Schematic Reference: Radio/Audio System Schematics

Diagnostic Test Tape/Tape Cleaner

Utilize the SA9412G to help in determining if the cause is related to one or more of the speakers or to the radio.

Always compare front speakers to front speakers, and rear speakers to rear speakers. Do not compare front speakers to rear speakers, as they could be different speaker sets and their mounting environments will most likely cause them to sound different from front to rear.

Diagnostic Tape Contents

Bass Frequency Test

The bass frequency test is useful to evaluate the low frequency response of the audio system. A 50 Hz (cycle per second) sine wave tone is used for this test.

Midrange Frequency Test

The midrange frequency test is useful to evaluate the midrange response of the audio system. A 500 Hz (cycle per second) warble tone is used for this test. A warble tone makes the sound source easier to locate. A warble tone is used in this test because a sine wave would make the sound appear to be coming from a point other than a particular speaker.

High Frequency Test

The high frequency test is used to evaluate the high frequency response of the audio system. A range of tones between 8500 and 9500 Hz (cycle per second) is used in this test to make the sound source easier to locate. The range of frequencies is used in this test to avoid the appearance of sound coming from a point other than a particular speaker.

Full Range Test

The full range test can be used for the evaluation of numerous audio system problems. For example, placing the FADE and BALANCE controls at their mid-positions allows a comparison of output to be made using an A/C mulitmeter. When evaluating speaker performance, listen for all 3 distinct sounds (BASS, MID, and HIGH) while this test is running.

Speaker Buzz and Rattle Test

This portion of the diagnostic test tape and the use of the FADE and BALANCE controls can be useful for isolating rattles and buzzes to a particular speaker. As the sound frequency continuously changes from low to high, listen for rattles or buzzes that occur at particular frequencies. This test is designed to duplicate the rattles or buzzes that occur at frequencies that are difficult to produce during normal operation.

Tape Motor Speed Test

A 2-minute time period is marked in this section of the diagnostic test tape for the purpose of checking cassette player motor speed. Improper motor speed affects the cassette tape sound. Motor speed is acceptable if the time taken for the test is between 116--121 seconds (1 minute and 56 seconds--2 minutes and 1 second).

Cassette Tape Player Cleaning

To clean the tape player head and capstan, the cassette tape cleaning cartridge included with Saturn Special Tool SA9412G , Diagnostic Tape and Tape Head Cleaning Kit, is recommended. Cassette tape players should be cleaned after 30 hours of tape operation, they can be cleaned more often.

Saturn radios equipped with a cassette tape player have a CLEAN indicator in the LCD display. The CLEAN indicator activates after 30 hours of tape player operation.

The recommended cassette tape head cleaning cartridge is a scrubbing type tape head cleaning cartridge. The preferred tape head cleaner and solution is available as part of the audio system diagnostic kit. It is recommended the cassette tape head cleaning cartridge be replaced if the felt pads appear soiled or worn.

Noise Diagnostics

This portion of the diagnostic tape is silent and allows for easier diagnosis of noise/interference issues.

Important: The following information lists the most probable cause of the concern to the least probable cause followed by the appropriate test for that condition. If the list leads to a replacement of a component, always inspect for a poor connection before proceeding with the replacement. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

1. Speaker output circuit resistance high

Test the appropriate speaker output circuits for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

2. Defective Speaker

Replace the appropriate speaker. Refer to Speaker Replacement Reference .