Kenwood TK-280 User Manual

VHF FM TRANSCEIVER
TK-280
© 2000-4 PRINTED IN JAPAN
B51-8521-00(S) 553
SERVICE MANUAL
GENERAL ................................................................................. 2
SYSTEM SET-UP ..................................................................... 2
OPERATING FEATURES......................................................... 3
REALIGNMENT ...................................................................... 16
CIRCUIT DESCRIPTION ........................................................ 20
SEMICONDUCTOR DATA ..................................................... 26
DESCRIPTION OF COMPONENTS....................................... 32
PARTS LIST............................................................................ 33
EXPLODED VIEW .................................................................. 40
PACKING ................................................................................ 41
ADJUSTMENT ........................................................................ 42
TERMINAL FUNCTION .......................................................... 52
PC BOARD VIEWS
DISPLAY UNIT (X54-3210-12) ............................................ 53
TX-RX UNIT (X57-6192-70) ................................................ 59
SCHEMATIC DIAGRAM ......................................................... 65
BLOCK DIAGRAM .................................................................. 69
LEVEL DIAGRAM ................................................................... 71
OPTIONS ................................................................................ 72
SPECIFICATIONS ...............................................BACK COVER
CONTENTS
CAUTION
When using an external power connector,
please use with maximum final module
protection of 9V.
Photo is E type with KRA-14
Knob (ENC)
(K29-5232-03)
Knob (VOL)
(K29-5231-03)
Cabinet assy
(A02-2055-53)
(16 keys)
Badge
(B43-1106-14)
Packing
(G53-0896-02)
(16 keys)
Panel assy
(A62-0535-04)
Knob (PTT etc)
(K29-5157-03)
Helical antenna
(T90-0680-05):T
(T90-0695-15):E
E VERSIONS

Kenwood TK-280 Specifications

General

frequency range	146 to 174MHz
channel spacing	25kHz/20kHz/12.5kHz
battery voltage	DC 7.5V ±20%
temperature range	–30˚C to +60˚C

Receiver

rf input impedance	50Ω
sensitivity 12dB SINAD (Wide/Narrow)	0.25µV/0.28µV
selectivity (Wide/Narrow)	70dB/65dB (EIA), 73dB/63dB (ETS)
intermodulation (Wide/Narrow)	70dB/65dB (EIA), 65dB (ETS)

Transmitter

rf power output high	5W
rf power output low	1W
rf output impedance	50Ω
spurious	-70dB

Weight and Dimensions

height with KNB-16A battery	5.33” (135mm)
width with KNB-16A battery	2.29” (58mm)
depth with KNB-16A battery	1.34” (34mm)
weight with KNB-16A battery	1.01lbs (460g)

Summary

GENERAL / SYSTEM SET-UP

Introduction and Safety

System Setup Procedure

Step-by-step guide for setting up the transceiver and necessary accessories.

OPERATING FEATURES

Transceiver Controls and Indicators

Details physical layout, panel controls, programmable keys, and display icons.

Advanced Operating Modes

REALIGNMENT

Modes and Basic Procedures

Programming Modes

Details firmware programming, cloning, and self-programming procedures.

CIRCUIT DESCRIPTION

Receiver and Transmitter Circuitry

Control, Signalling, and Power Circuits

SEMICONDUCTOR DATA

EXPLODED VIEW

ADJUSTMENT

Test Equipment and Alignment Setup

Tuning Procedures

Step-by-step guide for adjusting transmitter and receiver parameters.

TERMINAL FUNCTION

Connector Pin Assignments

PC BOARD VIEW

SCHEMATIC DIAGRAM

SPECIFICATIONS

General and Performance Data

Lists overall transceiver specifications and performance metrics.