Kenwood TM-221A Service Manual

144MHz FM TRANSCEIVER
TM-221A/E/ES
SERVICE MANUAL
KENWOOD
©1987-3 PRINTED IN JAPAN
‘B51-3217-00 (O) 1551
Knob (Button)
(K29-3058-04) x 3
Metallic cabinet (Top)
{A01-1021-03)
Knob (Button)
(K27-0496-04) x 2
Panel ass’y*
(A20-)
KENWOOD © 14miz FM TRANSCEIVER TM-221A
16510
Knob (Main)
(K29-3060-04)
Knob (Button)
(K29-3070-04)
Knob (Button)*
{K29-)
Knob (Button)
(K29-3069-04)
Knob (Button)
(K29-3067-04)
Knob (Button)
{K29-3065-04)
CIRCUIT DESCRIPTION .........0-c0cee cues 2
SEMICONDUCTOR DATA ...........0seeees 12
DESCRIPTION OF ELEMENTS .............-. 13
PARIS LIST Gs tresses aOae der Beek Gtet a ahs 16
EXPLODED VIEW sis; cntnieiond eh ce aah eeahn 32
BACKING fick rvkin Ge ted hee tke aden dense 33
DISASSEMBLY ...........0eeceeeeceecuee 34
ADJUSTMENT ....... ccc 0ccceeececeuees 35
PC BOARD VIEWS
LCD ASS'Y (B38-0303-05) .......e.ees cues 41
VCO (X58-3090-00) .. 0. ec eee eee cece aces 44
DRIVE (X59-3120-00) .. 00.0. e cece eee eees 41
APC (15059190200)... 05 bs han ahaadneks 42
(F (X60-3140-00): ais-oy caduceus aeredhowd s 42
Knob (VOL, SQL)
(K29-3061-04) x 2
CONTENTS
Microphone*
(T91-)
* Refer to parts list on page 16.
Photo is TM-221A.
SOL (X59-3150-00) 2... ee eee cee 42
MIC (X59-3160-00) 21... eee eee ee eee 42
VOL (X59-3170-00) 2... ee eee 42
FINAL UNIT (X45-1330-03) ... 0... .. ee eee 43
FINAL UNIT (X45-1360-02) .. 2... 2... eee 43
CONTROL UNIT (X53-3040-XX). 2.2.2... eee 44
TX-RX UNIT (X57-3060-XX) 2... ee ee 45
SCHEMATIC DIAGRAM .................044- 49
LEVEL DIAGRAM ...............0-02 20 eee 53
BLOCK DIAGRAM ................200000- 54
TERMINAL FUNCTIONS ................0.- 55
TSU-5 (CTCSS UNIT) ©... eee ee ee eee 56
SPECIFICATIONS ................ BACK COVER

Kenwood TM-221A Specifications

General

Brand	Kenwood
Model	TM-221A
Category	Transceiver
Language	English

Summary

Circuit Description

Frequency configuration

Describes frequency selection and intermediate frequencies.

Receiver system

Explains the signal path and components in the receiver.

Transmitter system

Covers general operation, modulation, and power amplification.

PLL synthesizer

Explains the phase-locked loop system for frequency synthesis.

Digital control unit

Covers the microprocessor, peripherals, and input circuits.

Semiconductor Data

Electronic volume LC7532M (VOL IC1)

Electric characteristics and block diagram of the volume control IC.

Description of Elements

Final Unit

Lists elements and functions of the final power amplifier stage.

Control Unit

Lists elements and functions of the microprocessor control unit.

TX-RX Unit

Lists elements and functions of the transmit/receive switching unit.

VCO

Lists elements and functions of the Voltage Controlled Oscillator circuits.

IF

Lists elements and functions of the Intermediate Frequency stage.

Parts List

Capacitors

Lists capacitor types, values, and characteristics.

Resistors

Lists resistor types, values, and characteristics.

Exploded View

Packing

Disassembly

Replacement of Lithium Battery

Step-by-step instructions for battery replacement.

Adjustment

Required Test Equipment

Lists necessary tools and equipment for adjustments.

Common Adjustment

Details general adjustments for setting, reset, PLL, and frequency.

Receiver System Adjustment

Outlines adjustments for helical, IF trap, gain, and discriminator.

Transmitter System Adjustment

Covers adjustments for RF output, low power, RF meter, and deviation.

PC Board Views

Specifications