Garmin APOLLO GX SERIES Service Manual

Contents

Garmin AT Rev --7-46 GX Service Manual © 2004 Garmin ATIntercom/MonitorStep General Instruction Specific Instructions Expected Results1 Set all testequipment asspecified in TestEquipment Setup onpage 7-17.On the HP8920:1. Set AMPLITUDE to 1000μV.2. Set Ext. Load R 4 ohms.3. Set AFGen1 Freq. to 500Hz. Set AFGen2 Freq. to2000 Hz.4. Set AFGen2 To field toAudio out at 50 mV.2 Adjust volumecontrol on Commradio for 12 W.On the Comm radio, adjust thevolume control until the AC Levelreads 12 watts.≥12 watts output into 4 ohmload (mounted in test fixture) ata volume level from 0 to 12watts.3 Mute speaker test. On the test box, set INT/OFFswitch to INT.The speaker audio out will be0 W.When the Intercom switch is on,the speaker is disabled.4 Check headset. On the test box:1. Move the SPKR OUT cableto the HDPH test jack.2. Set the TEST HDPH/LOADswitch to TEST HDPH.When the Intercom switch is on,the Comm radio signal is routedto the headphones.5 Check headsetvolume.On the HP8920 set:1. EXT LOAD TO R to 100ohms.2. Adjust the volume control onthe HP8920 to monitor the0.500 kHz tone.The HP8920 AF Freq. meterwill read 0.500 kHz ± 15 Hz.6 On the Comm radio, adjustvolume control to read 0.280watts on the HP8920 AC Levelmeter.7 Set to reference. On the HP8920, select the ACLevel Field (W), then pressSHIFT REF SET and pushCURSOR CONTROL knob.The Comm channel is set asreference audio level.8 Check if microphonemutes radio.On the test box move theTEST/MIC1 switch to MIC1.The HP8920:1. AF Freq. meter will read1500 Hz ± 15 Hz.2. The AC Level Meter willread 1 dB greater thanreference.