Icom IC-T90A manual AF Unit, RF Unit, Top view Bottom view

Page 7

• AF UNIT	• AF UNIT	1st AF amplifier
Top view	Bottom view	1st AF amplifier
		(Q205: 2SD2216)





			AF mute
			AF mute
			(Q251: 2SJ364)
			AF power amplifier
			AF power amplifier
			(IC252: TA7368F)
			AM detector
			(Q201, Q202: XP6501)
	FM IF IC
	(IC151: TA31136FN)
	IF amplifier
	(Q102: 2SC4403)
	Crystal oscillator
	(X1: VR-583, 13.800 MHz)
	T5V regulator
	(Q11: XP1501, Q55: 2SB1132)
• RF UNIT	• RF UNIT

R3V regulator Q208: 2SA1576

Q209: XP1501

AM/FM switch (Q206: XP4315)

Top view	Bottom view
	Drive amplifier	629.995–999.90 MHz RF amplifier
	(Q52: 2SK3475)	(Q452: 2SK3475)
		75.995–229.995 MHz
		RF amplifier
		(Q351: 3SK320)

	Pre-drive	R3 regulator
	(Q54: 2SC5289)	R3 regulator
	Power amplifier	(Q353: XP4312)
	Power amplifier	0.495–29.995 MHz RF amplifier
	(Q51: 2SK3476)	0.495–29.995 MHz RF amplifier
	VCO circuit	(Q302: 2SC5006)
	VCO circuit
	1st mixer	29.995–75.995 MHz
	(IC351: ∝PC2757TB)	RF amplifier (Q303: 2SC5006)
	T3 regulator
	(Q56: XP4315, D50: MA6S121)
	144 MHz TX high-pass filter circuit
	50 MHz TX low-pass filter circuit

2 - 2

Image 7

Contents IC-t90a Sample Order IntroductionOrdering Parts Repair NotesTable of Contents General SpecificationsTransmitter WFM ReceiverFrequency MHz WFMBottom view Inside ViewsLogic Unit Top viewRF Unit AF UnitTop view Bottom view Removing the rear panel Removing the AF unit Disassembly InstructionsReceiver Circuits Circuit Description5 2ND if and Demodulator Circuits AF Unit 4 1ST Mixer and 1ST if Circuits RF, AF and VCO UnitsRF Circuit Squelch Circuitaf and Logic Units AF Amplifier Circuit AF Unit2ND if and Demodulator Circuit Transmitter Circuits APC Circuit PLL CircuitsAPC Circuit RF Unit GeneralPLL Circuit VCO Divider Circuit VCO and RF UnitsVoltage Line Power Supply Circuits2 R3V Switch IC AF Unit IC51 Port AllocationsCPU Logic Unit IC1 SEG35 CtselDtcs LCDPreparation Adjustment ProceduresOperation on the Adjustment Mode Operation on the Output Power AdjustmentJIG ConnectionAD-92SMA Voltage Trimmer AdjustmentPLL Lock VCOL19 VCO UnitRF Unit L16 L456Frequency Adjustment Mode AdjustmentsReference DialAdjustment Mode Adjustments PH ch 53.900 MHz Transmitting 8V 145 MHz Displayed frequency Connect an amme 45 a R326 Logic UnitR325 R365Ctcss Coil DetectorTracking L151 AF UnitCP0 IC151, pin 12 SD lineDisplayed frequency Connect a DC volt Maximum voltage Meter Adjustment Adjustment Condition OperationOrder Description Section Parts ListCoil Eljre 3N9Z-F Ceramic ECJ0EB1H681K Connector AXK6S30445P Ceramic ECJ0EC1H060C Encoder Trimmer Tantalum ECST1EY474R Ceramic ECJ0EC1H2R5B Accessories Mechanical Parts and DisassemblyChassis Parts AF Unit VCO Unit Logic UnitRF Unit Chassis PartsName SEMI-CONDUCTOR InformationTransistors and Fets DiodesDUP Board LayoutsTOP View MC1 MicrophoneSQL PTT Logic unitBottom View SP1RF Unit RF unit VCO Unit AF UnitEXT.SP EXT.MICREMOTO S253S252 Logic Unit Block DiagramLoop LPF HPF Drive BPF ANT FIL AMP Chassis11 1 Logic Unit Voltage DiagramIC5 2SK3476 11 2 RF UnitBU4094BCFV 11 3 AF UnitURL 32, Kamiminami, Hirano-ku, Osaka 547-0003, Japan