User's Manual

16
Noise Suppression
All CAM electronics are designed for maximum electrical noise rejection. In some instal-
lations however, electrical noise may affect the quality of sound reproduction.
If electrical noise is present after installing your Slidebar radio, 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.
1-Check all ground connections. Remove paint away from painted surfaces to secure a .
good electrical ground.
2-Check battery posts. If contacts are corroded or loose ,clean and tighten both
. terminals.
3-Check battery or add fluid if needed.
4-Check condition of spark plug and distributor leads. Worn or damaged leads will
. generate noise than can be very difficult to elim
inate.
5-Check installation of factory noise suppressor(s). Verify that the connections are . . .
solid. Refer to the vehicles service manual for nose suppressor location or allow a . .
qualified mechanic to inspect the device (s) for you.
6-(Optional) Some professional installers will install a simple L.C. noise filter even if . .
. there is no noise present in the system. This is a simple and relatively inexpensive . .
device available at your nearest Autosound dealer or electronic supply store. Most . .
filters designed for car stereos carry a current rating of 3 amps or more. Follow the . .
manufacturers installation instructions. This filter is installed in the power lines of the .
car stereo.
Sources Of Electrical Noise
Alternator Noise
This noise is generally a high pitched whine present with 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 .
electronic or automotive supply store)in the power lines of your radio. This filter . .
should be rated at 3 amps minimum.
2. Start the car’ s engine.switch on the lights (to accentuate the noise) and switch . .
on the USA-740. If noise is still present, proceed to step 3.
3. Install an alternator noise filter (available from your Autosound dealer or your . . .
nearby electronic or automotive supply store). Follow manufacturer’s installation . .
instructions.
Antenna Noise
A static or crackle heard through the speakers, usually when the car is running ,but
sometimes present with the ignition off. If a crackling static if present, follow the steps
outlined below to confirm the antenna as the source of the noise.
1. Start the car engine.
2. Switch on the radio.
3. Adjust the volume so that noise is audible.
4. Reduce volume setting of the car stereo but do not switch it off
. If noise decreas. .
es or disappears, the signal is most likely being picked up by the car antenna. If the
noise persists after following the steps listed below, proceed to ignition Noise.