Troubleshooting & Fault Diagnosis Flashcards

A 70-volt distributed audio system has several speakers with low volume and others with correct volume on the same zone. What should be measured first?

Answer: The tap wattage settings on the transformers in the quiet speakers

In 70V systems, individual speaker volume is set by transformer tap wattage; quiet speakers likely have an incorrect or lower tap setting than intended.

A CCTV system records video at a much lower frame rate than configured. The cameras stream smoothly when viewed live. What is the most probable cause?

Answer: Insufficient storage write speed or NVR processing capacity causing recording throttling

Smooth live viewing but low recorded frame rate indicates the NVR's disk write speed or processing capacity cannot sustain the configured recording frame rate.

An HDMI extender over Cat6 works at 1080p but fails to pass a 4K signal. The cable run is 120 feet. What is the issue?

Answer: The extender's bandwidth rating does not support 4K at that cable distance

4K signals require higher bandwidth, and many HDMI extenders have distance limitations that decrease further at higher resolutions than their rated spec.

After a DSP firmware update, all audio zones produce a 1 kHz test tone continuously. What should be done?

Answer: Reload the configuration file from backup, as the update may have reset the DSP to factory default

A continuous test tone after a firmware update typically means the device reverted to factory default, and reloading the saved configuration will restore normal operation.

A video wall using an LED display controller shows correct images on most panels but one panel displays shifted or tiled content. What is the likely cause?

Answer: Incorrect panel position/address mapping in the video wall controller configuration

Shifted or incorrectly tiled content on a single panel indicates the video wall controller has that panel mapped to the wrong position in the configuration.

A surge protector in a rack shows its protection indicator light is off (not illuminated). What does this mean?

Answer: The surge protection MOV components have been sacrificed and the unit no longer provides surge protection

A protection indicator that is off (rather than lit green) on most surge protectors signals that the internal MOVs have absorbed a surge and are depleted, requiring unit replacement.

During commissioning, a control system macro runs correctly the first time but fails on the second execution. What is the most common cause?

Answer: Timing delays in the macro are insufficient for devices to complete their response before the next command is sent

Macros that succeed on first run but fail on subsequent runs typically lack sufficient delay commands between steps, causing commands to arrive before the device is ready.