Icom S-14217HZ-C1 User Manual

SERVICE
MANUAL

VHF/UHF DUALBAND FM TRANSCEIVER

S-14217HZ-C1
Nov. 2005

INTRODUCTION

This service manual describes the latest service information
for the

IC-E7 VHF/UHF DUALBAND FM TRANSCEIVER

the time of publication.

MODEL VERSION SYMBOL

Europe EUR

IC-E7

To upgrade quality, all electrical or mechanical parts and internal
circuits are subject to change without notice or obligation.

Italy ITR

France FRA

United Kingdom UK

at

DANGER

NEVER connect the transceiver to an AC outlet or to a DC

power supply 3.7 V. Such a connection could cause a fire or
electric hazard.

DO NOT expose the transceiver to rain, snow or any liquids.

DO NOT reverse the polarities of the power supply when

connecting the transceiver.

DO NOT apply an RF signal of more than 20 dBm (100 mW)
to the antenna connector. This could damage the trans­ceiver's front end.

ORDERING PARTS

Be sure to include the following four points when ordering
replacement parts:

1. 10-digit Icom parts number

2. Component name and informations

3. Equipment model name and unit name

4. Quantity required

<SAMPLE ORDER>

5030002860 LCD A01B004X IC-E7 Main unit 5 pieces
8810008990 Screw PH B0 2×10 ZK IC-E7 Chassis 10 pieces

Addresses are provided on the inside back cover for your
convenience.

REPAIR NOTES

1. Make sure the problem is internal before disassembling the transceiver.

2. DO NOT open the transceiver until the transceiver is disconnected from its power source.

3. DO NOT force any of the variable components. Turn them slowly and smoothly.

4. DO NOT short any circuits or electronic parts. An insulated turning tool MUST be used for all adjustments.

5. DO NOT keep power ON for a long time when the transceiver is defective.

6. DO NOT transmit power into a signal generator or a sweep generator.

7. ALWAYS connect a 30 dB to 40 dB attenuator between the transceiver and a deviation meter or spectrum analyzer when
using such test equipment.

8. READ the instructions of test equipment thoroughly before connecting equipment to the transceiver.

Icom, Icom Inc. and logo are registered trademarks of Icom Incorporated (Japan) in the United States, the United
Kingdom, Germany, France, Spain, Russia and/or other countries.

TABLE OF CONTENTS

SECTION 1 SPECIFICATIONS

SECTION 2 INSIDE VIEWS

SECTION 3 DISASSEMBLY INSTRUCTIONS

SECTION 4 CIRCUIT DESCRIPITON

4 - 1 RECEIVER CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 1

4 - 2 TRANSMITTER CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 2

4 - 3 PLL CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 3

4 - 4 PORT ALLOCATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 4

4 - 5 POWER SUPPLY CIRCUITS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 5

SECTION 5 ADJUSTMENT PROCEDURES

5 - 1 PREPARATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 1

5 - 2 FREQENCY AND TRANSMIT ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 - 4

5 - 3 RECEIVE ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 5

SECTION 6 PARTS LIST

SECTION 7 MECHANICAL PARTS AND DISASSEMBLY

SECTION 8 SEMICONDUCTOR INFORMATION

SECTION 9 BOARD LAYOUTS

9 - 1 MAIN UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 1

9 - 2 PA BOARD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 1

9 - 3 VCO BOARD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 1

SECTION 10 BLOCK DIAGRAM

SECTION 11 CIRCUIT DIAGRAM

SECTION 12 BC-164

SECTION 1 SPECIFICATIONS

GENERAL

• Frequency range :

Version Transmit (MHz) Receive (MHz)

[EUR],

[UK]

[ITR]

[FRA]

• Operating mode : FM, AM*, WFM* (*RX only)

• Memory channels : 1000 channels

• Call channels : 2 channels

• Scan types : Fu ll/Program/Priority/

• Frequency stability : ±6 ppm (–10°C to +60°C)

• Tuning steps : 5/6.25/8.33/9/10/12.5/15/20/

• Antenna impedance : 50 Ω (SMA type)

• Power supply requirement : Specifi ed Icom's battery

• Current drain :

• Operating temp. range : –10°C to +60°C

• Dimensions
(projections not included)

• Weight
(antenna, BP-243 included)

• MIC/SP connector : 4-conductor 3.5 (d) mm; (

TRANSMITTER

• Output power :

• Modulation system : Variable reactance frequency

• Maximum deviation : ±5.0 kHz

• Spurious emissions : Less than –60 dB (TX High)

144.000–146.000

430.000–440.000

144.000–146.000

430.000–434.000

435.000–438.000

146.000–146.000

430.000–440.000

Memory Channel/Bank/
Bank-Link/Skip/Tone

25/30/50/100 and 200 kHz

pack only
(operating voltage 3.7 V)

TRANSMIT VHF High 1.5 A

Low 0.4 A (approx.)
UHF High 1.5 A
Low 0.5 A (approx.)

