Icom IC-H12 Maintenance Manual
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Icom IC-H12 Maintenance Manual

Vhf radiotelephone
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VHF RADIOTELEPHONE
(
channels)
12
l·C-H�2
MAINTENANCE MANUAL

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Summary of Contents for Icom IC-H12

  • Page 1 VHF RADIOTELEPHONE channels) l·C-H�2 MAINTENANCE MANUAL...

  • Page 2: Table Of Contents

    TABLE OF CONTENTS SPECIFIC,�TIONS ........SECTION 2 - 1 - 2 SECTION OPERATING CONTROLS........3 - 1 - 4 ....... . . Cl RCUIT DESCRIPTION .
  • Page 5 A N TE N N A CO N N E CTOR Connect the su ppl ied flex i bl e anten na. An external anten n a can be used, u si n g a BNC conn ector. T R ANSMI T/BATT E R Y IN D I CATOR I l lu m i nates in the transmit m ode.
  • Page 6 SECT ION C I RCU I T DESC R IPTION RECE I VE R C I RCUI TS 1 - 1 A N T E N N A SW I TCHI N G C I R CU I T Signals from the antenna connector are fed to the antenna switching circuit through Chebyshev low-pass filter consisting of L229, L230, C295, C 297 and C298 in the P L L board.

  • Page 7: Pll Circuits

    TRANSMITTE R CIRCU ITS 3 - 2- MIC AMP L I F I E R C I R CU I T Audio signals from the microphone are fed to the limiter amplifier, consisting of 0125 � 0128, which has 6dB/Octave response between 3 00Hz and 3KHz. The output of the limiter amplifier is similar to rectangular waves and includes harmonics.

  • Page 8: Other Circuitry

    3 - 3 R E F E R E N C E F R E QU E N C Y GE N E R ATO R C I R CU I T Reference frequency generator IC203 consists o f a crystal oscillator and a highspeed divider. X 201 oscil­ lates at 7.
  • Page 9 • 2 L ED I N D I CA TO R C I R CUIT L E D is lit in the transmit mode, but when the power supply voltage becomes less than 5. 5V, it will ot be lit. e power supply voltage is divided by R148 and R149, and applied to the base of 0121.
  • Page 10 10.695MHz 455KHz RF Amp Noise Squelch Ceramic Crystal 1st Mixer 1st IF Amp 0101 Detector Filter Control Filter 0104, 0105 2SC2026 0103 F1101 Fl102 0113 0114, 0115 0102 2SK192 2SC2668 x 2 lOM 1589 o· 2SA1048 2SC2458 x 2 CFU455E2 2SC2668 �...

  • Page 11: Inside Views

    SECTION 5 INSIDE VIEWS MAIN UNIT L102-L104 (RX Band-Pass Filter)' F1101 (10.695MHz Crystal Filter)---_ __: PLL UNIT C286 (Driver Output Trimmer) J201 · J202 (Matrix Board Connectors) IC201 (TC9122 Programmable Divider) 5- 1...

  • Page 12: Mechanical Parts And Disassembly

    SECT I ON 6 MECHANICAL PA R TS AND DISASSEMBLY DI SASSEMBLY OF THE CASES Turn the powe r switch off a n d rem ove the power pack. Remove two screws on the rear panel a n d four screws on the bottom as shown in the fig ure. e t e front panel shown i n the figure .

  • Page 13: Disassembly Of Units

    • D I SASSEMBLY OF UN I TS FR O N T P A N E L R E A R P A N E L 30222 42289 42289 R ound head Screw hen you wish to program some opera tion frequencies ( cha n ne ls ) , remove the rear panel, then u plug the conne ctors between the ma trix board a n d...

  • Page 14: Ptt Spring Assembly

    © • To see the printed sides of the PC boards, open the chassis by removing two screws located a bove a n d below the PTT spring . CHASSIS A , B 30284 ---- 2 x 4-:: Flat ead screw M A IN UNIT PLL U N IT M A IN UN I T...

  • Page 16: Unit Bottom Assembly

    • UN IT BOTTOM ASS EMBLY (BOTTOM V IEW) ©t> REA R PAN EL ( H OW TO REP LACE CONTACT SPRING) Re move the sli din g gu ide by removing the four screws as shown . Re move the contact spring by removing the two screws as shown . Set the n e w contact spr i n g so that the spli t of the spring is on the positive side and the other end on the negative side.

