background image

Garmin AT 

 

Rev -- 

© 2004 Garmin AT 

GX Service Manual 

7-25 

Comm Test Procedures 

Tests and procedures for troubleshooting a defective GX Comm board and returning it to service are 
described in this section. The first section, a test data sheet, is presented in a generic format and lists 
and summarizes the tests that are needed to return the unit to service. The second section describes 
the return to service procedures specifically when using the HP8920 test set. 

Test Data Sheet – Comm Return to Service 

1.  Display and Controls 

Display and controls are accessed using the test mode. Test mode can also change calibration 
functions stored during manufacture or service. Do not change or adjust any functions while in the 
test mode unless specifically instructed to do so in this manual. 

The SL display is used during display and control tests. The SL display can be connected 
standalone. Refer to Test Equipment Setup on page 7-17 for details.   

Test Mode Page 

Enable the built-in test mode by pressing the NRST and SYS buttons on the SL display while 
switching the unit on. 

In test mode operation, the large knob is used to select the different test functions; the small knob 
is used to select additional pages for each test function. 

The Test Mode Page is the first page displayed in the test mode. 

TEST MODE   

When this page is displayed, pressing the MSG button will return the COM to normal mode 
operation. 

The large knob is not tested in this function. It is tested by default by selecting the various test 
functions. 

Display test function: _____ OK 

2. Transmitter Tests 

Power Out: 

1.  Connect a wattmeter to the antenna output and record the following unmodulated power 

levels. 

2.  13.8 VDC (+/- 5%) Power supply: 

25°C  + 4° 

-20°C  + 4° 

+55°C  + 4° 

118.00MHz ____8 watts min. 

118.00MHz ____7 watts min. 

118.00MHz ____7 watts min. 

126.5MHz ____8 watts min. 

126.5MHz ____  7 watts min. 

126.5MHz ____7 watts min. 

135.97MHz ___ 8 watts min. 

135.97MHz ___ 7 watts min. 

135.97MHz ___ 7 watts min. 

3.  10.0 VDC (+/- 5%) Power supply: 

118.00MHz ___ 6 watts min.  126.5MHz ____6 watts min.  135.97MHz ___ 6 watts min. 

Summary of Contents for APOLLO GX SERIES

Page 1: ...ibution is limited solely to authorized personnel The use disclosure reproduction modification transfer or transmittal of any portion of this work for any purpose in any form or by any means without t...

Page 2: ...copied transmitted disseminated downloaded or stored in any storage medium for any purpose without the express written permission of Garmin Garmin hereby grants permission to download a single copy of...

Page 3: ...nual supplement You can download most of our printed materials right off our website This is a good source of information for you and your customers We have the latest information about our products I...

Page 4: ...MAP FUNCTION SMART KEYS 2 4 MAP WAYPOINT KEYS 2 4 APOLLO GX FEATURES 2 6 CHAPTER 3 INSTALLATION MANUALS 3 1 CHAPTER 4 ANTENNA INSTALLATION GUIDES 4 1 CHAPTER 5 AIRCRAFT INSTALLATION TROUBLESHOOTING 5...

Page 5: ...MENT 8 19 NAV BOARD REPLACEMENT 8 20 SMART KEY REPLACEMENT 8 21 NAV BOARD SOFTWARE UPGRADE 8 22 COMM BOARD SOFTWARE UPGRADE 8 24 COMPLETE INITIALIZATION 8 25 CHAPTER 9 TROUBLESHOOTING 9 1 PRELIMINARY...

Page 6: ...LY SHEET 1 OF 2 10 4 FIGURE 9 3 COMM PCB COMPONENT LAYOUT REFERENCE ONLY SHEET 1 OF 3 10 6 FIGURE 9 4 NAV BLOCK DIAGRAM 10 9 FIGURE 9 5 COMM BOARD BLOCK DIAGRAM 10 10 FIGURE 9 6 VHF COMM MAIN PCA BLOC...

Page 7: ...s July 1999 Original Release January 2001 Revision A This revision incorporates changes in drawings due to previous ENs Refer to EN6010 EN6125 EN6320 EN6393 and EN6432 October 2004 Revision Changed UP...

Page 8: ...Garmin AT Rev viii GX Service Manual 2004 Garmin AT This Page Intentionally Left Blank...

Page 9: ...UPS Aviation Technologies for more information Updating Service Manuals It is required that all service centers have the latest revision of the service manuals prior to performing any maintenance The...

Page 10: ...ch with 1 Phillips driver bit Needle nose pliers Nut driver 0 312 Nut driver Solder iron grounded tip temperature controlled 600 700 degrees F Solder wick no clean Tech Spray p n 1815 100F 0 060 dia o...