RECEIVE Stand-by 80 mA (approx.)

Max. audio
Less than 150 mA

:

47 (W) × 81 (H) × 28 (D) mm

: 160 g (approx.)

2 kΩ/8 Ω

VHF

1.5 W (High)

0.1 W (Low; aprrox.)

UHF

1.0 W (High)

0.1 W (Low; aprrox.)

modulation

Less than –50 dB (TX Low)

0.495–999.990

144.000–146.000

430.000–434.000

435.000–438.000

0.495–29.995

50.200–51.200

76.000–135.995

144.000–146.000

430.000–440.000

1

/8′′)

RECEIVER

• Receiving system : Double conversion

• Intermediate frequencies :

• Sensitivity* :

Frequency (MHz) FM AM WFM

30.000–75.995

76.000–89.995

90.000–107.995

108.000–117.995

118.000–136.995 +3 dBµ

137.000–143.995

144.000–147.995 –15 dBµ

148.000–179.995 –14 dBµ

330.000–369.995 +5 dBµ

370.000–399.995 –10 dBµ

400.000–429.995 –13 dBµ

430.000–449.995 –15 dBµ

450.000–499.995 –5 dBµ

600.000–799.990

799.995–939.990

940.000–999.990 +5 dBµ

*FM and WFM are measured at 12 dB SINAD, AM is easured
at 10 dB S/N.

• Squelch sensitivity
(at threshold)

• Selectivity :

• Spurious image rejection : More than 40 dB

• Audio output power : More than 50 mW at 10%

All stated specifi cations are subject to change without notice or obligation.

superheterodyne system

FM, AM 1st; 46.35 MHz

2nd; 450 kHz

WFM 1st; 14.85 MHz

2nd; 450 kHz

(except spurious points; maximum sensitivity)

0.495–4.995

FM, AM More than 12 kHz/6 dB

–

–7 dBµ

–14 dBµ

0 dBµ

: Less than –15 dBµ

Less than 30 kHz/60 dB

WFM More than 150 kHz/10 dB

Less than 700 kHz/20 dB

distortion with an 8 Ω load

+7 dBµ

–5.000–29.995 +3 dBµ

–

+5 dBµ

–

–

+8 dBµ

–

1 - 1

SECTION 2 INSIDE VIEWS

CPU
(IC4: M30220FCRP)

PTT detector
(Q14: 2SA1832)

D/A convertor
(IC13: BH2220FVM)

Reference
frequency generator
(X1: CR-813 7.325MHz)

Reset IC
(IC2: R3112N291A)

Antenna switch circuit

+3V regulator
(IC10: R1111N321B)

PLL IC
(IC18: ADF4110BCPZ)

VCO board

AF volume
(IC7: SM6451B)

AF amplifier
(IC9: NJM2070M)

IF IC
(IC15: TA31136FNG)

1st mixer
(IC16:

PC2757TB)

Final amplifier*
(Q3: RQA003)

Drive amplifier
(Q2: 2SC5998)

Pre drive amplifier
(Q1: 2SC5006)

• MAIN UNIT (TOP VIEW)

Reference

Reference
frequency generator

frequency oscillator
(X1: CR-813 7.325MHz)

(X1: CR-813 7.325 MHz)

Reset IC

Reset IC
(IC2: R3112N291A)

(IC2: R3112N291A)

CPU

CPU
(IC4: M30220FCRP)

(IC4: M30220FCRP)

PTT detector

PTT detector
(Q14: 2SA1832)

(Q14: 2SA1832)

D/A convertor

D/A convertor
(IC13: BH2220FVM)

(IC13: BH2220FVM)

Microphone amplifier
(IC8: LMV324IPW)

• MAIN UNIT (BOTTOM VIEW)

AF amplifier

AF power amplifier
(IC9: NJM2070M)

(IC9: NJM2070M)

1st mixer

1st mixer
(IC16:

(IC16: µPC2757TB)

IF IC

FM IF IC
(IC15: TA31136FNG)

(IC15: TA31136FNG)

AF volume*

AF volume
(IC7: SM6451B)

(IC7: SM6451B)

µPC2757TB)

CTCSS filter
(IC5: LM2904PWR)

Antenna switch circuit

Antenna switching circuit

+3V regulator

+3V regulator
(IC10: R1111N321B)

(IC10: R1111N321B)

PLL IC*

* Located under the VCO board

PLL IC
(IC18: ADF4110BCPZ)

(IC18: ADF4110BCPZ)

VCO board

VCO board

2 - 1

• PA BOARD

Final amplifier*

Power amplifier*
(Q3: RQA003)

(Q3: RQA003)

Drive amplifier

Drive amplifier
(Q2: 2SC5998)

(Q2: 2SC5998)

Pre-drive amplifier

Pre drive amplifier
(Q1: 2SC5006)

(Q1: 2SC5006)

* Located bottom side of the point.

