CMRT Troubleshooting & Repair Techniques 3

Question 1

During radar maintenance, a technician discovers the modulator's pulse-forming network (PFN) capacitors are bulging. What action is required?

Accepted Answer

Discharge and replace the PFN capacitors immediately

Answer

Bulging PFN capacitors indicate failure and pose an explosion hazard; all capacitors must be safely discharged and replaced immediately.

Question 2

A radar technician uses a spectrum analyzer on the radar's IF output and finds the IF signal is broader than specification. What does this indicate?

Accepted Answer

IF filter bandwidth is too wide or a filter component has failed

Answer

A broader-than-specified IF bandwidth indicates a failed or degraded IF filter component allowing excessive noise into the receiver.

Question 3

What is the safest method to discharge a high-voltage radar modulator capacitor bank before performing maintenance?

Accepted Answer

Use an approved bleeder resistor discharge tool rated for the voltage

Answer

A rated bleeder resistor discharge tool safely dissipates stored energy in a controlled manner without risk of arc flash or equipment damage.

Question 4

A radar shows strong returns at all bearings at a fixed range, forming a complete circle. This phenomenon is called:

Accepted Answer

Fixed-range false echo or 'ring' due to internal reflection

Answer

A bright circle at a fixed range at all bearings indicates an internal reflection or standing wave within the radar's waveguide system.

Question 5

A technician replaces an S-band radar magnetron but the transmitter output power remains low. What should be checked next?

Accepted Answer

Modulator output voltage and pulse parameters

Answer

If output remains low after magnetron replacement, the modulator must be checked to ensure it delivers correct pulse voltage and width to drive the new magnetron.

(CMRT) Certified Marine Radar Technician Practice Test

(CMRT) Certified Marine Radar Technician Practice Test

CMRT Troubleshooting & Repair Techniques 3