Page 11: ...Make sure that you use the proper screw in each location Note the difference between countersunk and undercut screws Use appropriate screws 2 Be careful not to damage screws Screws with damaged thread...

Page 12: ...Garmin AT Rev 1 4 GX Service Manual 2004 Garmin AT...

Page 13: ...ersections and special use airspaces that makes the Apollo GX an encyclopedia of aviation It s what you d expect from UPS Aviation Technologies the first to provide a database in a general aviation na...

Page 14: ...PTK is activated or a Message MSG is received The GX50 60 also have external annunciator controls for OBS Hold and Approach Active Controls The Apollo GX uses a variety of controls to manage the featu...

Page 15: ...of options Editing is active on the items that flash on the display Press SEL a second time to deactivate selection MAP Graphic Moving Map The MAP key starts the moving map function The entire displa...

Page 16: ...lutter the map find waypoint information and setup your map information Map Waypoint Keys APT VOR INT NDB USR The map waypoint smart keys are present when the Moving Map pages are displayed Press the...

Page 17: ...o functions Flip Flop GX60 65 Press the Flip Flop key to switch between the active left most and standby right most frequency while in the Comm function You may use an optional external Flip Flop key...

Page 18: ...aypoint ident ETE and ETA to the TO and destination waypoints Altitude from altitude encoder converter input Minimum safe altitude and en route safe altitude information Map Displays Full screen map w...

Page 19: ...rack offset Alerts for Loss of navigation data Arrival at waypoint Special use airspace Full range 10 VDC to 40 VDC input supply voltage GPS Receiver Performance Specifications 8 channel parallel GPS...

Page 20: ...typical 1 4 A max at 27 5 VDC transmit Input power GPS navigation input 7 watts typical Input power communication input GX60 65 only 3 7 watts typical receive 28 watts typical transmit GX50 and GX60 6...

Page 21: ...Serial Interface 2 RS 232 for GX50 60 65 1 RS 232 for GX55 Physical Specifications Height 2 0 inches 5 08 cm Width 6 25 inches 15 88 cm Depth 11 125 inches 28 26 cm behind panel including mounting fra...

Page 22: ...igation data base Ten last used Ten user stored Two microphone inputs 12 watt audio amplifier VHF Comm Receiver Performance Specifications GX60 65 Class D Frequency range 118 000 to 136 975 MHz 760 ch...

Page 23: ...smit is locked out below 9 VDC input Modulation capability 85 with 100 mv to 1000 mv rms microphone input at 1000 Hz Duty cycle 100 Stuck mic time out 35 second time out reverts to receive TSO Authori...

Page 24: ...Garmin AT Rev 2 12 GX Service Manual 2004 Garmin AT...

Page 25: ...2004 Garmin AT GX Service Manual 3 1 Chapter 3 Installation Manuals Please refer to the Dealer s Only website at http www garmin com to download the latest installation manuals...

Page 26: ...Garmin AT Rev 3 2 GX Service Manual 2004 Garmin AT...

Page 27: ...2004 Garmin AT GX Service Manual 4 1 Chapter 4 Antenna Installation Guides...

Page 28: ...Garmin AT Rev 4 2 GX Service Manual 2004 Garmin AT...

Page 29: ...ircraft We have listed some steps that can be taken to reduce the effects of interference The intent here is to save you time and money on GPS installations The following provides some practical steps...

Page 30: ...have verified L1 interference during the pre installation checkout Install the GPS unit in the panel according to the manufacturer s instructions Run the antenna coax RG 142B and leave some extra lead...

Page 31: ...de of the aircraft Re install the ELT and repeat the interference tests If the ELT causes GPS interference you can install a GPS notch filter in line with the antenna Most of the case enclosures for E...

Page 32: ...Garmin AT Rev 5 4 GX Service Manual 2004 Garmin AT...

Page 33: ...ion use The GPS receiver module provides present position latitude and longitude date time RAIM and miscellaneous other satellite data to the NAV board The NAV board provides navigation functions betw...

Page 34: ...accept 2 MBIT 128K x 16 4 MBIT 256K x 16 or 8 MBIT 512K x 16 flash memories in the standard 48 pin TSOP package There are two sites on the board U102 U103 that can allow code flash memory in the range...

Page 35: ...y timed programming cycle During the programming cycle completion status can be read back from the device For more information on the EEPROM refer to the Atmel Nonvolatile Memory Data Book PCMCIA Data...

Page 36: ...power connection for the NAV board P701 like the GX60 65 The GX55 requires only a power connection to the 14 pin rear connector Front Panel E L Graphics Display The display assembly UPS Aviation Tech...

