Garmin GNC 420 Maintenance Manual
  1. Manuals
  2. Brands
  3. Garmin Manuals
  4. GPS
  5. GNC 420
  6. Maintenance manual

Garmin GNC 420 Maintenance Manual

400 series
Hide thumbs Also See for GNC 420:
Table of Contents

Advertisement

Quick Links

See also: Pilot Operating Handbook , Instruction Manual
400 SERIES
MAINTENANCE MANUAL
(GNS 430, GNC 420, GPS 400)
GNS 430 Shown
GARMIN International, Inc.
st
1200 E. 151
Street
Olathe, KS 66062 USA
190-00140-05, Revision C
October 2002

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the GNC 420 and is the answer not in the manual?

Questions and answers

Related Manuals for Garmin GNC 420

Summary of Contents for Garmin GNC 420

  • Page 1 400 SERIES MAINTENANCE MANUAL (GNS 430, GNC 420, GPS 400) GNS 430 Shown GARMIN International, Inc. 1200 E. 151 Street Olathe, KS 66062 USA 190-00140-05, Revision C October 2002...
  • Page 2 Initial Release ----- 01/26/01 Redraw 15007 10/22/02 Redraw 19319 GNC and GNS are trademarks of GARMIN Ltd. or its subsidiaries and may not be used without the express permission of GARMIN. Page A 400 SERIES MAINTENANCE MANUAL Rev. C P/N 190-00140-05...
  • Page 3 LIST OF EFFECTIVE PAGES Page Revision Page Revision Page Revision Page Revision 5-54 BLANK F7-24 BLANK viii 5-10 6-10 5-11 6-11 5-12 6-12 B-10 5-13 6-13 B-11 5-14 6-14 B-12 5-15 6-15 B-13 5-16 6-16 B-14 5-17 6-17 B-15 5-18 6-18 B-16 5-19...
  • Page 4 The table is current at the time of publication of this manual (see date on front cover) and is subject to change without notice. Authorized GARMIN Sales and Service Centers are encouraged to access the most up-to-date bulletin and advisory information on the GARMIN Dealer Resource web site at www.garmin.com using their GARMIN-provided...

  • Page 5: Table Of Contents

    1.1 INTRODUCTION ....................1-1 1.1.1 Versions Covered by this Manual..............1-1 1.2 FUNCTIONAL SUMMARY..................1-3 1.2.1 GPS 400......................1-3 1.2.2 GNC 420 ......................1-3 1.2.3 GNS 430......................1-3 1.3 REPAIR PLAN ......................1-4 1.4 SPECIFICATIONS....................1-4 1.5 GENERAL DESCRIPTION ..................1-4 1.5.1 Main Board ......................

  • Page 6: Paragraph Page

    SECTION 3 TROUBLESHOOTING Paragraph Page 3.1 TROUBLESHOOTING EQUIPMENT ..............3-1 3.2 TROUBLESHOOTING ORDER................3-1 3.3 TROUBLESHOOTING PROCEDURES ..............3-2 3.3.1 Fuses....................... 3-2 3.3.2 Power Supply Checks ..................3-4 3.3.2.1 Current Measurements..................3-4 3.3.2.2 Com Board ..................... 3-5 3.3.2.3 Glideslope Board..................... 3-6 3.3.2.4 Nav Board .......................
  • Page 7 SECTION 5 ALIGNMENT, CALIBRATION, AND TESTING Paragraph Page INTRODUCTION ....................5-1 RECOMMENDED TEST EQUIPMENT ............... 5-1 TEST SETUP....................... 5-3 STANDARD SIGNALS AND TEST LOADS............5-3 5.4.1 VHF Com Transceiver..................5-3 5.4.1.1 Standard Loads ....................5-3 5.4.1.2 Standard Signals ..................... 5-4 5.4.2 Glideslope .......................
  • Page 8 SECTION 5 ALIGNMENT, CALIBRATION, AND TESTING (continued) 5.7.2.8 Sidetone ......................5-18 5.7.2.9 MIC Intercom Test..................5-18 5.7.2.10 Receiver Sensitivity ..................5-18 5.7.2.11 TX Interlock ....................5-19 5.7.2.12 AGC Test....................... 5-19 5.7.2.13 Selectivity (25 kHz Mode) ................5-19 5.7.2.14 Selectivity (8.33 kHz Mode) ................5-20 5.7.2.15 Volume Control (Audio Output) ..............
  • Page 9 SECTION 5 ALIGNMENT, CALIBRATION, AND TESTING (continued) 5.7.4 Navigation Assembly I/O Tests ..............5-32 5.7.4.1 Localizer Course Deviation Test ..............5-32 5.7.4.2 To/From Deflection Output Characteristic Test ..........5-32 5.7.4.3 To/From Deflection Accuracy Test ..............5-32 5.7.4.4 Course Deviation Flag Output Characteristic Test ........5-33 5.7.4.5 Course Deviation Flag Test................
  • Page 10 SECTION 5 ALIGNMENT, CALIBRATION, AND TESTING (continued) 5.7.6.14 MAIN Vertical UP, DOWN Outputs..............5-47 5.7.6.15 MAIN To/From Output ................... 5-47 5.7.6.16 MAIN Lateral Flag Output................5-48 5.7.6.17 MAIN Vertical Flag Output................5-48 5.7.6.18 MAIN Lateral Super Flag Output ..............5-48 5.7.6.19 MAIN Vertical Super Flag Output ..............
  • Page 11 APPENDIX A GNC 420A AND GNS 430A DESCRIPTION ....................A-1 ‘A’ VERSION PART NUMBERS ................A-1 TROUBLESHOOTING..................A-1 DISASSEMBLY AND ASSEMBLY...............A-2 ALIGNMENT, CALIBRATION, AND TESTING............A-2 REPLACEABLE PARTS AND ASSEMBLIES............A-2 ASSEMBLY DRAWING ..................A-2 APPENDIX B CONNECTOR I/O DESCRIPTIONS I/O DESCRIPTION....................B-1 INTERNAL AND EXTERNAL CONNECTORS ............B-1 MAIN BOARD CONNECTORS................B-2 COM BOARD CONNECTORS ................B-11 NAV BOARD CONNECTORS ................B-12...
  • Page 12 Sub-Assembly, GNC 420 (Dwg. No. 015-00506-XX, Rev. N) ......7-13 Main Chassis Assembly, GNC 420(A) (Dwg. No. 015-00283-01, Rev. J ) ..7-15 Sub-Assy, GNC 420 Nav Chas, W/O Nav (Dwg. No. 015-00282-01, Rev. E ). 7-17 Sub-Assy, GNC 420A (Dwg. No. 015-00837-XX, Rev. A ) ........ 7-19 Main Chassis Assembly, GPS 400 (Dwg.
  • Page 13 6-21 Main Chassis Assy, GNC 420, 14/28V (Unit P/N 011-00283-11, Fig 7-6)..6-20 6-22 Main Chassis Assy, GNC 420, 14/28V DO (Unit P/N 011-00283-31, Fig 7-6) .. 6-21 6-23 Main Chassis Sub-Assy, GNC 420A, 28V (Unit P/N 011-00283-21, Fig 7-6)..6-22 6-24 Nav Chassis Sub-Assy, GNC 420/420A (Unit P/N 011-00282-01, Figure 7-7) .
  • Page 14 Table Page 6-25 Sub-Assy, CDU, GNC 420, Black (Unit P/N 011-00281-01, Figure 7-4) ... 6-23 6-26 Sub-Assy, CDU, GNC 420, Gray (Unit P/N 011-00281-05, Figure 7-4) .... 6-24 6-27 Sub-Assy, CDU GNC 420A, Black (Unit P/N 011-00281-01, Figure 7-4) ..6-25 6-28 Sub-Assy, CDU, GNC 420A, Gray (Unit P/N 011-00281-05, Figure 7-4) ..

  • Page 15: Introduction

    Versions Covered by this Manual This manual applies to the GPS 400, GNC 420, and the GNS 430. It also applies to the GNC 420A and the GNS 430A. The “A” identifies the 16 watt VHF COM transmitter as opposed to the 10 watt version.
  • Page 16 GPS 400: UNIT P/N COLOR 011-00504-00 Black 011-00504-10 Gray GNC 420: UNIT P/N COLOR OPERATING MINIMUM VOLTAGE XMIT PWR 011-00506-00 BLACK 28 V 10 W 011-00506-10 BLACK 14 or 28 V 10 W 011-00506-30 GRAY 14 or 28 V 10 W...

