TV flicker with light switches

TV flicker with light switches

Author
Discussion

beanbag

Original Poster:

7,346 posts

240 months

Wednesday 10th February 2016
quotequote all
I have a bit of a problem with my TV picture flickering every time I turn the lights on and off in my house.

It never used to do this so I'm not sure why it's happening now but I'll explain my set-up and what I've done up to now to try and fix it.

I have a Yamaha RX-V1900 amp with the following plugged into it:

- Sky+HD box (sound output is optical to the amp and not by HDMI)
- Apple TV (4th Gen)

This is then plugged into my TV all by HDMI cable.

The whole system is controlled by a Logitech Harmony system, and the Sky HDMI output plugs into an HDMI splitter to Ethernet extender so I can view the picture upstairs in my bedroom where I have an Ethernet to HDMI receiver.

I've no idea why but every time I hit the light switch the TV picture flickers. I've tried removing and trying everything individually but it's seems to be the amp is the culprit.

I thought perhaps there was a dip in voltage when I hit the lights so I decided to purchase an APC Voltage Regulator (keeping in mind it's already plugged into a high quality APC surge protector).

Nothing. Same problem. Somebody has suggested using a filter of sorts but the question is where and what is happening? I'd like to know before I splash out more money on more equipment!

Ideas?

beanbag

Original Poster:

7,346 posts

240 months

Wednesday 10th February 2016
quotequote all
anyone?

Salesy

850 posts

128 months

Wednesday 10th February 2016
quotequote all
How many lights on the circuit you are switching on? and what lights are they?

Does the same thing happen when you switch the kettle on?

megaphone

10,694 posts

250 months

Thursday 11th February 2016
quotequote all
Is it just the lights in the same room, or all lights?

Have you taken the surge protector out of circuit and tested again?

What type of lights do you have? Bulbs? low voltage down lights? 230v down lights? LED?

beanbag

Original Poster:

7,346 posts

240 months

Thursday 11th February 2016
quotequote all
Thanks for the replies.

I've had a play with my fuses and the lights appear to be on a different circuit to the plug sockets.

We also have a reverse air con unit that heats our home and the TV flickers when this comes on too, however since installing the voltage regulator, it has improved somewhat but it still occasionally happens.

Good point regarding the kettle. I'll try that tonight.

I've tried removing the amp from the surge protector and plugging it into the new voltage regulator, but not removed it entirely from any protective devices yet. I could try that tonight but I'm very hesitant to do that. It should be fine but going by what's happening now, I'm just cautious.

Regarding the bulbs in the house. They're all 230v LED spot bulbs. We've had them for well over a year now and until now, never caused a problem.

Also, on another point, I reduced the voltage regulator output to 220v. It was originally at 230v but I thought I could try a lower voltage as all my devices support this. (According to labels on the back).

I also tried 240v but the regulator reported a low voltage so we're at 220-230 in my home.

I've also been told to try a filter but not sure what this is....or could it even help? I've already got £120 of protection equipment!!!!

Cheers!


megaphone

10,694 posts

250 months

Thursday 11th February 2016
quotequote all
Why do you think you need a surge protector in the first place? Have you had issues in the past with dodgy power?

beanbag

Original Poster:

7,346 posts

240 months

Thursday 11th February 2016
quotequote all
megaphone said:
Why do you think you need a surge protector in the first place? Have you had issues in the past with dodgy power?
It's 100% needed. We get a lot of lightning storms and last big storm we had just over a year ago took out my amp so it had to be sent in for repairs.

I've had it on a surge protector since....

Watchman

6,391 posts

244 months

Thursday 11th February 2016
quotequote all
Does your surge protection keep a log? Would be interesting to see the size of the spike. You could then test switching things off and on all over the house without risking your AV kit.

I had a relatively cheap APC UPS once (£100) that you could download software for and keep an eye on things. It was quite interesting to see the mains voltage shift up and down from time to time.

beanbag

Original Poster:

7,346 posts

240 months

Thursday 11th February 2016
quotequote all
Watchman said:
Does your surge protection keep a log? Would be interesting to see the size of the spike. You could then test switching things off and on all over the house without risking your AV kit.

I had a relatively cheap APC UPS once (£100) that you could download software for and keep an eye on things. It was quite interesting to see the mains voltage shift up and down from time to time.
Nope, it's very basic stuff I have.

I have this voltage regulator:


http://www.amazon.co.uk/APC-LE1200I-Automatic-Volt...

And this surge protector (but with European sockets as I live in Spain):


http://www.amazon.co.uk/APC-PL8VT3-GB-Performance-...

Sadly there is no way to get a log. Is there anything I can buy to analyse this?

Also, would an RFI / Noise filter help?

megaphone

10,694 posts

250 months

Thursday 11th February 2016
quotequote all
beanbag said:
as I live in Spain):
Now you tell us!

beanbag

Original Poster:

7,346 posts

240 months

Thursday 11th February 2016
quotequote all
megaphone said:
beanbag said:
as I live in Spain):
Now you tell us!
hehe

Yeah, should have probably said that before. Just didn't think.

I've gone and bought some EMI/RFI graphite filters to put around the HDMI and power cables that I have. Reckon that will make much of a difference?

megaphone

10,694 posts

250 months

Thursday 11th February 2016
quotequote all
Yes dodgy Spanish electrics! smile

Does the amp have a ground/earth on the power lead?

beanbag

Original Poster:

7,346 posts

240 months

Thursday 11th February 2016
quotequote all
megaphone said:
Does the amp have a ground/earth on the power lead?
It should do. It's an IEC plug type.



