmed password by FPU and [#] key to clone.

OPERATING FEATURES

TK-290

4. Group Features

You can use these features using the programming soft-

ware (KPG-38D).

4-1. “TOT” (Time-Out Timer)

The transceiver has the “TOT”. This parameter selects

the period of time users can continuously transmit.

When the selected period passes, the transceiver gener-

ates an warning tone and stops the transmission.

4-2. “TOT” Pre-Alert

The transceiver has “TOT” pre-alert timer. This parameter selects the time at which the transceiver generates “TOT” pre-alert tone before “TOT” is expired.

“TOT” will be expired when the selected time passes from a TOT pre-alert tone.

4-3. “TOT” Re-Key Time

The transceiver has “TOT” re-key timer. This timer is the time you can not transmit after “TOT” exceeded. After “TOT” re-key time expired you can transmit again.

4-4. “TOT” Reset Time

The transceiver has “TOT” reset timer. This timer is the minimum wait time allowed during a transmission that will reset the “TOT” count.

“TOT” reset time causes the “TOT” to continue even after PTT is released unless the “TOT” reset timer has expired.

4-5. Group Delete/Add

The transceiver can set the delete/add in each group. If “Delete” is selected, the transceiver does not scan the deleted group in multi group scan.

4-6. Battery Save

This is the automatic battery saver during a standby mode operation. The receiver circuit is repeated on and off to conserve the battery life.

4-7. Signalling

Signalling “AND/OR” sets the audio unmute condition for any channel programmed with the option signalling (2Tone/DTMF).

AND : “AND” requires both the valid option signalling

and the programmed QT/DQT to be received for audio to

unmute (and initiate an option signalling decode alert).

OR : “OR” requires either the valid option signalling or

the programmed QT/DQT to be received for audio to

unmute (an option signalling decode alert is only initiated

if the proper option signalling is decoded).

5. Channel Features

You can use these features using the programming soft-

ware (KPG-38D).

5-1. Option Signalling

The transceiver is programmable to the option signalling (2-Tone decode program 1, 2-Tone decode program 2, 2Tone decode program 3, DTMF decode) to each channel. It is useful to receive an individual call.

Receive format is selectable “AND” or “OR” with QT/ DQT for each group. The radio response of option signalling is programmable “(Call) Alert tone” or “Transpond” for each option signalling (2-Tone decode program 1, 2-Tone decode program 2, 2-Tone decode program 3, DTMF).

5-2. PTT ID

PTT ID provides a DTMF ANI, MSK ANI or ANI board ID (if installed) to be sent with every time PTT (connect ID at beginning of transmission, disconnect ID at end of transmission, or both).

You can program PTT ID “on” or “off” for each channel. The contents of ID are programmed for each transceiver.

5-3. Busy Channel Lockout

Transmission is inhibited when the channel is busy. It is able to set this feature “Yes” or “No” for each channel.

5-4. Beat Shift

This is the feature that the microprocessor shifts its system clock frequency slightly to prevent the receive interference. This transceiver can program this feature “Yes” or “No” for each channel.

5-5. TX Power

You can set the transmission power “High” or “Low” for each channel. The each power setting is tuned at factory.

However, you can re-tune the power, using PC Tuning Mode of KPG-38D.

5-6. Wide/Narrow

You can set the occupied band width mode “Wide” or “Narrow” for each channel. It is useful for the operator to use the transceiver on various sites.

5-7. Scan Delete/Add

Scanning “delete/add” is programmable for each channel. Set the currently selected channel required to include in the scan sequence to “add”.

The operator can change the “delete/add” information using the key programmed to “delete/add” function.

5-8. Compander

This function reduces the noise on the communications channel used by the transceiver and improves reception.

If Wide/Narrow function is set to wide, this function doesn't perform.

TK-290

OPERATING FEATURES

6. Key Functions

You can use these features, using the programming software (KPG-38D). Selector function is selectable channel select or group select.

The functions for Toggle switch are listed page 8 (Fig. 2). Right position is active for programmed function on toggle switch except “group select”.

The functions for the top key are listed page 8 (Fig.2). Hold action and shift action are programmable.

The functions for side key are listed page 8 (Fig.2). Hold action and shift action are programmable.

The functions for microphone key are listed page 8 (Fig.2). Hold action is programmable.

6-1. No Function

Sounds error operation beep, and no action will occur. Use this function when the transceiver is required to be more simple operated.

6-2. AUX.

This function can be programmed when the voice scrambler board is not installed.

If this key is pressed, “AUX” icon lights on the LCD and AUX port which is inside of the transceiver turns to the high level. If pressed again, the “AUX” icon goes off and the AUX ports turns to the lower level.

6-3. Channel Down

If this key is pressed once, the channel number decreases by one step. If this key holds down for 500ms (approximate), the channel number decreases continuously.

This key works as the squelch level adjuster in a squelch level adjust mode. This key works as the OST (operator selectable tone) number selector in the OST mode. This key works as the SCR (voice scrambler) code selector in the voice scrambler code select mode.

6-4. Channel Up

If this key is pressed once, the channel number increases by one step. If this key holds down for 500ms (approximate), channel number increases continuously.

This key works as the squelch level adjuster in squelch level adjust mode. This key works as the OST (operator selectable tone) number selector in the OST mode. This key works as the SCR (voice scrambler) code selector in the voice scrambler code select mode.

6-5. Channel Name

This key switches the LCD display between the group/ channel number and the group/channel name.

6-6. Delete/Add

This key switches the currently displayed channel between “Delete” and “Add”.

