Port Allocations, 1 I/O Expander IC RF Unit IC2 | Motorola IC-T81E

4-5 PORT ALLOCATIONS

4-5-1 I/O EXPANDER IC (RF UNIT; IC2)

Pin	Port		Description
number	name		Description
number	name
4	Q1	Outputs	VHVCO3	regulator	control
4	Q1	signal.
		signal.

5	Q2	Outputs	VLVCO3	regulator	control
5	Q2	signal.
		signal.

6	Q3	Outputs	6MVCO3	regulator	control
6	Q3	signal.
		signal.

7	Q4	Outputs VCO shift signal for SHF,
7	Q4	UHF, 144 MHz and 50 MHz.
		UHF, 144 MHz and 50 MHz.

11	Q8	Outputs 12VCO3 regulator control sig-
11	Q8	nal.
		nal.

12	Q7	Outputs	UHVCO3	regulator	control
12	Q7	signal.
		signal.

13	Q6	Outputs UHF TX and RX regulator
13	Q6	control signal.
		control signal.

14	Q5	Outputs 1200 MHz TX and RX regula-
14	Q5	tor control signal.
		tor control signal.

4-5-2 I/O EXPANDER IC (RF UNIT; IC3)

	Pin	Port	Description
	number	name	Description
	number	name
	4	Q1	Outputs 300 MHz band RX regulator
	4	Q1	control signal.
			control signal.

	6	Q3	Outputs AM mode regulator control
	6	Q3	signal.
			signal.

	7	Q4	Outputs WFM band RX switching con-
	7	Q4	trol signal.
			trol signal.

	11	Q8	Outputs WFM band RX regulator con-
	11	Q8	trol signal.
			trol signal.

	12	Q5	Outputs 50 MHz band TX and RX reg-
	12	Q5	ulator control signal.
			ulator control signal.

	13	Q6	Outputs VHF band TX and RX regula-
	13	Q6	tor control signal.
			tor control signal.

• PLL circuit			VCO BOARD					D804,
			1200MHz VCO	Q351,				D805
			1200MHz VCO	Q354		Q823		D805
			Q350,	Q354		Q823		TX/RX	to transmitter circuit
			Q350,		Buff.	Amp.		TX/RX	to transmitter circuit
			D351,		Buff.	Amp.		SW
			D351,					SW
			D352
			430 MHz VCO		Q323
			Q321,		Q323			TX/RX	to transmitter circuit
			Q321,		Buff.	Amp.
			Q322,
			Q322,					SW
			D321,			Q823		SW
			D321,			Q823		D804,
			D322					D804,
			D322					D805
			144 MHz VCO					D805	to transmitter circuit
			144 MHz VCO						to transmitter circuit
			Q311,					TX/RX
			Q312,		Q313,	Amp.		TX/RX	to 1st mixer circuit
			D302,			Amp.		SW
			D302,			Q822		SW
			D311		D312	Q822		D802,	(IC601, pin 1)
			D311					D802,
			50MHz RX VCO		Buff.			D803
					Buff.

			Q301,			Q807
			Q302,			Q807
Q803			Q302,			Buff.
Q803			D301			Buff.
			D301
TUNE		50 MHz TX VCO							to transmitter circuit
		50 MHz TX VCO
				Q342		Q313
CTRL				Q342		Q313
CTRL				Buff.
			Q341, D341	Buff.		Buff.
			Q341, D341
Loop Q811,		Loop Q804,
filter	Q812	filter Q805		IC801 (PLL IC)
		8		IC801 (PLL IC)			2
		8					2
		13	Phase	Programmable		Prescaler	19
			detector	counter		Prescaler
"LOCKV" signal			detector	counter
"LOCKV" signal							3
to the IC1, pin 5			Programmable				3	PSTB
			Programmable		Shift register		4	CLK
			divider		Shift register		5	CLK
			divider				5	DATA
								DATA
X1		16
13.8 MHz
		5			1			Buff.
					1

			IC802 (PLL IC)		3	CLK		Q816
		16			4	CLK		Q816
		16			4	DATA
					5	DATA
					5	STB
						STB
				4 - 6

Image 13

Motorola IC-T81E, IC-T81A service manual Port Allocations, 1 I/O Expander IC RF Unit IC2, 2 I/O Expander IC RF Unit IC3

Contents

Multiband FM Transceiver Ordering Parts IntroductionRepair Notes Sample Order Table of Contents General SpecificationsTransmitter Version 50 MHz 145 MHz 440 MHz 1200 MHz MHz RX only Band ReceiverWFM WFM Logic Unit Inside ViewsRF Unit CPU Removing the Chassis Panel Removing the Shield Plate Disassembly InstructionsRemoving the Logic Unit Removing the RF Unit Logic unit Circuit Description Antenna Switching Circuits RF UnitReceiver Circuits Duplexer Circuit RF Unit 7 1ST Mixer Circuit RF Unit Transmitter Circuits APC Circuits RF Unit DRIVE/POWER Amplifier Circuits RF UnitMHz PA APC Control Circuit PLL Circuits Power Supply Circuits Voltage LineLine Description VCC 1 I/O Expander IC RF Unit IC2 Port Allocations2 I/O Expander IC RF Unit IC3 Pin Port Description Number Name CPU Logic Unit IC1 Preparation Adjustment Procedures‘ Required Test Equipment Connection PLL Adjustment ULV RF Unit Bottom ViewVLV RF Unit TOP View 6MLV Dial Receiver AdjustmentSensitivity VHF Logic Unit TOP View SSG MeterTop Push and hold MHz band 101 dBm Push and hold Displayed frequency445.000 MHz USA-1 SQL key Transmitter Adjustment HPF OFF LPF DeviationDtmf AUS, SEA =Surface mount Parts List Trimmer Ceramic ECUE1H121JCQ Transistor UN911D TX Coil Eljnd R10J 0.1U Themistor Ceramic ECUE1H060CCQ Ceramic ECUE1H390JCQ VCO Board Ceramic ECUE1H120JCQ Accessories Mechanical Parts and DisassemblyChassis Parts VCO Unit MP29 C Transistor and FET’S SEMI-CONDUCTOR InformationDiodes Logic Unit Board LayoutsTOP View IC1 Bottom ViewIC3 GND Pset Ifin IC6 RF UnitL912 J4 to Logic unit J1 IC3 MP1IC2 J302 to RF unit VCO BoardOUT 12VCOOUT VLVCO3 VHF GND VHVCO3 UVCO3 Uhfout GND 12VCO3 GND Q354 Block Diagram TX/RX Frequency Mode Xtal BPF PDA2, CK AMPTX/RX Buff ANT LPF HPF AMP Mode Xtal Initial BPF ResetMOD TX/RX Frequency ANT Buff HPF LPF YGR Logic Unit Section Voltage Diagram Oscin Mixin Oscout GND Mixout REC VCC DET Ifin Rssi 2NDLODEC Ifout Filout Quad WFM NTCCF20124AH 473KCT TXC COM3 COM2 Reset Power 12VCO COM2 ResetClonein VCC VIN Cpuhv COM4 COM3 COM2 COM1 VHF RF Unit400M 1200M 00M 50M1200MHz 400MHz PLST1 IN1 GND1ENB VCC2 LOK GND2 Icom America Inc Icom Inc 5566I-S