Garmin GMA 340, Maintenance Manual

Page 1: ...TENANCE MANUAL Garmin International 1200 E 151 Street Olathe KS 66062 USA 190 00149 02 Rev B June 2001 3 The document reference is online please check the correspondence between the online documentation and the printed version ...

Page 2: ...eto is strictly prohibited DESCRIPTION ECO Initial Release Add 340 Dual ADF and field replacement of main board 15949 GARMIN International Inc 1200E 15lStStreet Olathe KS 66062 USA Telephone 913 397 8200 Dealer Line 1 800 800 1420 Web SiteAddress www mrmin com INFORMATION SUBJECT TO EXPORT CONTROL LAWS This document may contain information which is subject to the Export Administration Regulations ...

Page 3: ... AND 52 PIN ASSIGNMENTS 2 4 SECTION 3 TROUBLESHOOTING 3 1 TROUBLESHOOTING 3 1 3 2 TROUBLESHOOTING PROCEDURES 3 1 3 3 POWER ON CHECK 3 5 3 4 28 V LIGHTING 3 5 3 5 14V LIGHTING 3 5 3 6 PTT ANNUCIATOR CHECK 3 5 SECTION 4 DISASSEMBLY AND REASSEMBLY 4 1 INTRODUCTION 4 1 4 2 TOOLS REQUIRED 4 1 4 3 DISASSEMBLING THE UNIT 4 1 4 4 REASSEMBLY 4 3 190 00149 02Rev B I The document reference is online please c...

Page 4: ...LOADED MICROPHONE VOLTAGE INPUTS 5 7 5 13 PILOT PTT TESTS 5 7 5 14 FUNCTIONAL TEST 5 8 TEST EQUIPMENT PRECAUTIONS 5 1 REQUIRED TEST EQUIPMENT 5 2 REAR CONNECTORS PRECAUTION 5 1 SECTION 6 REPLACEABLE ASSEMBLIES 6 1 LIST OF REPLACEABLE PARTS 6 1 SECTION 7 ASSEMBLY DRAWINGS 7 1 ASSEMBLY DRAWINGS 7 1 11 190 00149 02 Rev B The document reference is online please check the correspondence between the onl...

Page 5: ...sembly Front and Rear Detail 7 1 7 3 GMA 340 Final Assembly 7 2 Main Board Component Location Partial Layout 3 3 Power Input Board 3 4 LIST OF TABLES Table PAGE 2 1 Test Panel Parts List 2 2 2 2 J1 and 52 Pin Assignments 2 5 3 1 Front Panel Connector Detail 3 2 3 2 Main Board Connector Detail 3 3 3 3 Power Input Board Connector Detail 3 4 Field Replaceable Parts List 6 1 6 1 190 00149 02Rev B 111 ...

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Page 7: ...s are also provided One on the GMA 340 Dual ADF two on the other units The VOX intercom uses rotary knobs for volume and squelch adjustment while selection of all other functions is accomplished with the use of pushbuttons Marker HI and LO and button annunciation is accomplished with LED devices Front panel backlighting of button function squelch and volume control knobs is provided by LED Scontro...

Page 8: ...ects them to the appropriate output It also accepts audio from the aircraft avionics receivers and conditions the signals for use among the various phone and speaker outputs The Main Board Assembly also contains the Marker Beacon Receiver The marker receiver accepts the 75 MHz signal from the Marker Beacon Antenna The receiver attenuates the signal to the desired level for either high or low sensi...

Page 9: ...t The GMA 340 contains two 44 pin connectors designated J1 and 52 located at the rear of the unit When viewed from the rear the connectors appear as shown in Figure 2 1 To avoid misconnection to the unit it is recommended that the test harness connectors be secured to a fixture or unit rack mount 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O O O O O O O O O O O O O O 44 44 J2 J1 Figure 2 1 GMA 340 Rear Connecto...

Page 10: ... Jack Green Tip Jack BNC Female Insulated Connector 250 Jack 3 Conductor Insulated 211 Jack 3 Conductor Shoulder Washer Insulated 3 5mm Jack 3 Conductor Switch Pushbutton On Off Capacitor Ceramic 0 01uF 20 SOVDC 2 1 19 3 3 6 6 2 IResistor 24 Ohm 1OW II 6 I Resistor 470 Ohm 1 4W 5 Resistor 1K 5W 5 Resistor 4 7k 1 4W 5 Resistor 56 Ohm 5W Resistor 150Ohm 1 2W 5 Resistor 453 Ohm 1 4W 1 3 4 1 Table 2 1...

