Samsung 46" LCD LN46A750 colored vertical lines no image

[drclawscat]

Hi All, 1st post. Got a TV from a friend which went bad. It has colored vertical lines/bands running down it on power up. Seems to power up fine with no problem however.

I took it apart and found that out when the TV is on and I pop one of the ribbon cables attached to the TCON out jiggle it around a bit and pop it back in that the screen is working perfectly and is stable for as long as the TV is powered up.

As soon as I turn it off and power it back up the vertical lines are back. Good thing I know the panel is good, seems like the ribbon cables are fine since they produce a perfect picture after the 'popping cable trick'. I didn't notice any bulging leaking capacitors on the power supply.

Any leads as to what the problem might be? Seems like an issue on power up with all the ribbon cables attached, once one's popped out and put back in picture is fine and dandy.

on power up

disconnecting a ribbon cable (far right cable facing screen orientation)

reconnecting cable

TCON

Mainboard (?)

PowerSuppy and Caps closeups

[tom66]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

I have heard of this symptom with Samsung TVs when the output capacitors on the power supply fail -- however, the T-con on the sister model to this, LN4xA650 (European LE4xA656), is a very common failure. Does this TV have the 100/120Hz motion interpolation? It looks like the same T-con as in the A656, which I have replaced before.

[drclawscat]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

I have heard of this symptom with Samsung TVs when the output capacitors on the power supply fail -- however, the T-con on the sister model to this, LN4xA650 (European LE4xA656), is a very common failure. Does this TV have the 100/120Hz motion interpolation? It looks like the same T-con as in the A656, which I have replaced before.

Hi Tom, thanks for the quick reply. Yes according to the product page it does have the 120Hz motion interpolation. http://www.amazon.com/Samsung-LN46A7.../dp/B0014175OI

Is there a way I can test and isolate the TCON vs power supply knowing this info? I read the SMD fuses on the TCON could be a problem too. I was thinking about bridging the F1 fuse to see if that would help, then bridge the F2 fuse.

[tom66]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

If the fuses are blown, the t-con will not work at all.

You can try heating the power supply:
https://www.youtube.com/watch?v=Ggn_ggaPvc4

[ausheaven]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

Deleted

[ausheaven]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

Hi All, 1st post. Got a TV from a friend which went bad. It has colored vertical lines/bands running down it on power up. Seems to power up fine with no problem however.

I took it apart and found that out when the TV is on and I pop one of the ribbon cables attached to the TCON out jiggle it around a bit and pop it back in that the screen is working perfectly and is stable for as long as the TV is powered up.

As soon as I turn it off and power it back up the vertical lines are back. Good thing I know the panel is good, seems like the ribbon cables are fine since they produce a perfect picture after the 'popping cable trick'. I didn't notice any bulging leaking capacitors on the power supply.

Any leads as to what the problem might be? Seems like an issue on power up with all the ribbon cables attached, once one's popped out and put back in picture is fine and dandy.

on power up

disconnecting a ribbon cable (far right cable facing screen orientation)

reconnecting cable

TCON

Mainboard (?)

PowerSuppy and Caps closeups

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

--------------------------------------------------------------------------------

I don't know how old your TV is. These day with so call advanced technology thing are not supposed to last long.
This is just a farce.
It is only a mean for companies to legally fleecing consumers with unreliable product. One only need to walk around your suburb when your local authority collects your unwanted stuffs to see what has been thrown out. A big percentage are newie technology. Flat screen monitors, computer monitors, latest flat screen CRT TV, (99% are working), mobile phones, laptop computers (still working), battery operated drills, (100% working.throw away because battery pack is too expansive to replace or no longer available).
On top of that, look at the brand, you will be surprised most of them ones are prominently from as few specific companies. Working & non working.
It is time we consumer demand quality standard be applied.
I have a TV (CRT) which is 30 years old and it work very well with a HD set top. I only replaced it because during one of my yearly cleaning and vacuuming that I know it is at the end of it's life. The internal components are starting to peel.
In come one of this modern reputable TV. Within 3 years problem develop, lucky for me it was replaced because I have taken up a replacement insurance. The company knew that it will happened because it came from the mouth of their own technicians. One month out I would have to fork out good money for a new one. But will they take responsibility for the replacement. Not on my life they knew very well that it will not last another 30 years.
When you offer to buy the circuit diagram so that when it go karpoot you can fixed it they wouldn't even sell you one saying that it is proprietory.
Also. beware of the 3 or 5 year old for new replacement. Guarantee they will breakdown just outside these periods. I know of a company than promise you this for their computer monitors knowing very well that the capacitor they used were bad but do not bother to advice the public or do a recall. (I know because I repaired quite a few of them)
The morale of the story -
Greed is corrupt.
I hope you have luck with your repairs.

[tom66]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

Thank you for the rant... although, what you say is very much true, sadly.

Most of the TV's I've repaired are from Samsung who use good advertising/marketing to convince customers to buy the latest TV and throw away their old one.

If they don't do it the TV will go pop in a few years' time.

So now I don't advise -anyone- purchase any TV made by Samsung.