The “Add” channel contained in the scan sequence, and “Delete” channel is not contained. In the scan mode, this key switches the channel delete or add temporarily.

Toggle PF Keys Speaker/

Function Name Selector Switch

Aux Channel Down ✓✓ Channel Name ✓✓ Channel Select ✓ Channel Up ✓✓ Delete/Add ✓✓

Emergency Call Group Down ✓✓ Group Scan ✓ Group Select ✓✓ Group Up ✓✓ Home Channel ✓✓ Invert Display ✓✓✓ Key Lock ✓✓✓ Lamp ✓✓ Low Power ✓✓✓ Monitor ✓✓✓ Monitor Momentary ✓✓ No Function ✓✓✓ Operator Selectable ✓✓

Tone Operator Selectable ✓

Priority 1 Operator Selectable ✓

Priority 2 Scan ✓✓✓

Scrambler Shift ✓✓ SP Attenuation ✓ Squelch Level ✓✓ Squelch OFF ✓✓✓ Squelch Momentary ✓✓ Talk Around ✓✓✓

1 This function can be selected when the scrambler board has not

been installed.

2 This function can be selected when the ANI board has been in-

stalled.

3 This function can be selected when the scrambler board has

been installed.

Note : If “Shift” is pregrammed onto one of the PF keys or the toggle switch, the remaining PF keys can be programmed with two different functions. If “Shift” is programmed onto a PF key and the toggle switch, an error will occur and the function will not operate.

✓✓✓

Microphone

PF Keys

✓✓

Fig. 2 Programmable functions

OPERATING FEATURES

TK-290

6-7. Group Down

If this key is pressed once, the group number decreases by one step. If this key holds down for 500ms (approximate), the group number decreases continuously.

6-8. Group Up

If this key is pressed once, the group number increases by one step. If this key holds down for 500ms (approximate), the group number increases continuously.

This key works as the squelch level adjuster in the squelch level adjust mode. This key works as the OST (operator selectable tone) number selector in the OST mode. This key works as the SCR (voice scrambler) code selector in the voice scrambler code select mode.

6-9. Home Channel

Press this key once, the channel switches to the pre-programmed home channel. Press this key again, the channel goes back to the previous channel.

6-10. Invert Display

Press this key once, the displayed the group/channel number or group/channel name are inverted. Press this key again, the display returns to the normal.

For the operator who does not change the display and needs “Invert” only, refer “Invert Display” setting of optional feature.

6-11. Key Lock

Pressing this key causes the transceiver to accept an entry of only the [Shift], [KeyLock], [PTT], [Emergency], [LAMP], [Monitor], [Monitor Momentary], [Squelch Off], [Squelch Momentary], [SP MIC Attenuation] keys, [Selector switch], [Volume], [Toggle], [Lamp], [Moni], [Moni momentary], [SQ off] and [SQ momentary].

“Lock” is used to prevent users from unexceptable key press which might cause a transceiver malfunction. The display does not change while the key is being locked.

Switching the transceiver off and on or pressing Key Lock again cancels the key lock. Key locked transceiver can still receive. Pressing this key while scanning, keys are locked but a scanning continues.

6-12. Lamp

Press this key, the transceiver illuminates the display and keypad back lit approximate 5 seconds. Press this key again, the transceiver stops the illuminating.

Pressing any key except the LAMP key while the illuminated restarts the 5 second timer.

6-13. Low Power

Press this key, the transmission power of all channel changes to Low. Press this key again, the transmission power returns to programmed value.

6-14. Monitor

Monitor the channel before a transmission.

Press this key once, “MON” appears and unmutes speaker if a carrier is present, regardless of the specified signalling (including option signalling). Press this key again, “MON” disappears and mutes speaker.

Press this key after the Option Signalling is matched, the Option Signaling is reset and monitor is activated. DBD (Dead Beat Disable) mode is not reset by this operation.

6-15. Monitor Momentary

While pressing this key, the monitor function (refer 6-14) is activated. Release this key, the monitor function is deactivated.

6-16. Operator Selectable Tone

This key switches the pre-set decode QT/DQT and encode QT/DQT to OST (Operator Selectable Tone) tone pair.

Press this key, the transceiver enters to OST select mode. In this mode, the display shows “OFF” and the operator can select one of the OST tone pair using the channel up/down key or the group up/down key. The display shows

“TONE ✽ ✽” and tone pair No. ✽ ✽ is selected.

Press OST key again, the transceiver exits from the OST select mode, and returns to the group/channel mode with “OPT” icon. “OPT” icon means that the OST tone pair is selected. OST tone pair number or OFF can be memorized for each channel.

16 kinds of tone pair for OST can be programmed by KPG-38D. OST is useful to access the repeater with same radio frequency and different tone (QT/DQT).

6-17. Operator Selectable P1

If priority channel 1 is set as “Fixed” and “None” in the scan information. The operator can select the priority channel 1, using this key (operator selectable fixed P1).

Press this key on normal channel, the channel becomes to priority channel 1. Previous priority channel 1 returns to the normal channel. Press this key on the priority channel 1, the priority 1 will be lost (no priority 1).

6-18. Operator Selectable P2

If priority channel 2 is set as “Fixed” and “None” in the scan information. The operator can select the priority channel 2, using this key (operator selectable fixed P2).

Press this key on the normal channel, the channel becomes to the priority channel 2. Previous priority channel 2 returns to the normal channel. Press this key on priority channel 2, the priority 2 will be lost (no priority 2).

6-19. Scan

Press this key starts scanning. Pressing this key stops scanning.

6-20. Shift

This key activates “Shift + [Key]” function. It is useful when the numbers or more of the functions are necessary.

