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Troubleshooting: Chapter 4
28 RA150/300/500 Reference Manual
Symptom Cause Solution
Intermittent amplifier
input signal
Clean input connectors,
check wiring
If the sound cuts out for
a minute or two and then
returns, the amplifier
may be overheating and
cycling through thermal
protect mode
Check for short circuits in
the output wiring or
excessive ambient
temperature
Audio cuts in and out
Dirty volume pot Move volume pot up and
down several times
Blown fuse Obtain the proper size fuse
(see page 10) and replace it
Unit shuts down, all lamps
are off
Internal thermal fuse
activated
Shut off power and let
amplifier cool down
Defective loudspeaker
drivers
Replace drivers
In a multi-amplified
system with a low level
crossover network, bad
outputs from the
network, or improperly
connected loudspeakers
Check crossover and
connections. Check
speaker connections.
Thin or Muffled Sound
Balanced connector with
one side disconnected, or
no ground with an
unbalanced input
Make sure input cables are
connected to ground as
required
CARE AND MAINTENANCE
CLEANING
Disconnect the AC cord, then use a damp cloth to
clean the RA150/300/500’s metal and plastic
surfaces. For heavy dirt, use a non-abrasive
household cleaner such as Formula 409™ or
Fantastik™. DO NOT SPRAY THE CLEANER
DIRECTLY ONTO THE FRONT OF THE UNIT AS
IT MAY DESTROY THE LUBRICANTS USED IN
THE SWITCHES AND CONTROLS! Spray onto a
cloth, then use cloth to clean the unit.
REFER ALL SERVICING TO
ALESIS
We believe that the RA150/300/500 is one of the
best amplifiers that can be made using current
technology, and should provide years of trouble-
free use. However, should problems occur, DO
NOT attempt to service the unit yourself. Service
on this product should be performed only by
qualified technicians. NO USER-SERVICEABLE
PARTS INSIDE.