Page 37: ...of the transmitter is 118 000 to 136 975 MHz using 760 channels at 25 kHz spacing The user or pilot makes frequency selection Output Power With an input voltage of 12 to 40 volts DC the transmit outpu...

Page 38: ...6 GX Service Manual 2004 Garmin AT Frequency Stability The transmit frequency is controlled by a frequency synthesizer The synthesizer provides for a transmit frequency tolerance within 15 ppm require...

Page 39: ...out is required for all GX products Software verification is not required because the software was tested during development However you must verify that the proper version of software is installed Th...

Page 40: ...tellite based navigation system HDPH headphone HPF High Pass Filter HphLv headphone level Hz Hertz cycles per second I current measured in amperes IcmSq intercom squelch IF Intermediate Frequency IFR...

Page 41: ...and noise level on a received signal SPKR speaker SQ squelch SRAM Static Random Access Memory SVN Satellite Vehicle Number SW software TX transmit UC Unit Configuration V volts Vac aircraft supply vo...

Page 42: ...pleted Final Test Inspection Record results on the Service Data Sheet after completing all service and return to service tests A copy of the Service Data Sheet is located at the end of this manual Set...

Page 43: ...igital or equivalent GPS signal source A 34 GPS Antenna or equivalent DC power cable User supplied GPS antenna and coax User supplied GPS reference unit Factory certified GPS receiver If the HP8920 Co...

Page 44: ...l for the unit For Comm equipment setup see Equipment Setup under the Comm Return to Service Procedure Alternate Setup The avionics outputs may be tested by connecting the outputs to a standard instru...

Page 45: ...can be adjusted from min to max or a count of 000 full counter clockwise to 255 full clockwise Notes Use the A to D Input test in the built in test mode Although the GX50 55 does not use the volume c...

Page 46: ...TION Executing the system initialization will clear all customer information Fill out the Service Data Sheet located at the end of this manual For units returned for service or upgrade the reset EEPRO...

Page 47: ...NAV Test Procedures 1 CDI Output Description The CDI output is a differential output intended for driving a meter movement with a maximum load of 200 ohms Setup If the TST 10 test station is not avail...

Page 48: ...utputs as follows Down 150 mV 4 mVDC Mid 0 mV 2 0 mVDC Up 150 mV 4 mVDC Verify the VDI Down output to ground is 2 05 volts 0 1 VDC 3 TO FROM Flag Output Description The TO FROM flag output is a differ...

Page 49: ...nit to nominal input supply voltage Connect a 400 mA load between each of the annunciator outputs and aircraft supply voltage Vac If Vac 13 6 volts then a load resistor of 33 ohms can be used The load...

Page 50: ...ts NAV superflag and VDI superflag These outputs are open collector outputs capable of sourcing 400 mA from the aircraft supply voltage Vac input supply A valid condition is indicated by the output so...

Page 51: ...ential output voltage between the NAV Valid and NAV VDI Valid flag ground and VDI Valid and NAV VDI Valid flag ground outputs as follows Off Flagged 0 mV 5 mVDC On Not flagged 290 mV 15 mVDC 9 Serial...

Page 52: ...y that the signal level for each tracked satellite is equal to or greater than the normalized signal levels of the reference unit Verify navigation by entering a direct to waypoint on both the test an...

Page 53: ...beled with the desired unit of measurement such as W for watts If the new units are valid the measurement value displays in those units To change an underlined entry use the CURSOR CONTROL knob or the...

Page 54: ...350 Hz to 2500 Hz Audio frequency response 4 dB variation with 350 Hz to 2500 Hz 85 modulation Carrier noise 35 dB down Sidetone output Up to 280 mW into 100 load 120 mW into 500 load Duty cycle 100 S...

Page 55: ...ement procedure 3 Unplug the ribbon cable J606 on the Comm board 4 Plug the SL display into J603 on the Comm board The red wire on the ribbon cable goes towards the front of the chassis pin 1 5 Turn o...

Page 56: ...ESET on the HP8920 2 Press the TX function key from the SCREEN CONTROL 3 Using the CURSOR CONTROL knob and the DATA keypad set TX TEST screen Tune Mode AUTO MANUAL Tune Freq 127 5 MHz TX Pwr Zero Zero...

Page 57: ...50 dBm 1414 V Atten Hold On Off Output Port RF Out Duple AFGen1 Freq 1 0000 kHz AFGen1 To AM 30 AFGen2 Freq 1 0000 kHz AFGen2 To FM Off Filter 1 50 Hz HPF Filter 2 15 kHz LPF Ext Load R 4 AC Level Wa...

