e701i-a3 no picture but backlights

[Jim1590]

Re: e701i-a3 no picture but backlights

Don't think the blue screen is this issue. The issue here is black screen with no video input.

Try it with an input and double check all wires are seated properly.

Course I am guessing here. The experts will be by hopefully soon.

[tom66]

Re: e701i-a3 no picture but backlights

LCD TV panels often look dark blue with just a backlight and no picture. Perhaps that is what the poster is referring to.

[FieldGenEJ]

Re: e701i-a3 no picture but backlights

Hey guys, just read through all 20 pages of this. I have an E60I-a3 that kept shorting out TCON boards. Freakaftr8, would you mind elaborating on your scotch tape fix for the 60? From what I understand, you power up the tv with one icon cable disconnected and then you see which side looks normal with no horizontal lines and then cover pins on the other side?

[dgr8cycler]

Re: e701i-a3 no picture but backlights

I'm going to repair the t-con on the 601i to get me to that step and then hope that an alternative method can be done to fix the rest. What's this about the tape?

[FieldGenEJ]

Re: e701i-a3 no picture but backlights

Unfortunately the 60 inch version does not use side drivers like the 70 inch. However I am learning different methods to alleviate some of these symptoms even on the different model panels that do not use side drivers just like a 40 inch Samsung model UN40d5500 that I repaired this morning. It had the typical symptoms of flickering horizontal lines across the first top half of the screen caused by a short inside the panel. Removing the right hand t-con cable shows the left hand side of the screen working absolutely perfect. Connecting the right hand caused the lines to span horizontally across the screen essentially loading down the left side causing the problem spanning all the way across. The fix apply a small piece of scotch tape across a couple pins on the right hand cable driver going to the t-con to the panel. Problem solved. I have a feeling this is going to fix a lot of symptoms caused by horizontal lines across the screen on LCD TVs now!

I was talking about this post. I hope it works. I'm gonn order a tcon board this week and try.

[gormanrider8]

Re: e701i-a3 no picture but backlights

Hi All,

I have a Sony KDL-70R550A which so nicely uses the Sharp display for their 70". I have been troubleshooting it based on other threads and freakaftr8's help and I finally stumbled upon this thread.

I have attached 3 images to this post. The first image is the result when I removed the left TCON ribbon cable and leaving in the right TCON ribbon cable. The second picture is when I removed the right TCON ribbon cable and left in the left cable. This led me to believe there was a problem with the right cable/connector/panel.

After some investigating, a tiny piece of the TCON ribbon cable connector/header (on the bottom/LCD side of ribbon cable) was broken on the corner so i removed it and reseeded the ribbon cable. The third picture then shows a picture of my current and best results yet.

Now, I am unsure what family of problems I have from what I read in this forum: bad connection/seeding, bad drivers, or both. Before reading any forums I replaced the TCON board and powered on. Woops. So after measuring, both TCON boards have the transistor shorted (replacements are on their way). Do I need to go ahead and perform the tab driver removal? Or am I having a purely connection related problem? Or perhaps simply replacing the transistor will do? Thank you for your help. Especially freakaftr8

- Tyler

[vinceroger69]

Re: e701i-a3 no picture but backlights

just saw this new youtube video is it the same problem you guys have managed to fix
https://www.youtube.com/watch?v=IZQRVqtIfns

[budwich]

Re: e701i-a3 no picture but backlights

I don't think so.

[Jim1590]

Re: e701i-a3 no picture but backlights

gormanrider, what ribbon cables are you removing? For diagnosing, we are leaving the 4 ribbons into the tcon alone and unplugging the ribbon cable on the side of the tv where it is plugged into the side boards. Look at the lower corner of the tv on both sides, not the lower corner of the tcon. You have to remove a shroud to get to them.

Are you getting those pictures with a bad mosfet??

[freakaftr8]

Re: e701i-a3 no picture but backlights

That looks.like you have a short or multiple shorts on the left driver side bank. As the right 1/4 half of the screen looks good. When you say you had a broken ribbon cable are you talking about the L Shaped cable that goes from the bottom drivers to the side drivers on the left bottom corner of the panel?

Also that is really odd that the transistor shorted on a Sony before the mainboard caught the failure and shut down the TV. But I guess accidents do happen and nothing's perfect. I would definitely say the left driver side Bank is bad and I would try to remove it. But this is of course your discretion. Normally the transistor shorts if there is a short in the panel and it definitely looks that way.

You of course can always pull the black bezel shroud off in physically inspect those chip on film driver IC on the left side and see if any of them look burned or darkened around the center From there I'm pretty sure you'll find your answer

[freakaftr8]

Re: e701i-a3 no picture but backlights

This scotch tape fix doesn't apply to this panel. Only samsung 40 inch panels at the moment.

