Samsung LN46A750R1FXZA Possible Bad Panel Or T-Con

[jpruett79]

Hey Everybody

I'm looking for opinions on what could be wrong with this TV. From my limited experiences i believe that the most likely cause could be the panel or maybe the T-con board. I initially started to order a t-con to rule out the problem but the ones i have found have been priced higher than i want to pay without a second opinion. I would also like to rule out possible problems in the even i part the TV out. I would hate to sell a bad board to someone.

I have looked over all of the boards and haven't found any swollen caps or burn marks. I have not checked voltages on any of the boards as i haven't been able to find a service manual but i will keep looking for one.

[johnboy1313]

Re: Samsung LN46A750R1FXZA Possible Bad Panel Or T-Con

Have you opened the set yet? Being that the lines run the entire width of the panel, it's entirely possible that you have a bulging cap on the power supply. At any rate, I would guess something other than panel for the time being.

[Glitcher]

Re: Samsung LN46A750R1FXZA Possible Bad Panel Or T-Con

Do you have a photo of the panel with a source and picture playing? But I would probably best guess that this is a panel issue.

[jpruett79]

Re: Samsung LN46A750R1FXZA Possible Bad Panel Or T-Con

Guys thank you for the replies. This just got weird


johnboy1313

I have had the set open. I took that picture when i first got the tv. I did take it apart about 3 weeks ago and i took pictures of all the boards. I will go back and review those pictures. I did look at the caps and didnt see any swelled but i will look again.

Glitcher

Here is where it gets strange. So i could take a picture plugged the tv up back up and hooked my dvd player up to it. Initially i hooked it up hdmi. The picture came up briefly and then came up as mode not supported. So i changed to hdmi 2 and the same thing but as the picture went out i briefly got show for 2 seconds or so.

Now the tv is hooked up playing with component cables I do have vertical lines in places they dont go all way to the bottom and do not show up on a black background. When i first cut the tv on i didnt have them and they do seem to get getting worse slowly but the tv has only been on about 10 min now

I will have pictures up shortly. I think i took them too large and im having trouble uploading them. Will re-size then post.

[jpruett79]

Re: Samsung LN46A750R1FXZA Possible Bad Panel Or T-Con

Just a quick update. I haven't had time to take the tv apart again but i did go over my pictures closely and didnt see any swollen caps. But hopefully tomorrow i will get it back apart and look closer once one. I am starting to sway my thinking away from the panel to something signal related. It is still bothering me that the hdmi ports didnt work.

[tom66]

Re: Samsung LN46A750R1FXZA Possible Bad Panel Or T-Con

I have seen those lines (with working video) with a bad panel.

[jpruett79]

Re: Samsung LN46A750R1FXZA Possible Bad Panel Or T-Con

First of all Tom66 Thank you for your input. It is greatly appreciated. I have learned a lot from your post on this site. I have some more information. Do you still think it is a bad panel? I only ask not to second guess you but because i intend to part the tv out and don't want to risk selling a part i think is probably bad.

Secondly. I realize its been a couple months since i have been able to update this thread but i have had some more time to work on this set and have seen some strange behavior. I would like to share this information in case someone else ever runs into the same problem.

I hooked the tv back up today to take some pictures before parting out the tv. I wanted to test all the inputs to the mainboard before selling it as i take my reputation seriously and don't want to sell a part that i genuinely think is bad or has a high probability of being bad.

The first thing i hooked up was the coax signal and didnt have any lines at all. The picture looked great so that made me really scratch my head. Later some lines did appear after i had the tv on about 30 min.
The coax signal did always work.

The hdmi signals did work at first. At least input one and input 2 did. When i tried to hook up hdmi 3 the tv went to snow but 2 seconds and then i got the message mode not supported. When i went back to hdmi 1 and 2 i still got the mode not supported. After about 15 min i hooked hdmi 2 back up and it flashed between snow and the picture.

The component signals did always work but it did develop lines after about 3 min. The thing that seemed strange about the lines was they only appeared connected to text or a specific object on the screen. after watching for a few min i noticed that the lines followed the object they were connected to.
for example at one point one of the characters was carrying something and there were vertical lines connected to his hair as he walked across the screen the lines followed his head perfectly.

At one point i cut the tv off and then turned it right back on. When i did that i got a black screen with a bunch of vertical lines.

At one point i also noticed some horizontal lines but they didnt seem consisted and could have been a problem with the signal.

I am attaching a few of the photos i took to show the various states of the tv. If you think any more of a particular state would help i can add more.

Is it likely that the problem could be a video processor problem. Given my limited experience the only times i have seen these vertical lines were with a tcon and the rest i had decided was a bad panel but all of those were much more consistent problems.

[tom66]

Re: Samsung LN46A750R1FXZA Possible Bad Panel Or T-Con

It could be a tab bonding fault. I expect the main, t-con and power boards are just fine.

[jpruett79]

Re: Samsung LN46A750R1FXZA Possible Bad Panel Or T-Con

Could that cause the occasional "mode not supported" error when trying to use the HDMI connections. I guess that is the one that is throwing me off the most. Seems like its the TVs way of saying i don't know what to do with this signal.

[tom66]

Re: Samsung LN46A750R1FXZA Possible Bad Panel Or T-Con

Check your HDMI cable is good, as I had this issue with an intermittent HDMI cable.

[jpruett79]

Re: Samsung LN46A750R1FXZA Possible Bad Panel Or T-Con

I have tried two different cables but i will try a third. The second one i tried was a new but untested cable.

[jpruett79]

Re: Samsung LN46A750R1FXZA Possible Bad Panel Or T-Con

I did try a third cable. One i know that is good. I still got the mode not supported error. Im working now on taking the tv back apart. Im going to look over things one last time to see if i see anything.

[digitsync]

Re: Samsung LN46A750R1FXZA Possible Bad Panel Or T-Con

Your TV does not support all video resolutions from PC video card,
adjust your video mod according to the Samsung. Also if you try
to press Chanel keys while in PC input mode then you'll get the
warning message.

[jpruett79]

Re: Samsung LN46A750R1FXZA Possible Bad Panel Or T-Con

I realize this is an old thread but i wanted to update it with some new information in case someone runs into a similar problem.

I did scrap the tv and sold the parts on ebay. I did plainly list them for parts or repair at a deeply reduced price since i could not confirm the diagnosis. Based solely on the response the buyer left me in feedback the board was bad. I ask him for more info but he would not respond.

While this is not a concrete answer i hope it will help someone in the future.

Thanks to all of you that helped me with this one.