Troubleshooting & Repair Techniques Flashcards

A radar technician is troubleshooting a system where the display shows no video but the timebase sweep is visible. What does this indicate?

Answer: The video signal path from receiver to display has a fault

A visible sweep with no video indicates the timing and display hardware work but the video signal from the receiver is not reaching the display.

When performing a radar power output measurement using a calibrated power meter, what safety precaution is MOST important?

Answer: Ensure the power meter is rated for the radar's peak pulse power, not just average power

Radar peak pulse power can be hundreds of kilowatts even though average power is low; using an undersized power meter will damage it and give incorrect readings.

A technician finds corrosion inside a coaxial connector between the transceiver and antenna. After cleaning, what test should be performed before returning the system to service?

Answer: VSWR measurement to confirm acceptable impedance match

After cleaning and reconnecting a coaxial connector, VSWR must be measured to verify the connector provides a good impedance match and has not introduced reflections.

A radar technician is using a substitution method to isolate a fault. This technique involves:

Answer: Replacing suspected faulty modules with known-good units to identify the defective stage

Substitution troubleshooting replaces suspect modules with confirmed-good spares to isolate the defective stage quickly without detailed circuit analysis.

A radar's performance monitor shows a decrease in the sensitivity level (MDS — minimum detectable signal) over time. What is the most common cause?

Answer: Gradual magnetron frequency drift or aging reducing receiver-to-transmitter coupling efficiency

As a magnetron ages, its frequency can drift, reducing AFC lock quality and degrading receiver sensitivity as the IF passband becomes misaligned.

After completing radar repairs, a technician must perform a sea trial to verify performance. Which parameter is NOT typically verified during a performance check at sea?

Answer: Magnetron anode voltage under load

Magnetron anode voltage under load is an internal bench measurement and is not a standard operational sea trial performance parameter.

A technician uses an oscilloscope to examine the radar's trigger pulses and finds they are irregular with varying intervals. What is the most likely faulty component?

Answer: PRF (pulse repetition frequency) generator or timer circuit

Irregular trigger pulse intervals indicate a fault in the PRF generator or timing circuit, which establishes the repetition rate for all radar timing.