The magic kitchen lightswitch!

[Tomscar]

My fancy Sony Bravia TV started doing this just after Christmas … the screen would go black momentarily when switching the kitchen lights on or off and and return to normal after a few seconds. Not a random coincidence, I could do it at will!

Scratched my head and tried working out what had changed or been added to the electrics recently … added PS5, an Alexa and USB charging station.

Unplugging these made no difference.

Lightbulb moment … I'd changed the HDMI Signal Output setting on the Denon AV amp to 4K ‘Enhanced’ mode to take advantage of the UHD signal from the PS5.

My HDMI cables were installed before 4K ‘Enhanced’ or UHD was a thing and returning the Denon back to HDMI 4K ‘Standard’ sorted the problem … it appears the HDMI cable from the Denon isn't good enough or the correct standard. I live and learn.

 

[Sootywg]

I thought for a moment you were saying that the tv was switching the lights on and off!
Re read and now understand

 

[Tomscar]

I thought for a moment you were saying that the tv was switching the lights on and off!
Re read and now understand

Hi Sootywg ... it does read like that, I'll rephrase it

 

[PlasticMac]

My fancy Sony Bravia TV started doing this just after Christmas … the screen would go black momentarily when switching the kitchen lights on or off and and return to normal after a few seconds. Not a random coincidence, I could do it at will!

Scratched my head and tried working out what had changed or been added to the electrics recently … added PS5, an Alexa and USB charging station.

Unplugging these made no difference.

Lightbulb moment … I'd changed the HDMI Signal Output setting on the Denon AV amp to 4K ‘Enhanced’ mode to take advantage of the UHD signal from the PS5.

My HDMI cables were installed before 4K ‘Enhanced’ or UHD was a thing and returning the Denon back to HDMI 4K ‘Standard’ sorted the problem … it appears the HDMI cable from the Denon isn't good enough or the correct standard. I live and learn.

I'd check the kitchen lights circuit, especially the switch. Something is electrically noisy, I think.
Mac.

 

[Tomscar]

I'd check the kitchen lights circuit, especially the switch. Something is electrically noisy, I think.
Mac.

Thanks Mac, I was thinking the same at first then Google directed me to some of the AV forums ... it appears to be happening to some if using eARC HDMI with the wrong cable between TV and AV Amp ... mine's only a standard HDMI 1.4 cable and tested to pass 1080p (Blu-ray) bandwidth, it was fine for how it was previous.

The UHD 4k all singing and dancing output from the PS5 needs at least an HDMI 2.0b or 2.1 cable that wil allow upto 48 Gbps ... apparently all the HDR, VRR, 4K enhanced functions uses a massive bandwidth, wouldn't have crossed my mind if I hadn't read it!

The AV experts think the (wrong) cable acts like a bottle neck as it's being pushed to it's limit and electrical equipment such as microwaves or light switches can give enough of brief spike to upset the HDMI and blackout video and audio.

I think they're right in my case ... changing the settings back to 4K from 4K enhanced limits the bandwidth and the problem disappears ... and can be recreated by switching back to enhanced.

I've ordered a 2.1 cable and crossing my fingers

All the best ... Tom

 

[L162LZ]

Thanks Mac, I was thinking the same at first then Google directed me to some of the AV forums ... it appears to be happening to some if using eARC HDMI with the wrong cable between TV and AV Amp ... mine's only a standard HDMI 1.4 cable and tested to pass 1080p (Blu-ray) bandwidth, it was fine for how it was previous.

The UHD 4k all singing and dancing output from the PS5 needs at least an HDMI 2.0b or 2.1 cable that wil allow upto 48 Gbps ... apparently all the HDR, VRR, 4K enhanced functions uses a massive bandwidth, wouldn't have crossed my mind if I hadn't read it!

The AV experts think the (wrong) cable acts like a bottle neck as it's being pushed to it's limit and electrical equipment such as microwaves or light switches can give enough of brief spike to upset the HDMI and blackout video and audio.

I think they're right in my case ... changing the settings back to 4K from 4K enhanced limits the bandwidth and the problem disappears ... and can be recreated by switching back to enhanced.

