Jensen JHD1120 - Manual (Page 12)

JHD1120
10
CARE AND MAINTENANCE
• Keep the product dry. If it does get wet, wipe it dry immediately. Liquids might contain
minerals that can corrode the electronic circuits.
• Keep the product away from dust and dirt, which can cause premature wear of parts.
• Handle the product gently and carefully. Dropping it can damage circuit boards and
cases, and can cause the product to work improperly.
• Wipe the product with a dampened cloth occasionally to keep it looking new. Do not use
harsh chemicals, cleaning solvents, or strong detergents to clean the product.
• Use and store the product only in normal temperature environments. High temperature
can shorten the life of electronic devices, damage batteries, and distort or melt plastic
parts.
Ignition
The most common source of noise in reception is the ignition system. This is a result of the
radio being placed close to the ignition system (engine). This type of noise can be easily
detected because it will vary in intensity of pitch with the speed of the engine.
Usually, the ignition noise can be suppressed considerably by using a radio suppression type
high voltage ignition wire and suppressor resistor in the ignition system. (Most vehicles employ
this wire and resistor but it may be necessary to check them for correct operation.) Another
method of suppression is the use of additional noise suppressors. These can be obtained from
most professional mobile electronics retailers.
Interference
Radio reception in a moving environment is very different from reception in a stationary
environment (home). It is very important to understand the difference.
AM reception will deteriorate when passing under a bridge or when passing under high voltage
lines. Although AM is subject to environmental noise, it has the ability to received at great
distance. This is because broadcasting signals follow the curvature of the earth and are
reflected back by the upper atmosphere.
TROUBLESHOOTING
Symptom Cause Solution
No power The vehicle’s accessory
switch is not on If the power supply is properly
connected to the vehicle’s acces-
sory terminal, switch the ignition
key to “ACC” or “Run”
The fuse is blown Replace the fuse
No sound Volume is too low or system
is muted Adjust volume to audible level
Wiring is not properly con-
nected Check wiring connections
The operation keys do
not work The built-in microcomputer
is not operating properly
due to noise Press the RESET button
Cannot tune to radio sta-
tion, auto-seek does not
work The antenna cable is not
connected Check antenna cable
The signals are too weak Select a station manually