Troubleshooting & Repair Techniques Flashcards
7 cards from real CMRT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Troubleshooting & Repair Techniques flashcards as text
A marine radar displays a 'heading line' that drifts slowly over time. What is the most likely cause?
Answer: Gyrocompass or heading sensor drift
Heading line drift is caused by drift in the gyrocompass or heading sensor feeding data to the radar.
When testing a radar's TR (transmit/receive) limiter, a technician finds it has high insertion loss in the receive path. What symptom will this cause?
Answer: Reduced receiver sensitivity and poor target detection
High insertion loss in the TR limiter attenuates the received signal, reducing receiver sensitivity and degrading target detection.
A radar technician measures abnormally high anode current on the magnetron. What should be checked first?
Answer: Modulator pulse width and peak voltage
High anode current is typically caused by incorrect modulator pulse width or excessive peak voltage applied to the magnetron.
A radar system exhibits 'ringing' artifacts — bright concentric rings near the center of the display. What is the most probable cause?
Answer: Poor transmitter-to-antenna impedance match causing reflections
Ringing artifacts are caused by impedance mismatches in the waveguide or antenna, creating internal reflections that appear as concentric rings.
After replacing a radar display unit, the technician notices the range rings are no longer accurate. What is the most likely calibration step needed?
Answer: Calibrate the timebase (sweep) generator
Range ring accuracy depends on the timebase generator; calibrating it ensures range rings correctly represent true distances.
A technician notices the radar antenna makes a grinding noise during rotation. After inspection, what is the FIRST component to check?
Answer: Pedestal bearing assembly
Grinding noise during rotation most commonly indicates worn or damaged pedestal bearings requiring inspection and replacement.
A X-band marine radar's STC (Sensitivity Time Control) circuit is suspected to be faulty. What symptom would confirm this?
Answer: Persistent sea clutter at short ranges obscuring nearby targets
A faulty STC circuit fails to suppress near-range receiver gain, allowing sea clutter to overwhelm nearby targets.