AIS receiver MXA-5000

AIS RECEIVERS-14521XZ-C1Jan. 2009INTRODUCTIONCAUTIONThis service manual describes the latest technical informationfor the MXA-5000 AIS RECEIVER at the time of publication.NEVER connect the receiver to an AC outlet or to a DCpower supply that uses more than specified. This will ruinthe receiver.MODELVERSION[USA]MXA-5000[EUR]UNIT ABBREVIATIONS:C=CHASSISM=MAIN UNIT[EXP]To upgrade quality, any electrical or mechanical parts andinternal circuits are subject to change without notice orobligation.DO NOT expose the receiver to rain, snow or any liquids.DO NOT reverse the polarities of the power supply whenconnecting the receiver.DO NOT apply an RF signal of more than 20 dBm (100 mW)to the antenna connector.

This could damage the receiver’sfront-end.ORDERING PARTSREPAIR NOTESBe sure to include the following four points when orderingreplacement parts:1. Make sure that the problem is internal beforedisassembling the receiver.2. DO NOT open the receiver until the receiver isdisconnected from its power source.3. DO NOT force any of the variable components. Turnthem slowly and smoothly.4.

DO NOT short any circuits or electronic parts. Aninsulated tuning tool MUST be used for all adjustments.5. DO NOT keep power ON for a long time when thereceiver is defective.6. READ the instructions of test equipment throughlybefore connecting a test equipment to the receiver.1. 10-digit Icom parts numbers2. Component name3. Equipment model name and unit name4.

Quantity required<ORDER EXAMPLE>1190002850 S.IC CMX7032L9/TR IC12 MAIN UNIT 1 piece8110009660 Cover 2197 COVER (C) MP1 CHASSIS 3 pieceAddresses are provided on the inside back cover for yourconvenience.Icom, Icom Inc. and ICOM logo are registered trademarks of Icom Incorporated (Japan) in the United States, the UnitedKingdom, Germany, France, Spain, Russia and/or other countries.TABLE OF CONTENTSSECTION1SPECIFICATIONSSECTION2INSIDE VIEWSSECTION3DISASSEMBLY INSTRUCTIONSECTION4CIRCUIT DESCRIPITON4-1RECEIVE CIRCUITS . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14-3FREQUENCY SYNTHESIZER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-24-4AIS PROCESSOR IC (IC12) . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-34-5VOLTAGE DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3SECTION5ADJUSTMENT PROCEDURESECTION6PARTS LISTSECTION7MECHANICAL PARTSSECTION8BOARD LAYOUTSSECTION9BLOCK DIAGRAMSECTION10 VOLTAGE DIAGRAMSECTION 1.SPECIFICATIONSD GeneralD Receiver• Frequency coverage• Type of emission• Antenna impedance• Operating temp. range• Power supply requirement: 161.975 MHz, 162.025 MHz: 16K0F1D (GMSK): 50 Ω nominal: –20°C to +60°C; –4°F to +140°F: 12 V DC nominal (10.8 V to 15.6 V)(negative ground)• Current drain: 0.25 A• Dimensions (Projections not included)Without Angle: 132(W) × 34(H) × 155(D) mm5 3⁄16(W) × 1 11⁄32(H) × 6 3⁄32(D) inAngle attached: 158(W) × 39(H) × 155(D) mm6 7⁄32(W) × 1 17⁄32(H) × 6 3⁄32(D) in• Weight (Approx.)Without Angle: 400 g (14.1 oz)Angle attached: 460 g (16.2 oz)• DATA input interface: IEC61162-1: 2000 (4,800 bps)Sentence formatters : RMC, GGA, GNS, and GLLInput level: Less than 2 mA(When 2 V is applied)• DATA output interface:To navigation equipment : IEC61162-2 (38,400 bps)Sentence formatter: VDMOutput level: 5 V, 40 mA maxRS-422 ballanced typeTo PC: Baud rate 38,400 bpsSentence formatter: VDMOutput level: ±5 V, ±35 mA typicalRS-232C unballanced type• Sensitivity: 0.35 μV (typical)• Adjacent channel selectivity : More than 70 dB• Spurious response: More than 70 dB• Intermodulation: More than 65 dB• Hum and noise: More than 40 dB• Conducted spurious emission : Less than –57 dBm1-1SECTION 2.INSIDE VIEW• MAIN UNITPHOTO COUPLER(IC5)RS-422TRANSCEIVER(IC7)RF AMP (CH87B)(Q21)POWER DETECTION DIODE(D2)RS-232CTRANSCEIVER(IC9)BUFF(IC8)POWER DETECTION DIODE(D3)LIMITER(D11)RF AMP (CH88B)(Q11)BUFF(IC6)5V REGULATOR(Q26)8V REGULATOR(IC3)1ST IF FILTERS (CH87B)(FI4, FI5)VCO (CH88B)1ST IF FILTER (CH88B)(FI1)VCO (CH87B )1ST IF FILTER (CH88B)(FI2)AIS CODEC IC(IC12)IF IC (CH88B)(IC1)IF IC (CH87B)(IC2)3.5V REGULATOR(IC4)2ND IF FILTER BPF(FI3)RESET IC(IC13)RESET IC(IC14)CLOCK CONTROLLER(IC15)EEPROM(IC11)2-12ND IF FILTER (CH88B)(FI3)SECTION 3.DISASSEMBLY INSTRUCTION• Removing the MAIN UNIT1) Unscrew 4 screws from the bottom.3) Unscrew 4 screws from the MAIN UNIT, and remove theMAIN UNIT from the CHASSIS.CHASSIS assemblyMAIN UNITCHASSISTop cover2) Unsolder total of 6 points at the antenna connector.UNSOLDERSolderremoverMAIN UNITCHASSIS assembly3-1SECTION 4.CIRCUIT DESCRIPTION4-1 RECEIVE CIRCUITSAIS CHANNELSRF BYPASS CIRCUITTwo channels, CH87B (161.975 MHz) and CH88B(162.025 MHz), are assigned for use of AIS operationdue to the international regulation.

