Troubleshooting & Fault Diagnosis Flashcards
7 cards from real CPI 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 & Fault Diagnosis flashcards as text
A newly installed in-ceiling speaker produces audio from one driver only (woofer works, tweeter silent). What is the most likely cause?
Answer: Crossover network failure or disconnected tweeter terminal
A silent tweeter with a functional woofer in the same enclosure typically indicates a failed crossover component or a disconnected tweeter lead.
A control processor reboots spontaneously every few hours. No error code is displayed. What is the first thing to check?
Answer: Ambient rack temperature and ventilation
Spontaneous reboots without error codes in a rack environment are frequently caused by thermal shutdown due to inadequate ventilation or excessive rack temperatures.
An IP intercom doorbell rings the indoor unit but two-way audio does not work in either direction. Video is fine. What should be investigated?
Answer: SIP/VoIP audio codec mismatch or firewall blocking RTP audio ports
Video working but audio failing bidirectionally over IP often indicates a SIP codec mismatch or firewall rules blocking the RTP ports used for audio streams.
A structured wiring panel's coaxial splitter shows strong signal at the input but weak signal at all outputs. What is the most likely fault?
Answer: Signal attenuation from a defective or incorrect-value splitter
Uniform weak output at all ports with strong input signal points to the splitter itself either being defective or having a higher split ratio than the signal budget allows.
After an electrical storm, a networked AV system loses communication between the controller and all devices. What physical component should be inspected first?
Answer: Ethernet switches and surge protectors for damage
A storm event causing total network communication loss across all devices most likely damaged network switches or failed surge protection devices.
A door lock controlled by a 12 VDC magnetic lock fails to release when valid credentials are presented, but the access panel shows 'Access Granted'. What is the likely fault?
Answer: The relay or locking hardware wiring between the controller output and the lock is open or the lock has failed
When the controller grants access but the lock does not release, the fault lies in the physical circuit between the controller relay and the lock, or in the lock mechanism itself.
A rack contains multiple pieces of equipment, and the circuit breaker trips when all equipment is powered on simultaneously. What is the corrective action?
Answer: Sequence power-on using a switched PDU or load calculations to stay within circuit capacity
Inrush current from powering all devices simultaneously can exceed breaker ratings; using a sequenced PDU spreads the load over time and prevents tripping.