Why is my HDMI signal dropping out?
The HowToAV team takes a look at some simple quick fixes if your HDMI cable signal is failing or your HDMI device isn't displaying correctly on your TV or screen.
When it comes to connecting an AV source such as your Sky TV, Blu Ray player or Xbox to your TV or display, it's more than likely that the video cable you'll be using is a HDMI cable. But what happens if the picture disappears, or even worse, no picture appears in the first place?
Here are some simple fault-finding solutions when your HDMI input doesn't give you an image.
What to do when there is no video signal?
If your HDMI audio video signal is faulty, not working or repeatedly dropping out - then don't panic! - there's probably nothing drastically wrong. It could be something as simple as a loose connection on the back of the AV source device, or just a simple cabling issue. This brings us to the first point of our top tips to start with - to check the basics!
Check your HDMI cables and connections - Make sure that everything is seated in the right place, plugged in where it should be, connected properly. And also - as simple as it sounds - check that the power to your source device is switched on of course. (We're all guilty of it!) It could be the power's not been switched on and, therefore, no signal can pass through.
Try changing the HDMI input - Your HDMI video signal includes more than just video and audio signals. Among other things it also includes EDID (Extender Display Identification Data) and HDCP (High Bandwidth Digital Content Protection). These additional signals are designed to provide better compatibility and security between the devices on your home entertainment / AV system.
However - these additional communication signals between your devices need to repeatedly complete successful 'handshakes'. If that handshake isn't being met, in effect your audio video devices will stop communicating with one another and the HDMI signal might fail or repeatedly drop out. So simply by changing the HDMI channel from 1 to 2, could solve the problem and then present you with your image.
Top tips to fix a HDMI fault:
- Check there isn't a loose connection on either the Source or Display end of the HDMI cable.
- Try disconnecting and reconnecting the HDMI cable at each end.
- Check the obvious! Is the Source device (eg. DVD / BluRay player) switched on?
- Try changing HDMI channel inputs on your display - there may be an issue with either the EDID or HDCP 'handshake'.
- Is the HDMI cable itself faulty? Try an alternative HDMI cable.
- Try altering the resolution - the display device may not be capable of supporting the resolution the Source is trying to deliver.
- If the HDMI cable distance is longer than 10 metres, then it may be worth considering a HDMI Repeater or HDMI Extender kit.
What is an HDCP handshake?
HDMI / HDCP Handshake issues occur when the source doesn't accept the keys from HDMI Distribution equipment. HDCP handshaking issues are problems with Video or Audio on your display (Most commonly caused by a High-bandwidth Digital Content Protection (HDCP) encryption.
Can HDMI cables fail?
If you are still having HDMI signal problems after going through these tips, it could be a faulty HDMI cable. Either it's brand new and some things don't work straight away out of the box meaning it could be that the cable is not working. Or the HDMI cable has failed or been damaged. The most common course for a problem is a bad connection between the HDMI cable and the device. This is common if you are plugging and unplugging the cable regularly. A simple HDMI cable tester might tell you if the cable is wrong or you can simply try another cable and hopefully this will rectify the problem and give you the image that you need.
What resolution is your system set to?
It's important to check that the HDMI output resolution of your AV Source device matches that of your TV/screen resolution. If the source is giving the incorrect resolution and is too high for the screen to handle, you're likely to experience signal drop out or no display atall. So if you drop down the resolution on the source, this may then give you the image on the screen.
Is there a standard HDMI cable length limit?
Checking the cable distance/length is another HDMI troubleshooting tip. Though we do offer some general guidance on HDMI cable distance limitations, there are a whole host of technical and environmental factors that can affect the performance of your HDMI signal/cable and therefore, the distance your signal will transmit.
We always recommend testing your HDMI cables and devices prior to installation. But after installation there are additional factors which may affect the signal performance:
- Resolution / Bandwidth
- Transmission distance
- Interference (from other electrical/electronic devices or cables
A simple test to check if your HDMI cable is exceeding the distance of your AV system is simply to temporarily move your devices closer together and reconnect the system using (tested!) shorter HDMI cables.
If the signal fault has gone, then you need to consider a better quality or high speed HDMI cable.
Alternatively, you could try a HDMI Repeater to improve the signal or a HDMI Extender Kit which allows HDMI signals to be transmitted over distances of 40-100metres.
Any other cable trouble-shooting tips?
In summary when you're fault-finding, just try to change one thing at a time. If you try and change too many variables, you're never really sure which part of the system might be wrong, so, try one thing, if that doesn't work, move onto the next. And secondly don't panic. It probably is nothing too severe, just try and work through the problem methodically.
Want help with HDMI products or system design?
CIE is one of the UK's leading and most innovative professional AV distributors and is a leading provider of HDMI and HDBaseT professional systems and devices.
With over 50 years experience in supply and system design for many of the UK's largest, high profile audio projects, our AV experts provide a unique level of technical support and customer service.
Call the CIE AV experts now on T. 0115 9770075 or email us at [email protected]
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