The MXA-5000 hascapability of receiving both of channels; CH87B and CH88Bsimultaneously.MXA-5000 equips two antenna connectors; one isconnected to the antenna, another one is connected to thetransceiver, thus no AIS-dedicated antenna is necessary.When MXA-5000 is turned OFF or the connectedtransceiver is in transmitting, the [RADIO] and [ANTENNA]connectors are connected directly (bypassed) by the RFbypass circuit (RL1).RF signals from the protector are passed through thelimiter (D11) and then separated into each channel, CH87B(161.975 MHz) and CH88B (162.025 MHz) at the matchingsection (L21, C49, 50).

The separated RF signal is appliedto appropriate RF AMP.RF signals from [ANTENNA] are passed through thecoupling capacitor (C21) and RL1, and applied to the divider(L2, 3, C10, 16, 17, R8).• RF AMP (CH87B: 161.975 MHz)The divided RF signals are applied to both of the connectedtransceiver via [RADIO] connector and the RF amplifier forAIS receive circuit via the protector (D5, L6, 7, C11, 13).Q21To the 1st IF mixerRFAMPBPFBPF161.975 MHzRF POWER DETECTION CIRCUITRF AMP (CH87B: 161.975 MHz)The RF detection circuit detects the transmission signalfrom the connected transceiver, and the detected signalcontrols the RF bypass circuit.The CH87B signal from the matching section is amplifiedby Q21, and passed through the BPF (L32–34), then downconverted into the 30.875 MHz of 1st IF signal by the 1stmixer (Q22).When connected transceiver starts transmitting, a portionof RF signals from the transceiver is passed through theattenuator (R19, 20) and the BPF (L8, 9, C22–25, 30,R24), then rectified by D3.

