e701i-a3 no picture but backlights

[augiedoggy]

Re: e701i-a3 no picture but backlights

Out of curiosity how are you removing the scratches. I've tried lots of methods but they were not successful.

a white eraser its a slow process but it seems to be working... Ive read petroleum jelly or even white candle wax can hide them as well.

[dick_barton]

Re: e701i-a3 no picture but backlights

Thanks.

[augiedoggy]

Re: e701i-a3 no picture but backlights

Thanks.

I have a mat screen and was told the eraser is a no no on a glossy screen... also Ive read magic erasers work well too when used dry.

[sjrku]

Re: e701i-a3 no picture but backlights

Mission successfully accomplished, perfect picture. FWIW, ordered my t-con off of shopjimmy. Hopefully I can put the TV back together! Thanks, all. Good stuff.

[sjrku]

Re: e701i-a3 no picture but backlights

I should also mention it was the right side when facing front of TV that went bad if we're keeping track.

[TR Immortal]

Re: e701i-a3 no picture but backlights

Yes you should see the same voltages with the t-con connected to the panel. That is if the panel is not taking down the t-con. However there is always the slight possibility that you could have problems with the mainboard causing a no picture condition however voltages are present. And then there's always a slight possibility that both side drivers on the left and right could be bad. Do you have some kind of image being projected to the TV not just the black screen with a no signal? It would be easier to plug in an HDMI and use the input button to cycle to that port and listen for sound before you go any further then you can disconnect both bottom corner tabs plug in each side individually to the t-con and see if you get some image at all.

Ok, after testing the voltages with the panel connected, i found that with only the right ribbon disconnected, all power in the t-con board dropper to zero except for the 100 cap which only drops about 1 volt. With only the left side disconnected all of the power in the t-con board drops to zero including the 100 cap. But with both sides disconnected i found that the power stays the same. Do you thing any of the components on the bottom board, such as any of the resistors, are bad, causing it not to work?

I also was able to get a couple vertical lines with both ribbons disconnected.

[freakaftr8]

Re: e701i-a3 no picture but backlights

You will get vertical lines if neither side is connected. This is normal because the horizontal drivers are not being regulated or controlled to send a horizontal picture matrix to the LCD panel so the panel does not understand what to do with the horizontal frequency. It's starting to sound like both sides of your panels horizontal tabs are bad sadly. This panel cannot run with both sides disconnected or you see the outcome with just the vertical stripes. Without physically having my hands on it I can tell you that this sounds like the best scenario here. What I would do now is physically inspect each tab with a very good bright light and a magnifying glass see if you see a tab that looks damaged or melted on both the right and left side.

[budwich]

Re: e701i-a3 no picture but backlights

Ok, after testing the voltages with the panel connected, i found that with only the right ribbon disconnected, all power in the t-con board dropper to zero except for the 100 cap which only drops about 1 volt. With only the left side disconnected all of the power in the t-con board drops to zero including the 100 cap. But with both sides disconnected i found that the power stays the same. Do you thing any of the components on the bottom board, such as any of the resistors, are bad, causing it not to work?

I also was able to get a couple vertical lines with both ribbons disconnected.

two dumb questions, first what signal are you inputting in / on. Next, are the only cables you are "playing with" on /related to the tcon?

I hope you have more fet's ... :-)

[TR Immortal]

Re: e701i-a3 no picture but backlights

two dumb questions, first what signal are you inputting in / on. Next, are the only cables you are "playing with" on /related to the tcon?

I hope you have more fet's ... :-)

yes, the only cable o have messed with are the two white ribbons on each side of the tv and the two connecting to the bottom of the t con.

I also checked each of the tabs on the left and right sides, but they look perfect to me (compared to the pics that i have saw of bad tabs).

Any advice?

[freakaftr8]

Re: e701i-a3 no picture but backlights

yes, the only cable o have messed with are the two white ribbons on each side of the tv and the two connecting to the bottom of the t con.

