Inspection Procedure 7

Inspection Procedure 7: Noise Is Present While Moving (AM).

DIAGNOSIS

STEP 1. Ask the driver about the noise.

1. Find out the following information from the owner.
2. Place where the noise occurs.
3. Locality conditions (valley, mountain, etc.)
4. Name and frequency of stations affected by noise

Q : What type of noise is detected, vehicle noise or external noise?

Vehicle noise : It may not be possible to prevent noise if the signal is weak. Go to Step 2.

External noise : In almost all cases, prevention on the receiver side is next to impossible when the signal is weak. Go to Step 4.

STEP 2. Ask the driver about the location where the noise occurs

Q : Does the noise occur when entering or near a particular structure (building, tunnel, mountain, etc.)?

YES : Go to Step 3.

NO : Go to Step 4.

STEP 3. Check if the noise can be eliminated by adjusting the radio.

1. Adjust the radio as follows.
2. Change to a different station with a stronger signal. This will boost the systems resistance to outside interference.
3. Suppress high tones to reduce noise.

Q : Has the noise been eliminated?

YES : The noise has now been eliminated. Inform the customer that it is normal to hear noise while receiving a weak station.

NO : Go to Step 4.

STEP 4. Check for the noise.

Q : Does noise still exist?

YES : If there is still more noise than on other similar radios find out the type of noise. Ask the owner for the name and frequency of the affected stations, and consult with the radio manufacturer service center.

NO : System is operating normally.