CABLE NAME: LT 3007
 
UNIT UNDER TEST: Garmin GPS400, GPS500, GNC420, GNC520, GNS430, GNS530

 

ADDITIONAL UNITS REQUIRED FOR TESTING OF MAIN UNIT:

Linaire parallel altitude encoder (supplied with this harness)

DC POWER SUPPLY
AUDIO DISTORTION ANALYZER
RADIO TEST SET - HP8920A or suitable substitute
PRECISION TRACK SELECTOR
GPS ANTENNA - GARMIN GA 56
 

OPTIONAL UNITS AND SIMULATORS TO AID IN TESTING MAIN UNIT:

LVI2106 LINAIRE CABLE for GARMIN GI102A and GI106A indicators

Customer supplied Serial Buss Simulator to supply RS-232 and ARINC 429 buss signals for additional testing of the unit. Not required to meet Garmin testing.
 

POWER REQUIREMENTS: 28VDC for tests. 14VDC/28VDC for the 14/28 volt versions of the Garmin units.
LAMP POWER REQUIREMENTS: 0-28VDC or 5Vpeak square wave at 500Hz applied to LT 6 tip jack 36.

See 5.8.6.26 Lighting Buss Input in Garmin manual for test.
 

SWITCH IDENTIFICATION:
Altitude Encoder connects to LT 6 P3 (DB25S control head connector).
Section A A1,A2,A4 altitude code lines.
Section B B1,B2,B4 altitude code lines.
Section C C1,C2,C4 altitude code lines.
Section D D4 altitude code line.

Lines are grounded based on the octal code.
0 = all open
1 = A1 or B1 or C1 grounded
2 = A2 or B2 or C2 grounded
4 = A4 or B4 or C4 or D4 grounded
7 = all grounded

ALTITUDE ALARM AUDIO, on Altitude encoder, has not been implemented by Garmin at this time.
 

The cable box switches, LEDs and Jacks are Identified on the side of the box.
 
LT 6 POWER switch applies power to the panel, cable and to the GPS board connector.
CABLE BOX COMM/OFF switch applies power to the COMM board connector.
CABLE BOX NAV/OFF switch applies power to the NAV VOR board connector.
CABLE BOX TEST/DEMO switch in the center off position places the unit in normal mode at startup. The TEST position places the unit in the test mode at startup. The DEMO position places the unit in the demo mode at startup.
 
CABLE BOX OBS/CDI switch is an external control (GNS 430, 530 only)
CDI position will toggle display of GPS and VOR/ILS on the main indicator.
OBS position will toggle between GPS OBS and GPS Auto modes.
CABLE BOX COMM/NAV REMOTE transfer switch is an external control.
COMM position will toggle COMM Active and Standby frequency.
NAV position will toggle NAV Active and Standby frequency.
CABLE BOX DME/COMMON in the DME position the switch grounds the DME Common line enabling the DME channeling.
 
CABLE BOX LOAD pushbutton and LOAD rotary switch and tip jack.

The pushbutton is used to apply current thru a load to the load tip jack for connection via jumper wire to test the annunciate lines and tuning lines for full load capability. The rotary load switch selects the required load. The load LED lights when the jumper wire is connected to a low and the button is pushed.
 

CABLE BOX PATCH A/B when connected to PATCH A provides the following signals to the LT 6 panel for testing.
TJ TO MAIN  TO  PANEL METER TO/FROM
TJ FROM MAIN FROM  
TJ DEV L MAIN LEFT PANEL METER NAV DEV
TJ DEV R MAIN RIGHT  
TJ NAV FLAG + MAIN LATERAL FLAG + PANEL METER NAV FLAG
TJ NAV FLAG - MAIN LATERAL FLAG -  
TJ OBS H MAIN OBS H  
TJ OBS C MAIN OBS C  
TJ OBS D MAIN OBS D  
TJ OBS E MAIN OBS E  
TJ OBS F MAIN OBS F  
TJ OBS G MAIN OBS G  
TJ DEV U MAIN UP PANEL METER GS DEV
TJ DEV D MAIN D  
TJ GS FLAG + MAIN VERTICAL FLAG + PANEL METER GS FLAG
TJ GS FLAG - MAIN VERTICAL FLAG -  
TJ 21 MAIN OBI CLOCK  
TJ 22 MAIN OBI DATA  
TJ 23 MAIN OBI SYNC  