I also checked each of the tabs on the left and right sides, but they look perfect to me (compared to the pics that i have saw of bad tabs).

Any advice?

Okay this is going to get a little Advanced but should be pretty simple. On each side you have basically an upper horizontal board and a lower horizontal driver board connected by a small flat white ribbon cable connecting the upper to the lower boards. This will be on both sides. What you're going to do is disconnect the little white ribbon cable that is connecting the upper to the Lower Side drivers on both sides . Then hook up the white t-con cable on the right side first see if you have one half lower picture. If you do then disconnect that side and then try the left side and see if you have the lower half of the picture working. At least we'll be able to tell if the lower drivers or the upper drivers are shorted are in the horizontal side drivers. This you will be doing while both corner ribbons are connected connecting the lower bottom vertical drivers to the lower side bottom drivers

[budwich]

Re: e701i-a3 no picture but backlights

yes, the only cable o have messed with are the two white ribbons on each side of the tv and the two connecting to the bottom of the t con.

I also checked each of the tabs on the left and right sides, but they look perfect to me (compared to the pics that i have saw of bad tabs).

Any advice?

you didn't answer my first dumb question... what signal are you inputting.

[TR Immortal]

Re: e701i-a3 no picture but backlights

Okay this is going to get a little Advanced but should be pretty simple. On each side you have basically an upper horizontal board and a lower horizontal driver board connected by a small flat white ribbon cable connecting the upper to the lower boards. This will be on both sides. What you're going to do is disconnect the little white ribbon cable that is connecting the upper to the Lower Side drivers on both sides . Then hook up the white t-con cable on the right side first see if you have one half lower picture. If you do then disconnect that side and then try the left side and see if you have the lower half of the picture working. At least we'll be able to tell if the lower drivers or the upper drivers are shorted are in the horizontal side drivers. This you will be doing while both corner ribbons are connected connecting the lower bottom vertical drivers to the lower side bottom drivers

Ok, so i decided to re-seat all of the connectors along the sides of the tv just to be safe. After doing so i found that the power in the t-con board no longer drops to zero with only the right side connected (looking at it from the front).
I was also able to get a picture on screen where half of it was black and the other half was white, but i didn't have anything connected to the tv.

However, the left side is still causing the zero volts in the t-con board.

I also tried what you mention before, and with the left upper board disconnected i still didn't get a picture.

And to answer your question budwich, I did not have anything connected to the tv... so no input.

I can post pics if you need them, and how would i tell what input channel the tv is on if i were to connect something to it.

[budwich]

Re: e701i-a3 no picture but backlights

first thing I would do is put on my glasses... :-)
make sure you always know that the cables are connected properly as they can easily be "misaligned". Anyways, as for input, I was asking because if you don't input something, then you need to "create an image"... so you need to hit things like menu on the remote and be aware where to look on the screen as to where a picture might be especially when you may only be seeing "half screens".... thus if you see nothing on one side, it could be because there is nothing being displayed on that side.

Further, it appears that now you are finally getting somewhere as "normally" a disconnected tcon cable will generate a white screen on the side that has been disconnected.

I don't understand what you mean by "I was also able to get a picture on screen where half of it was black and the other half was white, but i didn't have anything connected to the tv." what "picture" are you seeing if you had nothing connected??????

My guess right now is that if you disconnect the left side corner cable (at the bottom of the panel... going between the side edge board and the bottom edge board) and leave the tcon fully connected, you will get a picture on the screen.

[TR Immortal]

Re: e701i-a3 no picture but backlights

first thing I would do is put on my glasses... :-)
make sure you always know that the cables are connected properly as they can easily be "misaligned". Anyways, as for input, I was asking because if you don't input something, then you need to "create an image"... so you need to hit things like menu on the remote and be aware where to look on the screen as to where a picture might be especially when you may only be seeing "half screens".... thus if you see nothing on one side, it could be because there is nothing being displayed on that side.

