Garmin APOLLO GX SERIES, Service Manual

Page: 85 / 166

Garmin AT Rev --
© 2004 Garmin AT GX Service Manual 7-47
Step General Instruction Specific Instructions Expected Results
9 Check for the two
tones Connect a headset to the test
box and adjust Comm radio
volume to a reasonable level
and monitor the two tones.
The following receiver tests are not required for return to service. They are
included for troubleshooting.
Speaker Output Response
Step General Instruction Specific Instructions Expected Results
1 Set all test
equipment as
specified in Test
Equipment Setup on
page 7-17.
2 On the HP8920:
1. AFGen1 to AM 85%.
2. AMPLITUDE to 1,000 µV.
3. Ext. Load R to 4 ohms.
3 Move test cable. On 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 as
reference. On the HP8920, Select AC
Level. Push SHIFT (Blue key)
push REF SET, then push the
CURSOR CONTROL knob. AF Level will be 0 dB.
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 required to complete the
following tests.
7 On the HP8920, push the SHIFT
(blue key) CONFIG keys under
SCREEN CONTROL. Select
Notch Coupl. Set to AFGen1.
Push the PREV key under
SCREEN CONTROL to return to
RX TEST. Lock notch filter to AF Gen1
Freq.
8 Notch filter freq. to
350. On the HP8920, select AFGen1
Freq. Set to 350 Hz.
9 Record AC Level. Will be <3 dB 350 Hz.