Page 11: ... COMI KEY COMI MIC COM3 KEY COM2 KEY COM2 MIC PA MUTE MIDDLE MKR SENSE EXT SPKR PASS HS R PASS HS L COP HS R COP HS L PIL HS R HS OUTPUTS MUSlCl L MUSlCl R TEL RING MUSIC2 L ALT WARN MUSIC2 R PIL MIC COP MIC PASS1 MIC NAV2 PASS2 MIC NAV PASS3 MIC COM3 PASS4 MIC COM2 COMI 5LOAD MIC WIPE 0 0 ACFT PWR ACFT GND INPUTS ON ON OFF OFF SWAP TONE MASQ ENABLE INHIBIT PWR 0 LGT GND 28V 14V TP GND ACFT LGT OF...

Page 12: ...elden wire 83318and 83333 or equivalent for two and three conductor shielded pairs respectively 9 Both rotary switches have a dedicated BNC connector for convenient connection to the test equipment Deck A common of each rotary switch is wired to the appropriate BNC center conductor Deck B common of each rotary switch is wired to the appropriate BNC outer conductor 10 The TP GNDjack is the single p...

Page 13: ...Headset R Pass Headset Gnd Tel Ringer Gnd Tel Ringer In Connector 52 Pilot Headset Gnd CO PilotHeadset Gnd CO PilotHeadset L CO Pilot Headset R 14V Lgt LoI28V Lgt Lo 14V Lgtl28V Lgt Lo 14V Lgtf28V Lgt Aircraft Power Aircraft Power Aircraft Ground Aircraft Ground PA Mute ICS Mute Inhibit ICS Mute Inhibit Return NC Pilot Headset L 8 Ohm Select Reserved Tone Enable Swap Swap Return NC Music 1 L In Mu...

Page 14: ...ibit ICS Mute InhibitReturn Music2 R DME In Music2 Gnd DME Gnd Pass 1 MicGnd Pass2 Mic Gnd Pass3 MicGnd Pass4 Mic Gnd Figure 2 3 Test Panel Schematic Diagram Dual ADF in Parentheses Sheet 1 of 4 2 6 190 00149 02Rev B The document reference is online please check the correspondence between the online documentation and the printed version ...

Page 15: ...Cop Mic In Cop Mic Key COPILOT MIC ACFT LGT SELECT 14VLgt LoI28V Lgt Lo d 14VLgtl28VLgt Lo 14v 14V Lgtl28V Lgt LGT Music2 Gnd s Music2 L Music2 R MUSIC2 IN Pass2 Mic g gs2 Pass4 Mic Gnd Music1 Gnd A Pass4 Mic A Music1 R PASS 4 MUSIC 1 MIC IN Figure 2 3 Test Panel Schematic Diagram Sheet 2 190 00149 02Rev B 2 1 The document reference is online please check the correspondence between the online docu...

Page 16: ...ACFT GND TP GND SWAP Swap o i o SwapReturg ICS MUTE INHIBIT 0 ICS Mute Inhibit ICS Mute Inhibit Return NOTE All loadsare QW 5 unlessotherwisenoted ACFT GND TP CHASSIS The document reference is online please check the correspondence between the online documentation and the printed version ...

Page 17: ...ingGnd At Wam Gnd b Pilot Mic In ADF Gnd DME Gnd Nav 2 Gnd Cop Mic In Pass 1 Mic Pass4 Mic MICLOAD EXTMKR LAMPLOADS 56 OHM 5W X3 ExtMkr Lamp 1 ACFTGND Pilot MicGnd Cop Mic Gnd Pass 1Mic Gnd 0 Pass2 Mic Gnd Pass3 MicGnd Pass4MicGnd N C EXTSPKR LOAD 24 OHMllO W x6 KzzL I I I U Spkr Gnd 9 8 Ohm Sel ACFTGND The document reference is online please check the correspondence between the online documentati...

Page 18: ... shield of 12 piece and soldering in place 3 Install heat shrink tubing over spliced area sufficient to completely insulate splice Shrink to fit 4 Terminate all 3 ends with typical BNC connectors as shown in example Figure 2 4 Audio Coax Cable Assembly 2 10 190 00149 02 Rev B The document reference is online please check the correspondence between the online documentation and the printed version ...

Page 19: ...his manual to ensure that the repaired area is operating correctly and that other areas have not been damaged during the repair procedure 3 2 TROUBLESHOOTING PROCEDURES This troubleshooting guide is designed to allow isolation of malfunctions to the power input board or the front panel subassembly These checks reference specific tests in Section 5 TESTING of this document Referring to the disassem...