  • Page 17: Functional Summary

    14 or 28 volt operation for 10 watt transmitter; 28 V only for 16 watt transmitter. 1.2.3 GNS 430 Performs all functions of a GNC 420. VOR and ILS Localizer Receivers. ILS Glideslope Receiver. 400 SERIES MAINTENANCE MANUAL Page 1-3 P/N 190-00140-05 Rev.

  • Page 18: Repair Plan

    This manual is designed to allow the user to perform board-level repair. If necessary, the unit can be returned to GARMIN for complete service work. Contact GARMIN at the address given on Page A (inside cover) for further service information.

  • Page 19: Com Board

    The GPS Module contains a twelve channel parallel receiver that is capable of tracking and using up to twelve visible satellites for position, velocity, and time calculations. The GPS Receiver is designed to operate with the GARMIN GA 56 antenna (P/N 011-00134-00). The GPS Module interfaces with the Main Board via connector J101.

  • Page 20: Glideslope Board

    1.5.5 Glideslope Board The Glideslope Board contains a processor controlled Glideslope Receiver which operates from 329.15 MHz to 335.00 MHz in 150 kHz increments for 40 Glideslope channels. 1.5.6 Inverter Board The Inverter Board supplies high voltage for display operation. 1.5.7 CDU Assembly The main components of the CDU Assembly are the Liquid Crystal Display (LCD), Keyboard...

  • Page 21: Special Tools And Test Equipment

    This section identifies the special tools and test equipment needed to maintain the 400 Series Units. Standard equipment is not listed. For any questions regarding special tools and test equipment contact GARMIN at the following address: GARMIN 1200 E. 151st Street...
  • Page 22 This page left intentionally blank. Page 2-2 400 SERIES MAINTENANCE MANUAL Rev. C P/N 190-00140-05...

  • Page 27: Troubleshooting

    SECTION 3 TROUBLESHOOTING Each unit in the 400 Series contains static sensitive components. Observe proper anti-static procedures when testing the unit. Hazardous voltages exist on the Inverter Board (all units). Under normal operating conditions the voltages range up to 2500 Vac peak to peak. Under open circuit conditions voltages can range over 8000 Vac peak to peak.

  • Page 28: Troubleshooting Procedures

    TROUBLESHOOTING PROCEDURES 3.3.1 Fuses Check for blown fuses on the Main Board, Com Board, and Nav Board as shown in Figures 3-1 through 3-4. If blown fuses are found, try to determine the cause of the fuse failure before installing a new fuse. F850 F852 F854...
  • Page 29 LOCATION OF F600 (7A FUSE) ON -00/-02/-03 COM BOARDS Figure 3-2. Com Board Fuse Location/F600 LOCATION OF F600 ON -04 REV C COM BOARDS TO PRESENT (F600 REPLACED WITH R611, EXCEPT ON -04 REV A AND B BOARD) Figure 3-3. Com Board Fuse Location/F600 (Replaced by R611) 400 SERIES MAINTENANCE MANUAL Page 3-3 P/N 190-00140-05...

  • Page 30: Power Supply Checks

    F501 1 AMP F502 1 AMP Figure 3-4. Nav Board Fuse Locations 3.3.2 Power Supply Checks 3.3.2.1 Current Measurements Taking intra-board and external current measurements is one way of determining a faulty board. To measure the currents, use a spare ribbon cable and spread the cable wires, then use a DC probe to measure the current in the appropriate wire (connector pin).

  • Page 31: Com Board

    Table 3-1. Unit Board Power Supply Max Current Allowed Unit (Main Board) Unit Max Current (A) Max Current (A) Status @ 27.5 V @ 13.8 V (Optional) GPS 400 0.66 1.32 GNC 420 RX—0.99 RX—1.98 TX—3.36 TX—7.32 GNS 430 RX—1.17 RX—2.34 TX—3.98 TX—7.96 ALL UNITS 0.014...

  • Page 32: Glideslope Board

    3.3.2.3 Glideslope Board Replace the Main Board if any voltage on the G/S Board is not within tolerance. Replace the G/S Board if excessive current is measured. Table 3-3. Glideslope Board Power Supply Tolerances Connector/Pin Voltage (V) Tolerance (V) Max Current Comments (mA) J25 Pin 2...

  • Page 33: Static Messages

    I-1110 I-100 Figure 3-5. Processor Location (Main Board) STATIC MESSAGES The unit informs the user of operational status using the messages listed in Table 3-5. These messages can help in isolating a faulty assembly. Table 3-5 also shows the recommended action for each message.
  • Page 34 Table 3-5. Static Messages MESSAGE RECOMMENDED ACTION Stored data was lost Replace Main Board (see paragraph 4.5.5) Main processor requires service Replace Main Board (see paragraph 4.5.5) Memory battery low Replace Memory Battery (see paragraph 4.7.1) No differential GPS position Replace GPS Module (see paragraph 4.5.5) VLOC remote transfer key stuck Replace NAV Receiver (see paragraph 4.5.6)
  • Page 35 Table 3-5. Static Messages (continued) COM remote transfer key stuck Verify that Remote Transfer Key Line is not stuck before replacing COM Board Replace Com Board (see paragraph 4.5.4) Heading input failure Replace Main Board (see paragraph 4.5.5) CDI key stuck Replace Flex Cable (see paragraph 4.5.2.1) Replace Key Board (see paragraph 4.5.2) Replace Main Board (see paragraph 4.5.5)

  • Page 36: Testing Failures

    TESTING FAILURES Another approach in troubleshooting is to perform testing on a unit according to the test procedures given in Section 5. To save time, only perform the minimum amount of testing in order to isolate the suspect board. Table 3-6 lists recommended actions based on failures that occur during testing.
  • Page 37 Table 3-6. Testing Failures Main Board (continued) TEST FAILURE TEST RECOMMENDED ACTION PARAGRAPH GPS Antenna Bias 5.7.6.10 Replace GPS Module (see paragraph 4.5.5) GPS Noise 5.7.6.11 Replace GPS Module (see paragraph 4.5.5) Replace Main Board (see paragraph 4.5.5) Satellite Tracking Test 5.7.6.12 Replace GPS Module (see paragraph 4.5.5) Replace Main Board (see paragraph 4.5.5)

  • Page 38: Sidetone

    Table 3-7. Testing Failures COM Board TEST FAILURE TEST PARAGRAPH RECOMMENDED ACTION Power Input Check 5.7.2.1 Replace Main Board (see paragraph 4.5.5) Replace Com Board (see paragraph 4.5.4) RF Power Out 5.7.2.2 Replace Com Board (see paragraph 4.5.4) Frequency Stability and 5.7.2.3 Replace Com Board (see paragraph 4.5.4) Tolerance...

  • Page 39: Centering Accuracy

    Table 3-8. Testing Failures NAV Board TEST FAILURE TEST RECOMMENDED ACTION PARAGRAPH Localizer Course Deviation Test 5.7.4.1 Replace Nav Receiver Board (see paragraph 4.5.6) To/From Deflection Output 5.7.4.2 Replace Nav Receiver Board (see paragraph 4.5.6) Characteristic Test To/From Deflection Accuracy Test 5.7.4.3 Replace Nav Receiver Board (see paragraph 4.5.6) Course Deviation Flag Output...
  • Page 40 Table 3-10. Testing Failures NAV Receiver TEST FAILURE TEST PARAGRAPH RECOMMENDED ACTION Voice/Ident Audio Output Level 5.7.3.1 Replace Nav Receiver Board (see paragraph 4.5.6) Voice/Ident Audio Frequency 5.7.3.2 Replace Nav Receiver Board (see paragraph 4.5.6) Response Voice/Ident Audio Distortion 5.7.3.3 Replace Nav Receiver Board (see paragraph 4.5.6) VOR AGC 5.7.3.4...

  • Page 41: External Connectors

    EXTERNAL CONNECTORS Figure 3-6 shows the external connectors and their corresponding pin numbers for each unit. 22 23 67 68 77 78 57 58 13 14 Figure 3-6. External Connectors CONNECTOR I/O DESCRIPTIONS Appendix B contains the pin names, numbers and a brief input/output description for the external and internal connectors of each 400 Series unit.
  • Page 42 This page left intentionally blank. Page 3-16 400 SERIES MAINTENANCE MANUAL Rev. C P/N 190-00140-05...

