AUDIO: Basic troubleshooting for car stereo systems


You may encounter operating problems with your car stereo system that you may or may not be able to solve on the spot. It is always better to understand the possible causes, resolve some of the problems and identify those that require servicing. Here are some common symptoms and a basic troubleshooting guide.


There is an unbalanced sound coming from the built-in loudspeakers. In other words, one channel seems to be louder than the other, even though there is no faulty or distorted source from the tape or audio-CD recordings.

Possible causes

l The cassette head is dirty.

l Balance is turned all or most of the way to one side.

l There is a faulty cable connection between amp and tweeter.

l One of the loudspeakers is decelerating due to the tweeter having worn out.

l Input/output jacks on the rear panel of the amp are dirty; in other cases, the internal circuits of the amp might possibly be degrading.

What to do

l Clean the cassette head with a head-cleaner tape.

l Check and adjust balance.

l Make sure all cable or wire connections on the unit and on all speakers are secure, and the cable for each connection does not touch anything other than its respective connection.

As to other matters concerning internal circuitry, you shouldn’t try to repair the system yourself but rather take it to a qualified technician or contact your dealer.

Be aware that a driver is normally seated closer to the right- than the left-hand speaker, thus making for unavoidably unbalanced sound. Most car audio shops will as a result adjust the system so that all speaker channels are balanced.


There is a noise or hum coming from the speakers, noticeably from mid-to lower-range frequencies.

Possible cause

Hum and noise problems are difficult to tackle as they can be caused by any number of factors, some of which are:

Internal factors

l The cords or cable connections – including soldering points – may be defective or loose. This will cause interference from the RFI.

l Internal circuits in some low-quality front-end players.

l Electrical supply from the battery is insufficient.

External factor

Sometimes, you may wonder whether noise is caused by the spark plugs of nearby motorcycles. If so, the fault could arise from poor electrical shielding of cable connections.

What to do

Internal factors:

l Make sure all cable or wire connections on the unit are secure.

l Check that the system’s grounding cord is properly connected to the GND terminal.

l If possible, try to go for a high-quality front-end player in your system since the hum or noise occurring from low-quality units is, in most cases, almost impossible to rectify.

External factor

This is impossible to tackle by yourself. You need to take the car back to your audio dealer for reinstallation, if necessary.


Discs skip momentarily.

Possible causes

l The pick-up lens is worn out.

l The CD is defective as a result of fingerprints or scratches, which can deactivate the lens operation.

What to do

If the disc has fingerprints or scratches, clean it with a soft cloth – wiping from centre to edge. But if the lens is worn out, better to change to a new player. Typically, front-end CD players have a lifetime of up to four years. In most cases, I would recommend putting in a new unit rather than repairing an ageing one.


Sudden weak signals from FM/AM radio broadcasts.

Possible cause

This may be caused by obstruction to the antenna due to distance from the city, or poor connections.

What to do

Check that the antenna connections on the receiver or tuner are properly connected to the input terminal. Using an effective directional antenna could improve the signal.


The radio unit fails to turn on, or nothing seems to happen when the power-on button is pressed.

Possible causes

l The power cord is not plugged in, or is not completely mounted.

l Power supply is insufficient.

l The electrical circuitry has been completely ruined.

What to do

Check each connection point step by step. Make sure the power cord and all connections are securely plugged in. If the front-end player is working but no sound is coming from the speakers, check if the LED on the amp is still lit. If not, the amplifier may have short-circuited. If so, get to a qualified technician or consult your dealer immediately.

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