I guess the next question is if the earth on the socket is actually properly wired in. How would I check that without electrocuting myself? I've got a multimeter that I can use....

Watchman

6,391 posts

244 months

Thursday 11th February 2016
quotequote all
I thought finding a suitable home electricity data logger would be easy on Google but apart from the wild answers Google gives me (axes and chippers for "logging"), the only relevant replies appear to be stupidly expensive.

There's a product from Owl but it only logs as granular as 12 second intervals, and I can't work out if it outputs to a PC where you can benefit from cheaper storage and better interrogation of the log files. For spikes, you need constant logging not interval-based. I'm surprised something cheap and relevant isn't more easy to find.

The software from APC was pretty decent but looking for the same now doesn't give me the results I remember. I'm sure it's APC's "smart" series that provides the software but I can't see exactly what I remember. For example:

http://www.ebuyer.com/81906-apc-sc420i-smart-ups-4...

Regardless, something like a full-on UPS will isolate your kit from the dirty mains but if you need more than a half KW output, they start to get expensive.

Watchman

6,391 posts

244 months

Thursday 11th February 2016
quotequote all
Yeah, here you go. It's the APC Powerchute software.

http://www.tomshardware.com/reviews/ups-rescue,166...

You need the UPS to be able to connect to and read the mains but you do get a chart.

Phew - thought I was going mad. Now you just have to find the cheapest UPS that will run this software I guess.

beanbag

Original Poster:

7,346 posts

240 months

Friday 12th February 2016
quotequote all
Cheers. I may very well return the APC voltage regulator but since I have 30 days with Amazon and I've ordered the graphite filters, I'm going to wait and try with these first. (Fingers crossed)!!!

westom

25 posts

159 months

Friday 12th February 2016
quotequote all
beanbag said:
I may very well return the APC voltage regulator
Read manufacturer specifications before buying it.

For example, that near zero protector will ignore all transients until voltage well exceeds 500 volts. Light switch created noise is a single or ten volt transient. Why would that APC do anything useful?

Voltage regulator also does not provide useful numbers. Especially since, well AC voltage can drop so low that incandescent bulbs dim to 50% intensity. Even voltage variations that great are already made irrelevant by a better voltage regulator already inside the TV - and all other electronics.

You have defined what is probably noise. No good solution can be recommended without first defining how a noise (created by that switch) is getting into the TV. Are filters on the TV's power supply so inferior (to other TVs) that tiny voltage spikes can blow through? Is the noise really getting into the cable signal thereby confusing that signal?

This much you know - switching is causing noise. And noise is causing signal interference. Were cable and AC electric properly earthed where both enter the building? Is some device on the cable between that incoming cable and TV? That box with an inferior filter on its power supply to then connect switch noise into the cable signal?

All are examples of what you must do to locate the defect long before buying any magic box solution.

Meanwhile those APC 'magic' boxes do little - and costs much. Especially a protector whose joules are near zero surge protection. But again, learn from spec numbers rather than just feel it is a quality product. Your solution is probably from some other manufacturer of integrity.

beanbag

Original Poster:

7,346 posts

240 months

Friday 12th February 2016
quotequote all
I'm still completely lost with everything however I made a bit of a discovery today.

I plugged in my multimeter into a socket and turned the lights on and off. When switching them off, the voltage would spike, sometimes to 1500v+

https://youtu.be/jdxSaMX9QAI

Is this normal? I also noticed the same when our A/C unit switched on and off and that's meant to be on another circuit....

Watchman

6,391 posts

244 months

Friday 12th February 2016
quotequote all
westom said:
Is the noise really getting into the cable signal thereby confusing that signal?
Ah - very pertinent. I thought about this but couldn't suggest a way of measuring it or mitigating it.

What if, for example, the EM noise isn't on the mains cable itself? What if it's induced onto the signal cable?.. or worse - just so persistent in your house that it's directly inducing noise in your AV kit's circuitry?

See if you can borrow a proper battery UPS, or even just an inverter that you can plug into your car battery. At least rule out (or in) that the induced EM is on the mains cabling.

westom

25 posts

159 months

Friday 12th February 2016
quotequote all
beanbag said:
Is this normal? I also noticed the same when our A/C unit switched on and off and that's meant to be on another circuit....
No way any appliance is creating 1500 volts. First, transient that would blow through internal protection inside all appliances. Second, that 1500 volt generator would destroy itself.

Your meter does report a transient. But remember, that transient is too fast for any meter to accurately measure. Frequency components of a transient may be causing strange behavior in the meter. That meter only says something is creating a transient.

Obviously an oscilloscope would make it easy. But other tools can be useful. For example turn a long wave and portable radio to a distant station. Then use that radio as a transient detector to locate source of that noise and wires that are carrying it. Same can be done with a long wave and AC powered radio to determine which circuits have greater noise - or if that noise is even one AC wires.

Watchman's UPS un-plugged from AC mains is another useful tool.

For example, a switch can be going bad; no longer operates with sufficient hysteresis or oontacts may no longer apply with sufficient force. Radio is even used by AC utilities to find defects long before those cause failures. IOW a switch may be operating similar to how early Marconi radios transmitted radio signals. Furthermore that switch behavior may change with certain loads removed. More relevant facts.

A noise transient is described that causes / interferes with the radio frequency signal. Next step is to identify the source and where it connects before trying to fix it. One thing we do know - no way anything is creating a 1500 volt spike for that long - and not destroying itself and other appliances.

BTW, in conferences where EMI/EMC/RFI is discussed, many if not most are bald. Because this problem causes much head scratching?


Edited by westom on Friday 12th February 22:49