TK-290

OPERATING FEATURES

6-21. Squelch Level

The preset squelch level is varied in user mode (0 to 15). Press the key programmed to “squelch level”, the transceiver enters to “squelch level adjust mode”.

The squelch level can be adjusted by group “up/down” function key or channel “up/down” function key. Press the key programmed to “squelch level” again, the adjusted level is memorized and returns to the normal user mode.

6-22. Squelch Momentary

While pressing this key, the transceiver unmutes speaker regardless of an existence of a carrier and “MON” appears and busy “LED” lights on.

Release this key, the transceiver mutes the speaker and “MON” disappears and busy “LED” lights off.

6-23. Squelch Off

Press this key, the transceiver unmutes speaker regardless of the existence of a carrier and “MON” appears and busy “LED” lights.

Press this key again, the transceiver mutes the speaker and “MON” disappears and busy “LED” lights off.

6-24. Talk Around

Press this key, the transceiver uses the receive frequency and the tone for transmission.

The operator can call the other party directory (without repeater). Press this key again, the talk around function goes off.

9. Data Programming (PC Mode)

9-1. Preparation and Connection

TK-290 transceiver is programmed by using a personal computer, programming interface cable KPG-36, and programming software KPG-38D.

The programming software can be used with an IBM-PC or compatible machine. Figure 3 shows the setup for programming.

9-2. Programming Interface Cable KPG-36 Description

The KPG-36 is required to interface TK-290 to the computer. It has a circuit in its D-sub 25pin connector case that converts RS-232C logic level to TTL level.

KPG-36 is used to connect between TK-290 universal connector and RS-232C serial port of computer.

9-3. Programming Software KPG-38D Description

KPG-38D is the programming software for TK-290 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-290 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-38D for example to harddisk first then use it.

KPG-38D instruction manual part No. : B62-0814-XX.

6-25. Emergency Call

Press this key, the transceiver enters to an emergency mode. In this mode, the channel is switched to the programmed emergency channel automatically and starts transmission with an emergency ID code which is programmed to ANI board.

The display depends on “Emergency Channel Display” setting.

6-26. SP Attenuation

Press this key once, the volume level of speaker-microphone is attenuated. Press this key again, the volume level of speaker-microphone returns to the previous level.

7. 2-Tone

Built-in 2-Tone decoder (decoder program 1, decoder program 2, decoder program 3) is available for option signalling. It is possible to use individual call or group call.

8. DTMF

Built-in DTMF encoder is available for dialing (Manual dial, Auto-dial (9 memory), Re-dial (1 memory)) (Keypad model only). Built-in DTMF decoder is available for option signalling.

It is possible to use individual call, group call, DBD (Dead Beat Disable).

KPG-36

IBM-PC

KPG-38D

Fig. 3

REALIGNMENT

11: GREEN (5M)

TUBE

SCREW

8: YELLOW (PF SW)

2: RED (RX AF OUTPUT) 3: BLACK (RX AF OUTPUT)

10: BROWN (GND)

6: BROWN (MIC GND)

5: WHITE (MIC INPUT)

7: BLUE (PTT SW) GND → ON

Shorted

Cut the pattern between SSW and GND.

CN2

TK-290

1. Mode

User mode

PC mode PC programming mode

PC test mode

PC tuning mode

Self programming mode

Panel test mode LCD all lamp mode

Firmware programming mode

Mode Function

User mode Customer use this mode

PC mode Communication between the radio

and PC (IBM compatible).

It requires the KPG-38D

PC programming mode Frequency, signalling and features

write to the radio and read from

the radio.

PC test mode Check the radio using the PC.

This feature is included in the FPU.

Self programming mode Frequency, signalling and features

write to the radio.

Panel test mode Dealer use to check the fundamen-

(Refer to Adjustment) tal characteristics.

Firmware programming mode

Re-write the firmware of the flash

ROM.

Channel setting mode

Group setting mode

Function setting mode

Clone master mode

Panel tuning mode

Clear function

3. Self Programming

Write mode for frequency data and signalling etc. Mainly

used by the person maintaining the user equipment.

3-1. Enter to the self programming mode

Turn the power switch on, with the lead wire with plug PF (8 pin) shorted to the E (10 pin) lead (Figure 5), or delete R491 (SELF, Figure 6) in the TX-RX unit and turn the power switch on while pressing the [Side 1] and [Side 2] keys.

Note :

This mode (self programming mode) cannot be set when it has been disabled with the FPU.

• Additional Modification of the Plug

It‘s available to enter the self programming mode by modifying the pattern of lead wire as following.

Fig. 4

Lead wire with plug (E30-3287-08)

2. How to Enter Each Mode

User mode Power on

PC mode Power on begins the USER MODE.

Self programming mode Hold down the [Side 1] key and the

Panel test mode Hold down the [Side 2] key and

Firmware programming mode

Mode Operation

[Side 2] key, turn the radio power

on.

[PTT], turn the radio power on, and

release [PTT] first.

Held down the [Side 2] key and

[PTT], turn the radio power on, and

release [Side 2] key first.

Fig. 5

TK-290

5kHz step

6.25kHz step

7.5kHz step

2.5kHz step

1.25kHz step

TP5

TP4

X57-5390-10 Component side

SELF

R491

REALIGNMENT

3-2. Channel Setting Mode

Set data for each channel while in this mode. After first

entering Self programming mode, select the “CHAN” display with [Top 1] [Top 2] and press [PTT] to set Channel Setting mode. Once in Channel Setting mode, select the group that needs setting with the [Top 1] [Top 2] keys and press [PTT]. Next select the channel for setting with the [Top 1] [Top 2] keys and press [PTT]. The setting items and setting data will then appear so reset the data with the [Top 1] [Top 2] keys and press [PTT]. When finished, the display shifts to the next setting item. After finished setting all items press [PTT] to return to Group selection. Changes in the frequency CH steps and the QT/DQT steps can be made in [Side 1].

