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Chapter 4: Troubleshooting
RA150/300/500 Reference Manual 27
CHAPTER 4
TROUBLESHOOTING
TROUBLESHOOTING INDEX
Once all gain adjustments are made and proper operation is confirmed, no special considerations are required for
Alesis Reference Series amplifiers. Aside from the front panel gain controls, there are no user adjustments or
routine maintenance operations necessary (or available). If you experience problems while operating your
RA150/300/500, please use the following table to locate possible causes and solutions before contacting Alesis
Product Support for assistance.
Symptom Cause Solution
No audio from outputs No input audio Hook up inputs
Bad cables Replace the cables.
Amplifier is turned
down
Set levels to "12:00" or above
Is the amplifier very hot?
Is the ambient
temperature and/or the
air flow in the rack high?
If so, the amplifier may
be in thermal protect
mode (PROTECT LEDs
on)
Normal operation will resume
when its internal temperature
has dropped to reliable levels.
Power is not connected Time for a coffee break.
Low output power Line voltage set
improperly
Set the switch on the back panel
to the "120 V" position
Bass disappears, speakers
sound out of phase
Amplifier accidentally
set to "Bridge Mono"
mode when wired for
stereo
Set the switch on the back panel
to the "stereo" position
Make sure that the
RA150/300/500 and its audio
cables are kept away from
power cables, other power
transformers and wall warts.
Buzz from outputs Input cables are crossing
a power cable or near a
transformer
Use balanced inputs instead of
unbalanced
Bad cables Replace the cable with a new,
high-quality cable.
Problem with the source Try plugging a known line-level
source to the amplifier inputs to
see if the problem remains.
Noise induced from a
bad AC ground or noisy
AC circuit
Connect to a different electrical
circuit; use balanced inputs or
plug amp and source into the
same AC circuit