Further, it appears that now you are finally getting somewhere as "normally" a disconnected tcon cable will generate a white screen on the side that has been disconnected.

I don't understand what you mean by "I was also able to get a picture on screen where half of it was black and the other half was white, but i didn't have anything connected to the tv." what "picture" are you seeing if you had nothing connected??????

My guess right now is that if you disconnect the left side corner cable (at the bottom of the panel... going between the side edge board and the bottom edge board) and leave the tcon fully connected, you will get a picture on the screen.

Yes that is correct, and by picture i just meant that i saw half of the screen black and half white.

Also im not for sure what is going on with the boards on the right side of the screen. Any time i touch or bump them the bottom half of the screen gets distorted. I was able to get a somewhat clear view of "no signal" but i had to hold the board at a weard angle for it to show up.

Do you think there might be a shortage in one of the ribbons leading to the sceen?

[budwich]

Re: e701i-a3 no picture but backlights

well!!!! based on the picture, your issue appears to be on the left side.... as you can see the horizontal "issue". As suggested, with the current "setup" that gave your that picture, hit the menu button for the tv... what do you get on the screen?

Further as suggested, disconnect the lower left corner cable (as described previously), input a signal, hit the menu key whatever, what do you get?

[budwich]

Re: e701i-a3 no picture but backlights

Actually, my first comment should have been... give us a picture of the back of the set showing us exactly what you have disconnected / connected to get the picture that you posted as I am confused.... I don't see any white screen.

[freakaftr8]

Re: e701i-a3 no picture but backlights

Ok TRImmortal please provide an image on the screen now. Something besides a no signal, so we can have a good look at the picture with video supplied. Well go from there.

[brando70]

Re: e701i-a3 no picture but backlights

I've had similar issues as everyone and I've gone through a couple Tconns now so I want to make sure I don't screw this up again. Standard scenario as the rest - black screen, backlight works, audio works. So replaced Tconn first time hoping that would do it, plugged everything back in and died again within 2 minutes of use.

Tried new replacement Tconn and checked output voltage seemed good. After reading more, I plugged one output ribbon in at a time from the Tconn, choosing left side to connect first. Turn on and picture shows up on that half the screen while the non connected side is black. Saw menu and looked ok. Then I disconnected left side, connected right Tconn ribbon and saw the reverse, with non connected half being black again and saw the vizio logo looking a bit faded on startup but visible on the right side, and then Tconn died again.

I assume all signs point to right side being bad, but I did try to look at the driver chips on both sides of the tv and saw nothing obviously burned. I guess I just want to be sure there's nothing else to check first before I attempt plugging in the new Tconn I just got. I saw something about leaving both tconn output ribbons connected but disconnecting the corner ribbons instead? (In my pic that would be 2R/L or 3R/L). Is there an advantage to doing that for troubleshooting?

Any advice is welcome. Hopefully my annotated pics can help others for future clarification, please feel free to use as needed.

Note: Annotations are labeled as looking at the back of the TV upright:






Link to album:
http://imgur.com/a/LpUqS

[brando70]

Re: e701i-a3 no picture but backlights

Guess I can't edit posts, just thought I'd further clarify pic:

General overview of back of TV. Upside down as you can see, hopefully labels can help. From Tconn ribbons (yellow) to connector (1R/L) then from board on the bottom (blue) to corner ribbon (pink) to side drivers (green). Connectors are shown at arrow locations 1, 2, and 3. Annotations are labeled as looking at the back of the TV upright:




Link to album:
http://imgur.com/a/LpUqS[/QUOTE]

[budwich]

Re: e701i-a3 no picture but backlights

one reason for doing the "corner cable disconnect" while having all other cables connected is that you get a "full display". IF you are wise and input a known test pattern (smpte color bars or equivalent), you can then readily analyse the screen to look at what is happening... if anything. This may confirm your findings or possibly point to other issues which need further investigation.