  • Page 44: Introduction

    SECTION 4 DISASSEMBLY AND ASSEMBLY INTRODUCTION Repairing the unit is accomplished by removing and replacing defective boards. To help disassemble and reassemble the unit in order to access the boards, look at the assembly drawings in Section 7 and the parts lists in Section 6. Each unit in the 400 Series contains static sensitive components.
  • Page 45 NAV DATA CARD REMOVAL AND INSERTION Before disassembly begins, remove the Jeppesen NavData® card supplied with the unit. The card can be installed or removed when the unit is on or off. Insert the card with the swing arm handle at the bottom and the label facing to the left (see Figure 4-1). To remove the NavData Card: 1.
  • Page 46 UNIT DESIGN Each unit consists of a Main and Nav Chassis, CDU Assembly, and a Top Cover. The Main Chassis has a Top and Underside Cavity which contains replaceable boards. The following is a typical order of disassembly: 1. Remove the Top Cover. 2.
  • Page 47 4.5.2.1 Disassemble the CDU Assembly Remove the Flex Assemblies (Figure 7-4) 1. Remove the VOL w/’C’ and VOL w/’V’ Knobs (18 and 19). 2. Remove the Push ‘CRSR’ and Push ‘C/V’ knobs (21, 22, 20, and 28). 3. Remove the Hex Nuts holding the Push ‘CRSR’ and Push ‘C/V’ shafts to the CDU Bezel (13).
  • Page 48 4.5.4 Remove Faulty Boards from the Main Chassis Top Cavity Remove the Top Cover (see paragraph 4.5.1) to access the Main Chassis Top Sub-assemblies. COM Board (Figure 7-2) Steps 5 and 6 apply to 28V/10W units only. 14/28V and 28V/16W units have no posistor, no brass spacers, and use two screws to hold down the PA transistor.
  • Page 49 GPS Module (Figure 7-2) 1. Disconnect the Ribbon Cable from the GPS Module (011-00474-XX). 2. Remove screw (211-60234-11) attaching the Map Board (012-00296-00) to the Main Chassis (125-00034-01). Remove 3 of 5 screws (211-63234-10) attaching GPS Module (011-00474-XX) to the Main Chassis (125-00034-01) and remove the GPS Module.
  • Page 50 Glideslope Board (Figure 7-3) 1. Remove the Glideslope Board Cover (115-00221-00). 2. Disconnect the Ribbon Cable (325-00063-01) from the Glideslope Board (012- 00212-XX). 3. Unsolder the connector wire from the Coax Connector (330-00070-03). 4. Remove the three screws (211-60234-04) attaching the Glideslope Board (012- 00212-XX) to the Nav Chassis (125-00035-00) and remove the Glideslope Board (012-00212-XX).
  • Page 51 1. Remove the Main Board (paragraph 4.5.5). 2. Remove all electrical grounds from the unit, so if using a grounded tip soldering iron, the battery will not be shorted upon removal. 3. Unsolder the battery leads from the bottom side of the Main Board. 4.
  • Page 52 SECTION 5 ALIGNMENT, CALIBRATION, AND TESTING INTRODUCTION This section provides unit-level alignment, calibration, and testing information for the 400 Series units. The procedures in this section can be performed before troubleshooting begins to help identify a faulty board, or as a return to service test after repair has been completed. All tests can be performed without accessing the inside of the unit.
  • Page 53 Avionics Signal Generator IFR or Marconi 2030 w/options one and six. BF Goodrich Precision Track Selector Digital Voltmeter—HP 34401A GPS Antenna—GARMIN GA56 (P/N 010-10040-01) Power Supply capable of 10-33 Volts @ 10 Amps—HP 6267B Radio Test Set—HP 8920A Modulation Analyzer HP 8901 The RF Signal Generator must have at least a 0.2 parts per...
  • Page 54 BIRD UNIT UNDER 30 dB 50 OHM LOAD WATTMETER 50 WATT ATTENUATOR TEST RF INPUT NOTE 5 0 O H M L O A D IS N O T R E Q U IR E D IF 3 0 d B AT T E N U AT O R IS U S E D . T H E 3 0 d B AT T E N U AT O R W IL L L O W E R T H E V S W R T O <...
  • Page 55 5.4.1.2 Standard Signals COM RF Level Units All specifications given for the com transceiver are in HARD units. To arrive at these units adjust the RF generator to the level specified and insert a 6 dB pad at the output of the RF generator.
  • Page 56 Standard Glideslope Centering Test Signal Standard Glideslope centering test signal is a standard Glideslope test signal in which the difference in depth of modulation of the 90 and 150 Hz signals is less than 0.002 ddm. Standard Glideslope Deviation Test Signal Standard Glideslope deviation test signal is a standard Glideslope test signal in which the difference in depth of modulation of the 90 and 150 Hz signals is 0.091 ±...
  • Page 57 G/S Super Flag Load (G/S SUPER FLAG OUT) One standard super flag load shall be 56 ohms connected between G/S SUPER FLAG OUT J6-38 and GND J6-41. ARINC 429 Transmitter Load (VLOC 429 OUTA/OUTB) The standard ARINC 429 transmitter load shall be 2.4K ohms resistance and 250 pF capacitance between the differential outputs VLOC 429 OUTA J6-24 and VLOC 429 OUTB J6-23, and 2.4K ohms resistance and 250 pF capacitance connected from each of the outputs to ground.
  • Page 58 Standard VOR Audio Test Signal Standard VOR audio test signal is a standard VOR test signal to which is added a 1000 Hz signal, amplitude modulating the carrier 30%. Standard Audio Test Signal Standard audio test signal is a RF carrier amplitude modulated 30% at 1000 Hz. The RF input signal shall be at a level of -53 dBm and have a frequency within 0.001% of the assigned carrier frequency.
  • Page 59 Standard Localizer Centering Test Signal Standard localizer centering test signal is a standard localizer test signal in which the difference in depth of modulation of the 90 and 150 Hz signals is less than 0.001. Standard Localizer Deviation Test Signal Standard localizer deviation test signal is a standard localizer test signal in which the difference in depth of modulation (ddm) of the 90 and 150 Hz signals is 0.093 +/-0.002.
  • Page 60 ALIGNMENT Board alignment is not recommended on any of the 400 Series units. Alignment is performed on individual boards at the factory before being shipped as replacement items. CALIBRATION Calibration can be performed for the following: COM Frequency Frequency Spacing SQ 250 –...
  • Page 61 5.6.1 Com Setup Page Fields 5.6.1.1 Com Frequency The Com Frequency field selects a VHF communication frequency. For purposes of setting the squelch, sidetone levels and mic gain, only the frequencies 118.000, 127.000, and 136.975 MHz can be used. If any adjustment is made at one of these frequencies, it should be made at all three frequencies.
  • Page 62 5.6.1.5 Sidetone The sidetone audio output level is independent of the COM volume knob on the unit. The SIDETN field sets the sidetone audio output level. The sidetone can be set to any value between zero and 63. The higher the number, the greater the sidetone volume. SIDETN ___________ OK 5.6.1.6 MIC Gain...
  • Page 63 TEST PROCEDURES 5.7.1 Test Mode In order to perform certain tests in the following section, the GNS 430 must be put into test mode, which allows access to the Test Pages (Figure 5-4). To put the unit in the test mode, ground Test Pin (J1-76) and turn the unit on.
  • Page 64 Figure 5-4. Test Pages 400 SERIES MAINTENANCE MANUAL Page 5-13 P/N 190-00140-05 Rev. C...
  • Page 65 5.7.2 Com Testing Before starting com testing, note the following: 1. Disable the audio compressor unless otherwise specified. The compressor can be disabled for testing purposes by manually grounding the SQUELCH/COMPRESSOR TEST input at Pin 3 of J2. 2. The 8.33 kHz channel mode uses a channel ID that does not match the actual operating frequency.