Fig. 6

When enter the self programming mode, “FUNC” ap-

pears after “SEL” is displayed for half a second.

Selecting any of Channel setting, Group setting, Function setting, or Clone master with the [Top 1] [Top 2] keys and then pressing [PTT] sets the Setting mode for that time.

Key operations in Self programming mode are as follows.

[Selector switch] : Not used

[PTT] : Functions as a RUN or Execute key

[Top 1] : Use as a Down key

[Top 2] : Use as an Up key

[Side 1] : Use for select channel steps in Chan-

nel setting mode, or switching for

QT/DQT. [Side 2] : Use as a cancel key [Orange] : Add or delete frequencies in Channel

setting mode [Toggle] : Flipping this to the right while in

Channel setting mode, shifts to MHz

steps.

No. Function name Display Remarks

Select 1.–1 during 1–160~160–1

Group/Channel

1 RX frequency R150.0125 Receive frequency

2 RX signalling RX 023N Receive QT/DQT

3 TX frequency T150.0125 Transmit frequency

4 TX signalling TX 250.3 Transmit QT/DQT

5 Option signalling 2ToneA OFF, DTMF, 2ToneA,

6 DEL/ADD D/A ADD Delete, Add

7 Wide/Narrow WIDE Wide. Narrow

8 PTT ID ID OFF OFF, ON

9 TX power POW HI High, Low

Busy channel lockout

11 Beat shift SFT OFF OFF, ON

group selection

1–1. during

channel selection

(Dot on right edge is

lit up during 1 step

changes)

(Dot on right edge is

lit up during 1 step

changes)

2ToneB, 2ToneC

BCL OFF OFF, ON

• Channel step display

Attach the lead wire with plug

[Side 1] + [Side 2] + Power on

“CHAN”

[Top 1] [Top 2]

“GROUP”

[Top 1] [Top 2]

“FUNC”

[Top 1] [Top 2]

“CLONE”

“SEL”

[PTT]

REALIGNMENT

TK-290

• Operation

1. Select the setting value with the [Top 1] [Top 2] keys.

2. Press the [PTT] and the selected value is backed up and

operation shifts to the next item for setting.

3. Press [Side 2] on the Group selection screen in order to

return to Self programming mode.

• Note

1. Different sample displays are shown.

2. Setting item No.s are displayed with a 7-segment 2-digit

figure on the LCD.

3. Self programming mode cannot be set when set to

Disaable with the FPU.

4. A red LED lights up during TX frequency and TX signal-

ling.

5. Press [Orange] on the TX, RX frequencies setting screen

in order to clear in the channel frequencies data.

6. Press [Orange] on the signalling setting screen in order to

change or off the signalling function.

7. Flipping [Toggle] to the right during setting of RX, TX fre-

quencies and performing Up/Down operation allows frequencies to be changed in MHz steps.

8. The RX and TX frequencies can be entered with the num-

ber pad keys.

• Flow Chart

Self programming mode

[Top 1] [Top 2]

Channel setting mode

[PTT]

Group selection

[Side 2]

Channel selection

[Side 2]

1. RX frequency

[Side 2]

2. RX signalling

[Side 2]

3. TX frequency

[Side 2]

4. TX signalling

[Side 2]

5. Option signalling

[Side 2]

6. Scan Delete/Add

[Side 2]

7. Wide/Narrow

[Side 2]

8. PTT ID on/off

[Side 2]

9. TX power Hi/Low

[Side 2]

10. Busy channel lockout on/off

[Side 2]

11. Beat shift on/off

[Side 2]

[PTT]

Orange Orange

OFF

Orange Orange

DQT I DQT N

Orange

OFF

Orange Orange

DQT I DQT N

Orange

3-3. Group Setting Mode

Set data for each Group while in this mode. After first entering Self programming mode, select the “GROUP” display with [Top 1] [Top 2] and press [PTT] to set Group Setting mode. Once in Group Setting mode, select the group that needs setting with the [Top 1] [Top 2] keys and press [PTT]. Next select the channel for setting with the [Top 1] [Top 2] keys and press [PTT]. The setting items and setting data will then appear so reset the data with the [Top 1] [Top 2] keys and press [PTT]. When finished, the display shifts to the next setting item. After finished setting all items press [PTT] to return to next Group selection.

No. Function name Display Remarks

Select Group GRP 1 1~160

1 Battery save BATT L OFF, Short, Mid, Long

2 Time out timer TOT 60

3 TOT pre alert TOT.P 10 OFF, 1s~10s (1s step)

4 TOT rekey time TOT.K 2 OFF, 1s~60s (1s setp)

5 TOT reset time TOT.S 2 OFF, 1s~15s (1s step)

6 Group Delete/Add D/A ADD Delete, Add

7 Signalling SIG AND AND, OR

OFF, 30s~300s (30s step)

• Operation

1. Select the setting value with the [Top 1] [Top 2] keys.

2. Press the [PTT] and the selected value is backed up and

operation shifts to the next item for setting.

3. Press [Side 2] on the Group selection screen in order to

return to the Self programming mode initial display.

• Note

1. Different sample displays are shown.

2. Setting item No.s are displayed with a 7-segment 2-digit

figure on the LCD.

3. Self programming mode cannot be set when set to Dis-

able with the FPU.

