APX_DPX Amps.qxd
2/6/2008
4. Increase the volume and verify that the amplifier reproduces the audio at full
frequencies without distortion.
If you hear distortion check the connections and verify that the gain control is set
correctly. Another cause of distortion could be underpowered or damaged
speakers. Refer to Troubleshooting.
6. TROUBLESHOOTING
Indicator lights
The APX2181, APX4361, DPX1851 and DPX11551 have lights that indicate
amplifier status.
Blue top
Red end-
LED
panel light
On
Off
On
Alternating between
red and blue
Slow blink
Slow out-of-sync
blink
Quick blink
Quick in-sync
blink
3 blinks,
3 blinks,
then pause then pause
No Audio
• L ow or no remote turn-on voltage: check remote connections at the amplifier
and source unit.
• Blown amplifier fuse: replace with a new fast-blow fuse (same rating).
• Power wires not connected: check battery and ground wiring at the amplifier
and check the battery connections.
• Speaker leads shorted: check speaker continuity to ground; it should not show a
common ground.
• Speakers not connected or are bl own: check speaker connections at the
amplifier and measure at speakers. Measure coil impedance at amplifier with
speaker wires disconnected.
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Blue end-
panel light
Off
Off
Off
Off
Meaning
Amplifier running normally
In thermal protection mode
Over voltage;
reduce the input voltage
Short circuit protection
Repeated shorts detected;
remove the short circuit, wait
5 minutes for error condition
to clear; or clear condition by
removing the main power, for
example, by pulling the fuse.
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