CBT - Certified Broadcast Technologist Equipment Troubleshooting and Maintenance Questions and Answers

Question 1

A broadcast engineer is troubleshooting a persistent 60 Hz hum in the studio's main audio console. All equipment is powered on, and audio is passing, but the hum is present on all channels. Which of the following is the MOST likely cause of this issue?

Accepted Answer

A ground loop caused by multiple ground paths between interconnected equipment.

Answer

A 60 Hz hum is the classic symptom of a ground loop. This occurs when audio equipment is connected to ground at multiple points, creating a loop that acts as an antenna for electromagnetic interference from AC power lines. While a faulty cable or incorrect gain staging can cause noise, they are less likely to produce a consistent hum across all channels. Digital clocking errors typically result in clicks, pops, or distorted audio, not a steady hum.

Question 2

When performing maintenance on a high-power FM transmitter, a technician needs to test the transmitter's output stage without broadcasting a signal over the air. Which piece of test equipment is essential for this procedure?

Accepted Answer

An RF dummy load

Answer

An RF dummy load is a device that simulates an antenna, allowing a transmitter to be tested at full power without radiating signals. It absorbs the RF energy and converts it to heat. Testing a transmitter without a proper load (like an antenna or a dummy load) can cause the power to be reflected back into the transmitter, potentially causing severe damage. A spectrum analyzer, oscilloscope, or field strength meter are used for measuring signals, but not for safely absorbing the transmitter's full power output.

Question 3

A remote television broadcast is experiencing intermittent video signal loss, presenting as a black screen that comes and goes. The camera, power supply, and recorder have been tested individually and are working correctly. Which of the following is the MOST probable cause to investigate next?

Accepted Answer

A damaged or loose BNC or SDI cable connection.

Answer

Intermittent signal loss, such as a flickering or black screen, is frequently caused by physical connection issues. Damaged cables or loose connectors (like BNC or SDI) can easily lead to a temporary loss of signal continuity. Incorrect white balance would affect color, not the presence of the signal. A format incompatibility or audio clipping would present different symptoms and would likely be consistent, not intermittent.

Question 4

Which of the following is a critical preventive maintenance task for equipment located at a transmitter site to ensure optimal performance and prevent failure?

Accepted Answer

Regularly cleaning air filters and verifying proper cooling system operation.

Answer

Transmitter equipment generates a significant amount of heat. Ensuring that cooling systems are functioning correctly by cleaning air filters and checking fans is a crucial preventive maintenance task to prevent overheating and equipment failure. The other options are related to studio or office maintenance and do not directly impact the health and operation of the transmitter equipment itself.

Question 5

A broadcast technician notices that a video feed from a new camera has a slight rolling horizontal bar and distorted picture. The camera is powered from a separate AC circuit than the video switcher it is connected to. What is the most likely solution?

Accepted Answer

Use a ground loop isolator on the video line.

Answer

The symptoms described, such as rolling bars, are classic indicators of a ground loop in a video system. This often occurs when interconnected equipment is powered from different AC circuits, creating a difference in ground potential. A ground loop isolator is designed to break this DC path for the current, thereby eliminating the interference. Changing the lens, shutter speed, or bit rate would not address the underlying electrical interference issue.

(CBT) Certified Broadcast Technologist Practice Test

(CBT) Certified Broadcast Technologist Practice Test

CBT - Certified Broadcast Technologist Equipment Troubleshooting and Maintenance Questions and Answers