Troubleshooting
Problem
Possible Causes
Action
No Sound
Amplifier
Connect a known working test speaker to the amplifier outputs. If
there is no sound, check all electronics are on, the signal routing is
correct, the source is active; the volume is turned up, and so on.
Correct/Repair/Replace as necessary. If there is sound, the problem is
in the wiring.
Wiring
Verify you have connected the correct wire pairs to the amplifier. Play
something at low level through the amplifier (for example, from a CD
player or tuner). Connect the test speaker in parallel with the
malfunctioning line. If the sound has gone or is very weak, the line has
a short in it (possibly a severe scrape, pinch, or staple puncture). If
the sound level is normal the wire is open (possibly a cut wire or
missed connection). Using the test speaker, move down the line and
test each connection/junction until you find the problem and correct
it. Observe proper polarity.
Verify you have the inputs and outputs connected to the correct wires.
If the subwoofer input panel is not correctly wired, there will be little
or no sound. Observe proper polarity.
Poor Low-
Frequency
Response
Speakers Wired Out-
of-Polarity
When two speakers are connected out of polarity (out of phase), the
low frequencies will cancel each other acoustically. Carefully observe
the wire markings or tracers on your speaker wires. Verify the
amplifier (+) terminal is connected to the red speaker terminals and
the amplifier (-) terminal is connected to the black speaker terminals.
Improperly Wired
Subwoofer Panel
Using a test speaker as described above, verify all amplifier and
speaker wires are connected to their proper terminals with the correct
polarity. Reversing just one set of amplifier wires can cut out all bass
output from the subwoofer.
Intermittent
Output such as,
Crackling or
Distortion
Faulty Connection
Check all connections at amplifier and speakers to ensure they are
clean and tight. If the problem persists, it may be in the amplifier or
wiring. See other actions above.
Constant Noise
such as Buzzing,
Hissing, Humming
Defective Amplifier
or other Electronic
Device
If the noise is present but no program material is playing, the likely
cause is the signal chain in the electronics. Evaluate each component
as necessary to isolate the problem.
Poor System
Grounding or
Ground Loop
Check and correct the system grounding, as required.
5
Premium Cabinet Loudspeakers
Troubleshooting | en
19
Bosch Security Systems B.V.
Installation manual
2017.08 | 01 | F.01U.345.357
Summary of Contents for LB20-PC15-4D
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