Key Topic 45: Equipment Faults-2

Question 1

8-45F1: A circuit card in a RADAR system has just been replaced with a spare card. You notice the voltage level at point E in Fig. 8F12 is negative 4.75 volts when the inputs are all at 5 volts. The problem is:

A. The 25 K resistor is open.
B. The 100 K resistor has been mistakenly replaced with a 50 K resistor.
C. The op amp is at the rail voltage.
D. The 50 K resistor has been mistakenly replaced with a 25 K resistor.

Answer 1

D. The 50 K resistor has been mistakenly replaced with a 25 K resistor.

Question 2

8-45F2: A defective crystal in the AFC section will cause:

A. No serious problems.
B. Bright flashing pie sections on the PPI.
C. Spiking on the PPI.
D. Vertical spikes that constantly move accros the screen

Answer 2

B. Bright flashing pie sections on the PPI.

Question 3

8-45F3: The RADAR display has sectors of solid video (spoking). What would be the first thing to check?

A. Antenna information circuits failure.
B. Frequency of raster scan.
C. For interference from nearby ships.
D. Constant velocity of antenna rotation.

Answer 3

C. For interference from nearby ships.

Question 4

8-45F4: In the circuit contained in Fig. 8F12, there are 5 volts present at points B and C, and there are zero volts present at points A and D. What is the voltage at point E?

A. -1.5 Volts.
B. 3.75 Volts.
C. 23.75 Volts.
D. 4.5 Volts.

Answer 4

A. -1.5 Volts.

Question 5

8-45F5: If the TR tube malfunctions:

A. The transmitter might be damaged.
B. The receiver might be damaged.
C. The klystron might be damaged.
D. Magnetron current will increase.

Answer 5

B. The receiver might be damaged.

Question 6

8-45F6: The indicated distance from your own vessel to a lighthouse is found to be in error. What circuit would you suspect?

A. Range ring oscillator.
B. Video amplifier.
C. STC circuit.
D. FTC circuit.

Answer 6

A. Range ring oscillator.