Page 20: ...ation Front Panel Pin 1 1 I Pilot II J1 Pin 22 I I CREW II J1 Pin 23 I I TEST II J1 Pin 18 I Table 3 1 Front Panel Connector Detail Dual ADF in Parentheses 3 2 190 00149 02Rev B The document reference is online please check the correspondence between the online documentation and the printed version ...

Page 21: ... Table 3 2 Main Board Connector Detail Dual ADF in Parentheses 190 00149 02Rev B 3 3 The document reference is online please check the correspondence between the online documentation and the printed version ...

Page 22: ...Lgt LO In II J1 Pin 1 I I A C Gnd II 53 Pin 5 I I A C Pwr out II J3 Pin 6 I Table 3 3 Power Input Board Connector Detail cl 0 c 3 4 190 00149 02Rev B The document reference is online please check the correspondence between the online documentation and the printed version ...

Page 23: ...place the power input board in the unit 3 If proper voltage is measured at both J1 and 52 replace the main board in the unit 3 5 14V LIGHTING If the unit fails the Lighting check in step 5 1 1 3 of the test procedure perform the following steps 0 0 0 0 0 0 Verify ACFT LGT switch on the test panel is set to 14V Verify 13 75 V applied to panel lightingjacks of test panel Verify 13 14 5 V between pin...

Page 24: ...ton is pressed and held see front panel pinout 3 Verify continuity from flex cable to appropriate pin see front panel pinout 4 Verify proper operation of annunciator lamDtest 5 Remove the front panel assembly Verify continuity from flex cable to appropriate pin see front panel pinout assembly Verify continuity at appropriate pin when failing button is pressed and held see front panel pinout 6 Rein...

Page 25: ...S for exploded views of the front panel and the unit 4 2 TOOLS REQUIRED Standard shop equipment is used to remove and replace the major assemblies of the unit 4 3 DISASSEMBLING THE UNIT I N O T E I Numbers in parenthesis refer to item numbers in table 6 1 and bubble numbers shown in figures 7 1 and 7 3 4 3 1 Removing Top and Bottom Covers Figure 7 3 1 Remove five screws 11 securing the top cover t...

Page 26: ...uelch 2 control knobs by grasping each one and pulling forward 4 Using a 7 16 nut driver or deep well socket remove the two nuts attaching each volume control shaft to the front panel 5 Remove four screws two at the top 9 and two at the side 10 securing the plastic front panel bezel to the chassis Note that the two top screws are slightly longer than the side screws 6 Carefully pull the front pane...

Page 27: ...ove four screws 11 securing the rear connectors to the chassis Carefully slide the main board 14 assembly forward from the chassis and off the installation screw shaft 7 4 4 REASSEMBLY 4 4 1 Main Board Assembly Figure 7 3 1 Carefully slide the main board 14 assembly onto the installation screw shaft 7 and into the chassis 2 Secure the main board rear connectors to the chassis with four screws 11 3...

Page 28: ... screws or damage to the plastic bezel could result I 4 4 4 Front Panel Assembly Figure 7 3 1 If the front panel circuit board has been removed from the front panel bezel for any reason reinstall as described in paragraph 4 4 3 step 6 2 Ensure that one spring washer 8 is in place on each volume control shaft 3 Carefully place the front panel assembly 1A and 1B over the volume control shafts and on...

Page 29: ...the shaft and pass the shaft through the blue plastic shaft retainer guide 4 Install the snap ring on the shaft making sure that one washer is against either side of the chassis frame 5 Check for security If the blue plastic shaft retainer guide appears loose glue in place with a spot of Loctite 401 or similar cyanoacrylate adhesive on each leg 4 4 7 Installing Top and Bottom Covers Figure 7 3 1 T...

Page 30: ...This page intentionally left blank 4 6 190 00149 02Rev B The document reference is online please check the correspondence between the online documentation and the printed version ...

Page 31: ...T EQUIPMENT PRECAUTIONS To prevent introducing errors resulting from the connection of voltmeters oscilloscopes and other test equipment across the input and output of the GMA 340 all audio voltage measurements should be differential The HP 8920B RF Test Set supports this measurement technique refer to HP 8920B user s manual Test equipment ground clips must not be left attached to the GMA 340 even...

Page 32: ... David Clark H10 135 5 6 TEST PANEL Section 2 SPECIAL TEST EQUIPMENT provides a layout and schematic diagram for fabricating a suggested test panel 5 7 BENCH TESTING Unless otherwise specified the unit should be tested with all volume and squelch knobs fully CW This test is performed manually with covers in place 5 8 TEST EQUIPMENT SETUP Connect the GMA 340 and related test equipment to the test p...