Page 58: ...t level adjustment limit The system settings are enabled by pressing the NAV button for about three seconds The LED above the NAV button will turn off Rotate the large knob to select the function The...

Page 59: ...dphone audio level HphLv 015 Full transceiver functions are operational during this function including transmit Note The headphone level is an 8 bit value with a range of 0 to 255 Intercom Squelch Thr...

Page 60: ...es can be swapped Primary is not modifiable when it is the standby frequency displayed as Mode 6 Mode 4 Fixed two channel radio Both frequencies are fixed Frequencies CAN be swapped Mode 5 7 Toggle lo...

Page 61: ...s used to display the input level required to break squelch by microphone1 Mic1 Sqlch 005 Note The VOX level is an 8 bit value with a range of 0 to 127 from the noise level detector as read into the c...

Page 62: ...255 Low Display Light Level Adjustment Limit This function controls the lower brightness level in the automatic adjustment range This is the brightness used when in total darkness Lo Dsp Lvl 00 Note T...

Page 63: ...or details Test Mode Page Enable the built in test mode by pressing the NRST and SYS buttons on the SL display while switching the unit on In test mode operation the large knob is used to select the d...

Page 64: ...o 28 milliwatts 1 67 Vrms across 100 ohms Sidetone drive capable of 280 mW _____ OK Sidetone reading for 28 mW _____ Microphone Bias Measure the voltage across the microphone input with a 1 k ohm load...

Page 65: ..._ down at least 65 dBc 3 Receiver Tests Headset Output Level 1 Inject a 1000 V RF signal with 85 AM modulation into the Comm antenna port 2 Channel the Comm to the same frequency as the signal generat...

Page 66: ...8 000 MHz __________ NLT 6 dB 126 500 MHz __________ NLT 6 dB 135 950 MHz __________ NLT 6 dB 5 Vary the signal generator output power until 6 dB SINAD is obtained Record this value below reference se...

Page 67: ...ect a test box to the headphone output line adjust volume to a reasonable level and listen for the two tones The low tone is from the radio receiver and the high tone is from the intercom Intercom and...

Page 68: ...with 85 AM modulation at 1 kHz into the Comm antenna port 2 Channel the Comm to the same frequency as the signal generator 3 Connect a 100 ohm resistor and AC power meter or voltmeter across the heads...

Page 69: ...io distortion it should not exceed 5 Dynamic range _____ OK Weather Channel 1 Inject a 1000 V RF signal with 3 kHz FM modulation on 162 4 MHz into the Comm antenna port 2 Channel the Comm to the same...

Page 70: ...tive and standby frequencies are not the same Push the flip flop momentary switch several times Verification Verify the frequencies flip flop when pressing the momentary switch TX Power Step General I...

Page 71: ...RMS at 1000 Hz 4 On the test box press the PTT switch to RX 5 On the test box move test cable from MIC1 connector to MIC2 connector Repeat steps 2 through 4 with MIC2 Sidetone Audio Level and Adjustm...

Page 72: ...n the test box press the PTT switch to RX 6 1 On the HP8920 set the AF Anl In to Audio In 2 Set AC Level to W 7 On SL display press and hold the NAV button about 3 seconds until SW VER X X is displaye...

Page 73: ...ified in Test Equipment Setup on page 7 17 2 Remove test equipment load Disconnect the 8920 AUDIO OUT cable from the test box Put the TEST1 MIC1 switch in MIC1 3 Measure the DC voltage at the test sta...

Page 74: ...t may be necessary to set INCR divide10 or INCR SET or INCR X10 to obtain a reading of I 0 00100 for fine adjustment NOTE Due to the 35 second time out the PTT switch may be toggled from RX to TX to m...

Page 75: ...ed Results 1 Set all test equipment as specified in Test Equipment Setup on page 7 17 On HP8920 set AFGen1 to 20 mV 2 Key the transmitter On the test box press the PTT switch to TX 3 Adjust audio leve...

Page 76: ...n1 Freq 9 Change notch filter freq to 350 Hz On the HP8920 set the AF Gen1 Freq to 350 Hz 10 On the test box press the PTT switch to TX 11 Record distortion Will be 10 distortion at 85 modulation 12 O...

Page 77: ...se floor 4 Get to Marker Menu Using the CURSOR CONTROL knob select Main Push and rotate the knob clockwise to Marker 5 On the test box press the PTT switch to TX 6 Peak carrier and set to reference In...