I've ordered a 2.1 cable and crossing my fingers

All the best ... Tom

How longs the HDMI cable Tom? I've had problems in the past with my setup because I needed to use cables around 7m long and HDMI signal at 4k is touch and go at that length. In the end I swapped the std cables for Fibre Optic cables (HDMI and DisplayPort) they're quite expensive but I've never had any problems with signal interference or loss since

 

[DarkInferno]

I'd personally swap your kitchen light switch out anyway as it may be arcing noise from worn/damaged contacts that is interfering with your signal, and for the price of a light switch its not worth not doing just for peace of mind.

If you have a florescent tube light in the kitchen the ballasts of these can be notoriously noisy especially when they start to get some age on them.

 

[Tomscar]

How longs the HDMI cable Tom? I've had problems in the past with my setup because I needed to use cables around 7m long and HDMI signal at 4k is touch and go at that length. In the end I swapped the std cables for Fibre Optic cables (HDMI and DisplayPort) they're quite expensive but I've never had any problems with signal interference or loss since

Thanks for the heads up L162LZ ... all the inputs to the Denon amp are fairly recent 1 metre length HDMI 2.0 ... I've two monitor outputs from the amp hidden in the walls, one to the TV and the other to a 1080p projector ... both these are on the long side at 10 metres. All worked great before adding the PS5 ...

What I've noticed and now starts to make sense ... if I stream Amazon Prime movies direct from the TV through eARC they don't show as Dolby Atmos on the Denon display. Hoping this is down to the 1.4 cable.

I did see the fibre optic cables and may have to go down that route.

 

[Tomscar]

I'd personally swap your kitchen light switch out anyway as it may be arcing noise from worn/damaged contacts that is interfering with your signal, and for the price of a light switch its not worth not doing just for peace of mind.

If you have a florescent tube light in the kitchen the ballasts of these can be notoriously noisy especially when they start to get some age on them.

Thanks Darkinferno, yes that's great advice about the light switch from you and Mac and can swap for a new one ... the HDMI cable is 10 metres long and installed into the wall about ten years Old ... I don't think Ultra HD was even a thing in home theatre back then

All the ceiling lights are modern flush mounted LED units and the only pendant lights are over a worktop and these also have LED bulbs. It's only happening when the pendant lights are switched on and off. I wonder if it's the LED bulbs ... and the lightswitch seems a good shout also.

 

[L162LZ]

Thanks for the heads up L162LZ ... all the inputs to the Denon amp are fairly recent 1 metre length HDMI 2.0 ... I've two monitor outputs from the amp hidden in the walls, one to the TV and the other to a 1080p projector ... both these are on the long side at 10 metres. All worked great before adding the PS5 ...

What I've noticed and now starts to make sense ... if I stream Amazon Prime movies direct from the TV through eARC they don't show as Dolby Atmos on the Denon display. Hoping this is down to the 1.4 cable.

I did see the fibre optic cables and may have to go down that route.

My std cable worked ok for a few years but then as connections oxidised it started to drop out regularly and screen would go black for a few seconds. The fibre cables on the longer runs sorted this. Also if you have very long runs you can get hdmi to cat5 or 6 converters. Have used these in the past in some of our conference rooms in the office. Have a set here if you need to try them, think they're only 1080p though, not 4k
Regards Dave

 

[Tomscar]

My std cable worked of for a few years but then as connections oxidised it started to drop out regularly and screen would go black for a few seconds. The fibre cables on the longer runs sorted this. Also if you have very long runs you can get hdmi to cat5 or 6 converters. Have used these in the past week n some of our conference rooms in the office. Have a set here if you need to try them, think they're only 1080p though, not 4k
Regards Dave

Thanks for the kind offer Dave, I've a new lightswitch and a high-speed 2.1 cable coming tomorrow, will see how it goes and hopefully have UHD working and no blinking telly ... I'll update when it's done

 

[L162LZ]

Thanks for the kind offer Dave, I've a new lightswitch and a high-speed 2.1 cable coming tomorrow, will see how it goes and hopefully have UHD working and no blinking telly ... I'll update when it's done

These are what I use for any HDMI runs over 10m. Actually they do support 4k up to 40m and 1080p up to 70m. I hadn't realised as the AV setup in the offices was only 1080p as the streaming setup couldn't cope with anything higher

 

[Tomscar]

These are what I use for any HDMI runs over 10m. Actually they do support 4k up to 40m and 1080p up to 70m. I hadn't realised as the AV setup in the offices was only 1080p as the streaming setup couldn't cope with anything higher

Thanks Dave, maybe have to go down that route and all information gladly received

 

[Tomscar]

Just an update as promised ... what an operation that was but all seems well now ... and learned a few things I hadn't realised were things!