Hey guys, just read through all 20 pages of this. I have an E60I-a3 that kept shorting out TCON boards. Freakaftr8, would you mind elaborating on your scotch tape fix for the 60? From what I understand, you power up the tv with one icon cable disconnected and then you see which side looks normal with no horizontal lines and then cover pins on the other side?

[freakaftr8]

Re: e701i-a3 no picture but backlights

Unfortunately this repair patch does not apply to 60 inch panels as they do not have side drivers the horizontal driving is controlled through the vertical ribbon drivers.

I'm going to repair the t-con on the 601i to get me to that step and then hope that an alternative method can be done to fix the rest. What's this about the tape?

[SportsterPaul]

Re: e701i-a3 no picture but backlights

An update on the refurbished E701I-A3 I bought from Fry's Electronics and that died in a week with the exact same symptoms-- back light OK, no picture. Fry's said they would take it back no questions asked and they did. No restocking, no reverse shipping. They sent an email a few days after picking up the TV saying that they received it and that they refunded my credit card.

I note that Fry's no longer ships this TV, its only available for in-store pickup. I sent them this thread, so maybe they can see it is a risk to have to take back all these defective refurbs.

I waited a few weeks and kept checking prices. I wanted a Sharp LC-70SQ15U. I need VGA so I can use it as a computer monitor as well as a TV. The SQ has extra sub-pixels to make it easier to downscale 4K content. To me the big deal was that I have to assume they cannot use the same row driver chips, or at least the chips are newer and not defective like on the Vizio, despite knowing that the Vizio used a Sharp panel.

B&H Photo had LC-70SQ15U for 1600 bucks brand new. No more refurbs for me, ever. It came today and it seems to be a much nicer TV than the Vizio. Better menus, better remote better made, so far it looks great. I hope it lasts longer than a week, unlike that Vizio. One thing great about the Sharp is that they publish detailed dimensions of the TV, which was critical for me since I built a plywood entertainment center to mount the TV. When I wrote Vizio asking for exact mounting dimensions, they said they didn't have a drawing. No Vizio for me ever again.

I love to see even more people have made the fix on the Vizio-- Thanks to this forum and its great members.

[Jim1590]

Re: e701i-a3 no picture but backlights

A quick update on mine, as well as wanting to make sure I am on the right path.

I replaced the mosfet on one of my two tcon's. My sodering skills are not that great and it looks like a poor connection. But I have a new one coming (at least advertised as new.) I have the second board and one more mosfet. Keeping those as back ups.

I pulled the left side ribbon cable going to the drivers. Left as we are looking at the back, right side while watching. Turned the tv on and got lines along the bottom half of the screen and a white line starting on the left hand side of the picture extending about 1/3rd of the way across the set horizontially. I turned the tv back off and checked the mosfet. Appeared to still be good but the reading was now around 380.

Removed the other side (right as lokking at the back, left while looking at the picture) and got the vizio v to show up with a bunch of lines across the screen. No color to the v, it was grey. After 3-4 seconds the whole screen went to black. No response when hitting the menu key. Unplug and plug back in, power button got the same v and lines going to black.

Thoughts: My repair job was novice level at best. The poor connections was causing the lines and black out.I will wait for the new board to arrive. I am thinking the right side disconnected means that my problem is with those drivers. Since I had no picture at all with the other side unplugged, those should be ok as the right side is causing the issue. I will leave it unplugged and put in the new board. I "should" at that point get a decent picture but have a dark half of the screen, maybe some lines. If that is what I get, I can remove those drivers to fix the whole issue.

Am I thinking right?

Thanks

[gormanrider8]

Re: e701i-a3 no picture but backlights

Thanks everyone for your input. Sorry for the ambiguity of which ribbon cables I removed in my previous post.

--I repeated the test with the TCON board fully connected and only the LEFT bottom corner 90deg ribbon cable removed (as seen in the first picture).
--The results of that is the second picture.
--Still a good image on the right side but looked identical as when I had all ribbon cables connected (see image 3).
--The 4th picture is the results when I didn't have either of the corner 90deg ribbon cables attached.

As far the side driver tabs on the left, none of them look smoked or bad or hot to the touch when powered. The left side of the screen does come in and out of picture when I apply pressure. This leads me to want to go ahead and take them out.

And for the TCON transistor, my PCB is different than the one freakaftr8 posted in the first page. So I may be probing the wrong transistor on my 2 TCON boards, but the same transistor on both boards are shorted. This could be by design and maybe I'm probing the wrong FET.

Thanks for all your help again. I'm really hoping I can bring this TV to life.

