Troubleshooting - ADS 5120D Installation & Operation Manual

Audio Design Services Ltd., St David's House, Adcroft Street, Higher Hillgate, STOCKPORT SK1 3HW.

TROUBLESHOOTING

Symptom Possible Cause
No ac power
Amplifier is off
ac power
LED does
ac fuse blown
not light
No dc power
dc power ac power
LED does connected
not light
Internal dc fuse
blown
Sound Incorrect level
output is settings
very low
Impedance
Sound
mismatch or a
output is
short on the
low and
loudspeaker line
distorted.
Amplifier
Oscillation
gets very
hot.
Poor signal
ground
Excessive
Earth loop is
hum or
present
noise
Ensure that the supply cable is correctly connected
to the mains outlet and the supply is turned on.
Switch on amplifier by pressing the on/off switch.
Remove ac power cord from mains supply and
amplifier. Remove and check fuse. Only replace
fuse with the same type and rating – DO NOT USE
A HIGHER RATED FUSE. If the fuse has failed
and a replacement also fails, contact your supplier.
Check that 24Vdc is present at the dc input
terminals on the rear of the amplifier.
If ac power is being used, the amplifier
automatically switches the LEDs to show which
supply is being used.
These amplifiers must only be opened by
competent, qualified personnel to replace this fuse.
Check the gain controls on the rear of the amplifier,
the input level controls and the master output level
control.
Check the loudspeaker circuit impedance (the
minimum is shown in the specification). Check for
any short to ground.
Make sure that the loudspeaker circuits are kept
away from sensitive microphone circuits. If these
cross, make sure they do so at right angles.
Check all signal sources to ensure that the ground
(screen) connections to the amplifier are good.
If other equipment with a ground connection is
being used an earth loop may form causing hum.
Disconnect the screen connection at the amplifier.
DO NOT DISCONNECT THE SAFETY EARTH
FROM ANY EQUIPMENT.
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Remedy