SECTION 3 DISASSEMBLY INSTRUCTIONS

• Removing the chassis

1 Remove the battery pack.
2 Remove the jack cap A and unscrew the antenna nut B.
3 Remove the dial knob C.
4 Unscrew 2 screws D and lift up the chassis in the direction

of the arrow.

C

A

B

Chassis

D

• Removing the MAIN unit and PA board

1 Unscrew 2 screws A, then remove the LCD panel B.
2 Unscrew 5 screws C and dial nut D.
3 Unsolder 2 points E.

A

B

D

C

C

C

E

C

MAIN unit

5 Incline the chassis as figure below and disconnect the

speaker cable E.

6 Remove the chassis from the front panel.

E

Front panel

Chassis

4 Release the projection F, and remove the MAIN unit.
5 Unsolder 11 points G and remove the PA board from the

MAIN unit.

MAIN unit

F

MAIN unit
(Top side)

PA board

G

3 - 1

SECTION 4 CIRCUIT DESCRIPTION

4-1 RECEIVE CIRCUITS

4-1-1RF CIRCUITS (MAIN UNIT)

This transceiver has 4 RF circuits to provide wide receiving
range. The received signals from the antenna connector
(CHASSIS; J1) are applied to each RF circuits for the frequency
coverage, and amplified within the frequency coverage.

• While receiving 0.495–76 MHz

The 0.495–76 MHz band signals are passed through the
three low-pass filters (LPF; L32, L34, L39, L42, C284, C290,
C294, C307, C314), then applied to the RF amplifier (Q38)
via the band switches (D30, D43) and LPF or BPF.

The 0.495–30 MHz band signals are passed through the
LPF (L20, C241, C242, C247), the 30–76 MHz signals are
passed through the Bandpass Filter (BPF; D39, L21, L24,
C238, C256) before being applied to the RF amplifier (Q38).

The amplified signals are applied to the 1st mixer (IC16, pin

1) via the band switch (D16).

- 0.495–76 MHz -

0.495–30 MHz

LPF

D39

BPF

30–76 MHz

D43

D16

to the
1st mixer
(IC16, pin 1)

Q38

RF

amp

D30

• While receiving 76–300 MHz

The 76–300 MHz band signals are passed through two LPFs
(L39, L42, C307, C314) and a couple of High-pass Filter (HPF;
L33, C287, C293) and LPF (L29, L31, C266, C269, C276,
C283, C514, C516), then applied to the RF amplifier (Q42) via
the antenna switching circuit (D35, D38) and the LPF (D53,
L44, C295, C303).

The amplified signals are then applied to the 1st mixer (IC16, pin

1) via the BPF (D27, D28, D31, D36, L10, L11, L22, L23, C208,
C210, C216, C228, C233, C243) and band switch (D21).

- 76–300 MHz -

D27, D28,
D31, D36

D21

BPF

to the
1st mixer
(IC16, pin 1)

Q42

RF

amp

D53

LPF

D35, D38

ANT

SW

LPF

• While receiving 300–500 MHz

The 300–500 MHz band signals are passed through the LPF
(L42, C314) and a couple of HPF (L38, C302, C306) and
LPF (D41, D45, L26, L30, C255, C257, C262, C275, C282,
C289, C515), then applied to the RF amplifier (Q43) via the
antenna switching circuit (D34, D37) and the BPF (D55, L36,
L106, C304, C522, C523).

D44
AT T

HPF

3 LPF’s

LPF

LPF

2 LPF’s

LPF

LPF

from the
antenna

from the
antenna

• While receiving 500–999 MHz

The 500–999 MHz band signals are passed through the HPF
(L41, C311, C313) and band switch (D54), then applied to
the RF amplifier (Q45) via the attenuator (D46). The amplified
RF signals are applied to another RF amplifier (Q39) via the
BPF (D33, D40, L15, L27, L28, C229, C237, C245, C252,
C261). The amplified RF signals are then applied to the 1st
mixer (IC16, pin 1) via the band switch (D23).

