If the sound amplifier suddenly stops functioning, it is most likely due to damage to the speaker's voice coil or poor assembly. Even if you are not an expert on the basics of radio engineering, you can repair the amplifier yourself.
Necessary
- - soldering iron with solder;
- - heat-conducting paste;
- - tester;
- - magnifying glass.
- - set of screwdrivers.
Instructions
Step 1
Disconnect all speakers, mains power, and signal wires from the amplifier, and remove it from the equipment stand. Take care of the lighting.
Step 2
Remove the upper and lower covers of the amplifier - use a suitable screwdriver to unscrew the fastening bolts, then carefully dismantle both covers.
Step 3
If necessary, clean the interior of the device from dust with a vacuum cleaner.
Step 4
Examine the amplifier boards. Use a magnifying glass to see even the smallest details.
Step 5
First of all, check the power supply transformer. Using a tester, check the voltage at all terminals of the transformation windings, starting with the power diode bridge. If everything is in order, check and replace, if necessary, the mains fuse.
Step 6
Turn on the amplifier, then measure the voltage at the input of the diode bridge again. In the absence of the latter, evaporate the diode bridge. Check the integrity of the diodes with a tester. Replace the bridge if necessary.
Step 7
Before soldering a new diode bridge, make sure that the output transistors of the amplifier are in good condition and that their cases are not shorted to the radiator. If you find faulty transistors, replace them. If necessary, dismantle serviceable parts from the radiator, then mount them back using mica gaskets. To improve heat dissipation to the radiator, lubricate them with heat transfer paste.
Step 8
The next step is to check the details of the power amplifier. When the output transistors are damaged, the small resistors connecting the transistors to the previous amplifier stage often suffer along with them.
Step 9
The electrodes of the capacitors of the power supply must not be short-circuited to each other. Check it.
Step 10
After making sure that there are no short circuits on the supply buses, faulty elements of the output amplifier, reinstall the diode bridge, the mains fuse, and then make a test switch. If there are no faulty parts, the amplifier is immediately ready for use.
Step 11
Install the bottom and top covers in their places, check the speaker impedance, which should correspond to the value in the device's passport. After making sure that the speakers are working properly, connect the mains power, signal wires and speakers to the device.
