GAI-Tronics ICP9000 Navigator Series Console Installation and Service Manual - Manual (Page 49)

ICP9000 Navigator Installation and Service Manual Console Diagnostics
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Test 2 – Audio Loop Test
Before running this test, any external connections that configure the console for 2-wire operation should
be removed. Test 2 allows testing the wire line input and output audio paths for any channel. To execute
this test, place different audio sources on the receive wire line connections for each channel to be tested.
The output on each of the console’s channels should be the sum of these audio sources.
For example, if 1000 Hz is placed on the receive wire line connections for channel 1 and 2000 Hz is
placed on the receive wire line connections for channel 12, then a signal that is the sum of the 1000 Hz
and 2000 Hz signals should be present on the transmit wire line connections on every channel.
If the audio loop test fails, check the connection between the channel I/O pins and the slave board. If
these connections are in order, then the slave board should be replaced.
N OTE : For proper operation, the slave must be configured as a 4-wire using JU602, JU606, JU610, and
JU614.
Test 3 – Output Adjust
N OTE : Use this test to adjust the overall line output (transmit) level for each channel.
Test 3 allows setting the level of high level guard tone output on the console’s wire lines. During this
test, 2000 Hz is output on each channel. Pressing a channel’s
VOL Up/Down buttons allows increasing or
decreasing the level of the tone output on that channel.
When the output level on each channel matches the desired level of high level guard tone (usually +2
dBm), press
M ODE to exit the Audio Diagnostics menu. Then, you are prompted to save the output levels
just selected. To save these levels, press 1; to abandon changes and exit, press 2.
Test 4 – Gain Stage Test
This test allows verifying that the output gain control circuitry for each channel is working properly.
Upon entry into this test, 2000 Hz at the highest output level (approximately +10 dBm) is placed on each
channel’s wire line. Then, every 4 seconds, the level of this tone is decreased by 6 dB until it reaches the
lowest level changes back to the highest setting, and the test begins again. If this test fails, the slave
board should be replaced.
Test 5 – Input Level Adjust
N OTE : Use this test to adjust for the proper line input (receive) level for each channel.
This mode allows the expected input level for each channel to be set to control the non-compressed level
of the each receive audio compressor. If the receive audio for a channel is expected to be -12 dB, the
level for that channel should be set to -12 dB. The MCU adds this amount of gain to the channel in order
to achieve the optimum internal operating audio level. During compression, this gain is reduced to keep
the receive audio at a nominal level. When the audio is no longer above the compression threshold, the
MCU releases the compressor back to the original setting. The range is 0 dB to –24 dB, in 6 dB steps.
Press
M ODE to exit this test.