Page 78: ...2 nd harmonic carrier 13 Record level Harmonic frequency will be down 65 dB 14 On the test box press the PTT switch to RX 15 Test all harmonics up to limit of equipment Repeat steps 9 to 15 for 382 5...

Page 79: ...to TX The modulation should be 85 This is displayed as AM Depth on the top right of the screen 5 Un key the transmitter On the test panel press the PTT switch to RX 6 Activate Spectrum Analyzer Turn t...

Page 80: ...RSOR CONTROL knob This center carrier on the screen 14 Turn CURSOR CONTROL knob to Lvl field on the right side of the display 15 Set carrier reference level Press SHIFT REF SET Press CURSOR CONTROL kn...

Page 81: ...creen typical 52 dB 27 On the test box press the PTT switch to RX 28 Add or subtract 62 5 kHz to get new center freq Add 0 0625 MHz for the upper side band or Subtract 0 0625 MHz for the lower side ba...

Page 82: ...e Comm radio adjust the volume control until the AC Level reads 0 280 watts 0 280 watts output into 100 ohm load mounted in test fixture at a volume level from 0 to 280 mW Speaker Audio Level Step Gen...

Page 83: ...2 watts 5 Open squelch On the Comm radio pull the Squelch knob out disable squelch 6 Get 6 dB SINAD reading and record reference sensitivity On the HP8920 1 Set the value field in the SINAD meter read...

Page 84: ...Intercom switch is on the speaker is disabled 4 Check headset On the test box 1 Move the SPKR OUT cable to the HDPH test jack 2 Set the TEST HDPH LOAD switch to TEST HDPH When the Intercom switch is...

Page 85: ...the test box connect the HP8920 audio in cable to SPKR OUT 4 Adjust volume control on Comm radio for 12 W On the Comm radio adjust the volume control until the AC Level reads 12 watts 5 Set AF Level a...

Page 86: ...Ext Load R 100 ohms 3 Move test cable On the test box connect the HP8920 audio in cable to HDPH 4 Adjust volume control on Comm radio for 280 mW On the Comm radio adjust the volume control until the A...

Page 87: ...ld select Distn Headset at 1000 Hz distortion should be 5 6 NOTE Option 019 required for the HP8920A If Option 019 the notch filter option is not installed an external variable notch filter will be re...

Page 88: ...the one of many field Speaker at 1000 Hz distortion should be 5 6 NOTE Option 019 required for the HP8920A If Option 019 the notch filter option is not installed an external variable notch filter will...

Page 89: ...Adjust volume control on Comm radio for 12 W On the Comm radio adjust the volume control until the AC Level reads 12 watts 12 watts output into 4 ohm load mounted in test fixture at a volume level fr...

Page 90: ...into 4 ohm load mounted in test fixture at a volume level from 0 to 12 watts 5 Open squelch On the Comm radio pull the Squelch knob out disable squelch 6 Find 6 dB SINAD reading On the HP8920 set the...

Page 91: ...a small x indicates the TX function is disabled 3 Test squelch On the Comm radio press NRST to put channel the WTH into secondary channel The Comm radio will have no audio out 4 Test monitor On the Co...

Page 92: ...070 TRANSMIT MIC1 2 INTCOM LVL 000 SIDTON LVL 127 LO DSP LVL 00 HI DSP LVL 50 TEST MODE Field Customer setting Default Reading TEST MODE Not changeable DISPLAY TEST Not changeable 000 CONTROLS Not ch...

Page 93: ...5 must be configured to match the operation supported by the installation This includes IFR VFR approach and Search and Rescue operation selections 1 In test mode rotate the large knob to the Install...

Page 94: ...ecked using an inline wattmeter in the antenna coax using frequencies near both ends of the band The VSWR should be 2 1 and is not to exceed 3 1 A VSWR of 2 1 will cause a drop in output power of appr...

Page 95: ...eck the database to ensure it is for the right coverage area and check the expiration date To check the database a Press SYS rotate the large knob to the System Info page and press ENTER b Rotate the...

Page 96: ...Garmin AT Rev 7 58 GX Service Manual 2004 Garmin AT...

Page 97: ...he right hand side with a small circuit board on top This is the navigation circuit board with the GPS receiver on top In the GX60 and GX65 in addition to the NAV board there is a Comm board on the le...

Page 98: ...Garmin AT Rev 8 2 GX Service Manual 2004 Garmin AT Figure 8 1 GX55 Assembly Board Locations...

Page 99: ...Garmin AT Rev 2004 Garmin AT GX Service Manual 8 3 Figure 8 2 GX 50 60 65 Assembly Board Locations...

