ZETRON 4000 Series, Installation Manual

Page: 96 / 418

Common Control Equipment Installation
96 025-9533Y
Setting Initial Receive Level
To perform the diagnostic tests, it is necessary to do a rough setup of the Receive Gain
sensitivity. Connect an oscilloscope to TP1. Set the scope for 0.5 VAC per division. From
the console, generate a 1 KHz tone at approximately 2 Vpp to the coupler.
While supplying this signal, adjust the Receive Gain (R2) for a 1 Vpp signal at TP1. JP-1
sets the discriminator buffer gain. If you are not able to reach this level, move the jumper
at JP-1 from position A to B.
If an oscilloscope is not available, a VOM set for AC volts can be used. Adjust the
Receive Gain (R2) for a 0.3 VAC-RMS signal at TP1.
Accessing the Diagnostic Tests
To access the tests, power up the unit while holding the Connect button down. Continue to
hold it down for at least 3 seconds. When the
Ring
LED starts blinking rapidly, you may
release the Connect button. The Ring LED should continue to blink. The phone coupler is
now in diagnostic mode.
Test 1: Transmit Audio Gain
1. Begin with jumper JP7 in the A (HI gain) position. Verify that the Ring LED is
blinking rapidly. Press the
Connect
button to begin the test. Verify that Test 1 is
running: you should see one
1
/
3
-second blink of the Ring LED every 3 seconds.
2. Test 1 sends a 1 kHz test tone to the console. Using an oscilloscope, adjust the
transmit level potentiometer (R3) for 0.5 Vpp at the connector P1-5.
3. Next, monitor the audio level on the Series 4000 dual-channel card AGC test point.
Adjust the 4W Rx potentiometer for knee of compression.
4. The test will run for 3 minutes and then time out, unless the
Connect
button is
pressed again. If the test is allowed to time out, the system will return to normal
service. If the
Connect
button is pressed before the test times out, Test 2 will start.
Note This value is set at the factory and should never need to be
adjusted again.
Note
This test is performed at the factory and should never need to be
done again.