Plasma tv interfering with DSL connection. Please Help

Hi there, i am new to this so please be gentle lol.
My DSL connection keeps dropping everytime i switch my plasma tv on, this has only been happening for the past 6 days and i have had the tv a year, and the same wireless router since 2007. I have been and bought a new router which makes no differance what so ever and moved the router to the other side of the house which makes no difference too. I was wondering if anyone would know if buying a power conditioner would make any difference to this. It would be greatly appreciated if anyone could help or who has had the same problem.

What else has changed?

It could be that the background noise on the line has changed significantly and that the additional EMI/RFI from the television is enough to cause a loss of sync, OR the television has an internal problem and is causing a lot more EMI.

The EMI is probably radiated rather than conducted and a power conditioner is unlikely to make any difference.

Where does the phone line run?

Can you get the router stats for the line with television off, just after switch on and a few minutes later.

Might also be worth getting Router Stats Lite, set the sample time as low as it can go and run that whilst turning the television on and seeing how the SNR jumps around.

Edited by MHC (Wed 25-Jan-12 09:11:10)

If you have any phone extensions then try the modem from the test socket under the removeable faceplate on the master socket.

If that works then fit an ADSL faceplate.

Another option is you have diy phone extensions using flat cable replace it all with CW1308 spec cable, the twists help to reduce the effects of interference

hi there, thank you for replying. I will state i am not that up on computers etc so need things explaining in simple terms lol. The only things that has changed back in Nov last year i bought a sony 3d surround sound system, the Dsl light and the online light stays on while the surround sound is on. Within 3secs of turning the TV on the Dsl light flashes and goes off and the online light too. The phone socket is behind the tv along side the hdmi cable for the sky, i have no phone cable plugged into the sky. I have plugged the router into the test socket behind the faceplate on the wall, and the Dsl light stays on but router will not go online.

Almost certainly there is a large amount of radiated Electro Magnetic Interference or Radio Frequency Interference (EMI / RFI) being created and that is reducing the headroom the DSL signal has - referred to as Signal to Noise Ration (SNR) or how much greater the signal is than the background noise. If the SNR drops too low the modem cannot hold sync and will drop out.

Your first move should be to disconnect EVERY connector on the TV, Sky box, Sony Surround Sound, Speakers, DVD player, Amplifier &c and I mean EVERY one. And then refit all of them ensuring they are fully home. A connector with some corrosion can be a source of interference.


How long is the cable from socket to modem - and what type is it?

hmmmmmm i am not sure what kind the cable is but that has been replaced with a new one since i have been having problems and i have done the same with the filter too. The cable is approx 2 metres long. I have removed every cable the other day from my appliances, but i will do it again and see if i can come up with anything.

Is the phone socket a master or extension?

Having removed and replaced cable sonce - no need to try again. It was to ensure ALL were firmly installed.

Can you get a long, twisted pair, phone extension and try te modem well away from the TV?

Master. the Tv is at one end of the house and my bedroom at the other which has a phone socket in too, so i tried it in there, the self same thing happens when plugged in there, so thats why i havent bothered with an extension because i didnt think it would make any difference, with it not even working in the bedroom.?

You are right ... and have tried most of the simple things!

Is the ring wire connected from Master to Secondary? Wire on terminal 3. If it is, remove it at both ends.

After that, you need to start looking at RFI issues and that is a black art! I would start looking at moving the TV away a meter or so. Try again, DSL works then it is radiated RFI, if DSL fails could be anything. Try at 2m and see what happens. If it is caused by radiated RFI then put a sheet of aluminium foil between TV and router and try again.


What may have happened is a component in the TV has failed or partially failed but not so that it can be seen does not cause the TV to fail.

Sounds like the TV or electrical supply (or plug/socket etc.) may be failing or having a problem.

Try running an extension lead from another part of the house (preferably from a different ring main - from the kitchen or upstairs perhaps) so the router and TV are on different circuits to see if that changes anything.