Page 100: ...PES LOW LINT Removal 1 Before starting this procedure fill out a Service Data Sheet if this has not already been done These are located at the back of this manual 2 Power the unit off and disconnect p...

Page 101: ...back of this manual 2 Remove the chassis cover see Chassis Cover Replacement procedure 3 Remove the battery from the battery holder Replacement 1 Put the new battery 148 1702 in the battery holder Ori...

Page 102: ...the front 4 Unplug the 34 pin ribbon cable from the back of the display controller board Replacement 1 Plug the 34 pin ribbon cable in the back of the display unit This header on the display controlle...

Page 103: ...Garmin AT Rev 2004 Garmin AT GX Service Manual 8 7 Pin 33 Pin 34 Figure 8 3 Ribbon Cable Placement on Bezel Assembly and NAV Board...

Page 104: ...ove the bezel assembly see Bezel Assembly Replacement procedure 4 For GX60 or GX65 remove the Comm board see Comm Board Replacement procedure 5 Remove the NAV board see NAV Board Replacement procedure...

Page 105: ...of this manual 2 Remove the chassis cover see Chassis Cover Replacement procedure 3 Remove the Comm board see Comm Board Replacement procedure 4 Locate the fuse F400 on the top view of the Comm Board...

Page 106: ...ransistor Q303 on the Comm board One is accessed through hole in shielding 9 Remove the other eight screws holding the Comm board to the chassis 10 Remove the Comm board from the chassis Replacement 1...

Page 107: ...Bezel Assembly Replacement procedure 9 Test the unit to verify proper operation see Return to Service procedures 10 Replace the chassis cover see Chassis Cover Replacement procedure 11 Using the Serv...

Page 108: ...switch shafts using the 0 050 hex driver 6 Remove the five screws holding the display controller board to the bezel 7 Carefully lift the display controller board off the display board unplugging the...

Page 109: ...shafts Apply Loctite 664 0042 to the setscrews Tighten the setscrews using the 0 050 hex driver Space the knobs 0 010 off the bezel so they will turn smoothly Space the outer knob from the large knob...

Page 110: ...t procedure 4 With the front of the unit facing you the GPS board is on standoffs on the NAV board on the right inside the chassis 5 Remove the three screws and the slotted nut holding the GPS board 6...

Page 111: ...on the right inside the chassis 5 Remove the cover from the GPS board by lifting it by the four corners 6 Remove the three screws and the slotted nut holding the GPS board 7 Carefully lift the GPS bo...

Page 112: ...the back of this manual 2 Power the unit off and disconnect power from the unit 3 Remove the bezel assembly see Bezel Assembly Replacement procedure 4 Remove the display see Display Replacement proced...

Page 113: ...this manual 2 Power the unit off and disconnect power from the unit 3 Remove the three knobs from the front of the bezel assembly using the 0 050 hex driver Replacement 1 Replace the three knobs 262...

Page 114: ...ee Display Replacement procedure 5 Press the old lens from the bezel by pushing on it from the back The adhesive will break loose 6 Clean the adhesive surfaces on the bezel using a clean wipe and isop...

Page 115: ...sconnect power from the unit 3 Remove the chassis cover see Chassis Cover Replacement procedure 4 Desolder the old fuse from the right rear corner of the NAV board using a grounded tip temperature con...

Page 116: ...sis 8 Remove the screws four on the GX55 two on the GX50 60 65 that hold the D sub connector on the back of the chassis 9 On the GX55 remove the filler plate by sliding it up out of the rear of the ch...

Page 117: ...Bezel Assembly Replacement procedure 4 Remove the display see Display Replacement procedure 5 Peel off the soft key flex circuit assembly Replacement 1 Peel the paper backing off the soft key flex ci...

Page 118: ...DO NOT press ENTER at this point or all user waypoints will be lost 11 Turn the small knob until USER NVRAM appears on the screen 12 Press ENTER When NVRAM reset is complete Hexadecimal numbers should...

Page 119: ...e from there If that doesn t solve the problem perform steps 6 7 8 and 9 above and press ENTER at the RESET ALL screen If that doesn t resolve the problem replace the NAV board see NAV Board Replaceme...

Page 120: ...manual 2 Power the unit off 3 Remove the chassis cover see Chassis Cover Replacement procedure 4 Locate the socketed integrated circuit near the front of the Comm board No number shows designating whi...

Page 121: ...ress ENTER 8 When initialization is complete hexadecimal numbers should appear on the screen in the bottom left and bottom right corners These are checksums The same checksums should show on both side...

Page 122: ...Garmin AT Rev 8 26 GX Service Manual 2004 Garmin AT...

