Could an electrical problem cause an intermittent fault with our TV?

[Debian]

Hi all,

I’m not an electrician by the way, I am just an average Joe looking for some advise.

About a month ago we bought a cheep LCD TV for the kitchen.

After a month, the TV would intermittently display a white picture, you could hear audio but could not see a picture.

I tried a different set top box, a different cable and a DVD player. The fault stayed with the TV

We took the TV back to the shop, but they could not find a fault with it.

We took the TV home, continued to use it, again the same fault happened.

We took the TV back to the shop, this time they replaced it. They did not test it this time.

After about two days with the new TV, the screen went black - again audio could be heard.

There is no pattern, some times the picture is fine, sometimes not. Once we lose the picture, we turn it off at the mains, then back on, sometimes this cures the fault. Sometimes it doesn’t.

Now we have moved the TV into another room to see if the fault follows, after two days it has not happened again.

I am beginning to think the power at the mains is faulty.

Is there a device I can plug in to the mains that would show me if mains in the kitchen was fluctuating or not providing enough output?

I had thought “we’ve got a another faulty TV”. But in our bedroom, one of the mains sockets sends my wife’s alarm clock mental. The LCD display looks shafted with a dodgy display.

I am just wondering if the mains is flaky.

We have only been here 6 months. None of the other mains outlets seem to cause a problem.

Could it me another dodgy TV?

 

[Spudnik]

Im sure one of the others may give you better advice, however, i would first suggest that maybe employ the services of a competent electrician to carry out an inspection on the electrical installation to make sure everything is as it should be.

Oh and welcome by the way

 

[mnmwill]

Agree with Jason on this m8, call a local Electrician and arrange to get your installation tested.

 

[Griz80]

Most of the time when you connect AV equipment to the television and you have sound and no picture it means there is an issue with the scart lead - either it isn't pushed in all the way, the scart connection is faulty or the scart lead itself is faulty ( check the pins).

 

[ghost]

Definately sounds like there may be a problem on the first circuit if it does not do it when it is plugged in elsewhere in the house. I agree you need somebody to look at it. If you let us know where you are maybe somebody on here may be local to you.

 

[ian.settle1]

Definately sounds like there may be a problem on the first circuit if it does not do it when it is plugged in elsewhere in the house. I agree you need somebody to look at it. If you let us know where you are maybe somebody on here may be local to you.

How do you know that the 2 rooms are on seperate circuits it could be as suggested that it is the scart lead not plugged in properly asr that the when the TV is moved the plug is not making correctly after firtst plugging in.

But there again he did say it was a cheap TV so it could be down to a bad batch being manufactured

 

[Debian]

How do you know that the 2 rooms are on seperate circuits it could be as suggested that it is the scart lead not plugged in properly asr that the when the TV is moved the plug is not making correctly after firtst plugging in.

But there again he did say it was a cheap TV so it could be down to a bad batch being manufactured

Thanks to everyone for replying.

I have tried a different cable. The TV is using HDMI. As part of my extensive diagnosis, I did try a scart cable. It still had the same fault.

To confirm, I tried a DVD player through scart and HDMI on two freesat boxes. The TV is the common denominator!

I only really thought mains could be the fault because our bedroom appears to have a dodgy socket as well.

From the replies I've seen, it looks like I need to get an electritian.

What are the potential cuases and fixes of this?

I imagine it's hard to say, but is this type of fault a massive job to fix?

 

[mnmwill]

Try and have a look here m8 http://www.electriciansforums.net/e...lectricians-your-area-local-electricians.html.

You may find asomeone local to you who you can contact to have a look first hand.

Good Luck

 

[Madmole]

I would suspect the aerial personally, or a reversed polarity somewhere

 

[Adam W]

Yes, I think a polarity check would be a good start.

 

[sparkdog]

I would suspect a faulty telly or freeview box.Many faults are temperature sensitive and even a few degrees can make a difference.The most common fault on LCDs is a blank screen with sound usually caused by the inverter board and if its a cheap telly its not worth doing.Also modern tellys use lead free solder which is pretty useless and rapidly goes brittle causing dry soldered joints.Unlikely mains fluctuations would cause any problem as most sets now are highly stabilised and filtered and work OK down to 100 volts or less.

 

[Sparkymarky72]

Hi Guys,
I am new to the forum, but I am a rare breed an AV Engineer with a 17th edition and electrical install experience,

SO HERES YA ANSWER! -

only 2 things can cause the faults your describing ..

1. IS AN INCOMPATIBILITY between the devices that are rigged up on the HDMI bus on your TV - ie one device is sending a lower/ or higher HD frequency than the other.(trying turning on/off alternatly) / or TV has a problem with a resolution its receiving. 570p 720p 1080i/p so on...(also use good HD cables) - You did say TV was cheap though...

2. The other is a frequency problem in your mains supply ie - its slightly higher/lower than 50hz or fluctuates or is dirty, - Try a filter extension lead -and get a good one - Probably going to cost more than TV did though...

An LCD tv mainly runs on low voltage DC although the mains is 240v AC it has a built in power transformer to convert to about 30-40v DC, to run the electronics Its only the screen itself that relies on the mains frequency and it also uses a power INVERTER to back light itself so you can see the image!

-A typical 40" screen only runs at about 80watts consumption-

But this inverter/convertor changes the low voltage DC voltage to around 400v DC (but not a lot of current) to light/run the screen - Its even higher in plasma screens... So you can see why resolution and mains frequncies are important.

 

[Golden_Boy]

There is No way an AC supply can cause any of thse problems.... I will stake my reputation on it .. 40 years repairing TV setds allows me to say ... Take it back, get a refund and buy a decent product...

 

[Sparkymarky72]

Yes, It can - especially when it comes flat screen sets, - BTW I was a senior engineer at the dome in the Millennium - Looks like your reputations screwed! - good luck

 

[Spa Key]

Yes, It can - especially when it comes flat screen sets, - BTW I was a senior engineer at the dome in the Millennium - Looks like your reputations screwed! - good luck

Looks like yours is screwed as well.

But seriously, we all have differint opinions on subjects, nobody can stand up and say 'I'm right' until they've actually found the problem.

What make is the TV by the way?