INSPECTION PROCEDURE 21: Radio: Distortion on FM only: Diagnosis
- STEP 1. Check that the distortion is present when the radio is tuned to another station.
Q: Does the distortion persist when the radio is tuned to another station?
YES: Go to Step 2.
NO: The signal from that station is too weak.
- STEP 2. Relocate the reception area and check the radio.
Q: When relocating the reception area does the distortion increase or decrease?
YES: The cause may be multipath or fading noise. Multipath noise is the echo that occurs when the broadcast signal is reflected by a large obstruction and enters the receiver with a slight time delay relative to the direct signal (repetitious buzzing). A fading or buzzing noise may occur when the broadcast beam is disrupted by obstructing objects and the signal strength fluctuates within a narrow range.
NO: Replace the radio and CD player or radio and CD player with CD changer. Check that the distortion is resolved.