  • Page 17: Maintenance And Adjustment

    SECTION MAINTENANCE AND ADJUSTMENT MEASURING INSTRUMENTS REQUIRED FOR ADJUSTMENT FREQUENCY RANGE 170MHz (1) FREQUENCY COUNTER • BETTER ACCURACY THAN .: 1 BETTER SENSITIVITY 100mV or (2) SIGNAL GENERATOR FREQUENCY RANGE 0.1MHz· 170MHz 90dB (OdB OUTPUT VOLTAGE 1µV) • • (3) MULTIMETER 50KnNolt or better AC Ml LLIVOL TMETER MEASURING RANGE...

  • Page 18: Preliminary Checks

    PRELIMINARY CHECKS T R A N S MITTE R OUTPUT CHE CKS 50S1 Power M. Power Supply 8.4V o r Battery ( IC-CM3) Connect a 50 ohms RF wattmeter to the ANT connector. Setting the C-H 12 to any programmed channel and key the transmitter. Observe the RF power OUTPUT.

  • Page 19: How To Check

    Remove the transceiver case as shown on Page 6 - 1 . Use a screw driver that fits the screw. To open the hinge chassis remove the two screws as shown on Page 6 - 2. Attach an 8.0 - 1 1 .0V DC external power source to the battery clip or screw. Be sure to check the polarity.

  • Page 21: Basic Alignment Procedure

    BAS I C AL IGNMENT PR OCEDURE 7 . 5 P. L. L. CI R CU I T Loe Adjus ment 1. Connect the measuring instrument and set the control knobs as follows" • Connect an oscilloscope (l OMHz band width) to R21 7. •Connect oltmeter between R205 and ground.
  • Page 22 2. Se the channel select switch at a programmed channel. mode, adjust L211 for the programmed receiving frequency minus 10.695MHz. •In he recei •In he ransmit mode, adjust L 212 for the programmed transmitting frequency. •Se he channel at a duplex channel, and adjust L213...
  • Page 23 Dummy Millivolt- Oscillator Load meter Directional Coupler Deviation Meter Power Supply (8.4V) od la ion check ±10%. imum iation.: With 1KHz 12 0mV shall be 4. SKHz odula ion sensitivity: input voltage 12mV ± 3dB at 1 KHz. Deviation should be 3. 5KHz. Ra io: Connect he output...
  • Page 24 Frequency Check ec a 24 Hz ampl ifier to a frequency counter, check the frequency of X 101 (2nd OSC) loose couple. It should be: 10.240MHz ±400Hz. • ecei er Spurious Response Connec a spea er and millivoltmeter to the EXT terminal.
  • Page 26 Table of Frequencies and 'N' numbers to be utilized on the IC-H12 • Freq. LO Freq. LO F req. F req. 147.995 147. 995 153.155 150. 815 .185 . 845 .215 3 48 .8 75 .245 . 905 . 275 .935...
  • Page 27 • ' N ' ' N ' LO F req. L O F req. F req. F re q. . 530 148. 010 150.830 " . 56 0 37 0 . 860 " . 590 . 890 " . 620 .
  • Page 28 • ' N ' F re q. LO F req. 148. 005 154. 515 .6 65 .695 . 725 . 755 . 785 .8 15 . 8 45 . 875 . 905 . 935 46 2 . 965 .995 155.025 .

  • Page 29: Tage Charts

    SECT I ON VO LTAGE CHA RTS Me asuring instrument is a 50KD. / V multime ter. T RANS I STO RS VO LTAGE CHA RT • T RANSMIT REC E IVE :\IT \'O. C O L LECTOR EM ITTE R BASE COLLECTOR EM ITTER...
  • Page 30 • I C'S VO LTAGE CHART • Measu r i n g i nstrument is a 5 0KS1/V m u l t i meter. IN T R ANSM I T MO D E R E M A R K S M A I N M A I N I C 1 02...

  • Page 31: Oubleshooting

    SECTI ON 10 T R OUBLE SH OOT I NG • NO POW E R ON T A R T B a 1 t e r y i s d isc harged b a t t e r y c o n t a c t s R e v e r s e p o l a r i t y b a t t eries ( IC - C M 4 ).
  • Page 32 LOCK F AILUR E • S T A RT R e fer t o " N O POWER O N ". Y E S D e fective I C 2 0 3 (P L L u n it ). Y E S Defective 2 0 I ( P L L u n i t ) .
  • Page 33 N O R EC EPTIO N • S T A R T C h e c k o p e n e d wires or c o l d soldering between c o n ­ n ec t or a n d M A I u n it.
  • Page 34 NO TR ANSM I T R F POWE R S T A R T Check opened wires or cold soldering b etween con­ nector and M A IN u nit. Replace the wires or resolder them. Lock is fail e d . Refer to "...