Page 123: ...ement procedure GPS self test failure 1 GPS receiver board 2 NAV board 1 Initialize unit See Complete Initialization procedure 2 Replace GPS receiver See the GPS Board Replacement procedure for the un...

Page 124: ...ow battery voltage 2 Fracture between solder fillet and leads on battery holder 3 NAV board 1 Check battery voltage Replace if below 2 75V See Battery Replacement procedure 2 Replace the NAV board See...

Page 125: ...e the NAV board See NAV Board Replacement procedure Comm is interfering w GPS Some of the action steps are assuming that there are separate GPS and Radio units 1 Harmonics from Comm 2 Proximity of ant...

Page 126: ...and squelch levels to current spec See user setup procedure in the user s manual 2 Replace Comm board See Comm Board Replacement procedure Low transmit power No Tx No Rx 1 Antenna connections 2 Antenn...

Page 127: ...instrument interference is not the cause 2 Check the antenna 3 Replace Comm board See Comm Board Replacement procedure Stuck in simulation mode 1 A C installation 2 NAV board 1 Verify pin 7 of 37 pin...

Page 128: ...scales Software version 1 0 Replace the NAV board See NAV Board Replacement procedure Photocell is very sensitive Software version 1 0 Replace the NAV board See NAV Board Replacement procedure Won t...

Page 129: ...xadecimal Turn on cycle count increments by one each time the unit is reset or turned on 0224 is 1s byte 0229 1 Hexadecimal EEPROM failures checked each time unit is turned on 0230 1 Hexadecimal NVRAM...

Page 130: ...Garmin AT Rev 9 8 GX Service Manual 2004 Garmin AT...

Page 131: ...2004 Garmin AT GX Service Manual 10 1 Chapter 10 Drawings Component Layouts Figure 10 1 GX55 NAV PCB Component Layout Reference Only Sheet 1 of 3...

Page 132: ...Garmin AT Rev 10 2 GX Service Manual 2004 Garmin AT Figure 10 1 GX55 NAV PCB Component Layout Reference Only Sheet 2 of 3...

Page 133: ...Garmin AT Rev 2004 Garmin AT GX Service Manual 10 3 Figure 10 1 GX55 NAV PCB Component Layout Reference Only Sheet 3 of 3...

Page 134: ...Garmin AT Rev 10 4 GX Service Manual 2004 Garmin AT Figure 10 2 GX 50 60 65 NAV PCB Component Layout Reference Only Sheet 1 of 2...

Page 135: ...Garmin AT Rev 2004 Garmin AT GX Service Manual 10 5 Figure 10 2 GX 50 60 65 NAV PCB Component Layout Reference Only Sheet 2 of 2...

Page 136: ...Garmin AT Rev 10 6 GX Service Manual 2004 Garmin AT Figure 10 3 Comm PCB Component Layout Reference Only Sheet 1 of 3...

Page 137: ...Garmin AT Rev 2004 Garmin AT GX Service Manual 10 7 Figure 10 3 Comm PCB Component Layout Reference Only Sheet 2 of 3...

Page 138: ...Garmin AT Rev 10 8 GX Service Manual 2004 Garmin AT Figure 10 3 Comm PCB Component Layout Reference Only Sheet 3 of 3...

Page 139: ...Garmin AT Rev 2004 Garmin AT GX Service Manual 10 9 Block Diagrams Figure 10 4 NAV Block Diagram...

Page 140: ...Garmin AT Rev 10 10 GX Service Manual 2004 Garmin AT Figure 10 5 Comm Board Block Diagram...

Page 141: ...ion RX LO TX LO Lock Detect Audio AGC Voltage Noise Detect Voltage Display Output Control Input RS 232 I O RX TX Speaker Enable Headphone Enable Receiver Select Mic Select AGC Disable RX RF 1 8432MHz...

Page 142: ...isplayThermistor Volume Control Pot Crystal Thermistor 12 volt Supply 28 volt Supply CPU Reset System A to D Converter Display Interface A to D Reference 11 0592MHz 3 8 volts D0 D7 Display Data Displa...

Page 143: ...erence Divider Variable Divider Dual Mod Prescaler Oscillator 25KHz 25KHz 19 65MHz Ref Dac Buffer Amp Voltage Controlled Oscillator Loop Filter Binary Counter Power Supply Sync 307KHz RX LO TX LO 118...

Page 144: ...Control DAC Varactor Scaling Amplifier AM FM Control Switch 3rd IF Amp 21 4 MHz 2 Pole Xtal Filter RF Amp Audio Detector Rx RF Detected Audio 21 4 MHz 6 Pole Xtal Filter 1st IF Amp 2nd IF Amp IF AGC...

