Custom Autosound USA-230 User Manual
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Noise Suppression
All CAM Systems are designed for maximum electrical noise rejection. In some instal-
lations however, electrical noise may affect the quality of sound reproduction.
If noise is present after installing the USA-230, identify the source of the noise using
the descriptions under Sources Of Electrical Noise. To eliminate the noise follow the
procedures described under Elimination of the specific noise source.
Noise Suppression
1-Check all ground connections. Remove paint from painted surfaces to secure a
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good electrical ground.
2-Check battery posts. If contacts are corroded or loose, clean and tighten both
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terminals.
3-Check battery or add fluid.
4-Check condition of spark plug and distributor leads. Worn or damaged leads will
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generate noise than can be very difficult to eliminate.
5-Check installation of factory noise suppressor(s). Verify that the connections are
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solid. Refer to the vehicles service manual for nose suppressor location or allow a
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qualified mechanic to inspect the device(s) for you.
6-(Optional) Some professional installers will install a simple L.C. noise filter even if
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there is no noise present in the system. This is a simple and relatively inexpensive
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device available at your nearest Autosound dealer or electronic supply store. Most
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filters designed for car stereos carry a current rating of 3 amps or more. Follow the
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manufacturers installation instructions. This filter is installed in the power lines of the
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car stereo.
Sources Of Electrical Noise
Alternator Noise
This noise is generally a high pitch whine present with the engine running.The pitch of
the whine will vary as engine RPM varies. Alternator noise usually becomes more
apparent with an electrical load to the system. Switching the headlights on usually
increases the noise.
Elimination
1. Install an L.C.noise filter (available from your Autosound dealer or your nearby
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electronic or automotive supply store) in the power lines of your USA-230. This filter
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should be rated at 3 amps minimum.
2. Start the car’ s engine.switch on the lights (to accentuate the noise) and switch
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on the USA-230. If noise is still present, proceed to step 3.
3. Install an alternator noise filter (available from your Autosound dealer or your
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nearby electronic or automotive supply store). Follow manufacturer’ s installation
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instructions.