Page 33: ...KEY WMl MIC COM3 KEY PA MUTE MIOCCE MWI 0 EXl SPKR PASS Hs R P M ns L COP Hs R C Q P H s L PIL HS R OUTPUS MUSIC1 L MUSlCt R TEL RlNG MUSIC2 L ALT WPRN MUSIC2 R PH MIC COP MIC PASS1 MI PASS2 MIC N4Vl 7 J W M 3 COM2 PAS PASS3 MICMIC COM1 GMIC LOAD INPUTS OFF WPE S W P TONE MASQ ICS MUTE ENABLE INHIBIT INHIBIT IN HP 8920 0000 0000 0000 00000 RF INlOUT AUDIO OUT AUDIO IN 0 I I I I POWER SUPPLY CHASSI...

Page 34: ...lyzer Setting I RF Generator RF Gen Amplitude Audio In Lo 11FLOAT Filter 1 11 50 Hz HPF Setting OFF Gain Cntl 11AUTO Setting 11FAST Detector I AF Gen 1 Frea II 1 kHz I IAF Gen 1 To 11AUDlO OUT IAF Gen 2 To 11AUDIO OUT 5 4 190 00149 02Rev B The document reference is online please check the correspondence between the online documentation and the printed version ...

Page 35: ...e signal generator and the rf input on the unit To produce signal levels in these units set the RF Gen Volts to Volts EMF on the HP 8920B Configuration Page Adjust the RF level to the values specified 5 9 1 Input Voltages Unless otherwise specified all tests will be performed with power input voltages as follows 5 9 1 1 Main Power 27 5 Vdc 26 13 to 28 88 V 5 9 1 2 Panel Lighting 27 5 Vdc 26 13 to ...

Page 36: ...1 and 52 Pin Numbers 11Resistance I J1 pin 9 and 10 J1 pin 9 and 52 pin 16 J1 pin 9 and J2 pin 31 NGT 10 Q I J1 pin 25 and 26 11 16L2to 20 R I J1 pin 27 and 28 J1 pin 23 and 24 J1 pin 33 and 11 J1 pin34and 12 J1 pin 33 and 35 NLT 10 kR Set PILOT HEADSET LOAD to 150Q 5 11 POWER ON CHECK 1 On the Test panel set the ACFT LGT to 28 V 2 Set main power and panel lighting supply voltages to 27 5 V Apply ...

Page 37: ...D MICROPHONE VOLTAGE INPUTS COM 3 MIC 26 0 to 29 0 V NGT 1 V PA 26 0 to 29 0 V NGT 1 V COM 2 MIC 26 0 to 29 0 V 26 0 to 29 0 V Using a coax cable and BNC to banana plug adapter connect the DMM to test panel Inputs Rotary Switch BNC On the test panel set the MIC LOAD switch to 453 Ohms and verify the following PASS 3 MIC IPASS 4 MIC 11Approx 4 0 to 6 0 V I Set MIC LOAD switch to off PILOT PTT TESTS...

Page 38: ... all front panel pushbutton controls to verify proper selection and deselection of each LED 5 14 3 AnnunciatodLamp Test 1 Press and hold TEST on the GMA 340 and verify the following 2 All LED annunciators are lit and possess visually uniform brightness 3 All LED annunciators are dimmed but still visible when photocell is covered and that brightness is increased when photocell is well lit 4 All mar...

Page 39: ... signal applied in turn to the COM 1 COM 2 COM 3 NAV 1 NAV 2 DME ADF ADF 1 ADF 2 ALT WARN and TEL RING inputs verify the following 2 Output level is from 2 25 to 3 40 V 3 Distortion is NGT 5 5 14 5 3 Audio Frequency Response 1 2 3 4 5 6 Apply test signal to COM 1 IN Set the HP 8920 audio input to 0 dB Set FILTER I to 20 Hz FILTER 2 to 99 kHz and NOTCH FILTER off Set AFGEN 1 frequency to 100Hz Veri...

Page 40: ... COM 1 MIC on the GMA 340 Verify output from 0 70 to 1 40 V Verify distortion NGT 5 Repeat test with COM 2 MIC and COM 3 MIC selected on the GMA 340 and appropriate output monitored on the HP 8920B Turn PILOT PTT off 10 Repeat steps 5 through 8 above using COP MIC IN and COP PTT 11 Turn COP PTT off 5 14 6 2 Crew Microphone Frequency Response 1 2 3 4 5 6 7 8 9 Apply test signal to PILOT MIC IN On t...

