15
Troubleshooting
ˆ
Troubleshooting
We do not expect you to have any problems with your RadioShack MPA-125 100-Watt PA Am-
plifier, but if you do have a problem, this chart might help. If not, take the amplifier to your local
RadioShack store for assistance.
Symptom
Possible Cause
Suggestion
No power.
The fuse might be blown.
Check the amplifier’s fuse and replace it
if necessary (see “Replacing the Fuse”
on Page 17).
Sound source or speakers not con-
nected correctly.
Check all connections.
No sound.
Amplifier’s
MASTER VOLUME
,
MIC 1
,
MIC 2
,
MIC 3
,
MIC 4/PHONO, or
CD/
AUX controls set to minimum.
Adjust
MASTER VOLUME
,
MIC 1
,
MIC
2
,
MIC 3
,
MIC 4/PHONO
,
and
CD/AUX
.
Sound source or speakers not con-
nected correctly.
Check all connections.
A microphone or cable might be faulty.
Check all microphones and cables.
The speaker’s wiring might be shorted.
Check all connections.
The speakers might be the wrong
impedance.
Make sure all connected speakers have
the same impedance rating (see “Con-
necting the Speakers” on Page 8).
The speaker’s wires might be too
small.
Make sure the speaker’s wires are 18-
gauge (for wire lengths up to 25 feet) or
16-gauge (for lengths over 25 feet). For
the best results, use the shortest length
of speaker wire possible.
The amplifier might have shut down.
Turn the amplifier off and let it cool.
Make sure the amplifier is properly venti-
lated, then turn it back on.
Feedback.
FEEDBACK FILTER might need
adjustment.
Turn the amplifier off and let it cool.
Make sure the amplifier is properly venti-
lated, then turn it back on.
Microphones or speakers are too close
together.
Reposition the microphones and speak-
ers.
32-2003.fm Page 15 Tuesday, March 28, 2000 10:45 AM