The RF signals are also passedthrough the bypass relay (RL1), attenuator (R21, 22) andBPF (C26–29, 31, L10, 11, R23), then rectified by D2 too.IF AND DEMODULATOR CIRCUITS (CH87B: 161.975 MHz)The 1st IF signal from the 1st mixer (Q22) are filtered by FI4and FI5 to remove out-of-band signals. The filtered 1st IFsignal is amplified by Q23, then applied to the pin 16 of IC2.These rectified voltages are the reference voltage to switchRL1 (using Q1, 2, 4), thus the TX signal from the transceiveris fed to the antenna via RL1.IC2 contains 2nd Local oscillator, 2nd Mixer, Limiter andQuadrature detector in its package.At the same time, Q5 and D5 are turned ON to prevent TXsignals from the transceiver to enter into the RX circuit, untilthe RL1 is activated completely.The 30.425 MHz 2nd LO signal generated by the crystaloscillator X4 is applied to the pin 2 of IC2.

The 2nd LO signalis mixed with the 1st IF signal, then produced 450 kHz 2ndIF signal is output from pin 3. The 2nd IF signal is filtered bythe ceramic filter (FI6) to extract 450 kHz signal only, thenapplied to the pin 5 of IC2 again.• RF BAYPASS AND DETECTION CIRCUITSD11D5DiodeSwitchLPFLimiterThe 2nd IF signal is detected by Quadrature detector, thenoutput to the AIS processor IC as demodulated GMSKsignal.To RF AMPRL1(1/2)SpliterJ1The quadrature detector uses X3 and R172 as the phasedelayer, for adjustment-free detect circuit.To antennaRL1(1/2)J2To radio• IF AND DEMODULATOR CIRCUITS (CH87B: 161.975 MHz)Q1,2,4,D4RelayControlPowerDetectX3D2,3450KHzFI6CERAMICBPFQ23To AIS codecFMDET2ND IFAMPIFAM P2NDMIXFI4 FI5Q22XTALBPFFrom RF AMP30.875MHzfLO=131.100MHz2ND LOBUFFIC2:TA31136FNX44-130.425MHzRF AMP (CH88B: 162.025 MHz)4-2 FREQUENCY SYNTHESIZERThe CH88B signal from the matching section is amplified byQ11, and passed through the BPF (L22, 23, 24), and downconverted into the 21.7 MHz of 1st IF signal by Q12.VCO (CH87B: 161.975 MHz)The 1st LO signal for the CH87B is generated by Q47, andthe generated 1st LO signal is buffer amplified by Q43 andQ45.

The buffer amplified 1st LO signal is then applied tothe 1st mixer (Q22). Q44 is the buffer amplifier for the PLL(contained in IC12) feedback.• RF AMP (CH88B: 162.025 MHz)• VCO (CH87B: 161.975 MHz)Q11To 1st IF mixerRFAM PBPFBPF162.025 MHzQ 32D 21,D22Q33CP1OUTLOOPFILBUFFVCOQ35BUFFAIS CODEC(IC12)IF AND DEMODULATOR CIRCUITS (CH88B: 162.025 MHz)Q34The 1st IF signal from the 1st mixer (Q12) is filtered by FI1and FI2 to remove out-of-band signals, then amplified byQ13, then applied to the pin 16 of IC1.BUFFRF1+VCO (CH88B: 162.025 MHz)IC1 contains 2nd Oscillator, 2nd Mixer, Limiter, QuadratureDetector in its package.The 1st LO signal for the CH88B is generated by Q32, andthe generated 1st LO signal is buffer amplified by Q33 andQ35. The buffer amplified 1st LO signal is then applied tothe 1st mixer (Q12).

