How to perform power amplifier repair
How to perform power amplifier repair
- Amlifier
- April 20, 2021
An amplifier with no sound can be tough to repair. The repair’s complexity varies depending on the damaged part location, the component damaged and the nature of the damage. Any audio amplifier repair ranges from replacing the plug’s fuse to rewinding the primary transformers of power winding. You can try to fix the amplifier on your own with the following guide from professionals. In case the amplifier doesn’t come back to normal, seek the help of a professional.
Parts to know before amplifier repair
The amplifier or home stereo encompasses three main components- the preamp, power amp and speaker. The preamp performs the function of converting an audio signal into an electric current. The power amplifier receives the electric current that comes from the preamp. The power amplifier also adds the voltage to the signal and sends it to speakers.
The speaker may not produce a sound if there is a problem with the amplifier. The speaker won’t generate a powered signal, and hence it doesn’t make a sound.Another common cause of problems with amplifiers is the oxidation of electrical contacts and jacks. The jack acts as a connector to join the wire or plug to a circuit. A junk with gunk on it won’t conduct electricity, therefore, passing the signal to the next device in the line.
Sometimes the problem won’t be in the amplifier; instead, one of the connections between the source or the speaker might have a fault.
How to identify an amplifier problem?
Identifying a fault in an amplifier has always been easy. No sound, no power and bad sound indicate a faulty amplifier. Finding the problem’s source is a bit more difficult. The source might be in the audio unit that feeds the amplifier, such as a CD player, cassette deck, DVD player or speaker. A small tip here is first to remove all other audio sources entering the amplifier and stick only to the internal receiver and determine whether the unit is getting power or not.
Step by step guide for amplifier repair
- Turn your amplifier off at the wall and let it cool. Reduce the volume to zero
- Now again, turn on the amplifier, and if the LED illuminates, then there is no problem with the power supply; hence you can rule out that problem.
- Increase the amplifier’s volume gradually and try to perform normal operations. If sound comes from the speaker, but in a diminished quality or volume, the power amplifier works but not at its optimum capacity. This can be due to a loose connection in the windings. If you observe no sound coming from the speakers, the audio part is probably broken.
- Now, try unscrewing the back panel and removing the Chassis. Take the maximum care to prevent any damage to parts. Now unscrew the lid of the Chassis and reveal the circuit board. Observe the circuit board thoroughly and look for any signs of damage. The damage can be a blown fuse, transistor or anything else. You can identify them with typical brown discolourations.
- If the parts are blown, replace them with new ones.
- Take a close look at wiring and solder joints. Trace the path of wiring from the input and gently pull it. If the wiring is slack, a loose connection is a possible answer. Restore loose connections by soldering the joints and re-establish the connection. Brush the circuit and remove soldering residue.
- If there are no loose connections, search for any loose-fitting capacitors and resistors. While you examine with your fingers, if any of the parts come out, then it is shorted if the resistor doesn’t perform its function, the ability to regulate current fails.
- Now it’s time to test the resistors. To test the resistors, place the voltmeter probe directly following the first resistor on the signal chain. Now tune the meter to resistance and provide input power to the amplifier.
- The resistance value of each resistor will be printed on the side. The reading should be within 5 percent variance of the resistance value when you power up the amplifier; if the resistance value is outside the 5 percent variance, the resistor malfunctions. If the resistance value shows zero, then the resistor is completely blown.
- Replace the shorted resistor after your turn off the amplifier. Detach the solder joint on the circuit base and take out the resistor. Solder a new resistor in the place.
- The next step is to test the output transformer. Detach the transformer housing and reveal primary winding. Fasten the meter leads to the inside of the winding and turn on the amplifier. If you observe the transformer’s output reading the same as the power handling detail mentioned in the user manual, then the output transformer is perfect. Zero denotes a failed transformer, while a high reading denotes a leaking transformer. In both cases, the transformer needs to be replaced.
- Make use of an electrical contact cleaner and clean the terminals of speakers and input jacks to avoid further problems.
Hire a professional
You can perform minor amplifier repair on your own, while major problems like shorted amplifier need an expert hand. Instead of mending the problem and aggravating it, you can give the amplifier to a professional and make it work like magic. A professional has experience in handling amplifiers and solving them in an instant. A professional
- Has a lot of experience
- Show long-lasting results
- Have a standardized detection procedure
- Cost-effective
Bottom line
Amplifier repairs can seem tough, but with proper guidance, it is easy to mend an amplifier. Regular maintenance of the amplifier keeps it new forever.
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