- 500–999 MHz -

Q39 Q45

D23

RF

to the
1st mixer
(IC16, pin 1)

amp

D33, D40

BPF

RF

amp

D46
AT T

D54

HPF

from the
antenna

4-1-2 1ST IF CIRCUITS (MAIN UNIT)

The 1st IF circuits contain the 1st mixer, 1st IF amplifier
and the 1st IF fi lter. The 1st IF mixer converts the received
signals into a fixed frequency of the 1st Intermediate
Frequency (IF) signal. The converted 1st IF signal is fi ltered
at the 1st IF fi lters, then amplifi ed at the 1st IF amplifi er.

The received signals from the RF circuits are applied to the
1st IF mixer (IC16, pin 1), and converted into the 46.35 MHz
(AM/FM)/14.85 MHz (WFM) 1st IF signal by being mixed
with 1st Local Oscillator (LO) signals from the VCOs (VCO
BOARD).

While receiving 0.5–76 MHz band signals, the 1st LO signals
are generated at 50 MHz VCO (VCO BOARD; Q10, Q13,
D7, D8), and for receiving 76–280 MHz band signals, the 1st
LO signals are generated at 144 MHz VCO (VCO BOARD;
Q9, Q12, D6).

While receiving 280–999 MHz band signals, the 1st LO
signals are generated at 430 MHz VCO (VCO BOARD; Q8,
Q11, D5). If the receiving frequency is 500 MHz and above,
the VCO output signal is doubled at the doubler circuit (Q18)
before being to applied to the 1st mixer (IC16, pin 3).

The converted IF signal is passed through the 1st IF filter
FI3 (AM/FM mode) or FI2 (WFM mode) to filter out the
unwanted signal, then applied to the 1st IF amplifier (Q9).
The amplifi ed 1st IF signal is then applied to the FM IF IC
(IC15, pin 16).

• 1st IF CIRCUIT

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SIGNALS
FROMTHE6#/S

2ECEIVEDSIGNALS
FROMTHE2&CIRCUITS

The amplified signals are then applied to the 1st mixer
(IC16, pin 1) via the BPF (D26, D32, L13, L25, C204, C215,
C222, C236, C244, C520, C521) and band switch (D22).

- 300–500 MHz -

D22

to the
1st mixer
(IC16, pin 1)

Q43

RF

amp

D55

BPFBPF

D34, D37

ANT

SW

D41, D45D26, D32

LPF

HPF

LPF

from the
antenna

4 - 1

4-1-3 2ND IF AND DEMODULATOR CIRCUITS
(MAIN UNIT)

The 1st IF signal is converted into the 2nd IF signal and
demodulated in the FM IF IC. The FM IF IC contains 2nd
mixer, limiter amplifier, quadrature detector, etc. in its
package.

The 1st IF signal from the 1st IF amplifi er (Q9) is applied to
the 2nd mixer in the FM IF IC (IC15, pin 16), and converted
into the 2nd IF signal by being mixed with the 2nd LO signal
from the reference frequency oscillator (X2) tripled by the
tripler (Q29).

The converted 2nd IF signal is output from pin 3, and passed
through the 2nd IF filter via the FM/WFM switch (D12) to
suppress sideband noise.

• FM/WFM mode

In FM mode, the 2nd IF signal is passed through the BPF (FI1).
In WFM mode, the signal passed through the LPF (L2, C136).

The filtered 2nd IF signal is applied to the limiter amplifier
in the FM IF IC (pin 5) via the FM/WFM switch (D10). The
amplifi ed 2nd IF signal is FM-demodulated at the quadrature
detector section and output from pin 9. The demodulated AF
signals are applied to the AF amplifi er circuits.

• AM mode

The 2nd IF signal is passed through the FI1 and applied to
the AM demodulator circuit (Q19, Q20). The demodulated AF
signals are applied to the AF amplifi er circuits.

4-1-4 AF AMPLIFIER CIRCUITS (MAIN UNIT)

The demodulated AF signals from the demodulator circuits are
amplifi ed and fi ltered in AF amplifi er circuits.

• FM/WFM mode

The demodulated AF signals from the FM IF IC (IC15, pin 9)
are passed through the AF switch (IC14, pins 1,2) and AF fi lter
circuit (Q10, D5). The fi ltered AF signals are applied to the AF
amplifi er (Q12).

• AM mode

The demodulated AF signals from the AM-demodulator circuit
(Q19, Q20) are passed through the AF filter bypass switch
(Q28) and applied to the AF amplifi er (Q12).

The amplified AF signals are applied to the electric volume
(IC7, pin 11) and level adjusted. The level adjusted AF signals
are output from pin 12, and applied to the AF amplifi er (IC9,
pin 2) to obtain more than 50 mW of AF output power. The
power amplified AF signals are then output from pin 6, and
applied to the internal speaker (CHASSIS; SP1) or connected
external speaker via [MIC/SP] connector (J4).