While waiting for the postman to deliver the new light switch and hdmi cable I unplugged the existing cable from the TV and tried to recreate the light switch blacking out the screen ... the light switch didn't have any effect and the TV was normal ... doesn't prove the light switch is okay, just that the whatever is causing it seems to be via the hdmi cable.

Reconnected the old cable and can recreate the issue.

New HDMI 2.1 cable now installed between the Denon AV amp and the eARC TV output with all hdmi outputs again set back to 4K enhanced mode.
The problem appears to be fixed with no blinking screen.

Checked the connections in the light switch and maybe one was less tight than the other ... have a new one if needed.

Spent a few hours today reconfiguring how the hdmi interacts between each piece of kit and happy with the results.

Couldn't workout why the Denon amp wasn't displaying Dolby Atmos when watching an Amazon Prime movie (that's one advertised as being Dolby Atmos.)

A lot of googling and discovered that Amazon Prime movies appear to use the DD+ codec to stream ...it is compressed and not really pure Atmos.
The PS5 will play an UHD Blu-ray in Atmos if fed direct to the amp, but then you compromise the picture for HDR, VRR and all the other goodies that transform the visuals ... my current amp is from 2017 and not 2.1 compliant so can't pass the full package through to the TV.
Temporary solution is to link PS5 to Sony TV directly and use eARC back to the amp ... the picture and gaming is transformed but a slight compromise in that the amp now displays Dolby Tru HD when playing an Atmos Blu ray instead of Atmos.
I really can't tell the difference listening but believe it's the same codec in any case.

Pass me the paracetamol please

 

[L162LZ]

Just an update as promised ... what an operation that was but all seems well now ... and learned a few things I hadn't realised were things!

While waiting for the postman to deliver the new light switch and hdmi cable I unplugged the existing cable from the TV and tried to recreate the light switch blacking out the screen ... the light switch didn't have any effect and the TV was normal ... doesn't prove the light switch is okay, just that the whatever is causing it seems to be via the hdmi cable.

Reconnected the old cable and can recreate the issue.

New HDMI 2.1 cable now installed between the Denon AV amp and the eARC TV output with all hdmi outputs again set back to 4K enhanced mode.
The problem appears to be fixed with no blinking screen.

Checked the connections in the light switch and maybe one was less tight than the other ... have a new one if needed.

Spent a few hours today reconfiguring how the hdmi interacts between each piece of kit and happy with the results.

Couldn't workout why the Denon amp wasn't displaying Dolby Atmos when watching an Amazon Prime movie (that's one advertised as being Dolby Atmos.)

A lot of googling and discovered that Amazon Prime movies appear to use the DD+ codec to stream ...it is compressed and not really pure Atmos.
The PS5 will play an UHD Blu-ray in Atmos if fed direct to the amp, but then you compromise the picture for HDR, VRR and all the other goodies that transform the visuals ... my current amp is from 2017 and not 2.1 compliment so can't pass the full package through to the TV.
Temporary solution is to link PS5 to Sony TV directly and use eARC back to the amp ... the picture and gaming is transformed but a slight compromise in that the amp now displays Dolby Tru HD when playing an Atmos Blu ray instead of Atmos.
I really can't tell the difference listening but believe it's the same codec in any case.

Pass me the paracetamol please

Glad it's sorted for you gets very complicated especially if you want to get 4k through from multiple sources. My own issue was HDCP related as my "old" 4k monitor (NEC X651uhd) only supports HDCP 1.4 which was ok for input from my home theatre PC via Display Port but Amazon fire cube etc.. over HDMI will only allow 4k to HDCP 2.2 devices. I ended up using one of these in the output from the amp to spoof the later HDCP before I could get it to work properly!