[budwich]

Re: e701i-a3 no picture but backlights

You might help yourself out (and the forum) by inputting a known test pattern that can be found on a number of dvd's, useful one is the color bar test pattern. That makes it a lot easier to see / understand what you are looking at as opposed to a "random picture" that people may or may not know or see clearly.

You are likely on the right track as removing a corner cable and getting a reasonably good picture means that side has got something bad about it.

[euroryde]

Re: e701i-a3 no picture but backlights

So I thought I would try and fix another 70" as I had success the first time but I have ran into a problem, quick version. after removing tabs, new t-con tv is now working again but the screen quality isn't very good real pixelated / gassy looking pictures attached. I have tried cleaning all cables changed setting but nothing seems to be helping. Thnaks

[gormanrider8]

Re: e701i-a3 no picture but backlights

Good call Budwich thanks for the idea it made things more obvious. I repeated the test with the test pattern displayed and the left 90deg ribbon cable removed. The first picture is the test pattern I used. The second picture is the TV picture with the test pattern displayed. I used my laptop and HDMI to display the test pattern so the black regions on each edge of the TV are due to the different aspect ratios. I'm very convinced now it has bad left side drivers and I'm very tempted to pull them out.

However, I'm still not sure if I am probing the correct transistor/FET on my TCON board, which differs from the TCON used in the other models. On both of my TCONs, the FET near the power supplies has the same two pins shorted but there is another transistor on the backside that isn't shorted. I bought replacements (N-channel, 45V, 2A) and am ready to bring them into work and make the replacement but I am worried the FET is different on my TCON. Would it be possible to see the picture I am getting with a blown FET?

Thanks again.

[freakaftr8]

Re: e701i-a3 no picture but backlights

First I would check and make sure you didn't blow out your teeth on morning. Sounds like possibly you didn't have the ribbon cable seated Properly. When you plug in the bad side you might have taken out the transistor again But yes once you find your bad side the good side will show a decent 1/3 half of a picture precedent dark and blurry with most likely a few lines going through the screen. So it kind of sounds like your Right side facing the front might be the failure point However before you do this why don't you try supplying and some input or signal to it while you say goes blank. These TVs will go into immediate standby if it's set in PC mode where it's trying to accept a VGA signal so make sure that's not the case

A quick update on mine, as well as wanting to make sure I am on the right path.

I replaced the mosfet on one of my two tcon's. My sodering skills are not that great and it looks like a poor connection. But I have a new one coming (at least advertised as new.) I have the second board and one more mosfet. Keeping those as back ups.

I pulled the left side ribbon cable going to the drivers. Left as we are looking at the back, right side while watching. Turned the tv on and got lines along the bottom half of the screen and a white line starting on the left hand side of the picture extending about 1/3rd of the way across the set horizontially. I turned the tv back off and checked the mosfet. Appeared to still be good but the reading was now around 380.

Removed the other side (right as lokking at the back, left while looking at the picture) and got the vizio v to show up with a bunch of lines across the screen. No color to the v, it was grey. After 3-4 seconds the whole screen went to black. No response when hitting the menu key. Unplug and plug back in, power button got the same v and lines going to black.

Thoughts: My repair job was novice level at best. The poor connections was causing the lines and black out.I will wait for the new board to arrive. I am thinking the right side disconnected means that my problem is with those drivers. Since I had no picture at all with the other side unplugged, those should be ok as the right side is causing the issue. I will leave it unplugged and put in the new board. I "should" at that point get a decent picture but have a dark half of the screen, maybe some lines. If that is what I get, I can remove those drivers to fix the whole issue.

Am I thinking right?

Thanks

[freakaftr8]

Re: e701i-a3 no picture but backlights

You notice how everything looks nice and clean and perfect on the right side of your screen but the left side is dark you got some lines going through it where the lines ascending horizontally are keeping up with the right side of the screen which is still connected to the Tcon. This is because the left drivers are shorted out just remove them off the screen completely

Good call Budwich thanks for the idea it made things more obvious. I repeated the test with the test pattern displayed and the left 90deg ribbon cable removed. The first picture is the test pattern I used. The second picture is the TV picture with the test pattern displayed. I used my laptop and HDMI to display the test pattern so the black regions on each edge of the TV are due to the different aspect ratios. I'm very convinced now it has bad left side drivers and I'm very tempted to pull them out.

However, I'm still not sure if I am probing the correct transistor/FET on my TCON board, which differs from the TCON used in the other models. On both of my TCONs, the FET near the power supplies has the same two pins shorted but there is another transistor on the backside that isn't shorted. I bought replacements (N-channel, 45V, 2A) and am ready to bring them into work and make the replacement but I am worried the FET is different on my TCON. Would it be possible to see the picture I am getting with a blown FET?

Thanks again.