Displayed frequency, Push and hold, MHz USA-1 | Motorola IC-T81E

RECEIVER ADJUSTMENT (Continued)

The SQUELCH LEVEL adjustment must be performed on the normal mode after “S-METER ADJUSTMENT”.

					MEASUREMENT			ADJUSTMENT
	ADJUSTMENT		ADJUSTMENT CONDITION		MEASUREMENT		VALUE	POINT
								POINT

					UNIT	LOCATION		UNIT	ADJUST

	S-METER	9	• Displayed frequency :		Top			Push and hold
	(440 MHz band)		445.000	MHz [USA-1]	panel			the [SQL] key
			435.000	MHz [other]

•Connect the SSG to the antenna connector and set as:

		Level	: 0.63 µV*
			(– 111 dBm)
		Modulation	: 1 kHz
		Deviation	: ± 3.5 kHz
		• Connect a terminator to the [SP]
		jack.
		• Receiving

	10 • Set an SSG output level for the			SSG	Output level	0.35 µV – 1.1 µV	Verify
		S-meter to S3.				(-116dBm – -106 dBm)
		• Receiving

	11 • Increase an SSG output level.			Front	S-meter	Full scale	Verify
		• Receiving		panel
(1200 MHz band) 12		• Displayed frequency :		Top			Push and hold
		1270.000 MHz		panel			the [SQL] key
		• Connect the SSG to the antenna
		connector and set as:
		Level	: 1 µV*
			(– 107 dBm)
		Modulation	: 1 kHz
		Deviation	: ± 3.5 kHz
		• Connect a terminator to the [SP]
		jack.
		• Receiving

	13 • Set an SSG output level for the			SSG	Output level	0.56 µV – 1.8 µV	Verify
		S-meter to S3.				(-102dBm – -112 dBm)
		• Receiving

	14 • Increase an SSG output level.			Front	S-meter	Full scale	Verify
		• Receiving		panel

SQUELCH	1	• Displayed frequency :		Speaker		At the point where	LOGIC R733
LEVEL		445.000 MHz [USA-1]				the AF signal just dis-
		435.000 MHz [other]				appears
		• Connect the SSG to the antenna
		connector and set as:
		Level	: 0.1 µV*
			(– 127 dBm)
		Modulation	: 1 kHz
		Deviation	: ± 3.5 kHz

•Pre-set the R733 to maxmum clock-wise.

•Receiving

*This output level of the standard signal generator (SSG) is indicated as SSG’s open circuit.

• LOGIC UNIT TOP VIEW

R733

Squelch level adjustment

5 - 7

Image 21

Motorola IC-T81E, IC-T81A service manual Displayed frequency, Push and hold, MHz USA-1, SQL key, MHz other

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 SEMI-CONDUCTOR Information Transistor and FET’SDiodes Board Layouts Logic UnitTOP View IC1 Bottom ViewIC3 GND Pset Ifin IC6 RF UnitL912 J4 to Logic unit J1 MP1 IC3IC2 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