ZETRON 4000 Series, Installation Manual

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95
Series 4000 Phone Coupler (Optional)
3. Hybrid Adjustment
Each test runs for up to 3 minutes. During that time, if the Connect button is pressed
again, the next test will commence. The unit will return to normal operation mode in any
of these cases:
• The
Connect
button is pressed during test 3.
• The current test is allowed to time out.
• The
Connect
button is pressed and held for 3 seconds. Holding the
Connect
button
down to return to normal operation mode is acknowledged by a rapid blinking of
the
Ring
LED. The rapid blinking stops and the
Ring
LED goes out when the
Connect button is released.
Each test indicates that it is running by blinking its test number of
1
/
3
-second blinks (1, 2,
or 3
1
/
3
-second blinks) every 3 seconds.
Accessing the Test Points
To perform the tests and adjustments, the cover of the phone coupler must be removed to
gain access to the test points and some of the potentiometers.

To remove the cover
1. Disconnect the power cord from the unit.
2. Disconnect the phone line(s).
3. Disconnect all cabling.
4. Remove the three Phillips-head screws on the rear of the unit.
5. Slide the cover back, then lift it to remove it.
6. Reconnect the power cord and interface cables to P1.
7. Reconnect the phone line to the modular connector of each channel.
Test Points
Table 36: Test points
Note Tests 1 and 2 are performed at the factory. These two gain settings
should never again need to be adjusted. Test 3 needs to be
performed during installation.
TP1 Rx audio from the console at the output of the first gain stage.
TP2 Power Up Reset circuit. +5 VDC = Reset; 0 VDC = Operate.
TP3 Dial Click Decode circuit, after sensitivity adjustment.
TP4 Tx audio from the phone just after the hybrid.
TP5 “VP” bias voltage. Should be +2 VDC.