• AF CIRCUITS

IC14

12

AF switch

from
the FM IF IC
(IC15, pin 9)

from the
AM demodulator circuit
(Q19, Q20)

Q10, D5

AF

Filter

Q28

bypass

IC7

11 12 2 6

Ele. VR

AF
Amp.

Q12

IC9

Powe r
Amp.

Speaker

4-1-5 AGC CIRCUIT

A portion of the AM-demodulated signals are converted
into DC voltage, and fed back to the RF circuits as the AGC
(Automatic Gain Controller) signal.

The AGC signal controls the bias of the 1st IF amplifi er (Q9)
and RF amplifi ers (Q38, Q39, Q42, Q43, Q45) according to
the received signal strength to stabilize the demodulated AF
signal level.

4-1-6 SQUELCH CIRCUITS

• NOISE SQUELCH
The noise squelch mutes the AF output signals when no RF
signals are received. By detecting noise components in the
demodulated AF signals, the squelch circuit toggles the AF
power amplifi er ON and OFF.

A portion of the FM-demodulated AF signals from the
FM IF IC (IC15, pin 9) are passed through the noise filter
(R186, R187, R192, R196, R197, R204, C150, C152, C158,
C162, C164). The fi ltered noise signals are then applied to
the noise amplifier in the FM IF IC (IC15, pins 7, 8) to be
amplifi ed the noise components only.

• 2ND IF DEMODULATOR CIRCUIT

2nd IF signal to the AM demodulator (Q19, Q20)

Quodrature

Detector

9

FM-demodulated signals
to the AF circuits

X1

L103

8

Noise

Amplifier

Limitter

Amplifier

1110

735

R3V

Q51, Q52

D10

RSSI

4 - 2

(FM)
BPF

FI1

LPF

(WFM)

Detector

D12

15.3/45.9 MHz
2nd LO signal

2

Noise

FM IF IC (IC15)

1312

16

1st IF signal from the 1st mixer (IC16, pin 6)

“NOISE” signal to the CPU (IC4, pin 47)

“RSSI” signal to the CPU (IC4, pin 4)

D51

D52

×1

LPF

HPF

×3

Q29

TCXO

X2

The amplified noise components are converted into the
pulse-type signal at the noise detector section, and output
from pin 13 as the “NOISE” signal. The “NOISE” signal is
applied to the CPU (IC4, pin 47). Then the CPU outputs
“AFON” signal from pin 68 according to the “NOISE” signal
level to toggle the AF power regulator (Q46, Q47) ON and
OFF.

• TONE SQUELCH
The tone squelch detects the tone signal in the demodulated
AF signals, and opens the squelch only when matched sub­audible tone frequency is detected in the received signal.

While the tone squelch is in use, and the received signal
contains no sub-audible tone signal or mismatched tone
frequency, the tone squelch mutes the AF signals even if the
noise squelch is open.

A portion of the demodulated AF signals from the FM
IF IC (IC15, pin 9) are passed through the two-staged
CTCSS/DTCS fi lter (IC5, pins 5, 7 and pins 1, 2) to suppress
unwanted voice signals. The filtered CTCSS/DTCS signals
are applied to the CPU (IC4, pin 7).

The CPU decodes the CTCSS/DTCS signal, and outputs
“AFON” signal from pin 68 according to the set CTCSS/
DTCS signal to toggle the AF power regulator (Q46, Q47)
ON and OFF.

4-2-2 MODULATION CIRCUIT (VCO BOARD)

The modulation circuit modulates the VCO oscillating signal
with the AF signals from the microphone and the tone
signals from the CPU.

• MICROPHONE SIGNALS
The level adjusted MIC signals from the modulation volume
(Q34) are applied to the D5 (in transmitting on 430 MHz
band) or D6 (in transmitting on144 MHz band) to modulate
the VCO oscillating signal by changing the reactance of
D5/D6. The modulated VCO output signal is buffer-amplifi ed
by Q14 and Q19, and applied to the PA BOARD via doubler
switches (D13, D17) and TX/RX switch (MAIN UNIT; D18)
as a transmit signal.

• TONE SIGNALS
The CTCSS and DTCS signals are generated by the CPU
(IC4) and output from pin 141. The CTCSS and DTCS
signals are applied to the modulation circuit (VCO BOARD;
D5 or D6) via the tone fi lter (Q41). To ensure the modulation,
the DTCS signal is also applied to the the reference
frequency oscillator (X2, pin 1), after passing through the
DTCS fi lter (IC8, pins 1, 2) and modulation volume (Q48).

4-2-3 TRANSMIT AMPLIFIERS (PA BOARD)

The VCO output signal is amplifi ed to transmit output power
level by the transmit amplifi ers.

