Garmin GNS 430 - Page 72

400 SERIES MAINTENANCE MANUAL Page 5-21
P/N 190-00140-05 Rev. C
11. Verify the DMM reading is greater than the reference AGC voltage.
 127.002778 MHz ______VDC (NLT AGC reference voltage)
 126.997222 MHz ______VDC (NLT AGC reference voltage)
12. Adjust signal level to 10 mV.
 127.00737 MHz ______VDC (NGT AGC reference voltage)
 126.99263 MHz ______VDC (NGT AGC reference voltage)
5.7.2.15 Volume Control (Audio Output)
1. Enable compression (see Paragraph 5.7.2).
2. Apply a 100 µV, 118.5 MHz, 1 KHz tone modulated 30% signal to the unit.
3. Select 118.500 MHz.
4. Monitor the audio output.
5. Turn the volume control fully clockwise.
6. Verify a minimum of 7.07 Vrms at 500 ohms.
 Audio Output (Measured between J6-16 and 17) ________ NLT 7.07 Vrms
7. Turn the volume control fully counterclockwise (not past the detent OFF position).
8. Verify a maximum of 22 mVrms.
 Audio Output (Measured between J6-16 and 17) ________ NGT 22 mVrms
5.7.2.16 Audio Distortion Test
1. Apply a 10 mV, 85% modulated signal.
2. Measure the receiver audio distortion. Set volume for rated audio.
 350 Hz ______ < 25%
 1000 Hz ______ < 15%
 2500 Hz ______ <15%