Troubleshooting Analogue and HD Cameras

About half of CCTV service calls are diagnostic rather than installation work — an existing system has stopped behaving and the engineer needs to identify the fault fast. This section is the systematic fault-finding workflow that experienced installers use.

The diagnostic ladder

The lessons walk through the classic symptom set in order: no picture at all, intermittent picture, rolling lines, banding, colour loss, image flicker, image freezing on the recorder. For each, the section gives the most likely causes ordered from cheapest-to-rule-out to most expensive, the on-site test that distinguishes between them, and the fix. Common root causes — format mismatch (TVI vs CVI vs AHD), ground loops on multi-building sites, faulty BNC terminations, voltage drop on long DC runs, and damaged coax — each get their own segment.

Tools the troubleshooter uses

A multimeter, a portable test monitor, a known-good camera, a ground-loop isolator, and a UTP balun set are the minimum kit. Their use is shown in the lessons, not just listed. Troubleshooting is the closing section of BH’s CCTV training programme on bhcourses.ie, building on the basics, recorder and IP-camera modules that come before it. The deeper version, with field videos of fault reproduction and resolution, is on the Analogue HD Troubleshooting module on bhcourses.com.

When the fault is not the camera

A surprising number of “camera faults” turn out to be DVR misconfiguration (wrong format selection on hybrid units), power-supply failure that affects multiple cameras simultaneously, or a single failing baluns cluster. The diagnostic flow here forces those checks early so engineers don’t replace working cameras.