Figure 1-27 shows a small system consisting of four microphones connected to a two-channel...

Figure 1-27 shows a small system consisting of four microphones connected to a two-channel amplifier through a selector switch (SW1). Either the A set or the B set of microphones is selected and amplified. The output of the amplifier is connected to two speakers. Power to the amplifier is supplied by a single power supply that furnishes dc voltages to the amplifier and two batteries that provide power to two each of the microphones as shown.

Assume no sound is heard when the system is plugged in and turned on. Outline a basic troubleshooting plan by indicating the tests you would make to isolate the trouble to either the power supply, amplifier, a microphone, microphone battery, switch, speaker, or other fault.

Figure 1-27 A small system consisting of a two-channel amplifier and four microphones.