• Flow Chart

Self programming mode

[Top 1] [Top 2]

Group setting mode

[PTT]

Group selection

[Side 2]

1. Battery save

[Side 2]

2. Time out timer (TOT)

[Side 2]

3. TOT pre-alert

[Side 2]

4. TOT rekey time

[Side 2]

5. TOT reset time

[Side 2]

6. Scan group Delete/Add

[Side 2]

7. Signalling AND/OR

[Side 2]

[PTT]

TK-290

REALIGNMENT

3-4. Function Setting Mode

This mode allows making function settings for the transceiver. After first entering Self programming mode, select “FUNC” display with [Top 1] [Top 2] and then press [PTT] to set this mode. Function setting items are listed below.

No. Function name Display Remarks

1 Power on tone POW.T 15 (or C) Continuas, 0~31

2 Control tone CON.T 15 (or C) Continuas, 0~31

3 Warning tone WAR.T 15 (or C) Continuas, 0~31

4 Alert tone ALR.T 15 (or C) Continuas, 0~31

Minimum volume

6 Battery warning BATT ON Disable, Enable

7 Busy LED B.LED ON OFF, ON

8 TX LED T.LED ON OFF, ON

9 Invert Display LCD ON Disabel, Enable

10 Priority 1 P1 NONE

11 Priority 1 group 1.–1 1–1~10–16

Priority 1 channel 1–1.

13 Priority 2 P2 NONE

14 Priority 2 group 1.–1 1–1~10–16

Priority 2 channel 1–1.

16 Revert channel REVT 1 1~8

17 Squelch level SQ.LV 15 0~15

MIN.V 8 0~31

None, Selected, Fixed

(Priority 1= In fixed)

None, Selected, Fixed

(Priority 2= In fixed)

1 : Selected

2 : Last called

3 : Last used

4 : Sel+Talk back

5 : Priority 1

6 :

7 : Priority 2

8 :

Priority 1+Talk back

Priority 2+Talk back

• Operation

1. Select the setting value with the [Top 1] [Top 2] keys.

2. Press the [PTT] and the selected value is backed up and

operation shifts to the next item for setting.

3. Press [Side 2] on the Group selection screen in order to

return to the Self programming mode initial display.

• Note

1. Different sample displays are shown.

2. Setting item No.s are displayed with a 7-segment 2-digit

figure on the LCD.

3. Self programming mode cannot be set when set to Dis-

able with the FPU.

• Flow Chart

Self programming mode

[Top 1] [Top 2]

Function setting mode

[PTT]

1. Power on tone

[Side 2]

2. Control tone

[Side 2]

3. Warning tone

[Side 2]

4. Alert tone

[Side 2]

5. Minimum volume

[Side 2]

6. Battery warning on/off

[Side 2]

7. Busy LED on/off

[Side 2]

8. TX LED on/off

[Side 2]

9. Invert display on/off

[Side 2]

10. Priority 1 setting

[Side 2]

11. Priority 1 group selection

[Side 2]

12. Priority 1 channel selection

[Side 2]

13. Priority 2 setting

[Side 2]

14. Priority 2 group selection

[Side 2]

15. Priority 2 channel selection

[Side 2]

16. Revert channel

[Side 2]

17. Squelch level

[Side 2]

[PTT]

REALIGNMENT

TK-290

3-5. Clone Mode

1. Connect the cloning interface cable between the master side transceiver (source) and slave side transceiver (clone) as shown in the figure.

Cloning interface cable Part No. E30-3325-05

2. Set the master side transceiver to Self programming mode, and the transceiver display to “CLONE” with the [Top 1] key or [Top 2] key and press [PTT].

SEL CHAN CLONE

[Top 1] [Top 2]

[PTT]

A CLONE

[Top 1] [Top 2]

G CLONE

• Group Clone

1. To clone the transceiver group data and channel data within the group, as well as group alphanumeric data, use the [Top 1] key or [Top 2] key to switch the display on the master side transceiver from “A CLONE” to “G CLONE”.

A CLONE

2. Press [PTT] to show the group cloning selection.

3. Select the group with the [Top 1] or [Top 2] keys.

4. Press [PTT] to show the slave side group cloning selection.

5. Select the group with the [Top 1] or [Top 2] keys.

G CLONE

6. Press the master side [PTT] to start cloning.

GRP 1S

[Top 1] [Top 2]

[PTT] [PTT]

[PTT]

Red lamp flashes

GRP 1M

G CLONE

GRP 1S

END

3. Set the power switch on the slave side transceiver to ON.

4. The red LED on the master side transceiver flashes when cloning starts and an “END” message appears when cloning ends.

5. The green LED on the slave side transceiver flashes.

6. When a problem occurs during cloning, an “ERROR” message appears on the master side transceiver.

7. Pressing the [Side 2] key sets clone mode.

Note :

The master transceiver copies only to type matched

slave.

• All Clone

1. Press [PTT] on the master side transceiver to start cloning of all data except for the transceiver model type and alignment data.

A CLONE

Red lamp flashes

[PTT]

END

• Flow Chart

[Side 2]

All clone mode

[Side 2]

Self programming mode

[Top 1] [Top 2]

Clone master mode

[PTT] [PTT]

Clone lock

[PTT]

Password input

[ ] [ ] ··· [#]

All clone/group clone selection

[PTT] [Top 1] [Top 2]

[PTT]

Only the keypad model and

set to password with the FPU.

