What troubleshooting step should be taken first when receiving a customer complaint about video issues?

When addressing a customer complaint about video issues, the first troubleshooting step should focus on verifying the signal strength. This is crucial because video issues often stem from inadequate signal quality or interference, which significantly impacts the viewing experience. Checking the signal strength can reveal whether the issue is related to the incoming signal, as weak or fluctuating signals can cause problems such as pixelation, buffering, or complete loss of picture.

Other options may not address the root cause as effectively or might lead to unnecessary complications. For instance, resetting the entire system could clear temporary glitches but doesn't directly assess if there's a problem with the incoming signal. Checking the power supply is important, but it would be more relevant for issues with power-related functionality, not specifically video quality. Likewise, replacing all cables may be overly drastic and time-consuming if the core problem lies with the signal itself rather than with the physical connections. Starting with signal strength verification allows for a more efficient and targeted approach to resolving the customer's concerns.