            
 

CABLE BOX PATCH A/B when connected to PATCH B provides the following signals to the LT 6 panel for testing.
TJ TO VOR/LOC TO PANEL METER TO/FROM
TJ FROM VOR/LOC FROM  
TJ DEV L VOR/LOC LEFT PANEL METER NAV DEV
TJ DEV R VOR/LOC RIGHT  
TJ NAV FLAG + VOR/LOC FLAG + PANEL METER NAV FLAG
TJ NAV FLAG - VOR/LOC FLAG -  
TJ OBS H VOR OBS H  
TJ OBS C VOR OBS C  
TJ OBS D VOR OBS D  
TJ OBS E VOR OBS E  
TJ OBS F VOR OBS F  
TJ OBS G VOR OBS G  
TJ GS DEV U GS UP PANEL METER GS DEV
TJ GS DEV D GS DOWN  
TJ GS FLAG + GS FLAG + PANEL METER GS FLAG
TJ GS FLAG - GS FLAG -  
TJ SUPER FLAG NAV NAV SUPERFLAG LED  
TJ SUPER FLAG GS GS SUPERFLAG LED  
TJ 21 VOR OBI CLOCK  
TJ 22 VOR OBI DATA  
TJ 23 VOR OBI SYNC  

    LT 6 TIP JACKS Always connected.

TJ 16 TIME MARK OUT  
TJ 36 LIGHTING POWER INPUT  
TJ 33 TRANSMIT INTERLOCK  
TJ 3 SERIAL DME CLOCK  
TJ 4 SERIAL DME DATA  
TJ 5 GS IF AGC  
TJ 35 COM IF AGC  
     

   LT 6 SQUELCH switch Disable = SQUELCH/COMPRESSOR TEST
 

SERIAL BUSS A and the LOOP BACK A connectors provide for the loop back testing of the GPS RS-232 and ARINC 429 busses. This connection can be used to connect a serial buss simulator to the unit for testing and programming.
pin 1 GPS RS232 OUT 1 pin 2 GPS RS232 IN 1
pin 3 GPS RS232 OUT 2  pin 4 GPS RS232 IN 2
pin 5 GPS RS232 OUT 3 pin 6 GPS RS232 IN 3
pin 7 GPS RS232 OUT 4 pin 8  GPS RS232 IN 4
pin 9 ARINC 429 IN 1A pin 10 ARINC 429 IN 2A
pin 11 ARINC 429 OUT A pin 12 ARINC 429 IN 1B
 pin 13 ARINC 429 IN 2B pin 14 ARINC 429 OUT B
pin 15  GROUND    

    

SERIAL BUSS B and the LOOP BACK B connectors provide for the loop back testing of the VOR/ILS ARINC 429 busses. This connection can be used to connect a serial buss simulator to the unit for testing.
 
pin 1 VOR/ILS ARINC 429 OUT B pin 2  VOR/ILS ARINC 429 IN B
pin 3 VOR/ILS ARINC 429 OUT A pin 4 VOR/ILS ARINC 429 IN A
pin 9 GROUND    

 

CABLE BOX TIP JACK and LED IDENTIFICATION:

LED lights when line is active low.

18MHz10 VLOC19D ANNUNCIATE
2 4MHz 11 GPS 20 E ANNUNCIATE
3 2MHz 12 WAYPOINT 21 ALT ALARM(not implemented)
4 1MHz 13 TERMINAL 22 F ANNUNCIATE
5 800KHz 14 APPROACH 23 ILS/GPS APPR
6 400KHz 15 MESSAGE 24 LATERAL S’FLAG
7 200KHz 16 OBS 25 VERTICAL S’FLAG
8 100KHz 17 AUTO 26 LOAD
9 50KHz 18 INTEGRITY 27 ILS ENG
   28 VOR/LOC S’FLAG 29 GS S’FLAG

         

 

LT 6 PANEL TEST POINTS:

VOR/ILS AUDIO

SET AUX/COM > AUX

SET TEST/NORM > NORM

SET SPEAKER/PHONES > PHONES

SET PANEL METER > AUDIO RMS

OR Use Watt Meter with 500 ohms and connect to LT 6 Phone Jack.

