This Fix-It Guide on amplifier repair tells how an audio amplifier works, what often goes wrong, how to identify an amplifier problem, and what parts and tools you will need to fix it. It then gives simple step-by-step instructions for how to disassemble an amplifier and tells how to inspect an amplifier, and how to clean an amplifier. This guide also refers you to other Fix-It-Guides for more amplifier repairs.
An amplifier is an electronic device that magnifies and controls audio signal sources from a built-in AM-FM receiver as well as an external CD player, tape player, or other audio home-entertainment device. The output signal is fed to audio speakers.
What Can Go Wrong with an Amplifier?
Many things can go wrong with amplifiers, the most common being operator error. That is, if everything lights up but there is no sound, the speaker wires may not be connected or the speaker button may not be selected. Otherwise, the cord may be damaged or an internal fuse may be blown.
One of the most common causes of receiver problems is oxidation of electrical contacts and jacks. A jack is the connector used to mate a wire or plug to a circuit. A jack or plug that has gunk on it won’t conduct electricity, so the next device in line doesn’t get the signal.
Often, the problem is not in the amplifier but in one of the connections between it and either a source or the speakers. Use a continuity tester or a multimeter to check continuity of audio cords going in and out of the amplifier before attempting to open the unit up and look further.
How Can I Identify an Amplifier Problem?
Identifying the problem in an amplifier is easy: no power, no sound, or bad sound. Finding the source of the problem is a little more difficult. In some cases, the problem will actually be in an audio unit that feeds in to the amplifier such as a CD player, cassette deck, DVD player, or speaker.
One of the first things you can try is to remove all other audio sources from the amplifier and use only the internal receiver to determine whether the unit is getting power or good sound.
Once the chassis is open, look first for loose or burned wires.
What Do I Need for Amplifier Repair?
What Are the Steps to Amplifier Repair?
Amplifiers are assembled with many of the same components as other appliances, so fixing basic elements is similar. For example, cords may not consistently deliver electricity, switches and controllers can cause problems, and fuses may need to be replaced. Frequently, however, what the amplifier needs most is simply a thorough cleaning with some canned air and/or contact cleaner.
The first step in fixing internal parts in your amplifier is to open the unit up. Most amplifiers are encased in a two-piece housing–top-front and bottom-back.
Besides fuses accessed from the back of the cabinet, many amplifiers include one or more internal fuses.
Make sure that the electrical cord is unplugged from the wall receptacle.
Remove screws on the side, back, or bottom to separate the cover from the chassis.
Slide the two halves apart to expose the internal components mounted on the chassis (lower frame).
Inspect the internal end of the electrical cord for looseness or damage caused by being pulled (a common problem) and replace as needed.
If there is no power, but the cord works, look for an internal fuse. Test the fuse and replace as needed.
Use a can of compressed air to carefully blow away dust that is attracted to electronic components. If excessive, use a vacuum cleaner with a plastic tip (so delicate parts won’t receive static electricity) to clean the inside of the unit.
Use electrical contact cleaner to clean the input jacks and speaker terminals. If one of the input jacks is disconnected from the wires, either reconnect or resolder it.
Use a multimeter to test all fuses.
If none of these measures solves the problem, seek professional help. Modern audio equipment is built using delicate components that cannot be repaired; instead, they are replaced. Your audio professional will know which ones to replace, where to get them, and how to do the job.
Use a clean pencil eraser to clean cable pins on a regular basis. Use a quick shot of compressed air to remove eraser debris.