  • Page 66 3. Transmit Mode: +14/+28 Volt Radios (J2-11 and 12): Voltage _________ (+ 13.75 V) Tolerance _________ ( 0.2 V) Max Current Avg _________ (6.0 A) 5.7.2.2 RF Power Out 1. Set input voltage to 27.5 VDC (10 W, 28V units only) in TX mode at Pins J2-11 and 12. 2.
  • Page 67 Figure 5-5. Modulation Measurement Figure 5-5 shows the output of the Narda Crystal Detector displayed on an oscilloscope. The oscilloscope must be DC coupled in order for the modulation signal to be displayed correctly. 5.7.2.3 Frequency Stability and Tolerance Verify the RF carrier is within 0.0005 % (5 PPM). 136.50 MHz _________ Hz (error <...
  • Page 68 5.7.2.5 Carrier Noise Level 1. Apply a standard MIC input signal. 2. The demodulated noise on the transmitter output, without audio modulation, shall be at least 45 dB below the demodulated audio level obtained when the transmitter is modulated with a standard mic input signal.
  • Page 69 5.7.2.8 Sidetone 1. Apply a standard mic input signal. Measure com audio out and while transmitting, verify sidetone level is 1.4 Vrms 0.2 Vrms. 118.50 MHz ______ Vrms 127.50 MHz ______ Vrms 136.50 MHz ______ Vrms 5.7.2.9 MIC Intercom Test 1.
  • Page 70 5.7.2.11 TX Interlock 1. Apply an 10 V, 30% modulated, 1000 Hz RF signal. 2. Measure SNR at rated audio ( 7.07 Vrms). Sensitivity Reading 1______ 3. Enable TX interlock line. 4. Measure SNR again. Sensitivity Reading 2______ NLT 15dB difference between sensitivity reading 1 and 2 ______OK 5.
  • Page 71 7. Adjust the RF level to 20 µV. 8. Verify the DMM reading is greater than the AGC reference voltage. DMM reading ________VDC (NLT AGC Reference Voltage) 9. Adjust the signal generator frequency to 127.008 MHz. 10. Verify the DMM reading is greater than the reference AGC voltage. 127.008 MHz ______VDC (NLT AGC Reference Voltage) 126.992 MHz ______VDC (NLT AGC Reference Voltage) 11.
  • Page 72 11. Verify the DMM reading is greater than the reference AGC voltage. 127.002778 MHz ______VDC (NLT AGC reference voltage) 126.997222 MHz ______VDC (NLT AGC reference voltage) 12. Adjust signal level to 10 mV. 127.00737 MHz ______VDC (NGT AGC reference voltage) 126.99263 MHz ______VDC (NGT AGC reference voltage) 5.7.2.15 Volume Control (Audio Output)
  • Page 73 5.7.2.17 Audio Frequency Response 1. With compression disabled, apply a 30% modulated, 1 mV signal to the unit. 2. Verify the audio output does not change more than 6 dB from 350 Hz to 2.5 kHz. 3. Verify the audio-frequency response above 2500 Hz decreases, and at all frequencies above 4000 Hz, it is at least 18 dB below the output obtained at 1000 Hz.
  • Page 74 5.7.2.19 Squelch Test Note: Opened squelch—Audio Closed Squelch—No Audio 1. Enable compressor (see Section 5.7.2). 2. Set the unit and the RF signal generator to 127.000 MHz, 30% modulated with a 1 kHz tone. 3. Turn the RF level down below 1µV. 4.
  • Page 75 5.7.2.20 Frequency Modulation FM deviation is to be measured with an average responding detector, which is RMS sine wave calibrated. The result is to be divided by 0.707 to yield the mathematical peak deviation. 1. Modulate the transmitter with a standard modulator input signal. 2.
  • Page 76 5.7.3 Navigation Receiver Final Tests 5.7.3.1 Voice/Ident Audio Output Level 1. Apply a standard audio test signal having a RF level of -93 dBm. 2. Select maximum audio (volume control turned fully clockwise), and turn off the ident filter. 3. Measure 500 VOR/ILS AUDIO HI J6-16 with respect to 500 VOR/ILS AUDIO LO J6-17.
  • Page 77 5.7.3.3 Voice/Ident Audio Distortion 1. Apply an input level from the RF generator of -79 dBm. 2. Modulate a standard VOR audio test signal at 350 Hz, 1000 Hz, and 2500 Hz (must be in IDENT mode to pass 1000 Hz tone). 3.
  • Page 78 5.7.3.6 Receiver Quieting 1. Apply a -86 dBm RF level to the RF input. 2. Apply a Standard VOR Audio Test signal at 108.00 MHz. 3. Measure at the 500 VOR/ILS AUDIO HI J6-16 and 500 VOR/ILS AUDIO LO J6-17 outputs.
  • Page 79 5.7.3.9 VOR Flag Sensitivity A VOR/LOC +FLAG output voltage of greater than 260 mV fully conceals the indicator flag (‘HIDE’) and a VOR/LOC +FLAG output voltage of less than 125 mV fully reveals the indicator flag (IN VIEW). This test requires a Precision Track Selector or similar connected to the NAV OBS circuitry.
  • Page 80 5.7.3.12 VOR Course Deviation Sensitivity 1. Apply a standard VOR deviation signal at 108.00 MHz, –103.5 dBm RF level to the RF input. at a radial of 160 degrees ‘FROM’. 2. Apply a Precision Test Selector or similar device at 150 degrees in course angle. 3.
  • Page 81 5.7.3.16 Course Deviation Accuracy Test Apply a standard localizer deviation test signal, 90 Hz greater than 150Hz. Verify the deviation measured at VOR/LOC +LEFT with respect to VOR/LOC +RIGHT (VOR/LOC COMMON) is 90 mV 9 mV. _____OK 5.7.3.17 VOR OBS Bearing Accuracy 1.
  • Page 82 5.7.3.19 Spurious Response—VOR/LOC 1. Tune the VOR receiver to 117.95 MHz. 2. Verify the input signal level of an undesired image frequency of 77.15 MHz required to produce a detector-carrier (AGC) level obtained at the VOR/LOC IF AGC J6-7 output with a -93 dBm Standard VOR Audio Test Signal is not less than -13 dBm.
  • Page 83 5.7.4 Navigation Assembly I/O Tests 5.7.4.1 Localizer Course Deviation Test 1. Display the VOR/LOC/GS CDI Test Page (Figure 5-6). Figure 5-6. VOR/LOC/GS CDI Test Page 2. Display the following on the VOR/LOC/GS CDI Test Page and verify the following voltages, measuring across VOR/LOC +LEFT (J6-3) with respect to VOR/LOC +RIGHT (J6-4).
  • Page 84 6. Verify the following output: TO/FROM (VOR/LOC +TO) ______(-225 75 mV) 7. Display HIDE. 8. Measure VOR/LOC +TO (J6-1) with respect to VOR/LOC +FROM (J6-2). 9. Verify the following output: TO/FROM (VOR/LOC +TO) ______ mV (0 mV 5 mV) 5.7.4.4 Course Deviation Flag Output Characteristic Test Verify the Course Deviation Flag (VOR/LOC +FLAG) output is capable of driving up to three meter loads of 1000 ohms each.
  • Page 85 5. Verify the VOR/LOC SUPER FLAG OUT output voltage with respect to ground is 0 250 mV (50 ohm load). VOR/LOC SUPER FLAG OUT ______ mV 5.7.4.7 NAV Input Lines Monitor the “VOR DISCRETE INPUTS” Test Page and verify that toggling the below listed inputs between their active and inactive states, causes the appropriate status box to change states.
  • Page 86 5.7.4.9 NAV Serial DME Outputs Monitor the “VOR DISCRETE OUTPUTS” Test Page and verify that toggling the below listed outputs between their active and inactive states causes the output voltage on the appropriate line to switch between low (<.01 V) and high (>8.0 V) states. Serial DME Clock Low____ High ____ Serial DME Data...
  • Page 87 PAR DME 2 MHz Low____ High ____ (Input Switch must not be grounded for this test) PAR DME 4 MHz Low____ High ____ (Input Switch must not be grounded for this test) PAR DME 8 MHz Low____ High ____ Page 5-36 400 SERIES MAINTENANCE MANUAL Rev.
  • Page 88 5.7.5 Glideslope Final Tests 5.7.5.1 Glideslope Course Deviation Output Characteristic Test 1. Apply a standard course deviation input signal to the unit. 2. Measure GLIDESLOPE +UP (J6-32) with respect to GLIDESLOPE +DOWN (J6-31). 3. Verify the deviation output voltages (GLIDESLOPE +UP) for the following conditions. Full Scale Deflection (0.175 ddM input signal): ________ mV (150 ±15 mV)
  • Page 89 5.7.5.4 Glideslope Superflag Output Test 1. Select flag ‘HIDDEN’. 2. Verify GLIDESLOPE superflag output voltage is not less than PWR_IN minus 1.5 V. GLIDESLOPE Superflag Output ______ (NLT Power_IN minus 1.5 V) 3. Select Flag ‘IN VIEW’. 4. Verify GLIDESLOPE superflag output is 0 250 mV. GLIDESLOPE Superflag Output ______mV 5.7.5.5 Receiver Sensitivity...

