Samsung TV - Most of the screen has dimmed!

[rz82]

Samsung TV - Most of the screen has dimmed!

Hi everyone!

I hope you can help me with this one. My father is bedridden and loves TV...well he doesn't have anything else in his life sad.gif Unfortunately his TV has now dimmed and only a small part of it remained bright.

Please see below links:

FAULT: https://s24.postimg.org/577ytgp5h/tv_fault.jpg
LABEL OF TV: https://s27.postimg.org/9qstufaoj/tv_label.jpg

What can we do about it? we cannot afford to take the TV for repairs, I thought of sourcing the part myself and fixing it for him....would be grateful for your help.

Thanks

PS: I can manage to open TV, dismantle parts etc so I think I would manage

[downunder]

A tricky one, rz. The display is backlit by fluorescent tubes which don't display this type of behaviour. Suggest a few things.

Unplug the tv and disconnect the cable between the power supply and the main boards. Plug the tv back in and it should switch on and display backlights. Note if one side is still dark or if you get normal brightness across the entire screen. Not all Samsungs do this, so don't be dismayed if naught happens.

Between the main board and the small T-con board is a flat cable. Pull the connector at each end in and out a few times in case of dicky connections.

Between the T-Con and the display there are two flat cables. Pull out one cable and turn the TV on. Refit it and do the same with the other cable and report your findings.

Bruce

[rz82]

Hi dowunder...many thanks for your reply

I tried what you said but when I disconnected the main board from the PSU the TV wont turn on :) I cannot see any blown capacitors or dome shaped ones. Also I reseated all cables inside and the fault persisted. Could not locate any flat cables though....where is the T-con board located? Below are some photos I took this morning

https://s23.postimg.org/ixrgwedy3/tv_psu.jpg
https://s27.postimg.org/foedocs5f/tv_components_view.jpg
https://s28.postimg.org/4z8oucgul/tv_cable.jpg
https://s29.postimg.org/6v708xc2v/tv_mainboard.jpg
https://s23.postimg.org/7kksi4sd7/tv_backlight_part.jpg

[bonesy]

Very odd fault,a couple of questions come to mind.
Has this been a sudden thing or has it got progressively worse?
Have gone through the basics & checked the customer control settings,if there is a back light control bright dim ,where is it set?also some have an eco power mode,if so switch it off.It could just be,if set is on 24/7,then the back lights are just worn out & some how still just lighting,or the screen it self has had screen tab failure,which can cause drastic shading.

[downunder]

Hi rz,

T-Con is shown in your 2nd picture at top centre of the panel. My mistake, the cable is made up of twisted pairs. The connector at the bottom of the T-Con (under the metal shield) is the one you need to pull off and on a few times- remove that white glue first. You can observe the screen while doing this to see if there's any improvement.

Remove the T-Con cover and at the top of the board you'll see the other 2 flat cables. Each cable controls left half or right half of the screen. These are the ones I'd like you to disconnect one at a time and note the effect on the screen. Let us know the effect.

Bruce

[Turnip]

Picture is interesting as although bright RHS and dark in the centre the LHS is slightly brighter, also the change in brightness is very gradual which wouldn't be expected with a screen issue.

As we can't know the actual brightness, just relative brightness, tend to suspect it's an odd inverter issue, as in that case, ends can be brighter than the middle, esp. if tubes are all in parallel - Chris.

[rz82]

Checked connections again to no avail....:(

I ve posted the below links for a better view of the fault and how the TV is designed:

https://www.dropbox.com/s/qnhbwh7bwbu6zka/20170202_075639.mp4?dl=0
https://www.dropbox.com/s/7x827imbcfv2p5r/20170202_075718.mp4?dl=0

[downunder]

In your very first picture in your original post, what are all those artifact that appear just below the centre net of the court? I'm still intrigued by this problem.

If the backlight fluoros are that bad, as some portend, the TV's protection system should extinguish them totally. I'm leaning towards a bad LCD display.

You give no indication that you've tried unhitching the 2 flat leads at the top of the T-Con, one at a time, so we can see what effect it has in each half of the screen.

Bruce

[vinceroger69]

as your set looks like it uses two inverter boards one left one on the right is it possible one is faulty and the one board is trying too drive all the lamps hence not fully lit.

[rz82]

In your very first picture in your original post, what are all those artifact that appear just below the centre net of the court? I'm still intrigued by this problem.

If the backlight fluoros are that bad, as some portend, the TV's protection system should extinguish them totally. I'm leaning towards a bad LCD display.

You give no indication that you've tried unhitching the 2 flat leads at the top of the T-Con, one at a time, so we can see what effect it has in each half of the screen.

Bruce

The artifacts you are seeing are our reflections :)

[Davy]

It would be easy to see if it's the backlights or not.... this *might* be clearly visible looking from inside the set, sometimes there's unused holes in the metal frame that allows a glimpse of light to be seen, sometimes the light can also be seen around the tube connectors.

How about a T con fault as well as a screen problem that's already been mentioned?

Dave