Page 41: ...Microphone Gain ICS 5 14 7 1 Pilot Microphone 1 Apply 95 mV 1 kHz test signal to PILOT MIC IN 2 Monitor PILOT HEADSET L with the HP 8920B 3 On the GMA 340 adjust Pilot squelch fully CCW 4 Verify distortion NGT 5 when the output is adjusted to 3 0 V 5 Monitor PILOT HEADSET R and repeat this test 6 Set Pilot volume and squelch fully CW at the end of this test 5 14 7 2 Copilot Microphone 1 Apply 95 m...

Page 42: ...ortion NGT 5 On the test Panel set EXT SPKR LOAD switch to 4 Ohm Verify distortion is NLT 5 After completing this test turn PILOT PTT off Verify SPKR and PA deselected on the GMA 340 before continuing tests Squelch Characteristics Apply 1 0 V 1 kHz test signal to PILOT MIC IN and monitor PILOT HEADSET L with the Vary the Pilot squelch knob and verify that the MIC channel remains open for all squel...

Page 43: ...test signal to MUSIC 1 R Monitor COPILOT HEADSET R with HP 8920B and set reference to 0 dB Turn Copilot squelch knob fully CCW 10 Verify output NGT 40 dB 11 Turn Copilot squelch knob fully CW 12 Verify a delayed gradual return to 0 dB within 0 5 to 4 0 seconds 13 On the test panel set ICS MUTE INHIBIT switch on 14 Vary the Copilot squelch knob fully CCW and back to fully CW 15 Verify the output re...

Page 44: ...il the beacon A lamp is steady on 4 Verify RF level is from 300 to 500 pV 5 14 10 3 Low Sensitivity Test Select LO sensitivity on the G M A 340 5 14 10 3 1 Outer Marker 400 Hz 1 Set AFGEN 1 frequency to 400 Hz Set RF level to 1 3 mV 2 Verify all three marker lamps are off 3 Using the vernier knob increase the RF level until the beacon 0 lamp is steady on 4 Verify RF level is from 1 5to 2 5 mV 5 14...

Page 45: ... second and then reapply On the test panel press WIPE and monitor PILOT HEADSET L with the HP 8920B On the GMA 340 select MKWMUTE Set RF level to 4 mV Verify audio is present at PILOT HEADSET L On the GMA 340 press MKWMUTE Verify no audio is present at PILOT HEADSET L Verify MKWMUTE annunciator LED remains lit Turn RF output off for at least 1 second and then reapply 10 Verify audiois present at P...

Page 46: ...dset Passengers Copilot MUSIC 1 Passengers MUSIC 2 MUSIC 1 in DUAL ADF Selected radios Pilot Copilot Passengers MUSIC 1 MUSIC 1 Muting triggered by Copilot or Passenger ICS activity Aircraft radio activity MKR activity Pilot or Copilot ICS activity Aircraft radio activity MKR activity ICS activity When ICS Mute Inhibit 52 pin 13 is connected to ICS Mute Inhibit Return 52 pin 14 muting of MUSIC 1 w...

Page 47: ...4A 14B Assemblv II Garmin Part Numbers 011 00402 00 II Front Panel Assembly Silver Trim I Marker Beacon Lamp Rack Assembly Flexible Circuit Cables It Power Input Board Subassembly 462 00004 00 310 00019 00 012 00324 00 Installation Screw Shaft Jack Screw Assembly Washer 2 each e ring 233 00046 00 212 20004 00 232 00015 04 Screw 4 40 x 187 Black 211 60334 06 Screw TCM M2 x 0 4 x 6 0 211 10202 07 Ma...

Page 48: ... Rubber Washer 4 Black II I 250 00002 00 250 00035 00 Table 6 1 Field Replaceable Parts List Sheet 2 of 2 6 2 190 00149 02Rev B The document reference is online please check the correspondence between the online documentation and the printed version ...

Page 49: ...aid in assembly disassembly of the GMA 340 Audio Panel I 2 211 10 0209 7 462 00004 00 Figure 7 1 GMA 340 Front Panel Assembly Figure 7 2 Marker Lamp Rack Assembly Front and Rear Detail 190 00149 02Rev A 7 1 The document reference is online please check the correspondence between the online documentation and the printed version ...

Page 50: ...430 Figure 7 3 GMA 340 Final Assembly 7 2 190 00149 02Rev A The document reference is online please check the correspondence between the online documentation and the printed version ...