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Clear-Com PS-702 User Manual

Page 18

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P S - 7 0 2 T W O - C H A N N E L P O W E R S U P P L Y

3 - 2

Table 3-1: Troubleshooting Tips

Hum or buzz in system

Inductive pickup caused by close
proximity of main or remote stations
to power lines or transformers.

Relocate offending unit.

10

Ω chassis ground resistor is open.

Check the DC resistance for 10

Ω

between the chassis and pin #1 of
any intercom connector.

If this condition occurs, it is because the system ground came into contact with something that was hot with
respect to the power supply earth ground. If this occurs, carefully check the system ground and AC
distribution in the area.
This is a potentially dangerous situation. A shock hazard may exist between the metal boom of a remote
station headset and ground.

System feedback (acoustical)

Volume control at the remote station
is set too high.

Adjust.

Channel unterminated.

Set the PS-702 termination switch
for that channel to the on position.

A headset extension cord was used.

Headset extension cords are not
recommended.

440 Hz tone is present on either
or both channels

Test tone feature is on.

Set the test tone switch to the off
position.

Excessive crosstalk

High DC resistance in ground return. Use heavier cable; add additional

conductor(s) to ground return.

Multi-channel cable pairs are not
individually shielded.

Replace cable with individually
shielded pairs.

Headset cables are not wired
properly or shielded properly.

Correct wiring. Use headsets with
properly shielded wiring.

Program signal sounds
distorted

Overload of program in circuit.

Reduce program in level or reduce
the gain of the program signal at the
source, such as an audio mixer.

SYMPTOM

CAUSE

SOLUTION