4-2 TRANSMIT CIRCUITS

4-2-1 MICROPHONE AMPLIFIER CIRCUIT (MAIN UNIT)

The microphone amplifi er circuit contains AF amplifi er, IDC,
splatter fi lter, etc. The AF signals from the microphone (MIC
signals) are fi ltered and level-adjusted at this circuit.

The AF signals from the microphone are applied to the MIC
amplifi er (IC8, pin 13). The amplifi ed MIC signals are output
from pin 14, and passed through the IDC (Instantaneous
Deviation Control; IC8, pins 8, 9) and splatter fi lter (IC8, pins
5, 7).

The IDC limits the level of the amplitude of MIC signals to
prevent over deviation, and the splatter fi lter suppress 3 kHz
and higher audio components. The fi ltered MIC signals are
passed through the MIC mute switch (Q37) and modulation
volume (Q34).

While receiving, the voltage of R3V line is applied to the
base terminal of the MIC mute switch (Q37) to turn it ON,
thus the MIC line is connected to the ground and the MIC
signals are muted.

The modulation volume (Q34) adjusts the deviation
according to “MODSET” signal from the D/A converter (IC13,
pin 2).

The level adjusted MIC signals are then applied to the
modulation circuit (VCO BOARD; D5 or D6) to modulate the
VCO oscillating signal.

• MICROPHONE AMPLIFIER CIRCUITS

Mic.

IC8

MIC

13

IDC

98

14

SPLAT­TER

5

7

Q37 Q34

MIC mute

to the VCO

Mod. VR

The VCO output signal from VCO BOARD is passed through
the TX/RX switch (MAIN UNIT; D18) and level adjust circuit
(D1), and applied to the pre-driver (Q1), driver (Q2) and
power (Q3) amplifiers in sequence to be amplified to the
transmit output power level. The power amplified transmit
signal is passed through the antenna switching circuit (MAIN
UNIT; D34, D35) and fi lters.

4-2-4 TRANSMIT FILTERS (MAIN UNIT)

The power amplified transmit signal from the PA BOARD
is fi ltered at the transmit fi lters. The transmit fi lters prevent
unwanted RF signals being emitted to the air.

While transmitting on 144 MHz band, the transmit signal is
passed through the LPF (L12, C223, C227), antenna switch
circuit (D35, D38), a couple of LPF (L29, L31, C266, C269,
C276, C283, C514, C516) and HPF (L33, C287, C293), and
two LPFs (L39, L42, C307, C314) before being applied to
the antenna connector (CHASSIS; J1).

• 144 MHz

HPF

HPF

2 LPF’s

LPF

LPF

LPF

to the antenna

to the antenna

D35

ANT
from the
PA BOARD

LPF

SW

LPF

While transmitting on 430 MHz band, the transmit signal
is passed through the HPF (L14, C220, C226), antenna
switching circuit (D34, D37), a couple of LPF (D41, D45, L26,
L30, C255, C257, C262, C275, C282, C289, C515) and HPF
(L38, C302, C306, C310), and the LPF (L42, C314) before
being applied to the antenna connector (CHASSIS; J1).

• 430 MHz

D34 D41, D45

ANT
from the
PA BOARD

HPF

SW

LPF

4 - 3

4-3 PLL CIRCUITS

4-3-1 VCO CIRCUITS (VCO BOARD)

This transceiver has 3 VCOs; 50 MHz VCO, 144 MHz VCO
and 430 MHz VCO. The 50 MHz VCO oscillates the 1st LO
signals, 144 MHz VCO and 430 MHz VCO oscillate both
transmit output and 1st LO signals.

• 50 MHz VCO

The 50 MHz VCO (Q10, Q13, D7, D8) generates the 1st LO
signals for receiving 0.5–76 MHz band signals. The output
signals are amplified at the buffer amplifiers (Q14, Q19),
and passed through the doubler switches (D13, D17), and
then applied to the 1st mixer (IC16, pin 3) via TX/RX switch
(MAIN UNIT; D56).

If the receiving frequency is 500 MHz and above, the buffer­amplified signals are applied to the doubler circuit (Q18,
D14, D15) via doubler switch (D12). The doubled signals are
then applied to the 1st mixer (IC16, pin 3) via doubler switch
(D16) and TX/RX switch (MAIN UNIT; D56).

While transmitting, The VCO oscillates the transmit
frequency, and the VCO output signal is amplified at the
buffer amplifi ers (Q14, Q19), then applied to the PA BOARD
via TX/RX switch (MAIN UNIT; D18).

A portion of the VCO output signals generated at each VCO
are applied to the PLL IC (IC18, pin 5) via buffer amplifi er
(Q14) and LO amplifi er (Q2) for comparison signal.

• 144 MHz VCO

The 144 MHz VCO (Q9, Q12, D6) generates both of transmit
output signal for 144 MHz band and 1st LO signals for
receiving 76–280 MHz.

