Toshiba 46RV53CU - possible bad tab bonds or tcon?

[retiredcaps]

I'm trying to fix Toshiba 46RV53CU 46 inch LCD TV for someone.

History
=======
It was purchased brand new from Costco. The TV was made in August 2008. In 2009 it was serviced under warranty because it couldn't be turned on/off with the remote control. Now it is out of warranty.

Symptoms
========
When you turn it on, it has ghosting images. I'm told that after the TV warms up, typically 5 minutes, the ghosting images go away. They put this TV away for several months and they got a new TV. So whatever they told me may not be true anymore.

I have only had it for a couple of hours, but when I left it on for about 30 minutes, the "no video signal" ghosting image never went away.

It wasn't until I pressed the top right hand corner (when looking from the front) together that the ghosting went away.

I then unplugged the TV for about 30 minutes and let it cool down. After I turned it back on, the "no video signal" was ghosting again so I immediately pressed the top right hand corner and the ghosting went away.

I notice that if I gently twist and flex the TV, the ghosting will come and go even when the TV is warm. Once the ghosting goes away it will stay away, but I don't know for how long because I only watched it for about 20 minutes.

Analysis
========

1) I'm thinking the tcon is good.
2) I could have the infamous tab bond issue because this is a Samsung panel.
3) I could have a dodgy solder joint or connection somewhere along the thin panel board that runs the entire length of the TV.

Next Steps
==========

1) I will leave the TV off overnight and try flexing it again when it is cold to see if the ghosting goes away or not.
2) I will try reseating and cleaning the t-con connector.
3) I'm a bit hesitant to take the entire TV apart to get at the tab bonds, but will do so if people don't have any other suggestions.
4) From what I understand tab bonds are not fixable by the DIY even though "bumpers" might provide a temporary fix.

Suggestions are welcome!

PS. Believe it or not, even though I have participated and successfully helped "virtually" repair other people's TV, this is my first actual hands on repair on a LCD HDTV.

[Mr Bill]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

Pressing on the exact same spot clears the image along with twisting it is a pretty textbook diagnosis of tab bond failure. I am amazed that this is your first lcd repair with a 5500+ post count

[tibimakai]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

I agree with Mr.Bill. I'm in the same boat as you, but with a 46" Vizio(I haven't checked yet what brand of panel it has).
Hopefully I can do that wire resistor fix and it will be a permanent fix.

[retiredcaps]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

I am amazed that this is your first lcd repair with a 5500+ post count

Two years ago I would have NEVER thought I would be a regular contributor on this board. I was a complete electronics beginner in every aspect, but posts by mainly PlainBill caught my interest so I started following along and the adding some value here and there.

I have lots of hands on with computer lcd monitors which are essentially the same technology as a big screen lcd HDTVs. I usually get them for free or $5, but getting a free "broken" HDTV is usually difficult and I have not been actively looking so I do more "virtual" repairs than anything.

Additionally, a lot of the "broken" TVs are 2nd or 3rd tier crap low end brands and 40 inch or smaller. I have no interest in these crap TVs for myself, but paradoxically, I will happily fix the crappiest 17 inch no name lcd monitor if I can get it for free.

[tibimakai]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

just begin selling TVs and you will be switching fast from monitors to TVs.

[cashkennedy]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

I like working on monitors, as theyre usually much easier / cheaper to fix.

As the other people have said, this is classic bad top left tab. You meet every possibly symptom of this problem
46/52 screen size
samsung panel
pressing corner fixes problem
flexing screen fixed problem
problem fades when warmed up.

Using foam tape / or other methods, you can get the tab to stay down, and many people have been able to use the tv's succesffuly every since (1-1.5 years now, since most people started seeing these issues around 1 year ago).

You could also try the 10 watt resistor technique that is highly succesfful on 32" sony's , and as far as i know im the only person to ever try it on a 40" and it worked well. But 32" and 40" sonys have a different issue i believe, which is recognizable because pressing no tab makes the problem go away, and the ghosting is even across the whole screen. On the other hand the samsung 46/52 inch panel tab bonding ghosting issue is usually really bad on 1 side of the screen and no ghosting on the other side.

[cashkennedy]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

Incase you havent seen the videos

This is a fairly good video of the 46/52" tab bonding probem
http://www.youtube.com/watch?v=vCExlSnG4yY

and this is a video of the 32" (40") 10watt resistor technique
http://www.youtube.com/watch?v=9UrTVEC5LkA

[retiredcaps]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

Mr Bill, tibimakai, and cashkennedy,

Thank you for your feedback. After 2 days of letting it sit and some other tests, I do believe it is a tab bond issue now. When it is cold, I can twist the frame and get ghosting to appear and disappear.

I will try the vinyl bumpers and see how it goes.

To be continued ...

[budm]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

@retiredcaps, please keep us posted as the final repair. One thing that bugs me is that how bad tab can cause double images as shown in your pictures, since the X Gate drives lines and Source Drives lines are driven by pixel by pixel (just like painting picture by using X/Y coordinates at each fixed locations of the screen which is mapped out by the T-CON board to make pictures on the screen). Very strange indeed.

[retiredcaps]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

It will take me a few days to make progress. I have to clear out some major space to layout this TV, but I will report back for sure and this time it won't take 20 months to figure out.

[retiredcaps]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

I tried reseating all the tcon connectors that I could access. There is a possible removable connection from the two thin cables underneath the metal shielding, but that will require more time and space that I have right now. I have to remove the entire frame to get at it.

I took off the tcon metal shield and did some voltage measurements (VIN, VDD) and nothing was fluctuating. The sole voltage regulator measured 1.840V which is well within spec.

Anyway, I included a handheld pic with 1/80 exposure (best I could do today).

An ebay search shows that this tcon is used a variety of TV sets and manufacturers.

[Jasgriff]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

Whats the hole in the middle of the wise view chip?

[retiredcaps]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

Whats the hole in the middle of the wise view chip?

It is some sort of glue like substance. The chip is fully intact.

[retiredcaps]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

When I add the vinyl bumpers, I'm thinking of adding one thin layer of Kapton tape over top of the bumpers. My rationale is that all these big HDTVs run temperature hot and the bumpers may degrade over time from the heat? By adding a layer of Kapton tape, I may be able to prevent that?

I'm waiting for the Kapton tape to arrive for another long standing project so I won't be able to test this for about 30 days.

[Jasgriff]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

Whilst looking for a mainboard for my samsung I came across a control board that looked exactly like ur's. Atleast if its not the tab bonds then you will quickly be able to get hold of a board for cheap.

[kueberco]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

Mine has pretty much the same images as yours, Two driver ic's on the right side of my lcd are failing. I'm still in search of a new lcd panel. Good luck to you. Keep us posted.

[tibimakai]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

It looks like we are beginning to have a bigger and bigger group with this tab issue.
I'm in a same boat as you and I'm certain that I have the tab issue, because if I touch the top corner one it changes a lot the image.
My problem is that everybody shows the Sony fixes, but my panel's top PCB board and side tabs look different then everybody's else and I don't know if I can do that resistor+wire fix and where would I connect these.

[dd1001]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

Well what did you determine was the problem?

[antas]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

Hi guys. I have got a similar issue with my LG 42LH3000. Just replaced t-con board and have this issue with the picture. Is that means bad t-con board or something else? Thanks to all in advance for any help.

[antas]

Re: Toshiba 46RV53CU - possible bad tab bonds or tcon?

Any ideas, please?