S253S252 | Icom IC-T90A guide

The combination of this page and the previous page shows the unit layout in the same configuration as the actual P.C. Board.

AF unit

• BOTTOM VIEW

S253S252

VCO UNIT	S251
• BOTTOM VIEW		4
		4
UP	E	DN

3

1	2
2	3
	3

1

to RF unit
J251
1	30
CK	PDA/UL
DATA	VMOD
PLSTB	HV
J51 DASTB VSHFT
T43	+3
T50	PATMP
T14	B2C
B4C	+10V
AGC	BSFT
B1C	V2
VCC	FSET
B5	V3
B3	V1
GND	IF
REF	CHG

1516

9 - 6

Image 49

Icom IC-T90A manual S253S252

Contents

IC-t90a Ordering Parts IntroductionRepair Notes Sample Order Table of Contents General SpecificationsTransmitter Frequency MHz ReceiverWFM WFM Logic Unit Inside ViewsTop view Bottom view RF Unit AF UnitTop view Bottom view Removing the rear panel Removing the AF unit Disassembly Instructions Receiver Circuits Circuit Description 5 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 RF Unit PLL CircuitsGeneral APC Circuit PLL Circuit VCO Divider Circuit VCO and RF Units 2 R3V Switch IC AF Unit IC51 Power Supply CircuitsPort Allocations Voltage Line CPU Logic Unit IC1 Dtcs CtselLCD SEG35 Operation on the Adjustment Mode Adjustment ProceduresOperation on the Output Power Adjustment Preparation JIG ConnectionAD-92SMA PLL Lock Trimmer AdjustmentVCO Voltage RF Unit VCO UnitL16 L456 L19 Reference Adjustment Mode AdjustmentsDial Frequency Adjustment Mode Adjustments PH ch 53.900 MHz Transmitting 8V 145 MHz Displayed frequency Connect an amme 45 a R325 Logic UnitR365 R326 Ctcss Coil DetectorTracking CP0 AF UnitIC151, pin 12 SD line L151 Displayed frequency Connect a DC volt Maximum voltage Meter Adjustment Adjustment Condition Operation Order Description Section Parts List Coil Eljre 3N9Z-F Ceramic ECJ0EB1H681K Connector AXK6S30445P Ceramic ECJ0EC1H060C Encoder Trimmer Tantalum ECST1EY474R Ceramic ECJ0EC1H2R5B Accessories Mechanical Parts and DisassemblyChassis Parts RF Unit Logic UnitChassis Parts AF Unit VCO Unit Transistors and Fets SEMI-CONDUCTOR InformationDiodes Name TOP View Board LayoutsMC1 Microphone DUP Bottom View Logic unitSP1 SQL PTT RF Unit RF unit VCO Unit AF UnitEXT.SP EXT.MICREMOTO S253S252 Logic Unit Block Diagram Loop LPF HPF Drive BPF ANT FIL AMP Chassis 11 1 Logic Unit Voltage Diagram IC5 2SK3476 11 2 RF Unit BU4094BCFV 11 3 AF Unit URL 32, Kamiminami, Hirano-ku, Osaka 547-0003, Japan