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Remedy: Put electrical insulation filters into the antenna cable (Art.no.: 251001/251055).
If the interruption still didn’t appear then make the following:
6. Disconnect the minus line (-) of the audio system from point 1 and connect to the motor
block.
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Check if the interference has been removed.
7. In case the motor block should not solve the interference, than you have to scan the car body
while the engine is running with minus line of the system as long as the interference has
removed drastically.
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Lay bare this point (point 2) and free from underseal rests.
8. Fix screw with large diameter on this point. Polish the metal sheet around the screw and
protect with car body coating fat.
9. Fix all mass cables onto this screw or place the distributing cabinet and distribute to all
components (central mass point).
10. Remaining interferences can be removed with an LC-filter in the positive line.
The search for the central mass point can also be achieved by means of a millivoltmeter (lowest
potential drop) or by means of a milli ohmmeter (lowest resistor). Home position should always be
motor block or point 1.
The digital electronics in the vehicle area provides an unignorable interruption spectrum up to the
GHz area (interruption while radio reception and car telephone). The combinational circuit parts of
the amplifier, Digital tuner and CD-player contribute also to the current pollution. All these
interrupting spectrums can be found on the supplying lines and will be partly worked up.
The result is a roughness acoustic pattern with a fog on the tweeter area. The amplifiers will already
in the no load operation or in the smallest power range heated very high-by-high frequently
interrupting frequencies. The pre-amplifier of the amplifier cannot distinguish between music and
interrupting signal and amplifies everything according to its function, which is on the „Pre-In“ input
or on the current input. According to the manufacturer the best possible has been realized with the
amplifiers in order to attenuate such occurrences. This will be documented by the EEG-type
approval, which tests the amplifiers for irradiation disturbances and for self produced disturbances.
After the tests for EMV-limits have been passed, an e-number will be given. The frequency response
of the amplifiers should therefore for the stated reasons decline by at latest 30 kHz in order to
prevent an unnecessary heat up. At amplifiers in Class A or with pre-amplifiers in Class A, a heating
up will be unavoidable because of the higher static current also in a small volume range, which
should not be mixed up with the described interruption interferences.
The removing of the mentioned interferences can only be effected concertedly and requires already
for the installation of the system special knowledge in the field of interference elimination. In
addition you can find in the specialist literature and specialist publications convenient and practical
suggestions currently described. When observing the basic rules for cable installation, central mass
point and filtering of the current supply, a good screening can be provided when using quality
chinche cables. Special screening problems, which can occur according to each vehicle type
differently, must be removed from case to case by a specialist directly on the object.
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