  • Page 90: Agc

    5.7.5.6 Centering Accuracy 1. Apply a standard glideslope test signal to the unit. 2. Measure GLIDESLOPE +UP (J6-32) with respect to GLIDESLOPE +DOWN (GLIDESLOPE Common) (J6-31). 3. Verify the centering accuracy is 0 mV 7.8 mV. Centering Accuracy _________mV 5.7.5.7 1.

  • Page 91: Nose Bandwidth

    5.7.5.9 Nose Bandwidth 1. Apply standard glideslope test signal to the unit (-56dBm). 2. Find the AGC voltage and use it as a reference. 3. Vary the input signal frequency over the range of 17 kHz from the assigned channel frequency.

  • Page 92: Status Tests

    5.7.5.12 Status Tests 1. The following status bits shall be good with or without a standard glideslope test signal: GLIDESLOPE ROM_______OK GLIDESLOPE EEPROM _____OK GLIDESLOPE Synthesizer Lock__________OK 2. The following status bits shall be good when a standard glideslope test signal is applied to the RF input of the glideslope receiver: GLIDESLOPE Super Flag __________OK (this can be viewed on the VOR/LOC/GS CDI test page.

  • Page 93: Main Board Final Tests

    430 versions 011-00280-10 or 011-00280-30 must be verified operational with dual power switch in both positions (1 and 2). The “A” versions of the GNC 420 and the GNS 430 must be verified also. See the tables listed on page 1-2 for part numbers.

  • Page 94: Photocell

    5.7.6.4 Photocell 1. Turn the unit on in the test mode and verify brightness control is in photo mode, using the main lighting page. 2. With photocell uncovered, ensure display and keyboard backlight LED brightness is proper under normal conditions. _____OK 3.

  • Page 95: Memory Battery Voltage

    Figure 5-7. Main Lighting and Main Analog Test Pages B. Lighting Bus DC 1. Using the Main Lighting Test Page, change source to 14 VDC in both the DISPLAY and KEY fields. 2. Attach 12.0 VDC to unit pin J1-39. Ensure the power supply ground is connected to unit ground (J1-77, 78).

  • Page 96: Display Pattern Test

    _____OK 5.7.6.9 Unit Configuration Test Apply power to the unit and verify the successful display of the unit configuration (GPS 400, GNC 420, or GNS 430). _____OK 5.7.6.10 GPS Antenna Bias 1. Measure the DC voltage at the GPS antenna connector.

  • Page 97: Satellite Tracking Test

    1. Put the unit into Test Mode. 2. Turn the small right knob (CRSR) until you see the GPS Test Page (Figure 5-7). 3. Terminate GPS receiver into a 50 ohm load. 4. The “sgnl” number represents the receiver noise level. Verify this number is within the range of 1450 to 1750.

  • Page 98: Main Lateral Left, Right Outputs

    Figure 5-9. Main CDI/OBS Configuration Test Page 5.7.6.13 MAIN Lateral LEFT, RIGHT Outputs Measure J1-21 (output) relative to J1-22 (output) [Load—333 ohms (three 1000 ohm loads) across J1-21 and J1-22]. Note that full left/right ( 150 mV) are also available selections but are not tested.

  • Page 99: Main Lateral Flag Output

    5.7.6.16 MAIN Lateral Flag Output Measure J1-23 relative to J1-24. Load—333 ohms (Three 1000 ohm loads) across J1-23 and J1-24. ‘HIDE’______ (+375 80 mV) IN VIEW ______ (0 25 mV ) 5.7.6.17 MAIN Vertical Flag Output Measure J1-29 relative to J1-30. Load—333 ohms (Three 1000 ohm loads) across J1-29 and J1-30.

  • Page 100: Annunciate Outputs

    5.7.6.20 Annunciate Outputs Both the OBS and the AUTO outputs are switched by toggling the OBS selection on the Test Page. For: ANNUCIATOR NAV (VLOC) (J1-1) (J1-2) WAYPOINT (J1-3) TERMINAL (A) (J1-4) APPROACH (B) (J1-5) MESSAGE (J1-6) (J1-7) AUTO (J1-8) INTEGRITY (C) (J1-9) (J1-10)

  • Page 101: Obi Serial Interface

    2. Measure at applicable pin. Load—Resistor to external voltage source such that it will source 275 mA when grounded. Note: applicable output will sink this current when active (18 ohms/2W when pulled up to 5V). ACTIVE______ (0.3 VDC max) INACTIVE ______ (NLT pull-up voltage at minus 0.2V ) 5.7.6.21 OBI Serial Interface For:...

  • Page 102: Discrete Switch And Altitude Inputs

    5.7.6.22 Discrete Switch and Altitude Inputs For: INPUT NAME ALTITUDE C4 (J1-61) ALTITUDE C2 (J1-62) ALTITUDE C1 (J1-63) ALTITUDE B4 (J1-64) ALTITUDE B2 (J1-65) ALTITUDE B1 (J1-66) ALTITUDE A4 (J1-67) ALTITUDE A2 (J1-68) ALTITUDE A1 (J1-69) ALTITUDE D4 (J1-70) OBS MODE SELECT (J1-71) CDI SOURCE SELECT (J1-73)

  • Page 103: Arinc 429 Transmitters And Receivers

    5.7.6.23 ARINC 429 Transmitter and Receivers Unit outputs both HIGH and LOW speed signals at the same time in test mode while on the Main Status/Loopback Test Page, thus both speeds are tested simultaneously. For: GPS ARINC 429 OUT A (J1-46).

  • Page 104: Rs232 Ports

    5.7.6.24 RS232 Ports For: GPS RS232 OUT 1 (J1-56) GPS RS232 IN 1 (J1-57) GPS RS232 OUT 2 (J1-58) GPS RS232 IN 2 (J1-59) GPS RS232 OUT 3 (J1-41) GPS RS232 IN 3 (J1-42) GPS RS232 OUT 4 (J1-54) GPS RS232 IN 4 (J1-55) GPS RS232 1 1.

  • Page 105: Obs

    5.7.6.25 The load used in the OBS test consists of a calibrated OBS resolver, Precision Track Selector or equivalent, and must be connected to the GPS OBS inputs. The OBS bearing must be consistent to within 2 degrees of the bearing setting. If this output requires an alignment, this alignment can be done on the unit level by using the configuration page (NOTE: not the Test Page “MAIN CDI/OBS CONFIG”).