[PTT]

Group clone mode

[PTT]

"Master" group selection

[PTT]

"Slave" group selection

[PTT]

END

[Side 2]

[Side 2][Side 2]

TK-290

REALIGNMENT

4. Firmware Programming Mode

4-1. Preface

Flash memory is mounted on the TK-290. This allows the TK-290 to be upgraded when new features are released in the future. (For details on how to obtain the firmware, contact Customer Service.)

4-2. Connection Procedure

Connect the TK-290 to the personal computer (IBM PC or compatible) with the interface cable (KPG-36). (Connection is the same as in the PC Mode.)

4-3. Programming

1. Start up the programming software (KPG-38D), select

“firmware program” in the “Program” item, and press

the Return key on the personal computer. This starts up

the firmware programmer.

2. The top screen is displayed. Press any key to advance to

the next screen.

3. Set the communications speed (normally, 38400 bps)

and communications port in the Setup item.

4. Set the firmware to be updated by File select.

5. Held down the [Side 2] and [PTT]. Turn the TK-290 power

on, and release [Side 2] first. Until the display change to

“PROGRAM”.

6. Check the connection between the TK-290 and the per-

sonal computer, and make sure that the TK-290 is in the

Program mode.

7. Press F10 on the personal computer. A window opens

on the display to indicate progress of writing. When the

TK-290 starts to receive data, “PG” is appeared on 2 digit

sub display.

8. If writing ends successfully, the red LED on the TK-290

lights and the checksum is displayed.

9. If you want to continue programming other TK-290s, re-

peat steps 5 to 8.

4-4. Function

1. If you press the [Top 2] switch while “PROGRAM” is displayed, the checksum is displayed. If you press the [Top 1] switch while the checksum is displayed, “PROGRAM” is redisplayed.

2. If you press the [Top 1] switch while “PROGRAM” is displayed, 1 dot light (“M.”) to indicate that the write speed is low-speed (19200 bps). If you press the [Top 1] switch again while low-speed (19200 bps), 2 dot lights (“.M.”) to indicate, and the write speed becomes the high-speed mode (38400 bps). The communication speed changes 19200 bps, 38400 bps, 57600 bps (3 dots), and 115200 bps (4 dots) every time you press [PTT] and [Top 1].

Note :

Normally, write in the high-speed mode. When the Flash ROM is replaced, the initial communica-

tion speed for writing becomes 115200 bps.

5. Panel Test Mode

Setting method refer to ADJUSTMENT.

Notes :

• To start the Firmware Programmer from KPG-38D, the Fpro path must be set up by KPG-38D setup.

• This mode cannot be entered if the Main Program mode is set to Disable in the Programming software (KPG-38D).

CIRCUIT DESCRIPTION

TK-290

1. Overview

The KENWOOD model TK-290 is a VHF/FM hand-held transceiver designed to operate in the frequency range of 136 to 174MHz, the unit consists of a receiver, a transmitter, a phase-locked loop (PLL) frequency synthesizer, power supply circuits, a control unit.

2. Circuit Configuration by Frequency

The receiver is a double-conversion superheterodyne with a first intermediate frequency (IF) of 44.85MHz and a second IF of 455kHz. Incoming a signals from the antenna are mixed with the local signal from the PLL to produce the first IF of 44.85MHz.

This is then mixed with the 45.305MHz second local oscillator output to produce the 455kHz second IF. This is detected to give the demodulated signal.

The transmit signal frequency is generated by the PLL VCO, and modulated by the signal from the microphone. It is then amplified and sent to the antenna.

ANT

TX/RX : 136~174MHz

ANT

AMP

MCF

44.85MHz

XF301

180.85~218.85MHz

136~174MHz

AMP

1st MIX

Fig. 1 Frequency configuration

CF300,301

455kHz

FM IF

SYSTEM

45.305MHz

PLL

VCO

AMP

MIC

AMP

MIC

3. Receiver System

3-1. Front-end RF amplifier

The signal are then passed through an antenna matching coil, where the high-frequency components are amplified by a GaAs FET (Q200). 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.

3-2. First mixer

The 1st mixer uses the GaAs IC (IC200). The 1st mixer mixes the signal with the 1st local oscillator frequency from the VCO, and converts it to the 1st IF (44.85MHz).

The signal then passes through monolithic crystal filter (XF301) to remove unnecessary nearby frequency components. The signal from the MCF is used as the 1st IF signal.

3-3. IF amplifier

The 1st IF signal is amplified (Q302) and fed into IC300 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 (CF300, CF301 ; Wide, CF302, CF303 ; Narrow) and fed back into IC300 for additional amplification.

L201

BPF

Q200

RF AMP

MCF

XF301

L202

BPF

IF AMP

Q302

X300

45.305 MHz

L205

BPF

FM IF SYSTEM

L206

BPF

IC300

IC200

1st MIX

D602 D603

T/R SW

CF300,301

Wide

CF302,303

Narrow

Fig. 2 Receiver section

Item Rating

Nominal center frequency 44.85MHz Pass band width ±5~7kHz at 3dB Attenuation band width ±25kHz or less at 30dB

Ripple 1.0dB or less

Insertion loss 4dB or less Guaranteed attenuation 80dB or more at fo±910kHz

40dB or more within fo±1MHz

Terminating impedance 350Ω / 4.5pF

Table 1 Crystal filter XF301 (L71-0588-05)

TK-290

IC300

MIX, DET, IF

IC301

IC601 (2/2)

AF AMP

CF300 CF301

CF302 CF303

DE-

EMP

MUTE

EXP

HPF LPF HPF BEF

IC607

VOL

IC603

IC604 (2/2)

AF AMP

SWSW

13 16

Q15

INT AFC

EXT AFC

INT.SP

EXT.SP

AMP SW

2nd local

OSC

X300

IC1

CIRCUIT DESCRIPTION

3-4. Wide/Narrow changeover circuit

Narrow and Wide settings can be made for each channel by switching the ceramic filters CF300, CF301 (Wide), CF302, CF303 (Narrow).

