Noise Diagnosis

The following describes the ways that noise may enter a sound system and general solutions. See Symptom Table for specific symptoms and diagnosis. A Symptom Table

FRONTWAY NOISE
Any noise which is brought into the Radio system through the antenna. (Noise can be eliminated by unplugging the antenna from the back of the Radio.)

Some Causes:
- Poor grounding or missing grounds of: the antenna base; the receiver; some electrical components; body parts.
- Defective or marginal components: relays, solenoid, switches and electric motors.
- Something near the antenna coax or corrosion at antenna coax connections.

Solutions:
- Always verify grounding first. If more than one component interferes, a poor ground probably exists.
- Pinpoint the source: suppress, shield or replace.
- Reroute noisy wires if necessary.

SIDEWAYS NOISE
Any noise that enters the audio component by a radiated field through the component case. (Noise is reduced or eliminated when slowly removing the audio component from its fastened location.)

Some Causes:
Noisy wires or hoses behind or on top of the Radio or antenna coax lead-in.

Solutions:
- Suppress or shield the noisy wire or hose or reroute it.
- Shield the Radio case.
- Use aluminum or nickel tape and ground the tape whenever shielding. (Nickel tape will also stop magnetic interference, aluminum will not.)

BACKWAY NOISE
Noise that enters the audio component through its wiring harness, most commonly detected in the power and ground circuits. (Noise that can be heard at minimum volume and not frontway or sideway noise.)

Some Causes:
- Poor grounding of the Radio or of unsuppressed electrical components.
- Poorly routed wires or
- Defective suppression of electrical components.

Solutions:
- Suppression (capacitors, etc.) preferably can be installed at the noise source, then at the Radio or both.
- Switch pops are backway noise and best suppressed using capacitors.
- Squeals and buzzes are best suppressed using filter or generator whine packages.

HARNESS RELATED NOISE

Some Causes:
- Pinched wires, broken or shorted audio wires, defective connectors or speakers or a screw through a wire harness

Solutions:
- Localize problem to one side, front or back or speaker location.
- Verify speaker/amplifier operation using spare speaker/amplifier.
- Use channel swap harness (1226788) to check wiring.
- Track wiring for defects, brakes or shorts.

Note: Harness related noises have a tendency to be intermittent.