TV Repair DIY

Bexm

Hello. 
I'm hoping someone can point me in the right direction..
Our TV is about 8 yrs old and at the time was a really high spec one  (before we knew better and had kids and spent too much money on silly things), it has now decided to develope a fault and has a dark shadow on the top and randomly turns its self off, sometimes won't come back on until the following day
I love our TV, picture is good, it has the right ports and has 3D which new TVs don't appear to and has freesat which we need due to lack of aerial. 
But we either need to fix it or buy a new one. 
As we're trying to save money and can't really make it any worse I want to attempt a fix myself.. But I need advice on how to trouble shoot, but not sure where to look.. I can solder, build/fix computers etc but never done anythings with TV but not afraid to try! 

Can anyone direct me to anywhere online that maybe able to help? 
Bex

Browntoa

Dark shadow is backlights failed , depending on model probably £50 for parts. Switching off is either power board or motherboard , maybe sourced off eBay or powerboard may have an obviously blown capacitor .

Personally , on an 8 year old TV I'd just buy a new TV 

jsmith9

Don't even think about trying to repair it yourself - if it catches fire and burns your house down you won't be best pleased ! 

Mickey666

Bexm said:

Hello. 
I'm hoping someone can point me in the right direction..
Our TV is about 8 yrs old and at the time was a really high spec one  (before we knew better and had kids and spent too much money on silly things), it has now decided to develope a fault and has a dark shadow on the top and randomly turns its self off, sometimes won't come back on until the following day
I love our TV, picture is good, it has the right ports and has 3D which new TVs don't appear to and has freesat which we need due to lack of aerial. 
But we either need to fix it or buy a new one. 
As we're trying to save money and can't really make it any worse I want to attempt a fix myself.. But I need advice on how to trouble shoot, but not sure where to look.. I can solder, build/fix computers etc but never done anythings with TV but not afraid to try! 

Can anyone direct me to anywhere online that maybe able to help? 
Bex

Search for the symptoms using the model number of your TV.  it's quite possible that others have had the same problem and have repaired it.
TVs today are little more than a computer anyway, unlike in the good old days of CRTs with very high voltages and live chassis, which meant it was not really advisable for any DIY work.  So the good news is that repairs are unlikely to be dangerous, though the bad news is that component-level repairs are going to be practically impossible unless you have some very specialised equipment for removing and replacing SMD components.
Having said that, from your description, the symptoms sound like failed backlighting and possibly some sort of failed PSU component, which shouldn't be too difficult to repair if you can find the correct info and spare parts.
Given that the only real alternative is to buy a new one, there's little to be lost by trying to repair it.

chrisw

Although charity shops such as the Heart Foundation shops often sell decent TVs with a warranty (think it's 6 months) for £50 - £100.

Bexm

Browntoa said:

Dark shadow is backlights failed , depending on model probably £50 for parts. Switching off is either power board or motherboard , maybe sourced off eBay or powerboard may have an obviously blown capacitor .

Personally , on an 8 year old TV I'd just buy a new TV 

Thanks @Browntoa, was also thinking backlights but it doesn't always have the shadow, the power cycling seems related. No shadow and it stays on..!
There's no obviously blow capacitors! 

I'd like a new TV but would have to be the cheapest one as can't afford much and be really annoying if it's not as good as our current one when I could have fixed it. 

Browntoa

TVs are normally tolerant of X amount of backlight LEDs blowing before it black screens. Are you 100% sure it's turning of and not just going completely dark ? 

Bexm

@Browntoa, 100% it clicks off.. Then back on and then off.. And gets its self in a loop every few seconds. 

Sometimes will do it 3 or 4 times and will then stay on, sometimes will get stuck and continually do it even after unplugged for a few hours..
Usually comes back on the following day tho.. For a bit at least!

Can sometimes interrupt it by using the power button on the actual TV and it will then stay on for a bit.

When it's got its self in a cycle it will only turn off when there's a picture on the TV, eg if you turn it on but leave it on a channel that has no signal, so only black and the channel ID box, but as soon as you put any picture on (via smart, hdmi, standard channels anything) it'll switch off again, which makes me think something about the lights or something that cause a picture overloads it and makes it go off.

The shadow came and went first for a few weeks then random turning off but would always come back on, then it started doing the power cycling.. And is getting more frequent, spent all Christmas even with no TV ! 

Mickey666

A failing PSU perhaps?

fred246

If you put your model number into spares sites you will sometimes find a certain part keeps popping up on every site. That's because that part is the part that always fails first on that TV. Other than that google the TV model number and look on youtube for videos for your TV.

spenderdave

Almost certainly intermittent backlights, the set will turn off it if detects it (by current flow). Although replacement led strips are available from various sources there is quite a lot of work stripping the set and screen down to replace them and this is accompanied by a risk of cracking the display panel (when it is most definitely unrepairable). Unless you know what you are doing and have done the job before (including seeing a panel crack before your eyes - and ears) do not even think of doing it yourself.