Mitsubishi Electric 55624R(S)-MF Service Manual page 130

Noise type
Sounds are in paren-
these [
AM, FM: Ignition noise
[Popping, Snapping.
Cracking, Buzzing]
Other electrical compo-
nents
Static electricity
Caution
1. Connecting a high tension cable to the noise
filter may destroy the noise filter and should
never be done.
2. Check that there is no external noise. Since
failure due this may result in misdiagnosis
due to inability to identify the noise source,
this operation must be performed.
3. Noise prevention should be performed by
suppressing strong sources of noise step by
step.
NOTE
1. Condenser
The condenser does not pass
a s t h e n u m b e r o f w a v e s i n c r e a s e s w h e n i t
p a s s e s A.C. c u r r e n t ,
Increasing the engine
l
speed causing the pop-
ping sound to speed up,
and volume decreases.
Disappears when the
l
ignition switch is turned
to ACC.
Disappears when the
l
vehicle is completely
stopped.
Severe when the clutch
l
is engaged.
body part of the vehicle.
D.C.
current, but
impedance (resistance
TSB Revision
Cause
Mainly due to the spark
l
plugs.
Due to the engine noise.
l
Noise may appear as elec-
older.
Occurs when parts or wir-
ing move for some reason
and contact metal parts of
the body.
Due to detachment from
the body of the front hood,
bumpers, exhaust pipe and
muffler, suspension, etc.
against A.C.) decreases, and current flow is
facilitated. A noise suppressing condenser
which takes advantage of this property is in-
serted between the power line for the noise
source and the ground. This suppresses noise
by grounding the noise component (A.C. or
pulse signal) to the body of the vehicle.
2. Coil
The coil passes D.C. current, but impedance
rises as the number of waves increases relative
to the A.C. current. A noise suppressing coil
which takes advantage of this property is in-
serted into the power line for the noise source,
and works by preventing the noise component
from flowing or radiating out of the line.
Response
Noise filter
l
Noise condenser
l
Ground cable
l
Repair or replace electrical
components.
Return parts or wiring to their
position.
proper
by
Ground parts bonding.
Cases where the problem is
not eliminated by a single
response to one area are
common, due to several body
being imperfectly
parts
grounded.