And I found three cordless equipment in the bin at my workplace. Two drills, one screwdriver, all dead NiCd packs. I just pulsed them with a few amps (to break the internal short down), charged them up and got three working units

[drclawscat]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

That's pretty much what I've heard about their TVs from 2006-10, not sure if they've improved quality since based on the lawsuits. That being said if there's any easy enough fix to revive this tv for a few more years I'm game, since i did get it for free

[tom66]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

Indeed, they are fantastic TVs, when working. Some of the best LCD and plasma picture quality on the market (probably only behind Panasonic on plasmas.) I have one in my lounge right now, the LE40A656 in fact. It works great, after I replaced the bad capacitors. But most Samsung problems are not bad caps any more.

[Dgtech]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

I hope that more people like us can boycott this type of industry. I consider us in that group because we refuse to pay full price for our sets. Instead we repair one and keep it.

I work in electronics and I know that they will calculate how many of these sets will die within warranty and how many will die shortly after, and it's all acceptable. I agree, it's not made to last long but people will continue to buy more and keep these poor performing companies in business.

The fixes are getting harder and harder. For this reason, i dont repair any more: Westinghouse, Samsung, and Sony's - Board swapping gets too expensive. As the prices that I can sell them at get lower.

[tom66]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

I don't exclude myself from repairing any brands. I tend to avoid the cheapies, because there's little money to make. It also depresses me to see Samsung and Vestel build quality so I like to fix TVs that were built well in the first place but had manufacturing defects or design flaws (most good companies will admit this and issue service notes or even recalls.)

I think the way forward is for mandatory warranties of at least 5 years on all electronics sold, and incentives to make it 10 years.

[AdaKun]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

I want to post on this thread because it seems similar to my problem, I've replaced the Main-board, T-Con and even the LVDS cables and I'm still experiencing the same problem, I'm trying to pinpoint the problem and although I was losing hope i stumbled onto something that might point me to the right direction

I hope it's relevant to "drclawscat" problem.

Here are some video's I quickly made:

https://www.youtube.com/watch?v=E3OV...AvFT3VQTwVFFul

One shows the symptoms and the other shows me messing near the area I think has the problem.

Messing with that one cable/clamp I've actually was able to get picture perfect quality before, but once i clamp the ribbon back down it just goes away, and its only on that ribbon the rest of the ribbons and clamps works fine, and I get the same results messing with the ribbon & clamp on the T-Con too.

TV Info:

Samsung LCD

Model Code:
LN46A750R1FXZA

Serial No.
ALAU3CNQ901730D

Version:
SS02

and if its fixable I'd like to know how or what can fix it.

[tom66]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

I just remembered I have seen the exact same symptom on a Sony using a Samsung LCD panel -- a tiny chip on the top corner of the screen caused the problem. Obviously that made it non economical to repair as the screen was wrecked. However, it's possible a tab bond could cause the same symptoms and that -may- be repairable. I didn't realise the fading was gradual between modes.

[AdaKun]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

The thing about where the clip is, is that it is on a long green chip on the top left half of the screen which is attached to tabs like you say, if that is the problem, is it possible to find a replacement to the whole top left chip and just re-bond all the tabs? or maybe repair the clip itself.

[tom66]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

Sorry, I think you misunderstood me. I meant the glass itself had a chip which had broken some lines on the connections around the edge...

[drclawscat]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

I want to post on this thread because it seems similar to my problem, I've replaced the Main-board, T-Con and even the LVDS cables and I'm still experiencing the same problem, I'm trying to pinpoint the problem and although I was losing hope i stumbled onto something that might point me to the right direction

I hope it's relevant to "drclawscat" problem.

Here are some video's I quickly made:

https://www.youtube.com/watch?v=E3OV...AvFT3VQTwVFFul

One shows the symptoms and the other shows me messing near the area I think has the problem.

Messing with that one cable/clamp I've actually was able to get picture perfect quality before, but once i clamp the ribbon back down it just goes away, and its only on that ribbon the rest of the ribbons and clamps works fine, and I get the same results messing with the ribbon & clamp on the T-Con too.

TV Info:

Samsung LCD

Model Code:
LN46A750R1FXZA

Serial No.
ALAU3CNQ901730D

Version:
SS02

and if its fixable I'd like to know how or what can fix it.

Seeing that you replaced so much of the tv without success in fixing it, seems almost not worth the effort seeing the drop in price of TVs these days. Figuring that even if you we did get them working again it would be apt to fail again in the next 2-3 years with the pos quality in manufacturing they put into these things. Cost and effort start outweighing the benefits.

The only saving grace in this industry is the falling price of technology, I recall back in 2003 when a good 42 plasma was 8k!!!

[AdaKun]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

Your very right, It's getting close to the budget I set for myself. There is one more thing I'm willing to try, I was thinking about buying another Samsung 46 inch used with a broken screen, for the parts to repair the one I currently have, especially parts that I can't find so easily.

If that doesn't go well, I'm probably going to try to sell the parts.

But I really want to post a successful fix lol.

[cliff_hootarski]

Re: Samsung 46" LCD LN46A750 colored vertical lines no image

I've done that before on a Vizio (bought a broken screen TV for parts).
One month difference in manufacturing dates and all the internal parts were different. Samsungs may be different.