Motorola IC-T81A, IC-T81E service manual PLL Adjustment

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5-2 PLL ADJUSTMENT

The following adjustment must be performed at “ADJUSTMENT MODE”.

				MEASUREMENT						ADJUSTMENT
ADJUSTMENT		ADJUSTMENT CONDITION		MEASUREMENT					VALUE	POINT
ADJUSTMENT		ADJUSTMENT CONDITION							VALUE	POINT
				UNIT	LOCATION					UNIT	ADJUST

PLL LOCK	1	• Displayed frequency :		RF	Connect	the	DC	0.8	V – 1.8 V		Verify
VOLTAGE			51.000 MHz		voltmeter	or	an
		• Receiving			oscilloscope to VLV.


	2	• Transmitting			Connect	the	DC	1.8	V – 2.8 V
					voltmeter	or	an
					oscilloscope		to
					6MLV.

	3	• Displayed frequency :			Connect	the	DC	1.4	V – 2.4 V
			88.000 MHz		voltmeter	or	an
		• Receiving			oscilloscope to VLV.

	4	• Displayed frequency :						1.5	V – 2.5 V
			145.000 MHz
		• Receiving

	5	• Transmitting						1.5	V – 2.5 V

	6	• Displayed frequency :			Connect	the	DC	2.0	V – 2.5 V
			440.000 MHz		voltmeter	or	an
		• Receiving			oscilloscope to ULV.

	7	• Transmitting						2.0	V – 2.5 V

	8	• Displayed frequency :			Connect	the	DC	1.9	V – 2.9 V
			1270.000 MHz		voltmeter	or	an
		• Receiving			oscilloscope		to
					12LV.
		• Transmitting			12LV.
		• Transmitting

REFERENCE	1	• Displayed frequency :		Top	Loosely couple		the	1270.0000 MHz		Top	Push and
FREQUENCY			1270.000 MHz	Pannel	frequency	counter				panel	hold the
		• Transmitting			to the antenna con-						[SQL] key,
					nector.						then turn
											the [DIAL]

DETECTER	1	• Displayed frequency :		LOGIC	Connect	a digital-		1.0	V	LOGIC	L702
OUTPUT		445.000 MHz [USA-1] only			voltmeter	to	the
VOLTAGE		435.000 MHz [ohter]			check point Q.
		• Connect an SSG to the antenna
		connector and set as:
		Level	: 1 mV* (–47dBm)
		Modulation	: OFF
		• Receiving

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

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Contents Multiband FM Transceiver Introduction Ordering PartsRepair Notes Sample OrderTable of Contents Specifications GeneralTransmitter Version 50 MHz 145 MHz 440 MHz 1200 MHz MHz RX onlyReceiver BandWFM WFMInside Views Logic UnitRF Unit CPUDisassembly Instructions Removing the Chassis Panel Removing the Shield PlateRemoving the Logic Unit Removing the RF Unit Logic unitAntenna Switching Circuits RF Unit Circuit DescriptionReceiver Circuits Duplexer Circuit RF Unit7 1ST Mixer Circuit RF Unit Transmitter Circuits DRIVE/POWER Amplifier Circuits RF Unit APC Circuits RF UnitMHz PA APC Control CircuitPower Supply Circuits Voltage Line PLL CircuitsLine Description VCCPort Allocations 1 I/O Expander IC RF Unit IC22 I/O Expander IC RF Unit IC3 Pin Port Description Number NameCPU Logic Unit IC1 Adjustment Procedures Preparation‘ Required Test Equipment ConnectionPLL Adjustment RF Unit Bottom View ULVVLV RF Unit TOP View 6MLVReceiver Adjustment DialSensitivity VHFLogic Unit TOP View Meter SSGTop Push and hold MHz band 101 dBmDisplayed frequency Push and hold445.000 MHz USA-1 SQL keyTransmitter Adjustment Deviation HPF OFF LPFDtmf AUS, SEAParts List =Surface mountTrimmer Ceramic ECUE1H121JCQ Transistor UN911D TX Coil Eljnd R10J 0.1U Themistor Ceramic ECUE1H060CCQ Ceramic ECUE1H390JCQ VCO Board Ceramic ECUE1H120JCQ Mechanical Parts and Disassembly AccessoriesChassis Parts VCO UnitMP29 C Transistor and FET’S SEMI-CONDUCTOR InformationDiodes Logic Unit Board LayoutsTOP View Bottom View IC1IC3 GND Pset IfinRF Unit IC6L912 J4 to Logic unit J1IC3 MP1IC2 VCO Board J302 to RF unitOUT 12VCOOUT VLVCO3 VHF GND VHVCO3 UVCO3 Uhfout GND 12VCO3 GNDQ354 Block Diagram Mode Xtal BPF PDA2, CK AMP TX/RX FrequencyTX/RX Buff ANT LPF HPF AMPReset Mode Xtal Initial BPFMOD TX/RX Frequency ANT Buff HPF LPF YGRSection Voltage Diagram Logic Unit2NDLO Oscin Mixin Oscout GND Mixout REC VCC DET Ifin RssiDEC Ifout Filout Quad WFM NTCCF20124AH 473KCT TXC12VCO COM2 Reset COM3 COM2 Reset PowerClonein VCC VIN Cpuhv COM4 COM3 COM2 COM1RF Unit VHF400M 1200M50M 00M1200MHz 400MHzGND1 PLST1 IN1ENB VCC2 LOK GND2Icom America Inc 5566I-S Icom Inc