  • Page 106: Parts And Assemblies

    This section lists major parts of the 400 Series. The part numbers listed in this section of the manual are given to aid in assembly and disassembly of the unit only, not for identifying orderable parts. For orderable part information, see the GARMIN Aviation Distributor Service Parts Price List or contact GARMIN directly.
  • Page 107 GNC420/420A Table Part Description Unit P/N Figure 6-15 Sub-Assy, GNC420, 28V, Black 011-00506-00 6-16 Sub-Assy, GNC420, 14/28V, Black 011-00506-10 6-17 Sub-Assy, GNC420, 14/28V, Gray 011-00506-30 6-18 Sub-Assy, GNC420A, 28V, Black 011-00837-00 6-19 Sub-Assy, GNC420A, 28V, Gray 011-00837-10 6-20 Main Chassis Assy, GNC420, 28V 011-00283-01 6-21 Main Chassis Assy, GNC420, 14/28V...
  • Page 108 Miscellaneous Parts Part Part Description Unit P/N Figure F600 Fuse, Submini, Axial, 7 Amp 350-00003-15 F850 Fuse, SMT, Fast, 5 Amp 350-B0500-01 F853 Fuse, 1206, 0.75 Amp 350-B1075-00 F852 Fuse, 1206, 2 Amp 350-B1200-00 F851 Fuse, 1206, 3 Amp 350-B1300-00 R611 Resistor, 1W, .01 ohm, 1%, 2512 900-BR010-F0...
  • Page 109 6.2.1 GNS 430/430A Tables Table 6-1. Sub-Assy, GNS 430, 28V, Black (Unit P/N 011-00280-00, Figure 7-1) Part Number Part Name 011-00281-00 Sub-Assy,CDU,GNS430 011-00282-00 Sub-Assy,Nav Chassis,GNC400 011-00283-00 Sub-Assy,Main Chas,GNS430,28V 011-00460-40 Sub-Assy,Memory Card,Dummy 115-00218-00 SMP,Cover,Top,Main Chas,GNC400 115-00246-00 SMP,Hinge,GNC400,Front 115-00246-01 SMP,Hinge,GNC400,Rear 145-00480-02 PMP,Bezel Cover,GNS430 161-00201-00 Lbl,S/N,GNS430 161-00422-00...
  • Page 110 Table 6-3. Sub-Assy, GNS 430, 14/28V, Gray (Unit P/N 011-00280-30, Figure 7-1) Part Number Part Name 011-00281-04 Sub-Assy,CDU,GNS430,Gray 011-00282-00 Sub-Assy,Nav Chassis,GNC400 011-00283-30 Sub,Mn Chassis,GNS430,14/28V,DO 011-00460-40 Sub-Assy,Memory Card,Dummy 115-00218-00 SMP,Cover,Top,Main Chas,GNC400 115-00246-00 SMP,Hinge,GNC400,Front 115-00246-01 SMP,Hinge,GNC400,Rear 145-00480-02 PMP,Bezel Cover,GNS430 161-00201-08 Lbl,S/N,14/28V, GNS430,Gray 161-00422-00 Lbl,Prot Bezel Cover Warning 211-00052-01...
  • Page 111 Table 6-5. Sub-Assy GNS 430A, 28V, Gray (Unit P/N 011-00836-10, Figure 7-1) Part Number Part Name 011-00281-04 Sub-Assy,CDU,GNS430,Gray 011-00282-00 Sub-Assy,Nav Chassis,GNC400 011-00283-20 Sub,Main Chassis,GNS430A 011-00460-40 Sub-Assy,Memory Card,Dummy 115-00218-00 SMP,Cover,Top,Main Chas,GNC400 115-00246-00 SMP,Hinge,GNC400,Front 115-00246-01 SMP,Hinge,GNC400,Rear 145-00480-02 PMP,Bezel Cover,GNS430 161-00201-11 Lbl,S/N,GNS430A,Gray 161-00422-00 Lbl,Prot Bezel Cover Warning 211-00052-01 Screw,Shoulder,Special, Nylon...
  • Page 112 Table 6-6. Main Chassis Assy, GNS 430, 14/28V (Unit P/N 011-00283-10, Figure 7-2) Part Number Part Name 011-00474-01 Sub-Assy,GPS Module,GNC TSOII 012-00214-05 PCB Assy,Comm,10W 14/28V 012-00256-00 PCB Assy,GNC400 Inverter Bd 012-00296-00 PCB Assy,GNC400 Map Bd 012-00347-32 PCB Assy,GNS430 Main Bd,DO 115-00203-00 SMP,Cover,Cont,GNC400 Comm Bd 115-00205-00...
  • Page 113 Table 6-7. Main Chassis Assy, GNS 430, 14/28V, DO (Unit P/N 011-00283-30, Fig. 7-2) Part Number Part Name 011-00474-01 Sub-Assy,GPS Module,GNC TSOII 012-00214-05 PCB Assy,Comm,10W 14/28V 012-00256-00 PCB Assy,GNC400 Inverter Bd 012-00296-00 PCB Assy,GNC400 Map Bd 012-00347-32 PCB Assy,GNS430 Main Bd,D,O 115-00203-00 SMP,Cover,Cont,GNC400 Comm Bd 115-00205-00...
  • Page 114 Table 6-8. Main Chassis Assy, GNS 430, 28V (Unit P/N 011-00283-00, Fig. 7-2) Part Number Part Name 011-00474-01 Sub-Assy,GPS Module,GNC TSOII 012-00214-03 PCB Assy,Comm,2.5ppm TCXO 012-00256-00 PCB Assy,GNC400 Inverter Bd 012-00296-00 PCB Assy,GNC400 Map Bd 012-00347-32 PCB Assy,GNS430 Main Bd,DO 115-00203-00 SMP,Cover,Cont,GNC400 Comm Bd 115-00205-00...
  • Page 115 Table 6-9. Main Chassis Assy, GNS 430A, 28V (Unit P/N 011-00283-20, Figure 7-2) Part Number Part Name 011-00474-01 Sub-Assy,GPS Module,GNC TSOII 012-00256-00 PCB Assy,GNC400 Inverter Bd 012-00296-00 PCB Assy,GNC400 Map Bd 012-00347-32 PCB Assy,GNS430 Main Bd,DO 012-00611-00 PCB Assy,Comm Xcvr,16 Watt 115-00203-00 SMP,Cover,Cont,GNC400 Comm Bd 115-00205-00...
  • Page 116 Table 6-10. Nav Chassis Sub-Assy, GNS 430/430A (Unit P/N 011-00282-00, Figure 7-3) Part Number Part Name 012-00195-20 PCB Assy,Nav Rcvr,GNC400/500 012-00212-10 PCB Assy,GNC400 Glide Slope 115-00209-00 SMP,Cover,Cont,GNC400 Nav Bd 115-00213-00 SMP,Cover,RF,GNC400 Nav Bd 115-00214-00 SMP,Cover,Mdl,GNC400 Nav Bd 115-00221-00 SMP,Cover,GNC400 G/S Bd 115-00321-00 SMP,Fan Shield,GNC400 125-00006-00...
  • Page 117 Table 6-11. Sub-Assy, CDU, GNS 430, Black (Unit P/N 011-00281-00, Figure 7-4) Part Number Part Name 011-00340-00 Sub-Assy,Inc Dec Push Switch 210-00021-00 Nut,Hex,Reduced 211-00030-00 Pivot Pin,Power Switch 117-00028-00 Shaft,Pot,Machined,GNC4XX 430-00013-01 Knob Assy,Outer,GNC400/500 430-00013-01 Knob Assy,Outer,GNC400/500 117-00028-00 Shaft,Pot,Machined,GNC4XX 211-00030-00 Pivot Pin,Power Switch 210-00021-00 Nut,Hex,Reduced 011-00340-00...
  • Page 118 Table 6-12. Sub-Assy, CDU, GNS 430, Gray (Unit P/N 011-00281-04, Figure 7-4) Part Number Part Name 011-00340-00 Sub-Assy,Inc Dec Push Switch 210-00021-00 Nut,Hex,Reduced 211-00030-00 Pivot Pin,Power Switch 117-00028-00 Shaft,Pot,Machined,GNC4XX 430-00013-01 Knob Assy,Outer,GNC400/500 430-00013-01 Knob Assy,Outer,GNC400/500 117-00028-00 Shaft,Pot,Machined,GNC4XX 211-00030-00 Pivot Pin,Power Switch 210-00021-00 Nut,Hex,Reduced 011-00340-00...
  • Page 119 Table 6-13. Sub-Assy, CDU, GNS 430A, Black (Unit P/N 011-00281-00, Figure 7-4) Part Number Part Name 011-00340-00 Sub-Assy,Inc Dec Push Switch 210-00021-00 Nut,Hex,Reduced 211-00030-00 Pivot Pin,Power Switch 117-00028-00 Shaft,Pot,Machined,GNC4XX 430-00013-01 Knob Assy,Outer,GNC400/500 430-00013-01 Knob Assy,Outer,GNC400/500 117-00028-00 Shaft,Pot,Machined,GNC4XX 211-00030-00 Pivot Pin,Power Switch 210-00021-00 Nut,Hex,Reduced 011-00340-00...
  • Page 120 Table 6-14. Sub-Assy, CDU, GNS 430A, Gray (Unit P/N 011-00281-04, Figure 7-4) Part Number Part Name 011-00340-00 Sub-Assy,Inc Dec Push Switch 210-00021-00 Nut,Hex,Reduced 211-00030-00 Pivot Pin,Power Switch 117-00028-00 Shaft,Pot,Machined,GNC4XX 430-00013-01 Knob Assy,Outer,GNC400/500 430-00013-01 Knob Assy,Outer,GNC400/500 117-00028-00 Shaft,Pot,Machined,GNC4XX 211-00030-00 Pivot Pin,Power Switch 210-00021-00 Nut,Hex,Reduced 011-00340-00...
