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Engine Noise
Check connections and repair
wiring as necessary
Check connections and run
the RCA cables on a different
route away from sources of
high current
Check connections and bypass
additional components (cross-
overs and equalizers) between
the source unit and the ampli-
fier. Connect one component
at a time to determine the cul-
prit. Repair or replace compo-
nents as necessary
Disconnect existing speakers
and connect a test speaker to
the output terminals of the
Source unit. If noise is gone,
reroute the speaker cables
away from sources of high
current
Check ground connections and
connect amplifiers, signal pro-
cessors, and other components
to a central location or try a
different grounding point on
the chassis
Connect filter cap (Radio Shack
#272-1085) in-line on B+ as close
to blower motor as possible
Connect a .1
µ
f - .01
µ
f non-
polarized capacitor across
switch contacts
Symptom
Diagnosis
Remedy
Source unit is not
grounded properly
Noise is radiating into
RCA signal cable
Bad component in the
signal chain
Noise is radiating into
the speaker cables
Multiple grounds in the
audio system
No RF suppression of
blower motors
No RF suppression of
switches
TROUBLE- S
H
O
O
T
I
N
G
Radiated Noises