The WIDE (high level) and NARROW (low level) data is output from IC400 (I/O port expansion) pin 4.

When a WIDE (high level) data is received, Q303 turn off and Q304 turn on. When a NARROW (low level) data is received, Q303 turn on and Q304 turn off. D302, D303 are switched to ceramic filters when a high/low level data is received.

Q305 turns on/off with the Wide/Narrow data and the IC300 detector output level is changed to maintain a constant output level during wide or narrow signals.

R326

AFO

Q305

W/N “H” : Wide “L” : Narrow

IC300 FM IF SYSTEM

W/N

Q302

MXI

CD300

C316

MXO

R320

R322

IFO

QAD

IFI

• Control unit

The audio mute signal (AMP SW) from the microprocessor becomes Low in the standby and Q5, Q6 which are power supply circuit for IC1 turn off. When the audio is output, AMP SW becomes High to turn Q5, Q6 on, and voltage is supplied to power terminal VP of IC1.

Speaker switching is done from IC403 (TX-RX unit) by INT AFC or EXT AFC. First, the logic level at the speakers switching terminal (SSW) on the universal connector is input to the microprocessor (IC406 TX-RX unit). The microprocessor then outputs data to IC403 based on this input.

When there is no SP-MIC installed, this logic level is high. When the INT AFC is high, the EXT AFC goes low, so the AF signal is only input to the amplifier for the internal speaker (INT SP) of IC1. However, when a SP-MIC has been installed, this logic level is low, so the INT AFC goes low and the EXT AFC goes high. So that the AF signal is input only to amplifier for the external speaker (EXT SP) of IC1.

C330

Q303

Q304

C311

D302

R315

C331

CF300 CF301

R317

CF302 CF303

R318

R324

D303

R325

Fig. 3 Wide/Narrow changeover circuit

3-5. Audio amplifier circuit

• TX-RX unit

The demodulated signal from IC300 goes through IC301, and is amplified by IC601 (2/2), high-pass filtered, low-pass filtered, high-pass filtered, band-eliminate filtered, and deemphasized by IC607.

The signal then goes through an electronic volume control (IC603), an AF amplifier IC604 (2/2), and an AF switch (Q8 is on and Q7 is on of the control unit), and is routed to audio power amplifier (IC1 of the control unit), where it is amplified and output to the internal speaker.

C321

R328

Fig. 4 Audio amplifier circuit

3-6. Squelch circuit

It amplifies the demodulated noise signal from FM IC (IC300) after filtering through BPF circuit. Then, the amplified signal is coverted to DC signal by the detection circuit. The coverted signal is feeded through the microprocessor (IC 406) and the voltage level is detected by ADC (A/D converter) to control the squelch circuit.

OUT

DET OUT

NOISE

AMP

IC300

Q301

NOISE

D300

AMP

DET

IC406

BUSY

CPU

IC403

OUTPUT

EXPANDER

AMP SW INT AFC EXT AFC

Fig. 5 Squelch circuit

CIRCUIT DESCRIPTION

TK-290

4. Transmitter System

4-1. Microphone amplifier

The signal from IC3 (control unit) goes through the mute

switch (Q403).

When the SP-MIC is not attached, the microphone switching terminal (MSW) on the universal connector becomes High, and mute switch (Q403) is turned on. When the SP-MIC is attached, MSW is connected to GND at inside of SP-MIC. For this reason, Q403 is turned off, the internal microphone is muted, and only the input of the external microphone is supplied to the microphone amplifier of the TXRX unit.

The signal from microphone passes through the limiter circuit in D601, and through the high-pass filter, the ALC circuit, the low-pass filter, the high-pass filter, and pre-emphasis/IDC circuit in IC607. When encoding DTMF, mute switch (Q601) is turned off for muting the microphone input signal.

The signal passes through the D/A converter (IC603) for the maximum deviation adjustment, and enters the summing amplifier consisting of IC605 (1/2), and is mixed with the low speed data from the CPU (IC406).

The output signal from the summing amplifier goes to the VCO modulation input.

The other output signal from the summing amplifier passes through the D/A converter (IC603) again for the BAL adjustment, and the buffer amplifier (IC604 1/2), and goes to the VCXO modulation input.

4-2. Noise cancelling microphone circuit

The two signals from INT MIC (Main & Sub) are input to the positive (+) input (Sub) and to the negative (–) input (Main) of the IC3. If the same signal is input to both Main and Sub, the Main signal is canceled at the output of IC3 (pin

7). In other words, noise from nearby sources not directly connected to the transceiver enters the Main and Sub inputs at the same signal and is therefore canceled out.

When a signal is only input to Main and there is no signal at Sub, the Main signal is output as is, from IC3 (pin 7). In other words, only the voice audio of the operator in extremely close proximity to the Main MIC is input to Main so that the signal is output as is from IC3 (pin 7). Also, when the “N/C” switch is set to “L”, transistor Q14 turns off so Sub microphone turns off and operation is the same as above.

4-3. Drive and Final amplifier

The signal from the T/R switch (D602 is on) is amplified by the pre-drive (Q6) and drive amplifier (Q8) to 20mW. The output of the drive amplifier is amplified by the RF power amplifier (IC801) to 5W (1W when the power is low).