  • Page 121 6.2.3 GNC 420/420A Tables Table 6-15. Sub-Assy, GNC 420, 28V, Black (Unit P/N 011-00506-00, Figure 7-5) Part Number Part Name 011-00281-01 Sub-Assy,CDU,GNC420 011-00282-01 Sub-Assy,Nav Chassis,w/o Nav 011-00283-01 Sub-Assy,Main Chas,GNC420,28V 011-00460-40 Sub-Assy,Memory Card,Dummy 115-00218-00 SMP,Cover,Top,Main Chas,GNC400 115-00246-00 SMP,Hinge,GNC400,Front 115-00246-01 SMP,Hinge,GNC400,Rear 145-00480-02...
  • Page 122 Table 6-17. Sub-Assy, GNC 420, 14/28V, Gray (Unit P/N 011-00506-30, Figure 7-5) Part Number Part Name 011-00281-05 Sub-Assy,CDU,GNC420,Gray 011-00282-01 Sub-Assy,Nav Chassis,w/o Nav 011-00283-31 Sub,Mn Chassis,GNC420,Gray,DO 011-00460-40 Sub-Assy,Memory Card,Dummy 115-00218-00 SMP,Cover,Top,Main Chas,GNC400 115-00246-00 SMP,Hinge,GNC400,Front 115-00246-01 SMP,Hinge,GNC400,Rear 145-00480-02 PMP,Bezel Cover,GNS430 161-00201-09 Lbl,S/N, 14/28V, GNC420,Gray...
  • Page 123 Table 6-19. Sub-Assy, GNC 420A, 28V Gray (Unit P/N 011-00837-10, Figure 7-8) Part Number Part Name 011-00281-05 Sub-Assy,CDU,GNC420,Gray 011-00282-01 Sub-Assy,Nav Chassis,w/o Nav 011-00283-21 Sub,Main Chassis,GNC420A 011-00460-40 Sub-Assy,Memory Card,Dummy 115-00218-00 SMP,Cover,Top,Main Chas,GNC400 115-00246-00 SMP,Hinge,GNC400,Front 115-00246-01 SMP,Hinge,GNC400,Rear 145-00480-02 PMP,Bezel Cover,GNS430 161-00201-12 Lbl,S/N,GNC420A,Gray 161-00422-00 Lbl,Prot Bezel Cover Warning 211-00052-01...
  • Page 124 Table 6-20. Main Chassis Assy, GNC 420, 28V (Unit P/N 011-00283-01, Figure 7-6) Part Number Part Name 011-00474-01 Sub-Assy,GPS Module,GNC TSOII 012-00214-03 PCB Assy,Comm,2.5ppm TCXO 012-00256-00 PCB Assy,GNC400 Inverter Bd 012-00296-00 PCB Assy,GNC400 Map Bd 012-00347-22 PCB Assy,GNC420 Main Bd,DO...
  • Page 125 Table 6-21. Main Chassis Assy, GNC 420, 14/28V (Unit P/N 011-00283-11, Fig. 7-6) Part Number Part Name 011-00474-01 Sub-Assy,GPS Module,GNC TSOII 012-00214-05 PCB Assy,Comm,10W 14/28V 012-00256-00 PCB Assy,GNC400 Inverter Bd 012-00296-00 PCB Assy,GNC400 Map Bd 012-00347-22 PCB Assy,GNC420 Main Bd,DO...
  • Page 126 Table 6-22. Main Chassis Assy, GNC 420, 14/28V, DO, (P/N 011-00283-31, Figure 7-6) Item Description 011-00474-01 Sub-Assy,GPS Module,GNC TSOII 012-00214-05 PCB Assy,Comm,10W 14/28V 012-00256-00 PCB Assy,GNC400 Inverter Bd 012-00296-00 PCB Assy,GNC400 Map Bd 012-00347-22 PCB Assy,GNC420 Main Bd,D,O 115-00203-00 SMP,Cover,Cont,GNC400 Comm Bd...
  • Page 127 Cable,Coax,RG-178B/U,6.39 LONG 330-00070-04 Conn,Coax,Blind Mate,Thd Mt 334-00039-01 Header,Bd to Bd,2x5 334-00039-02 Header,Bd to Bd,2x6 670-10002-02 Xstr,Mosfet,N-Ch,BB,28V,250W Table 6-24. Nav Chassis Sub-Assy, GNC 420/420A (Unit P/N 011-00282-01, Figure 7-7) Part Number Part Name 115-00321-00 SMP,Fan Shield,GNC400 115-00337-00 SMP,Conn Cover,25D 125-00006-00 DCP Pawl,Latch,GPS150...
  • Page 128 Table 6-25. Sub-Assy, CDU, GNC 420, Black (Unit P/N 011-00281-01, Figure 7-4) Bub Number Item Description 011-00340-00 Sub-Assy,Inc Dec Push Switch 430-00013-01 Knob Assy,Outer,GNC400/500 430-00013-01 Knob Assy,Outer,GNC400/500 011-00340-00 Sub-Assy,Inc Dec Push Switch 211-60232-06 Screw,2-56x.187,PHP,SS/P,w/NYL 410-00012-01 Rtry Sw,Pot,w/Mom Push Sw, 012-00258-00...
  • Page 129 Table 6-26. Sub-Assy, CDU, GNC 420, Gray (Unit 011-00281-05, Figure 7-4) Bub Number Part Number Part Name 011-00340-00 Sub-Assy,Inc Dec Push Switch 430-00013-01 Knob Assy,Outer,GNC400/500 430-00013-01 Knob Assy,Outer,GNC400/500 011-00340-00 Sub-Assy,Inc Dec Push Switch 211-60232-06 Screw,2-56x.187,PHP,SS/P,w/NYL 410-00012-01 Rtry Sw,Pot,w/Mom Push Sw,...
  • Page 130 Table 6-27. Sub-Assy, CDU, GNC 420A, Black (Unit P/N 011-00281-01, Figure 7-4) Bub Number Item Description 011-00340-00 Sub-Assy,Inc Dec Push Switch 430-00013-01 Knob Assy,Outer,GNC400/500 430-00013-01 Knob Assy,Outer,GNC400/500 011-00340-00 Sub-Assy,Inc Dec Push Switch 211-60232-06 Screw,2-56x.187,PHP,SS/P,w/NYL 410-00012-01 Rtry Sw,Pot,w/Mom Push Sw, 012-00258-00 PCB Assy,GNC400 Interface Bd 210-00021-00 Nut,Hex,Reduced...
  • Page 131 Table 6-28. Sub-Assy, CDU, GNC 420A, Gray (Unit 011-00281-05, Figure 7-4) Bub Number Part Number Part Name 011-00340-00 Sub-Assy,Inc Dec Push Switch 430-00013-01 Knob Assy,Outer,GNC400/500 430-00013-01 Knob Assy,Outer,GNC400/500 011-00340-00 Sub-Assy,Inc Dec Push Switch 211-60232-06 Screw,2-56x.187,PHP,SS/P,w/NYL 410-00012-01 Rtry Sw,Pot,w/Mom Push Sw, 012-00258-00 PCB Assy,GNC400 Interface Bd 210-00021-00...
  • Page 132 6.2.4 GPS 400 Tables Table 6-29. Sub-Assy, GPS 400, 14/28V, Black (Unit P/N 011-00504-00, Figure 7-10) Part Number Part Name 011-00281-03 Sub-Assy,CDU,GPS400 011-00282-01 Sub-Assy,Nav Chassis,w/o Nav 011-00283-33 Sub,Main Chassis,GPS400,DO 011-00460-40 Sub-Assy,Memory Card,Dummy 115-00218-00 SMP,Cover,Top,Main Chas,GNC400 115-00246-00 SMP,Hinge,GNC400,Front 115-00246-01 SMP,Hinge,GNC400,Rear 145-00480-03 PMP,Bezel Cover,GPS400 161-00201-01 Lbl,S/N,GPS400...
  • Page 133 334-00039-02 Header,Bd to Bd,2x6 Table 6-33. Nav Chassis Sub-Assy, GPS 400 (Unit P/N 011-00282-01, Figure 7-7) The GPS 400 Nav Chassis Assy is the same as the GNC 420/420A Nav Chassis Sub-Assy Parts List (Table 6-24). Page 6-28 400 SERIES MAINTENANCE MANUAL Rev.
  • Page 134 Table 6-34. Sub-Assembly, CDU, GPS 400, Black (Unit P/N 011-00281-03), Fig 7-4) Part Number Part Name 011-00340-00 Sub-Assy,Inc Dec Push Switch 211-60232-06 Screw,2-56x.187,PHP,SS/P,w/NYL 410-00012-01 Rtry Sw,Pot,w/Mom Push Sw, 012-00258-00 PCB Assy,GNC400 Interface Bd 210-00021-00 Nut,Hex,Reduced 211-00030-00 Pivot Pin,Power Switch 117-00028-00 Shaft,Pot,Machined,GNC4XX 440-00016-03 LCD,Module,DSTN,Color,W/Lens...
  • Page 135 Table 6-35. Sub-Assembly, CDU, GPS 400, Gray (Unit P/N 011-00281-06, Fig 7-4) Part Number Part Name 011-00340-00 Sub-Assy,Inc Dec Push Switch 211-60232-06 Screw,2-56x.187,PHP,SS/P,w/NYL 410-00012-01 Rtry Sw,Pot,w/Mom Push Sw, 012-00258-00 PCB Assy,GNC400 Interface Bd 210-00021-00 Nut,Hex,Reduced 211-00030-00 Pivot Pin,Power Switch 117-00028-00 Shaft,Pot,Machined,GNC4XX 440-00016-03 LCD,Module,DSTN,Color,W/Lens...