Q34 is the buffer for PLL (contained inIC12) feedback.The 21.25 MHz 2nd LO signal generated by the crystaloscillator X2 is applied to the pin 2 of IC1. The 2nd LO signalis mixed with the 1st IF signal, then produced 450 kHz 2ndIF signal is output from pin 3.• VCO (CH88B: 162.025 MHz)The 2nd IF signal is filtered by the ceramic filter FI3 toextract 450 kHz signal only, then applied to the pin 5 of IC1.Q45Q44BUFFRF2+The 2nd IF signal is detected by Quadrature Detector, thenoutput to the AIS processor IC (IC12) as demodulatedGMSK signal.Q 42D31,D32AIS CODEC(IC12)CP2OUTLOOPFILVCOBUFFQ43BUFFThe quadrature detector uses X1 and R102 as the phasedelayer, for adjustment-free detect circuit.PLL• IF AND DEMODULATOR CIRCUITS (CH88B: 162.025 MHz)X1450KH zIC1Q13To AIS codecFMDETThe AIS processor IC (IC12) contains dual PLL synthesizerfor two AIS channels. TCXO (X5) generates 19.2 MHz signaland is used for both of system clock for AIS codec and PLLreference frequency.FI3CERAMICBPF2ND IFAM P2NDMIXIFAM PFI1 FI2Q12XTALBPFFrom RF AMP21.7MHzfLO=140.325MHz2ND LOBUFFX221.25MHzAIS DECODINGThe demodulated GMSK signal from the demodulatorcircuits is applied to the AIS processor IC (IC12), anddecoded into NMEA data format.The decoded NMEA signal is output from pin 50, and levelconverted into 5 V (from 3.5 V) by the buffer (IC8), thenapplied to IC7 and IC9.The NMEA signals are converted into RS-422 format byIC7, then output from (J8, pins 1, 2), or RS-232 format byIC9, then output from (J8, pin 5).4-24-3 AIS processor IC (IC12)PORT ALLOCATIONPinNo.PinnameDescription3RF I/P 1 VCO oscillation signal input for CH88B PLL.5Out CP1 Charge pump output for CH88B PLL.9RF I/P 2 VCO oscillation signal input for CH87B PLL.11Out CP2 Charge pump output for CH87B PLL.24RX1inDemodulated AF signals input for CH88B.26RX2inDemodulated AF signals input for CH87B.49RxData50TxData58EPSI5960NMEA+/NMEA- input.AIS data output.Serial data input from EEPROM.EPSClk Serial clock output to EEPROM.EPSOSerial data output to EEPROM.4-4 VOLTAGE DIAGRAMSFrom power supplyVCO, RX circuits, RF relay, etc.RS-232C driver, data converter,photo couppler, etc.IF IC, AIS decoder, EEPROM, etc.4-3SECTION 5.ADJUSTMENT PROCEDUREM REQUIRED EQUIPMENTSEQUIPMENTGRADE AND RANGEDC power supplyStandard signalgenerator (SSG)EQUIPMENTVoltageCurrent: 12.0 V DC: More than 1 AFrequency rangeOutput level: 150–170 MHz: 0.1 mV to 32 mV Terminator(–127 to –17 dBm)Digital voltmeterGRADE AND RANGEMeasuring rangeInput impedance: 0–10 V: More than 50 kΩImpedance: 50 ΩM ADJUSTMENTSADJUSTMENTOPERATIONRECEIVESENSITIVITY(CH88B)-PREPARATION-1 1) Connect a 50 Ω Terminator to [RADIO] terminal.2) Connect an SG to [ANTENNA] terminal.3) Connect a Voltage Meter to CP7 on the P.C.

board (refer to page5-3 for the location.).-ADJUSTMENT-2 • Adjust the voltage of CP7 with coils on the P.C. board (Refer topage 5-3 for the location).Remove the top cover to expose MAIN UNIT.(Refer to “DISASSEMBLY INSTRUCTION”)ITMAIN UN NA] [RADIO][ANTEN12 V batteryRedBlackSTANDARD SIGNAL GENERATORTERMINATOR(50 Ω)SETTINGFrequencyModulationDeviationLevel: 162.025 MHz: 1 kHz: ±3 kHz: −100 dBm (7 dBµ)5-1ADJUSTMENTPOINTVALUE––L22→L23→L24(In sequence,repeatedly)Max. voltageM ADJUSTMENTS (continued)ADJUSTMENTOPERATIONRECEIVESENSITIVITY(CH87B)-PREPARATION-1 1) Connect a 50 Ω Terminator to [RADIO] terminal.2) Connect an SG to [ANTENNA] terminal.3) Connect a Voltage Meter to CP8 on the P.C.