The RF power amplifier consists of two stages MOS FET transistor. The output of the RF power amplifier is then passed through the Transmit-Receive (TX-RX) antenna switching (D10 is on) and the harmonic filter (LPF) and the Internal-External (INT-EXT) antennal switching (in the universal connector) and applied to the antenna terminal.

In the

From

T/R SW

(D602)

REF

VOL

(IC3)

Q6 Q8 IC801 D10

Pre-

AMP

R35

R37

R39

Q13

DRIVE

AMP

VDD

DRIVE

POWER

AMP

IC7

(1/2)

VGG

TX-RX

ANT

IC7

(2/2)

LPF

universal

connector

ON→EXT

EXT-INT

ANT

Fig. 7 Drive and final amplifier and APC circuits

4-4. Internal-External (INT-EXT) antenna switching

The INT-EXT antenna switch housed inside the universal connector only switches to the EXT ANT side when an antenna speaker-microphone has been installed.

This INT-EXT antenna switch works mechanically and switches based on the operation shown in Figure 8.

EXT ANT

From

LPF

From

LPF

OFF

EXT ANT

INT ANT

Switch OFF

↓

Internal

antenna

Switch ON

↓

External antenna

EXT.

MIC

MAIN

MIC

SUB

IC3

N/C

AMP

(CONT)

MIC

Q403

Q404

MSW

D601

LIMIT

IC607

HPF

IC603

D/A

Fig. 6 Microphoen circuit

ALC

IC605 (1/2)

LSD

SUM AMP

Q601

18 19

LPF HPF IDC

COMP

IC603

D/A

TONE

PRE

EMP

IC604

(1/2)

BUFF

AMP

Fig. 8 Internal-External

antenna switching

IC10

VCO

VCXO

TK-290

CIRCUIT DESCRIPTION

4-5. APC circuit

The APC circuit always monitors the current flowing through the RF power amplifier (IC801) and keeps a constant current. The voltage drop at R35, R37, and R39 is caused by the current flowing through the RF power amplifier and this voltage is applied to the differential amplifier (IC7 1/2).

IC7 (2/2) compares the output voltage of IC7 (1/2) with the reference voltage from IC3, and the output of IC7 (2/2) controls the VGG of the RF power amplifier to make the both voltages to same voltage.

The change of power high/low is carried out by the change of the reference voltage. Q7, Q9, and Q13 are turned on in transmit and the APC circuit is active. (See Figure 7)

5. PLL Frequency Synthesizer

The frequency synthesizer consists of the VCXO (X1), VCO (L800), PLL IC (IC5) and buffer amplifiers.

The VCXO generates 16.8MHz. The frequency stability is

within ±2.0ppm (temperature range of –30 to +60°C). The

frequency tuning and modulation of the VCXO are done to apply a voltage to pin 1 of the VCXO. The output of the VCXO is applied to pin 8 of the PLL IC.

The VCO of TK-290 covers the 38MHz spread, setting frequencies in r1, r2 (receive) and t1, t2 (transmit) with a bias voltage applied to the –V terminal of the VCO. A zero (0) volt bias is applied at frequencies lower than r1, t1. Frequencies r1, t1 through r2, t2 are biased with –3 volts. Frequencies higher than r2, t2 are biased with –6 volts, and at 174MHz tp 178MHz are biased with –9 volts.

The relation of VCO frequency versus PLL lock voltage is shown in Figure 11.

The output of the VCO is amplified by the buffer amplifier (Q3) and routed to the pin 5 of the PLL IC. Also the output of the VCO is amplified by the buffer amplifier (Q5) and routed to the next stage according to T/R switch (D602,603).

The PLL IC consists of a prescaler, fractional divider, reference divider, phase comparator, charge pump. This PLL IC is fractional-N type synthesizer and performs is the 40 or 50kHz reference signal which is eighth of the channel step (5, 6.25 or 7.5kHz). The input signal from the pins 1 and 5 of the PLL IC is divided down to the 40 or 50kHz and compared at phase comparator. The pulsed output signal of the phase comparator is applied to the charge pump and transformed into DC signal in the loop filter (LPF). The DC signal is applied to the pin 4 of the VCO and locked to keep the VCO frequency constant.

PLL data is output from DT (pin 85), CLK (pin 84) and LE (pin 93) of the microprocessor (IC406). The data are input to the PLL IC when the channel is changed or when transmission is changed to reception and vice versa. A PLL lock condition is always monitored by the pin 30 (UL) of the microprocessor. When the PLL is unlocked, the UL goes low.

BUFF

VCXO

Q5SWD602,603

BUFF

To mixer

IC3

IC604

To drive amp

–VC

LPF

CPU

IC406

IC6

–V

DT,CLK,LE

L800

VCO

IC5

PLL

Fig. 9 PLL block diagram

CV voltage

r1 t1

r2t2512

Frequency

(MHz)

Fig. 10 CV voltage vs frequency

6. Power Supply Circuit

Battery +B is supplied via a 3A fuse from the battery terminal connected to the TX-RX unit. After passing through the power switch power supply (SB) is applied to the two AVR ICs, and AVR circuit.

IC401 supplies 5V (5CM) to the control circuit. IC402 supplies 5V (5M) to the common circuit.

AVR circuit (Q400, Q402, Q405, Q406) supplies voltage to the TX circuit and the RX circuit. 5C is common 5V and output when SAVE is not set at off. 5R is 5V for reception and output during reception. 5T is 5V for transmission and output during transmission.

SB 5M

CLK

STB1

5V REG

IC402

Q402,400,405

5TC 5CC

SHIFT

IC400

5M OE

Q401

5RC

DAT

Fig. 11 Power supply circuit

Q406

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