Garmin GTX 320 ATC Page 1 Maintenance Manual Download

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GTX 320 ATC TRANSPONDER

MAINTENANCE MANUAL

190-00133-02 (Rev B)

GARMIN

1200 E. 151st Street

Olathe, KS 66062 USA

16 March 1999

Summary of Contents for GTX 320 ATC

Page 1: ...GTX 320 ATC TRANSPONDER MAINTENANCE MANUAL 190 00133 02 Rev B GARMIN 1200 E 151st Street Olathe KS 66062 USA 16 March 1999...

Page 2: ...written consent of GARMIN International GARMIN 1200 E 151st Street Olathe KS 66062 USA Telephone 913 397 8200 or 1 800 800 1020 www garmin com REVISION RECORD Copyright 1999 by GARMIN Corporation All...

Page 3: ...S 1 1 1 4 EQUIPMENT DESCRIPTION 1 2 1 5 SCOPE OF MAINTENANCE 1 3 SECTION 2 SPECIAL TEST EQUIPMENT 2 1 INTRODUCTION 2 1 2 2 SPECIAL TOOLS AND TEST EQUIPMENT 2 1 SECTION 3 ALIGNMENT AND TESTING 3 1 INTR...

Page 4: ...scope TRANSPONDER The GTX 320 Transponder is an airborne radar transceiver It automatically receives interrogations from the ATCRBS and selectively replies with a specific pulse group code only to tho...

Page 5: ...The Main PCB Assembly contains the following circuits IF Amplifier and Pulse Discriminator Local Oscillator and Mixer Power Supply Programmable Logic Device Light Dimming Circuitry Modulator and Tran...

Page 6: ...NTENANCE Due to the overall complexity of the unit GARMIN recommends limiting field maintenance to the following Removal and Replacement of the Front Subassembly Transmitter Frequency Adjustment Trans...

Page 7: ...ated Test Panel Locally Fabricated Alignment Tool Locally Fabricated Antenna Test Cable Connector Locally Fabricated 2 3 1 Test Panel and Test Harness A Test Panel must be fabricated by the shop which...

Page 8: ...all opening place the ferrule over the coax braid flush against the coax outer insulation before performing the next step 4 Insert cable center conductor dielectric and shield braid through the sidewa...

Page 9: ...190 00133 02 Rev B 2 3 Figure 2 3 Test Setup Test Harness J102...

Page 10: ...lowing equipment or suitable substitute is used to adjust the transmitter frequency 1 Transponder DME Test Set IFR Systems ATC 1400A 2 Power Supply Topward 2000 3 Digital Oscilloscope Tek TDS 320 or s...

Page 11: ...VEL 50 dBm SLS ECHO OFF FREQUENCY POWER TOGGLE SWITCH F1 P1 ______ OK 3 Set the GTX320 transponder mode select control knob to the ON position ______ OK NOTE Allow the unit to warm up for approximatel...

Page 12: ...190 00133 02 Rev B 3 3 Figure 3 1 C620 and C635 Location...

Page 13: ...Time 50 nS to 200 nS Pulse Width 350 nS to 550 nS 5 Adjust C635 for maximum power output as read from the ATC1400A test set The power must be greater than 125 watts ______ 125 Watts 6 Verify that the...

Page 14: ...approximate 5 second delay before the unit transmits ______ OK 5 Rotate the mode select switch on the GTX320 to the ALT position The GTX320 shall continue to reply to valid interrogations ______ OK 6...

Page 15: ...om the MTL in Mode A 6 Increase the RF level to 50 dB above MTL The reply rate displayed on the ATC 1400A shall be at least 90 ________ 90 Reply Rate 3 3 3 5 Reply Pulse Characteristics 1 Set the osci...

Page 16: ...MTL a value of 21 dBm assuming an MTL of 71 dBm The percent reply shall be at least 90 as indicated on the ATC 1400A ______ Reply 3 3 3 7 Automatic Overload Control AOC 1 Set the SLS ECHO toggle swit...

Page 17: ...8 0 volts The unit must suppress the replies to any interrogations received during the time of the suppression pulse ______ OK 3 3 3 10 External Altittude Encoder Inputs 1 Set the digital oscilloscop...

Page 18: ...etween the P1 and P3 pulses as viewed on the oscilloscope and shown in Figure 3 4 ______ OK 7 Verify that the unit is correctly encoding the altitude by observing the XPDR CODE digital display on the...

Page 19: ...l appear next to the P3 pulse on the oscilloscope See Figure 3 5 5 Rotate the mode select switch to the SBY position 6 Press the IDENT button on the transponder The reply light shall turn on for appro...

Page 20: ...de select switch to the ALT position The ALT nomenclature and the four reply code digits shall be illuminated with a higher intensity than the OFF SBY ON and TST nomenclature ______ OK 3 3 3 16 TST Te...

Page 21: ...so that it returns to the ALT position The reply light shall remain on ______ OK 3 3 3 18 Numerical Reply Code Switches 1 Rotate the XPDR MODE switch on the ATC 1400A to position A 2 With the transpon...

Page 22: ...190 00133 02 Rev B 3 13 Figure 3 6 ATC 1400A Test Settings...

Page 23: ...for bent or broken pins on the 25 pin connector 4 Inspect for damage to the BNC connector 4 3 FRONT SUBASSEMBLY P N 011 00263 00 1 Remove power to the unit 2 Remove the bottom cover 5 screws to expose...

Page 24: ...Rev B 4 2 Figure 4 1 Front Subassembly Installation 4 4 CLEANING After reassembly clean the external surface of the transponder when inspection shows dirt smudges etc Wipe with a damp lint free stati...