JHD1120
CARE AND MAINTENANCE | TROUBLESHOOTING |
•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.
Symptom | Cause | Solution | |
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No power | The vehicle’s accessory | If the power supply is properly | |
| switch is not on | connected to the vehicle’s acces- | |
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| sory terminal, switch the ignition | |
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| key to “ACC” or “Run” | |
| The fuse is blown | Replace the fuse | |
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No sound | Volume is too low or system | Adjust volume to audible level | |
| is muted |
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| Wiring is not properly con- | Check wiring connections | |
| nected |
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The operation keys do | The | Press the RESET button | |
not work | is not operating properly |
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| due to noise |
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Cannot tune to radio sta- | The antenna cable is not | Check antenna cable | |
tion, | connected |
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work |
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The signals are too weak | Select a station manually | ||
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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.
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