4-3-2 PLL CIRCUIT

The PLL circuit provides stable oscillation of the transmit
frequency and receive 1st LO frequency. The PLL circuit
compares the phase of the divided VCO frequency with the

While receiving, the VCO oscillates the 1st LO frequency,
and the VCO output signals are amplified at the buffer

reference frequency. The PLL output frequency is controlled
by the divided ratio (N-data) from the CPU.

amplifiers (Q14, Q19). The buffer-amplified signals are
passed through the doubler switches (D13, D17), then
applied to the 1st mixer (IC16, pin 3) via TX/RX switch
(MAIN UNIT; D56).

The amplifi ed signals from LO amplifi er (Q2) are applied to
the PLL IC (IC18, pin 5). The applied signals are divided at
the prescaler and OSC counter according to the “PDA” signal
from the CPU (IC4, pin 32). The divided signal is phase-

While transmitting, the VCO oscillates the transmit frequency,

compared with the reference frequency at the phase detector.

and the VCO output signal is amplifi ed at the buffer amplifi ers
(Q14, Q19). The buffer-amplifi ed signals are passed through
the doubler switches (D13, D17), then applied to the PA
BOARD via TX/RX switch (MAIN UNIT; D18).

The phase difference is output from pin 20 as a pulse type
signal after being passed through the charge pump and loop
filter switch. The output signal is applied to the each VCO
(VCO BOARD) after being converted into the DC voltage (lock

• 430 MHz VCO

voltage) at the loop fi lters.

The 430 MHz VCO (Q8, Q11, D5) generates both of the
transmit output signal for 430 MHz band and 1st LO signals
for receiving 280–990 MHz.

The lock voltage for 50 MHz VCO (“LV1”) is generated by
being passed through the the loop fi lter A (Q11, Q13, R68,
R72, R74, R76, R80, R81, C72, C79, C80, C500) via the

While receiving, the VCO oscillates the 1st LO frequency,
and the VCO output signals are amplified by the buffer
amplifi ers (Q14, Q19).

loop filter switch A (IC22, pins 5, 6). The lock voltage for
144 MHz VCO and 430 MHz (“LV2”) is generated by being
passed through the loop filter B (Q54, Q56, R327–R331,
R337, C485, C486, C488, C501) via the loop fi lter switch A

If the receiving frequency is 500 MHz and below, the buffer-

(IC22, pins 1, 2) and B (IC19, pins 1, 2).

amplified signals are passed through the doubler switches
(D13, D17), then applied to the 1st mixer (IC16, pin 3) via
TX/RX switch (MAIN UNIT; D56).

If the oscillated signal drifts, its phase changes from that of
the reference frequency, causing a lock voltage change to
compensate for the drift in the oscillated frequency.

• PLL AND VCO CIRCUITS

VCO BOARD

50 MHz VCO

Q10, Q13, D7, D8

LV 2 LV 1 FIN

Loop filter

A

Loop filter

B

Loop filter

5

Switch A

2

430 MHz VCO

144 MHz VCO

IC22

6
1

20

Q8, Q14, D5

Q9, Q12, D6

PLL IC (IC15)

Charge

Pump

Phase

Detector

Buffer

amp.

Q14

OSC

Counter

Buffer

amp.

Q19

LO
amp.

Q2

Pre-

scaler

Doubler

D12

×2

D13

5

Q18

D16

D17

LO

Transmit signal

D18

D56

to the PA board

1st LO signals to the

1st mixer (IC16, pin 3)

2

IC19

“PUL” signal to the CPU (IC4, pin 35)

D51

15.3/45.9 MHz
2nd LO signal

D52

Loop filter

Switch B

×1

LPF

HPF

×3

1

15

Q29

Reference

Counter

8

Input Register

TCXO

X2

15.3 MHz

4 - 4

12
13
14

“PCK”
“PDA”
“PSTB”

PLL IC control signals
from the CPU (IC4)

MAIN UNIT

4-4 PORT ALLOCATIONS

4-4-1 CPU (MAIN UNIT; IC4)

Pin

Port

No.

Name

2 K2 Input port for [Y], [Z]keys.

3 K1 Input port for [BAND], [CALL] and [V/M] keys.

4 RSSI

5 VIN

6 CTONE Input port for WX signal.

7 RTONE Input port for CTCSS/DTCS signal.

14 ESIO I/O port for EEPROM (IC1) data.

15 ECK I/O port for the EEPROM (IC1) clock.

25 POWER

26 DSTB

28 CLS

29 VSTB

32 PDA

33 PSTB

34 PCK

35 PUL

41 LEDR

42 LEDG

43 UHFC

44 R3C

45 WFM

46 AM

47 NOISE

48 DTCS

49 TCON

Input port for RSSI signal for the S-meter
indicator from FM IF IC (IC15, pin 12).

