Porsche 996 TT, Руководство по ремонту

Страница: 1788 / 2099

Interference noises, checking cable connections
Note
Procedure for interference noises which enter the system via the audio connections. •
Work instruction Yes No
1
1. As an experiment with the radio switched
off, exchange the loudspeaker cables of the
loudspeaker involved in the complaint with
those of a fully functional loudspeaker at the
amplifier output.
2. Switch the radio on.
Is the loudspeaker involved in the complaint now
free of interference noise?
3. Check the plug
contacts of the
connecting cable on
the amplifier and
the loudspeaker.
4. Repair or clean any
defective connections.
Noise no longer present ’ End
Noise still present ’ Step 2
As an
experiment, use
a new cable
from the
amplifier to the
loudspeaker.
Noise
disappeared:
insert new
audio cables
and lay them
separately from
each other.
Noise no longer
present ’ End
Noise still
present ’ Step 4
2
5. With the radio switched off, exchange the
cables between the radio and the amplifier.
6. Switch the radio on.
Is the loudspeaker involved in the complaint now
OK?
7. Check the plug contacts of
the cable on the amplifier
and the radio.
8. Repair or clean any
defective connections.
Noise disappeared ’ End
Noise still present ’ Step 3
Install a
functional
amplifier
’ End
3
9. Check the audio wiring harness for a good
ground connection.
10. Measure with a multimeter at the negative
terminal of the battery. Repair the wiring
harness.
Noise still present?
As an experiment, insert new
leads between the radio and
the amplifier.
Noise still present: install new
amplifier and radio.
Noise remedied: install new
audio cables ’ End ’ End
4
11. Check the plug contacts of the connecting
cable on the loudspeaker.
12. Repair or clean any defective connections.
Noise still present?
As an experiment, install first
a functional amplifier and then
a functional radio
’ End ’ End
einordnung
Interference noises, checking cable connections 1725