  • Page 136: Assembly Drawings

    Figure 7-5—Sub-Assembly, GNC 420 (Dwg. No. 015-00506-XX, Rev. N) Figure 7-6—Main Chassis Assembly, GNC 420(A) (Dwg. No. 015-00283-01, Rev. K ) Figure 7-7—Sub-Assy, GNC 420 Nav Chassis, W/O Nav (Dwg. No. 015-00282-01, Rev. E ) GNC 420 CDU Assembly Drawing (Use Figure 7-4) GNC 420A: Figure 7-8—Sub-Assy, GNC 420A (Dwg.
  • Page 137 GPS 400: GPS 400 Assy Drawing (Dwg. No. 015-00504-XX, Rev. G, Figure 7-10) Figure 7-9—Main Chassis Assembly, GPS 400 (Dwg. No. 015-00283-03, Rev. J) GPS 400 Sub-Assy, Nav Chassis, W/O Nav (Use Figure 7-7) GPS 400 CDU Assembly Drawing (Use Figure 7-4) Page 7-2 400 SERIES MAINTENANCE MANUAL Rev.
  • Page 149 GNC 420A AND GNS 430A DESCRIPTION This appendix describes version A of the GNC 420 and the GNS 430. The ‘A’ versions contain a 16 watt VHF Com Transmitter as opposed to a 10 watt transmitter. There is one Com Board part number for the GNC 420 and GNS 430 ‘A’...
  • Page 150 The Com Voltage and Current requirements for the GNS 420A and GNS 430A are listed in Table A-2. Table A-2. Voltage and Current Supply Requirements Connector / Pin DC Voltage Tolerance(V) Max Current (DC) Conditions J2, Pins 11 & 12 +27.5 3.0 A Transmit Mode...
  • Page 151 GPS Module Nav and Glideslope Com Board LCD Flex Data Base Card Flex Map Board Inverter Board COM (GNC 420 AND GNS Aircraft Mounting Rack 430 ONLY) Antenna In/Out Main Board NAV (GNS 430 ONLY) Aircraft Mounting Rack Antenna In...
  • Page 152 Table B-2. Internal and External Connections (continued) INVERTER BOARD Main Board Display Module CCTF Display Module Heater GPS MODULE ( ALL UNITS) J101 Main Board Antenna In INTERFACE BOARD Data Card Flex Left Data Card Right Data Card DISPLAY MODULE LCD Flex DATA BASE CARDS -----...
  • Page 153 Table B-3. J1 Descriptions (continued) AIRCRAFT POWER MAIN +LEFT MAIN +RIGHT (2.5V Common) MAIN LATERAL +FLAG MAIN LATERAL -FLAG (2.5V Common) MAIN +TO MAIN +FROM (2.5V Common) MAIN +UP MAIN +DOWN (2.5V Common ) MAIN VERTICAL +FLAG MAIN VERTICAL -FLAG (2.5V Common) MAIN OBS ROTOR C MAIN OBS ROTOR H (Ground) MAIN OBS STATOR D...
  • Page 154 Table B-3. J1 Descriptions (continued) GPS RS232 IN4 GPS RS232 OUT1 GPS RS232 IN1 GPS RS232 OUT2 GPS RS232 IN2 ALTITUDE COMMON (Ground) ALTITUDE C4 ALTITUDE C2 ALTITUDE C1 ALTITUDE B4 ALTITUDE B2 ALTITUDE B1 ALTITUDE A4 ALTITUDE A2 ALTITUDE A1 ALTITUDE D4 OBS MODE SELECT SPARE INPUT B...
  • Page 155 B.3.3 J9 Table B-5. J9 Descriptions Pin Name Pin # Description 12 volt Supply to NAV board and G/S board from Main CPU board. 5V_NAV +5 volt Supply to NAV board and G/S board from Main CPU board. Ground. -12V -12 volt Supply to NAV board and G/S board from Main CPU board.
  • Page 156 B.3.5 J12 Table B-7. J12 Descriptions Pin Name Pin # Description LD1 through LD8 46-50 LOWER half display DATA output. CLK_ROW Pulse high for typically 310 ns at a period of 33.236 us (30.088 kHz). This line loads the next row of data in the display drivers.
  • Page 157 Table B-7. J12 Descriptions (continued) NOT USED ROT_R_LRGA Rotor Right Large A to C are the contacts of a single pole triple throw switch. The common of the switch is ground. ROT_R_LRGB Only one of the 3 is low at a time. ROT_R_LRGC ROT_R_SMLA Rotor Right Small A to C are the contacts of a single pole...
  • Page 158 Table B-8. J14 Descriptions (continued) ROT_L_SMLC Rotor Left Small A to C are the contacts of a single pole triple throw switch. The common of the switch is ground. Only one of ROT_L_SMLB the 3 is low at a time. ROT_L_SMLA ROT_L_SW Push switch on left rotary.
  • Page 159 B.3.7 J16 Table B-9. J16 Descriptions Pin Name Pin # Description CS_MAPN Chip Select Map Not. Output pulses low typically for 240 ns when map is accessed. Read Not. Output pulses low for typical times of 90, 150, and 210 ns, depending on wait states.
  • Page 160 B.3.8 J17 Table B-10. J17 Descriptions Pin Name Pin # Description FAN_HI Approx. 5 V. FAN_LO Used to switch fan off and on. B.3.9 P13 Table B-11. P13 Descriptions Pin Name Pin # Description 12 V dc output. CCFT_TA_NOT Cold Cathode Transmit A Not logic level output. Occurs at 58.5 kHz and is active low.
  • Page 161 COM BOARD CONNECTORS B.4.1 J2 Table B-12. J2 Descriptions Pin # Name RESERVED COM IF AGC TEST SQUELCH / COMPRESSOR TEST COM MIC KEY INTERCOM MIC HI COM MIC AUDIO HI COM AUDIO HI RESERVED RESERVED RESERVED AIRCRAFT POWER AIRCRAFT POWER RESERVED TRANSMIT INTERLOCK COM REMOTE TRANSFER...
  • Page 162 B.4.2 J26 Table B-13. J26 Descriptions Pin # Pin Name Description +12 VDC -12 VDC +5 VDC SERIAL_IN Asynchronous serial input. SERIAL_OUT Asynchronous serial output. DC_VOL_CONT High impedance A/D input. In the unit it is fed by the center tap of a 20K pot connected between +5V and Gnd.
  • Page 163 Table B-14. J6 Descriptions (continued) VOR/ILS AUDIO HI VOR/ILS AUDIO LO (GND) SERIAL DME CLOCK SERIAL DME DATA SER DME - CHAN REQ /PAR DME - 4MHZ SER DME - RNAV MODE /PAR DME - 2MHZ VOR/ILS DME COMMON VOR/ILS 429 OUTB VOR/ILS 429 OUTA VOR OBI CLOCK VOR OBI SYNC...
  • Page 164 B.5.2 J10 Table B-15. J10 Descriptions Pin # Pin Name Description +12VDC +5VDC -12VDC VLOC SERIAL IN Serial input from the Main CPU board to the NAV Board. This pin is not used. G/S SERIAL IN Serial input from the Main CPU board to the G/S board. G/S SERIAL OUT This is an asynchronous serial output from the G/S board to the Main CPU board.
  • Page 165 GLIDESLOPE BOARD CONNECTORS B.6.1 J25 Table B-17. J25 Descriptions Pin # Pin Name DESCRIPTION +12VDC +5VDC Ground. -12VDC G/S IF AGC The IF AGC output. 10K output impedance. G/S Composite Not Used. G/S SERIAL_IN Serial input from Main Board. G/S SERIAL_OUT Serial output from G/S Board to Main Board.
  • Page 166 INVERTER BOARD CONNECTORS B.8.1 J13 Table B-18. J13 Description Pin # Pin Name Description 11 to 14 V dc. CCFT_TA_NOT Cold Cathode Transmit A Not input. Occurs at 58.5 kHz and is active low. Inverter is capacitor coupled. CCFT_TB_NOT Cold Cathode Transmit B Not input. Occurs at 58.5 kHz and is active low.
  • Page 167 B.8.3 J27 Table B-20. J27 Description Pin # Pin Name DESCRIPTION HEATER VIN Heater high. The heater typical resistance is 16 ohms. HEATER GND Heater low. GPS MODULE CONNECTORS B.9.1 J101 Table B-21. J101 Descriptions Pin # DESCRIPTION Name TRAP 0 to 12 V dc 4 Khz PWM output used to position the GPS notch.
  • Page 168 B.11 DISPLAY MODULE CONNECTORS B.11.1 J22 See LCD Flex description (J12). B.12 DATA BASE CARD CONNECTORS J20 and J21 are the Data Base Card Connectors. B.13 MAP BOARD CONNECTORS B.13.1 P16 Table B-22. P16 Descriptions Pin Name Pin # DESCRIPTION CS_MAPN Chip Select Map Not.

This manual is also suitable for:

Gns 430Gps 400

Table of Contents