Amplifiers or home stereo have three main components: preamp, power amp and speaker. Your preamp converts the audio signal into an electrical current. Your power amplifier receives the electrical current from the preamp and adds voltage before sending the signal to the speakers. If there is a fault with the power amplifier, the speakers do not receive a powered signal and therefore don’t produce sound. The complexity of the repair depends entirely on the malfunctioning part and its location within the power amp.
Turn the amplifier back on. If the LED that indicates "on" is illuminated, you can rule out a problem in the power supply. Turn the volume dial up slightly and attempt normal operation. If there is sound coming from the speaker, but it is of diminished quality or volume, the power amplifier is functioning but not to its optimum capacity. This could be a loose connection. If no sound is coming out of the speakers, it is more likely that a part is broken.
Examine the printed circuit board. Look out for loose-fitting capacitors and resistors. When one of these parts comes away from the circuit, the circuit is shorted. Once a resistor is no longer performing its job of regulating current, the entire circuit fails.
Test the output transformer. Unscrew the transformer housing to expose the primary winding. Attach your meter leads to the winding inside the transformer and turn the amplifier on. The output transformer should give a reading approximately the same as the power handling detailed in the user manual. A zero reading indicates a shorted transformer coil. An unexpectedly high reading indicates an open (leaking) transformer. Both require replacement.