Icom IC-4008MKII Port Allocations, Power Supply Circuits Voltage Line, CPU Main unit IC1

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4-4 POWER SUPPLY CIRCUITS VOLTAGE LINE

LINE

DESCRIPTION

 

 

BATT

The voltage from the connected battery pack.

 

 

 

Common 3 V converted from the BATT line at

3V

the 3V regulator circuit (IC6). The circuit outputs

the voltage regardless of the power ON/OFF

 

 

condition.

 

 

+3V

Common 3 V converted from the BATT line at

the +3V regulator circuit (Q25, D4).

 

 

 

R+3

Receive 3 V cotrolled by the R+3 regulator circuit

(Q18) using the “RXV” signal from CPU (IC1).

 

 

 

 

Transmit 3 V converted from the BATT line at the

T+3

T+3 regulator circuit (Q27, Q28, D5, etc.) using

 

the “TXV” signal coming from CPU (IC1).

 

 

4-5 PORT ALLOCATIONS

4-5-1 CPU (MAIN unit; IC1)

Pin

Port

Description

number

name

 

 

 

 

 

 

Input port for the PTT switch from the

31

PTT2

external mic jack (MAIN unit; J1).

 

 

Low : External PTT switch is ON.

 

 

 

34

PTT1

Input port for the internal PTT switch.

Low : While PTT switch is pushed.

 

 

 

 

 

35

DOWN

Input port for the [DOWN] switch.

 

 

 

36

UP

Input port for the [UP] switch.

 

 

 

37

MODE

Input port for the [MODE] switch.

 

 

 

 

 

Input port for the POWER switch.

38

POWSW

Low : While POWER switch is

 

 

pushed.

 

 

 

 

 

Input port for PLL unlock signal from

45

UNLK

the PLL IC (RF unit; IC1).

 

 

Low : During unlock.

 

 

 

46

BEEP

Outputs beep audio signal.

 

 

 

 

 

Outputs volume mute switch (Q23)

48

RMUTE

control signal.

 

 

High : While squelched

 

 

 

 

 

Outputs control signal for the AF ampli-

49

AFON

fier regulator circuit (Q5, Q10, Q11).

 

 

High: When squelch is open.

 

 

 

50

PLLCK

Outputs clock signal to the PLL IC (RF

unit; IC1).

 

 

 

 

 

Pin

Port

Description

number

name

 

 

 

 

51

PLLDA

Outputs data signals to the PLL IC (RF

unit; IC1).

 

 

 

 

 

52

PLLST

Outputs strobe signals for the PLL IC

(RF unit; IC1).

 

 

 

 

 

53

POWER

Outputs control signal for the +3V reg-

ulator circuit (MAIN unit; Q25, D4).

 

 

 

54–56

CTCO0–

Output port for the CTCSS signals.

CTCO2

 

 

 

 

 

Outputs control signal for the MIC

57

TXMOD

amplifier (IC2).

 

 

Low : While microphone amplifier is

 

 

ON.

 

 

 

58

CTCIN

Input port for the CTCSS decode sig-

nals.

 

 

 

 

 

59

SQLIN

Input port for squelch level signal.

 

 

 

60

REMIN

Input ports for the control signal from

the external remote microphone.

 

 

 

 

 

61

BATIN

Input port form the connected battery

pack for low battery indication.

 

 

 

 

 

 

 

Input port for the RSSI signal from the

62

SENIN

FM IF IC (RF unit; IC2) to detect receiv-

 

 

ing signal strength level.

 

 

 

73

EEPCK

Outputs clock signal to the EEPROM

(IC3).

 

 

 

74

EEPDA

Outputs data signals to the EEPROM

(IC3).

 

 

 

 

 

Output port for power save function,

75

PSC

applied to VCO regurator circuit (RF

 

 

unit; Q13, Q14, D8, D9).

 

 

 

76

RXV

Outputs the R+3 regulator control sig-

nal (Q18).

 

 

 

 

 

77

TXV

Outputs the T+3 regulator control sig-

nal (Q27, Q28, D5, etc.).

 

 

 

 

 

 

 

Outputs control signal for LCD back-

78

LAMPC

light.

 

 

Low : While LCD backlight is ON.

 

 

 

 

 

Outputs internal microphone control

79

MICSW

signal.

 

 

High : While internal PTT switch is

 

 

pushed.

 

 

 

 

 

Outputs MIC mute signal for RING

80

MMUTE

function.

 

 

High : While RING signals are out-

 

 

put, etc.

 

 

 

4 - 3

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Contents UHF FM Transceiver LPD FM Transceiver Ordering Parts IntroductionRepair Notes Table of Contents Section Specifications ITA, ITA-1 CSA, CSA-1Channel Frequency List Ctcss Frequency ListMain Unit Inside ViewsRF Unit Removing the Main Unit Disasembly InstructionsRemoving the Rear Panel Removing the RF UnitReceiver Circuits Antenna Switching Circuit RF UnitCircuit Description RF Circuit RF UnitTransmitter Circuits PLL Circuits RF UnitPort Allocations Power Supply Circuits Voltage LineCPU Main unit IC1 Preparation Section Adjustment ProceduresEntering the Adjustment Mode Required Test EquipmentAdjustment DeviationR50 C63R206 TestSection Parts List Order DescriptionRF Board Coil Eljre 18NG-F C211 4030006860 Accessories Mechanical Parts and DisassemblyCabinet Parts Chassis Parts Unit abbreviation C Chassis PARTS, RF RF UNIT, M Main Unit Transistor and FET’S SEMI-CONDUCTOR InformationDiodes Main Unit Board LayoutsTOP View IC-4008A R58 Bottom View IC-4008AC55 C17 R23 C18 C52 PSC Batt MOD VOL GND RF Unit TOP ViewFI3 Bottom ViewBlock Diagram IC1Voltage Diagram DTA144EURF Unit 16, Kamihigashi, Hirano-ku, Osaka 547-0002, Japan 16, Kamihigashi, Hirano-ku, Osaka, 547-0002, Japan