  • Page 35: Ic Specifications

    SECTION IC SPEC I FICATIONS TC-9 1 22P ( BCD PROGRAMMABLE COUNTER) (Ta = 2S 0 C) MAX™UM RATI SYMBOL DESCRIPTION RATINGS UNIT Yo o Supply Voltage Input Voltage -0.3 - Yoo +0.3 TO P R Operating Temperat ure -30 - TSTR Storage Temperature - 5 5 - 1 2 5...
  • Page 36 MC-3 3 5 7 ( LOW POWER FM IF) MAXIMUM RA TINGS (Ta = 2 5 ° C) SYMBOL DESC R IPTION RATINGS UNIT Supply Voltage (M AX) Operating Supply Voltage In put Voltage 1 .0 R M S Operating Temperature TO P R -30 - +70 Storage Temperature...
  • Page 37 TC- 5 0 8 1 ( PHASE COMPARATO R ) RATINGS (Ta = 25 ° C) MAXIMUM SYMBOL DESC RIPTION RA T UNIT Supply Voltage I n put Voltage -0.3 - VD D +o.3 T O P R Operating Tempe rature -30 - - 5 5 - 1 2 5 T S T R...
  • Page 38 SECT I ON 12 PA RTS L I ST [ MA I N UN I T PA RTS] [EF PA RTS] BOA R D R E F . BOA R D R E F. D E SC R I PT I O N ( P A R T N O ) DESC R I PT I ON ( P A R T N O ) LOCAT I O N N O .
  • Page 39 • [ M A IN UNI T PA R TS ] [ M A IN UNI T PA R TS] BOA R D BOA R D R E F. R E F . D ESC R I P T I ON ( P A R T N O ) D E SC R I P T I O N (PA R T N O ) LOC A T I O N LOCAT I O N...
  • Page 40 • [ M A I N UN I T P A RTS ] [ P L L UNI T P A RTS] R E F . BOA R D R E F. BOA R D D E SC R I PT I O N (PA R T N O ) D E S C R I PT I ON (PA R T N O ) LOCAT I O N LOC A T I O N...
  • Page 41 • [ PL L UN I T PA R TS ] [ PL L U N I T PA RTS] BOA R D BOA R D R E F . R E F. D E S C R I P T I O N ( P A R T N O ) D E S C R I PT I O N ( P A R T N O ) N O .
  • Page 42 • [ M AT R I X UN I T P A R T S ) BOA R D R E F . D E S C R I PTI ON ( P A R T N O ) LOCAT I O N 2SA 1048-Y 0401 Transis or...
  • Page 43 /l.2411Hl XIII M AIN UNIT R 6 . 0 • IC 101 R 2.0 C /29 C IJ() � RI., � ..� Cl� I R2.0 C IZ& Rl/5 R11 7 C 12 1 J;� J;� Q 1 16 Q 115 9 114 f.
  • Page 44 Q.102 Q tOI L /05 C/08 RS. 6 IJ. 1 12 9. 1 ' 1 8 10'1 9. 1 0 1 (}. /06 9 1 0 4 R4. 2 14. 6 I T4.8 .SEND Lock�d 0 U nlt1t:.k. 0. 6 B l23 lt1.2 T.5.8...
  • Page 45 16 0,llS P L L U N I T LJI4. 8 V 4 . B V .,._ J�S @ fin P·P D204 � 20� lC 20 1 R4.8 R223 fOJ> \J� IC203 Cl X201 C24" lf O R22._ T, S i"'I' C2 47 R22 !5 T, Dup 4.1...
  • Page 46 V"l•cked ® Lo c ked 6 2 0 1 . 2� 9202 &204 GlOS C.226 '° R2/8 � "' C23 1 R219 I� l� � ® ,,_,. ,,_,, X 202 L21 1 D210 fi.2 0 6 X Z 0 2 3 8 . 8 Z 75 HHz X 2 0 3 �7 .
  • Page 48 I l l I I SENO 8A 7 TERY SLC· Z 6 UR r - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - � P L L p ,�...
  • Page 49 MATRIX UNIT " CH 11 CH 1 1 CH 10 CH 9 CH & CH 7 CH 7 CH 6 CH 6 CH 5 CH 4 CH 4 CH 3 CH 3 CH 2 CH 1 C H 1 ·© ••02 •...
  • Page 50 P L L UNIT 8 - 2...

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