CST Maintenance and Troubleshooting 3

Question 1

A camera shows a strong horizontal rolling bar across the image. This artifact is most commonly caused by:

Accepted Answer

Ground loop interference

Answer

Ground loops create a potential difference between equipment grounds, inducing 60 Hz hum that appears as a rolling horizontal bar on analog video.

Question 2

When troubleshooting an IP camera that intermittently drops from the network, what is the correct first diagnostic step?

Accepted Answer

Check PoE switch port utilization and power budget

Answer

Intermittent dropouts on PoE cameras often result from insufficient power budget or switch port overload, which should be verified before other steps.

Question 3

A technician is cleaning camera domes on a quarterly maintenance visit. Which cleaning agent should be avoided?

Accepted Answer

Ammonia-based glass cleaner

Answer

Ammonia-based cleaners can cloud polycarbonate dome covers over time, permanently degrading optical clarity.

Question 4

An NVR shows 'HDD Not Detected' after a fan failure event. What is the most likely explanation?

Accepted Answer

Overheating from the failed fan caused the HDD to shut down or fail

Answer

Fan failure leads to thermal overload, which can cause hard drives to power down or suffer permanent damage from excessive heat.

Question 5

What does a 'video loss' alarm on a DVR typically indicate in an analog camera system?

Accepted Answer

The camera has lost power or the coax connection is broken

Answer

A video loss alarm triggers when the DVR detects no sync signal on an input, most commonly due to camera power loss or a severed coaxial cable.

(CST) Certified Surveillance Technician Practice Test

(CST) Certified Surveillance Technician Practice Test

CST Maintenance and Troubleshooting 3