 

SPECIAL OPERATION NOTES:

GPS400, GNC420 & GPS500, GNC520 only require the connection of patch cable A to patch A/B on the cable box. All main indicator lines patch thru to the LT 6 panel for loading and metering.

GNS430 & GNS530 require using the patch cable A for testing the Main indicator, Main OBS and Main OBI signals. The patch cable B is for testing the VOR/LOC indicator, OBS, and OBI signals.

The LT 6 Deviation Load switch is set to position 4. This will load the Main Left & Right and Up & Down lines to 333 ohms and cut the meter reading in half of the total millivolts output on these lines. This is because Garmin chose to use 300mV level for testing. (150mV reading =300mV)

The LT 6 Flag Load switch is set to position 3. This will load the Main Lateral Flag (NAV) and Main Vertical Flag (GS) to 333 ohms.

The LT 6 panel meter in the TO/FROM position loads these lines to 200 ohms. The meter reads uA thru 1 load and to convert this to millivolts take the reading times .2, read the result as millivolts. (1000uA = 200mV) Additional loading of two more 200ohm loads depending on what other loads are connected to the LT 6 panel may be required for a total of three loads. ( indicator via LT 6 front panel connector and/or any load connected thru the rear connector on the LT 6 panel). Connect required resistor(s) to the LT 6 TO/FROM tip jacks.

 

Use of the LOADS in the cable box:

LOAD LED indicates load tip jack is jumped to a low when button is pushed.

LOAD Tip Jack: Connect a jumper wire between this jack and the tip jack that is being tested at full load.

LOAD Select switch: Select correct load for testing.

LOAD 1 position: 275mA load (+/- 10%) at 28VDC thru load tip jack when the push button switch is pressed. Also maximum loads for the Main Lateral Superflag.

LOAD 2 position: 25mA load (+/-10%) at 28VDC thru load tip jack when the push button switch is pressed. Also maximum loads for the Main Vertical Superflag.

LOAD OFF position: 5mA at 28VDC available thru load tip jack when the push button switch is pressed. No loads applied to Super flags.

LOAD 3 position: 5mA at 28VDC available thru load tip jack when the push button switch is pressed. Also maximum loads for the NAV Superflag.

LOAD 4 position: 5mA at 28VDC available thru load tip jack when the push button switch is pressed. Also maximum loads for the GS Superflag.
 

Startup Instructions:

LV 6 Switch positions.

Power/OFF > OFF
28V/14V > 28V
28V/5V LAMPS > OFF
Deviation > 4
Flag > 3
Meter > DC VOLT
TEST/NORM > NORM
Speaker/Phone > MUTE
All others OFF or Down

Start with the Power switches on the cable box set to OFF, Load switch to OFF, and TEST/DEMO in either TEST or center off position. LT6 panel switch 28V/5V LAMPS in the OFF position ( 28V position applies power to the cable box LEDs). Select 14/28V to 28V. Turn on Lt 6 power switch and then turn on unit under test. Check input voltage then select DC AMP on meter switch. The panel meter reads current to GPS main board.

To test the COM board current turn on the COMM Power switch on the cable box and observe the increase in current on the meter.

To test the Nav board current turn on the NAV Power switch on the cable box and observe the increase in current on the meter.

When current test is complete select Lt 6 panel switch 28V/5V lamps to 28V position.

Go to the GARMIN MAINTENANCE MANUAL and perform the required tests for the unit you are testing.

 

Note:

1. Remember to turn on the LT 6 28V lamps to power the LEDs in the cable box.

2: Checking the DME channeling requires grounding the DME Common line, to do this place the DME/COMMON switch on the cable box in the DME position and turn on the LT 6 28V lamps switch.

 

  Avionics Test Equipment Panels and Cables for bench testing of Aircraft Radio, Navigation, Audio Controllers, Radar and more. Linaire Engineering Inc.
Last modified: June 15, 2004