CCTV — Expert Guide
Why Is My CCTV Camera Not Working? Troubleshooting Guide
By the DC Fire & Security engineering team — installing and maintaining fire and security systems since 2010. Updated June 2026.
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Quick answer
Most CCTV faults come down to four things: power (failed PoE port, injector or PSU), connections (water in an external joint, loose RJ45), settings (changed IP address or recorder configuration), or hardware age (failed infrared LEDs, dying hard drive). Reboot the recorder and camera first — it genuinely resolves a large share of faults.
Camera shows 'no signal' or is offline
- Reboot the NVR and the camera (pull and re-seat the PoE cable) — first step, fixes plenty
- Check the PoE port: swap the camera onto a known-working port; if it comes alive, the port or its power budget is the issue
- Look for water ingress: external RJ45 joints that weren't gel-sealed corrode and fail — green or white crust on the connector confirms it
- Check the cable run: rodent damage and stretched joints in lofts are classic culprits
- IP conflicts: a new router or DHCP change can move addresses — cameras set to static IPs outside the new range vanish
Picture problems: black at night, foggy, flickering
- No night vision: infrared LEDs have a finite life — a camera fine by day and black at night usually needs replacement
- Foggy or hazy image: condensation inside the housing or a spider web across the lens; clean the dome and check the seal
- White glare at night: IR reflecting off an overhang, wall or the dome itself after the seal ring was refitted wrongly — reposition or re-seat
- Flicker: usually LED lighting interacting with shutter speed; change the camera's anti-flicker setting (50Hz in the UK)
Recorder problems: not recording, beeping, no playback
- Beeping NVR: almost always a hard drive error or full-disk event with overwrite disabled — check the recorder's log, enable overwrite
- Gaps in playback: motion-only recording with sensitivity set too low, or the drive dropping out intermittently before failing outright
- Hard drives in recorders work 24/7 and typically last 3–5 years — a recorder past that age with playback issues needs its drive replaced before footage is lost
- Wrong time on recordings: set NTP time sync so the clock survives power cuts; wrong timestamps ruin evidence
Frequently Asked Questions
Why does my camera work in the day but not at night?
Failed infrared LEDs or a stuck IR-cut filter. If you can't hear the faint click of the filter at dusk, the camera needs attention; failed IR usually means replacing the camera.
Why has my camera image gone black and white in daylight?
The IR-cut filter is stuck in night mode. A power-cycle sometimes frees it; a recurring fault means mechanical failure inside the camera.
How often should CCTV be serviced?
Annually for business systems: lens cleaning, seal checks, firmware updates, hard drive health, time sync and recording verification. Most failures we attend would have been caught at a service visit.
When should I call an engineer rather than keep trying?
After reboot, port swap and a visual check of connections. Persisting beyond that without test equipment tends to disturb working cabling — our diagnostic call-outs cover the Bedfordshire, Hertfordshire and London area.
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