Page 145: ...c Preamp AGC Bandpass Filter Noise Detector Speaker Modulator Preamp Headphone Amplifier Headphone Output Detected Audio Mic Input Noise Detect Voltage Enable Voltage Ref Dac Detected Audio Audio Sele...

Page 146: ...ervice Manual 2004 Garmin AT 7th Order Elyptic Function LPF Pre Driver Amp Antenna Switch RF AGC A Power Amp Driver Amp R R Tx LO 118 00 to 136 975 MHz Rx Tx Audio Modulation S Figure 10 11 VHF Comm T...

Page 147: ...st Supply Startup Pre Regulator Buck Supply Input Filter and Protection Audio Modula 12 Volt Audio In 27 5 VDC Supply Sync 27 5 VDC 27 5 VDC Max 10 8 VDC 27 5 V 3 3 Vo 5 Volts Power Input 10 40 VDC Sp...

Page 148: ...Garmin AT Rev 10 18 GX Service Manual 2004 Garmin AT Assembly Drawings Figure 10 13 GX55 Assembly Reference Only Sheet 1 of 2...

Page 149: ...Garmin AT Rev 2004 Garmin AT GX Service Manual 10 19 Figure 10 13 GX55 Assembly Reference Only Sheet 2 of 2...

Page 150: ...Garmin AT Rev 10 20 GX Service Manual 2004 Garmin AT Figure 10 14 GX50 60 65 Assembly Reference Only Sheet 1 of 2...

Page 151: ...CAN SECURE IN PLACE 10 WHEN INSTALLING ITEM 32 INSTALL WITH GATE OF PART FACING TOWARD BOTTOM OF BEZEL TRIM OFF EXCESS GATE IF NECESSARY 11 WHEN INSTALLING BEZEL ASSEMBLY TO CHASSIS ASSEMBLY MAKE SURE...

Page 152: ...Garmin AT Rev 10 22 GX Service Manual 2004 Garmin AT...

Page 153: ...OFT KEY GX96 172 0004 012 1 FUSE 125V 3A SLOW BLOW SMD 315 4110 00 1 KEYPAD 262 0052 00 1 KNOB INNER CONCENTRIC 262 0053 00 1 KNOB OUTER CONCENTRIC 262 0049 1 KNOB POWER DZUS RAIL NMC 565 1089 00 1 LA...

Page 154: ...evels available 310 5189 10 1 PLATE D SUB COVER 15 PIN SL GX 224 0403 7 SCREW UNDERCUT PAN HEAD PHILIPS 4 40 X 3 16 82 DEGREE STAINLESS STEEL 224 0404 5 SCREW UNDERCUT PAN HEAD PHILIPS 4 40 X 82DEG ST...

Page 155: ...ent compatibility please call Garmin AT Service Department at 800 525 6726 ext 3992 Please have the following information Unit model number unit part number unit mod level and unit software version Al...

Page 156: ...it mod level and unit software version Also have all your board part numbers board serial numbers and rev levels available 220 3002 1 NUT JAM BNC X 28 BRS NP 221 0440 3 SCREW PAN HEAD PHILIPS 4 40 X 7...

Page 157: ...CARD WORLDWIDE 138 0425 1 DATA CARD AMERICAS 138 0426 1 DATA CARD INTERNATIONAL Maintenance Supplies Part Num Qty Description 998 0083 A R NO CLEAN WIRE SOLDER 998 0475 A R NO CLEAN SOLDER FLUX PEN 5...

Page 158: ...Garmin AT Rev 11 6 GX Service Manual 2004 Garmin AT...

Page 159: ...2004 Garmin AT GX Service Manual 12 1 Chapter 12 Regulatory Documents 560 0925 00 GX55 STC Document 560 0926 00 GX50 60 65 STC Document...

Page 160: ...Garmin AT Rev 12 2 GX Service Manual 2004 Garmin AT...

Page 161: ...2004 Garmin AT GX Service Manual 13 1 Chapter 13 Service Data Sheet 561 6001 500 GX Series Service Data Sheet...

Page 162: ...Garmin AT Rev 13 2 GX Service Manual 2004 Garmin AT...

Page 163: ...___ Sidetone Level ___________________________ Headphone Level _________________________ TEST MODE NAV INFO Serial Ports Channel RX TX 1 ___________ ____________ 2 ___________ ____________ IFR APPROAC...

Page 164: ...ort Setup page Record serial port settings in the space provided If after upgrading software or servicing the unit the RX TX channels show GPS in both positions go back and perform the Software Upgrad...

Page 165: ......

Page 166: ......

Reviews: