P S - 7 0 4 F O U R - C H A N N E L P O W E R S U P P L Y
3 - 2
TROUBLESHOOTING TIPS
SYMPTOM
CAUSE
SOLUTION
System does not operate. No
power to the PS-704. Green
power
LED is not illuminated
and no
short
LEDs are
illuminated.
No AC power to the PS-704.
Check AC connection and cable. Plug
into dependable AC source.
PS-704 has an internal power supply
failure.
Unit requires servicing.
Red
short
LED illuminated.
Short or overload on that channel due
to a shorted or miswired cable.
Remove cables (one at a time) from
system until the faulty line is located.
Check for shorts between pins #1 and
#2. Once the short is removed, the
PS-704 will reset automatically and
the power will come back up within a
few seconds.
Defective remote station.
Check remote station and replace if
necessary.
All red
short
LEDs are
illuminated.
System is overloaded.
Remove cables (one at a time) from
system to help determine where the
excess current requirements lie.
Re-evaluate system current needs.
Short in multipair cable.
Remove cables (one at a time) from
system until the faulty line is located.
Check for shorts between pins #1
and #2.
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.
Warning: 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.
