Icom IC-T90A manual Adjustment Procedures, Preparation, ‘ Required Test Equipment

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SECTION 5 ADJUSTMENT PROCEDURES

5-1 PREPARATION

Some adjustments must be adjusted on the adjustment mode. When entering the adjustment mode, the 68 kΩ terminator (shown at page 5-2) is required.

REQUIRED TEST EQUIPMENT

EQUIPMENT

GRADE AND RANGE

EQUIPMENT

GRADE AND RANGE

 

 

 

 

 

 

DC power supply

Output voltage

: 11 V DC

Ammeter

Measuring capacity

: 10 A and 30 A

Current capacity

: 3 A or more

 

 

 

 

DC voltmeter

Input impedance

: 50 kΩ /V DC or better

 

 

 

 

Measuring range

: 1–10 W

 

 

 

 

 

 

Frequency range

: 300–3000 Hz

RF power meter

Frequency range

: 28–600 MHz

Audio generator

Measuring range

: 1–500 mV

(terminated type)

Impedance

: 50 Ω

 

 

 

 

 

SWR

: Less than 1.2 : 1

Standard signal

Frequency range

: 1–1300 MHz

 

 

 

Output level

: 0.1 µV–32 mV

 

Frequency range

: 0.1–600 MHz

 

generator (SSG)

 

 

(–127 to –17 dBm)

Frequency counter

Frequency accuracy : ±1 ppm or better

 

 

 

 

 

 

 

 

 

Sensitivity

: 100 mV or better

Oscilloscope

Frequency range

: DC–20 MHz

 

 

 

Measuring range

: 0.01–20 V

FM deviation meter

Frequency range

: 30–600 MHz

 

 

 

 

Measuring range

: 0 to ±10 kHz

Attenuator

Power attenuation

: 40 or 50 dB

 

 

 

 

 

 

 

ENTERING THE ADJUSTMENT MODE q Connect a 68 kΩ terminator to the [SP] jack.

w Push and hold the [SQL] and [8] keys, and then turn power ON.

OPERATION ON THE ADJUSTMENT MODE

Change the adjustment value

: [DIAL]

Change the adjustment channel or item [UP]

: [VFO] key

Change the adjustment channel or item [DOWN]

: [MR] key

Verify the setting condition

: [8] key

OPERATION ON THE “OUTPUT POWER” ADJUSTMENT

When adjusting the “OUTPUT POWER” adjustment, need to change the adjustment channel indicator manually.

When displayed channel indicator “DH” on the LCD at first, push the “0” or “.” keys to change the channel indicator as follow.

Pushing key

LCD (Before)

LCD (After)

 

 

 

“0” key

DH

PH

 

 

 

“0” key

PH

DH

 

 

 

 

 

 

Pushing key

LCD (Before)

LCD (After)

 

 

 

“.” key

DH

DL

 

 

 

“.” key

DL

DE

 

 

 

“.” key

DE

DH

 

 

 

5 - 1

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Contents IC-t90a Repair Notes IntroductionOrdering Parts Sample OrderTable of Contents Specifications GeneralTransmitter WFM ReceiverFrequency MHz WFMTop view Inside ViewsLogic Unit Bottom viewAF Unit RF UnitTop view Bottom view Disassembly Instructions Removing the rear panel Removing the AF unitCircuit Description Receiver Circuits4 1ST Mixer and 1ST if Circuits RF, AF and VCO Units 5 2ND if and Demodulator Circuits AF UnitRF Circuit AF Amplifier Circuit AF Unit Squelch Circuitaf and Logic Units2ND if and Demodulator Circuit Transmitter Circuits General PLL CircuitsAPC Circuit RF Unit APC CircuitVCO Divider Circuit VCO and RF Units PLL CircuitPort Allocations Power Supply Circuits2 R3V Switch IC AF Unit IC51 Voltage LineCPU Logic Unit IC1 LCD CtselDtcs SEG35Operation on the Output Power Adjustment Adjustment ProceduresOperation on the Adjustment Mode PreparationConnection JIGAD-92SMA VCO Trimmer AdjustmentPLL Lock VoltageL16 L456 VCO UnitRF Unit L19Dial Adjustment Mode AdjustmentsReference FrequencyAdjustment Mode Adjustments PH ch 53.900 MHz Transmitting 8V 145 MHz Displayed frequency Connect an amme 45 a R365 Logic UnitR325 R326Ctcss Detector CoilTracking IC151, pin 12 SD line AF UnitCP0 L151Displayed frequency Connect a DC volt Maximum voltage Adjustment Adjustment Condition Operation MeterSection Parts List Order DescriptionCoil Eljre 3N9Z-F Ceramic ECJ0EB1H681K Connector AXK6S30445P Ceramic ECJ0EC1H060C Encoder Trimmer Tantalum ECST1EY474R Ceramic ECJ0EC1H2R5B Mechanical Parts and Disassembly AccessoriesChassis Parts Chassis Parts Logic UnitRF Unit AF Unit VCO UnitDiodes SEMI-CONDUCTOR InformationTransistors and Fets NameMC1 Microphone Board LayoutsTOP View DUPSP1 Logic unitBottom View SQL PTTRF Unit RF unit AF Unit VCO UnitEXT.SP EXT.MICREMOTO S253S252 Block Diagram Logic UnitChassis Loop LPF HPF Drive BPF ANT FIL AMPVoltage Diagram 11 1 Logic UnitIC5 11 2 RF Unit 2SK347611 3 AF Unit BU4094BCFVURL 32, Kamiminami, Hirano-ku, Osaka 547-0003, Japan