Input port for volatage detection of attached
battery pack.

Input port for [PWR] key (S6).
LOW: When the key is pushed.

Outputs strobe signal to the D/A converter
(IC13, pin 8).

Outputs clock sift signal to the clock
frequency shift circuit (Q5).

Outputs VOL strobe signal to the electronic
VR (IC7, pin 14).

Outputs serial data to the PLL IC (IC18, pin 13),
electronic VR (IC7, pin 16) and D/A converter
(IC13, pin 6).

Outputs PLL strobe signal to the PLL IC
(IC18, pin14).

Outputs serial clock signal to the PLL IC
(IC18, pin 12), electronic VR (IC7, pin 15) and
D/A converter (IC13, pin 7).

Inputs PLL unlock signal ("PUL") from PLL IC
(IC18, pin15).

Outputs TX indicator LED (DS8; Red) control
signal to the LED driver (Q49).
"High": While transmitting.

Outputs RX indicator LED (DS8; Green)
control signal to the LED driver (Q49).
"High": While receiving.

Outputs UHF RF circuit control signal to the
band selector (Q36).
"High": While receiving on the UHF band.

Outputs receive circuit control signal to R3V
regulator (Q6).
"High": While receiving.

Outputs receiving mode (FM/WFM) switching
signal to the FM/WFM switches (Q16, Q17,
Q51, Q52).
"Low": While receiving in FM mode.

Outputs receiving mode (AM/FM) switching
signal to the AM demodulator switch (Q18)
and AF switch (IC14).
"High": While receiving in AM mode.

Inputs "NOISE" signal from the FM IF IC
(IC15, pin 13).

Outputs DTCS filter control signal to the
DTCS fi lter (Q41).

Outputs tone fi lter control (IC5) signal to the
CTCSS fi lter switch (Q8).

Description

Pin
No.

Port

Name

51 VHFC

52 PCON

53 +3SC

54 TXC

55 BEEP

56 TXU

57 TXV

58 VSHIFT

59 DBL2

60 DBL1

61 ATT

63 HFC

64 BCC

65 V3C

66 V2C

67 V1C

68 AFON

69 LIGHT

70 MMUTE

71 800C

73, 74DUD,

DCK

Description

Outputs VHF RF circuit control signal to the
band selector (Q36).
"High": While receiving on the VHF band
(76−300 MHz).

Outputs +3V line control signal to the +3V
regulator (IC10).
"High": While the transceiver's power is ON.

Outputs +3S line control signal to the +3S
regulator (Q3, Q4).

Outputs transmit circuits control signal to T3
regulator circuit (Q24–Q27).
"High": While transmitting.

• While receiving, outputs beep sound to the
electric volume (IC7, pin6).

• While transmitting, outputs 1750 Hz tone signal
to the microphone amplifi er circuit (IC8, pin 9).

Outputs UHF TX circuit control signal to TX
band switch (Q27).
"High": While transmitting on UHF band.

Outputs VHF TX circuits control signal to TX
band switch (Q27).
"High": While transmitting on VHF band.

Outputs oscilating frequency shift circuit
(VCO BOARD; Q5, D2–D4) control signal.
"High": D2–D4 are ON, and the oscillating
frequency is shifts down.

Outputs doubler switches (VCO BOARD;
D13, D17) control signal.
"High":While receiving 500 MHz and below.

Outputs doubler switches (VCO BOARD;
D12, D16) control signal.
"Low":While receiving 500 MHz and above.

Outputs attenuator control signal to the
attenuator controller (Q40).
"High":While attenuator is activated.

Outputs HF RF circuit control signal to the
HF band selector (Q35).

Outputs 0.5–30MHz receive circuit control
signal to the HF band selector (Q35).

Outputs 430 MHz VCO control signal to the
430 MHz VCO switch (VCO BOARD; Q3).

Outputs 144 MHz VCO control signal to the
144 MHz VCO switch (VCO BOARD; Q3).

Outputs 50 MHz VCO control signal to the
50 MHz VCO switch (VCO BOARD; Q4).

Outputs AF power amplifi er (IC9) control signal
to the AF power amplifi er controller (Q46, Q47).
"High": While the audio is emitted.

Outputs backlight control signal to the LCD
backlight (PA BOARD; DS1) driver (Q22).
"High": While the backlight is ON.

Outputs MIC line mute signal to the MIC
mute switch (Q37).
"High": MIC signal is muted.

Outputs 500
signal to the 800 MHz band selector (Q40).

Input ports for [DIAL].

–999 MHz RF circuit control

4 - 5