ISCET Component-Level Troubleshooting 3

Question 1

A technician suspects a leaky electrolytic capacitor. Which symptom best supports this diagnosis?

Accepted Answer

Lower than expected resistance reading on ohmmeter

Answer

A leaky capacitor has internal resistance paths causing lower-than-expected resistance readings, indicating dielectric breakdown.

Question 2

What is the primary purpose of an isolation transformer when troubleshooting line-powered equipment?

Accepted Answer

To prevent shock by isolating the chassis from AC line ground

Answer

An isolation transformer breaks the direct connection between the AC line and the equipment chassis, preventing shock hazards during testing.

Question 3

A zener diode in a voltage regulator circuit measures 0 V across it under load. What fault is indicated?

Accepted Answer

Zener is shorted

Answer

A shorted zener diode will drop 0 V, collapsing the regulated output voltage to near zero.

Question 4

When using signal injection to troubleshoot an audio amplifier, where should you begin injecting the test signal?

Accepted Answer

At the input of the first stage

Answer

Signal injection typically starts at the input of the first stage and progresses toward the output to isolate the faulty stage.

Question 5

An SCR in a power control circuit fails to trigger. Which component should be checked first?

Accepted Answer

The gate triggering circuit

Answer

SCR triggering depends on gate current; a faulty gate circuit is the most common cause of failure to fire.

(ISCET) International Society of Certified Electronics Technicians Practice Test