Component Tests and General Diagnostics
- NOISE PROBLEMS
a. Questionnaire for noise:
If is very important for noise troubleshooting to have good understanding of the claims from the customers, so that make the best use of following questionnaire and diagnose the problem accurately.
HINT: In the case that the noise occurrence condition does not meet any of the above questionnaire, check based on the "Trouble Phenomenon". For multipath and fading: Description and Operation
b. Matters that require attention when checking:
^ Noise coming into the radio usually has no harm for practical use as the noise protection is taken and it is hardly thinkable for an extremely loud noise to come in. When extremely loud noise comes into the radio, check if the grounding is normal where the antenna is installed.
^ Check if all the regular noise prevention parts are properly installed and if there is any installation of non-authorized parts and non-authorized wiring.
^ If you leave the radio under out of tune (not tuning), it is easy to diagnose the phenomenon as noise occurs frequently.
c. Antenna and noise:
Electronic signal received by the antenna will reach to the radio transmitting through the core wire of the coaxial cable.Any noise wave other than radio wave is mixed into this core wire, that naturally causes noise in the radio and poor sound quality in order to prevent these noises from mixing into the radio, the core wire inside the coaxial cable is covered with a mesh wire called shield wire. This shield wire shelters the noise and transmits it to the ground, thus preventing noise from mixing in. If this shield wire has grounding failure, that causes noise.
d. Choke coil and noise:
The choke coil is connected in the rear window defogger circuit. This is connected so to prevent noise from mixing into the radio by making the noise current included in the power source of the rear window defogger flow to the ground.
e. Antenna code continuity check and grounding point:
HINT: During troubleshooting, in case that the antenna code continuity check, grounding check and grounding check of the choke coil are needed, please check refering to the following illustration.
- COMPACT DISC PLAYER
Compact Disc (hereafter called "CD") Players use a laser beam pick-up to read the digital signals recorded on the CD and reproduce analog signals of the music, etc. There are 4.7 in. (12 cm) and 3.2 in. (8 cm) discs in the CD player.
HINT: Never attempt to disassemble or oil any part of the player unit. Do not insert any object other than a disc into the magazine.
NOTE: CD players use an invisible laser beam which could cause hazardous radiation exposure. Be sure to operate the player correctly as instructed.
- MAINTENANCE
Tape Player/Head Cleaning
a. Raise the cassette door with your finger. Next, using a pencil or like object, push in the guide.
b. Using a cleaning pen or cotton applicator soaked in cleaner, clean the head surface, pinch rollers and capstans.
CD Player/Disc Cleaning
If the disc gets dirty, clean the disc by wiping the surfaces from the center to outside in the radial directions with a soft cloth.
NOTE: Do not use a conventional record cleaner or anti-static preservative.
LOCATION
TROUBLESHOOTING
NOTE: When replacing the internal mechanism (computer part) of the audio system, be careful that no part of your body or clothing comes in contact with the terminals of the leads from the IC, etc. of the replacement part (spare part).
HINT: This inspection procedure is a simple troubleshooting which should be carried out on the vehicle during system operation and was prepared on the assumption of system component troubles (except for the wires and connectors, etc.).
Always inspect the trouble taking the following items into consideration.
^ Open or short circuit of the wire harness
^ Connector or terminal connection fault
^ For audio systems with anti-theft system, troubleshooting items marked (*) indicate that "Troubleshooting for ANTI-THEFT SYSTEM" should be carried out first.