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Audio Design Services Ltd., St David’s House, Adcroft Street, Higher Hillgate, STOCKPORT SK1 3HW.
TROUBLESHOOTING
Symptom Possible
Cause
Remedy
ac power
LED does
not light
No ac power
Amplifier is off
ac fuse blown
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.
dc power
LED does
not light
No dc power
ac power
connected
Internal dc fuse
blown
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.
The ADS 5240 Plus must only be opened by
competent, qualified personnel to replace this fuse.
Sound
output is
very low
Incorrect level
settings
Check the trim controls on the rear of the amplifier,
the input level controls and the master output level
control.
Sound
output is
low and
distorted.
Amplifier
gets very
hot.
Impedance
mismatch or a
short on the
loudspeaker line
Oscillation
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.
Excessive
hum or
noise
Poor signal
ground
Earth loop is
present
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.
