Video intercom screen black or poor image: causes and fixes

The first thing we do when we get a call about a video intercom image is ask exactly how it looks, because each symptom points to a different origin. Broadly speaking, there are two families of fault:

• Completely black screen: no video signal reaches the monitor or the screen doesn't switch on. Points to the camera, video wiring, power supply or a faulty monitor.
• Lines or ghosting on the image: the signal arrives but degraded. Usually deteriorated wiring, joints in poor condition or incorrect termination of the video line.
• Blurry or unsharp image: almost always the camera optics: dirt, scratches on the lens window or internal condensation.
• Washed-out or backlit image: too much light hitting the camera; typical of panels facing the afternoon sun, very common in Valencia.
• Intermittent image: it comes and goes; suspect a loose wire, a faulty distributor or an oxidised connector.

These are the causes we come across most often when repairing Fermax video intercoms in Valencia and its metropolitan area, from most to least frequent:

• Faulty street panel camera: it works outdoors in all weathers and is the most punished video component. If it fails, no flat gets an image.
• Deteriorated video wiring: the coaxial or video pair suffers from damp, building work and badly made joints. It causes lines, ghosting or intermittent dropouts.
• Faulty monitor: a dead screen, damaged video module or loose internal connector. If it only fails in your flat, it's the prime suspect.
• Brightness and contrast settings: more common than you'd think: an adjustment wheel turned to minimum makes the monitor look broken.
• Direct sunlight on the camera: at certain hours the image burns out or appears backlit. It's corrected by reorienting the panel, fitting a visor or adjusting the camera.
• Condensation or dirt on the lens: in damp areas or near the sea, the lens window fogs up from inside and the image looks veiled or blurry.

In VDS and DUOX Plus systems there can also be "electronic" causes: a faulty video distributor or incorrect programming after replacing a unit. And remember the image is only one part of the system: if the call or the door release also fail, it's worth reviewing the 6 most common Fermax intercom faults to get the full picture.

This guide table sums up the above so you can locate the source of the fault based on what you see on your monitor:

As you can see, the decisive question is whether the problem affects one flat or all of them: that separates an individual repair from a communal fault.

Before requesting a visit, spend a few minutes on these safe checks, which need no tools and don't involve opening any equipment:

• Check the brightness and contrast wheel or buttons on the monitor: turn them up to maximum and try again.
• Ask a neighbour whether their image looks fine: it's the single most informative check.
• Look at the camera window on the street panel: if it's dirty on the outside, clean it with a soft dry cloth.
• Note whether the fault occurs only at certain hours (direct sun) or at night too: write it down for the technician.
• Confirm that audio and door release work: it helps establish whether the fault is video-only.

If the image is still poor after all this, it's time for a diagnosis with instruments: measuring the video signal, checking distributors and testing with a reference monitor. That's where the technician comes in. And if the door release is failing along with the image, take a look at our article on what to do when the door release doesn't work.