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Old 10-05-2015, 02:55 AM   #21
mmartell
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Default Re: e701i-a3 no picture but backlights

Those measurements are to be taken with power off. If you had power there you would have shorted that part if it wasn't shorted already. Looks like you also destroyed the coil. Probably still repairable.
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Old 10-05-2015, 09:54 AM   #22
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Default Re: e701i-a3 no picture but backlights

Agreed. You can replace a coil but I would use a dvm in diode test mode. Although you can achieve results with your meter you can't have the power on while you do this.

Here's a thought. Just test power at this point. If you have 24v or so the + side of the silver round capacitor on the left side of the board in the picture your ok. Test it like this turn your voltmeter to DC voltage and use the red lead against the plus side of that capacitor the black lead against one of the screw lug terminals on the tcon board. If you have voltage there the rest of the board is functional and you can use it.
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Old 10-05-2015, 10:20 PM   #23
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Default Re: e701i-a3 no picture but backlights

Quote:
Originally Posted by mmartell View Post
Those measurements are to be taken with power off. If you had power there you would have shorted that part if it wasn't shorted already. Looks like you also destroyed the coil. Probably still repairable.
Ya but there may be more stuff smoked on the board- do you think whatever I damaged is limited to only what is on that board? I ended up ordering yet another through Encompass parts- I went with the green choice. I just want to make sure I safeguard the thing while I test the set.
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Old 10-05-2015, 11:10 PM   #24
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Default Re: e701i-a3 no picture but backlights

If you follow the steps I provided yo u should be ok.
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Old 10-06-2015, 06:05 AM   #25
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Default Re: e701i-a3 no picture but backlights

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Originally Posted by freakaftr8 View Post
Agreed. You can replace a coil but I would use a dvm in diode test mode. Although you can achieve results with your meter you can't have the power on while you do this.

Here's a thought. Just test power at this point. If you have 24v or so the + side of the silver round capacitor on the left side of the board in the picture your ok. Test it like this turn your voltmeter to DC voltage and use the red lead against the plus side of that capacitor the black lead against one of the screw lug terminals on the tcon board. If you have voltage there the rest of the board is functional and you can use it.

Ok so your saying that coil that I that I had ripped most of the cover from may be fried? I never broke it away from its solder spots though. What do those readings that I had gotten mean- before the damage was done? Do you think I could have damaged anything else?
I'll try the voltage test but I dont have a line on getting a cool, transister- I couldn't even find an SOT N channel mosfet with 45 v 2A anywhere. I do have a another t-con coming from encompas.
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Old 10-06-2015, 01:22 PM   #26
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Default Re: e701i-a3 no picture but backlights

I'd just wait for the new tcon to come in. Then make sure the right side drivers are disconnected from the bottom drivers via that white ribbon cable on the right lower side of the screen. It's the one about 3/4 inch wide located on the lower side of the side driver board on the right side of the screen.

If you get a picture most likely the right side of the screen is going to be dim. but there will probably be some horizontal lines in the picture that don't look dim. Whatever it looks like please post a picture first

Last edited by freakaftr8; 10-06-2015 at 01:24 PM..
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Old 10-07-2015, 06:20 PM   #27
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Default Re: e701i-a3 no picture but backlights

You got it- the newer t-cons not in yet- so undo that low ribbon cable behind lower right then replace the t-con, and I'm safe to plug in and power on. Hopefully before the bedore the end of the week…
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Old 10-07-2015, 06:42 PM   #28
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Default Re: e701i-a3 no picture but backlights

If the right side is in fact the problem. Then yes that should be all you have to do.
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Old 10-08-2015, 10:23 PM   #29
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Default Re: e701i-a3 no picture but backlights

Well the t-con came in. I unplugged the lower, right 3/4 ribbon cable. I then installed the new t-con board then plugged in a source- a chromecast dongle. Then the moment of truth I had my phone ready to take a shot but then plugged in the power cord and turned it on. The screen was somewhat black, then you could see 3,4,5 or 6 thin red lines that were making up the lower, left middle portion of the V which faded away then the set went into a moderately backlit screen. I tried the menu button which did nothing and turning the set off and on not able to repeat the same thing. The next thing I tried was redoing the whole process reversing the ribbon cables with no repeat of the initial screen. All I would get is the same as before- dim backlights with recognition the backlights are on then brighter or morderate backlights. I dont know if I damaged the t-con. I also am thinking could this be the LED inverter thats located on the power board? Im not sure what to try and test next?
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Old 10-08-2015, 11:34 PM   #30
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Default Re: e701i-a3 no picture but backlights

Ok. Can you locate the transistor marked COXA or something like that? Middle right side of the board.with the ribbons on the bottom, lvds cable connectors on top.? Need a ohms reading between center pin with black probe and red probe on each other 2 pins. Looking for 500 ohms thereabouts. If 0 ohms then the board shorted.

Possibly because the ribbons on the left hand side of the screen may be the shortest one and not the right side
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Old 10-11-2015, 12:50 PM   #31
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Default Re: e701i-a3 no picture but backlights

Ya the COXA 16...Just a re-cap from before...with the power cord unplugged, 3/4" lower right LED driver cable disconnected and NEW t-con installed, I plugged in and hit powert. This is when I got the brief faintly visible image of a 'V' to show up on the black screen which quickly disappeared. Shutting off and turning on repeatedly didn't bring up again so I dont think shutting off, plugging in the lower right LED cable and unplugging the lower left did anything since I'm convinced the board was blown from only the lower right cable being disconnected. Testing the silver capacitor in DC mode on the meter didn't move the needle and neither did the COXA in ohm mode from your instruction. I also tried and read that with power on and disconnecting/ reconnecting one LVDS cable at a time while watching the screen may show some type of something flash on the screen- it didn't work. All this leads me to think the t-con is clearly blown. I also took out the main board since I was unsure if it could have been damaged not knowing the distribution of power back and forth with all the boards. I took out the main board and put it back in my relatives 60" that I fixed previously since they are the same board which worked fine telling me theres no effect on the main board. Do you know how can I find the source of whats blowing the t-con. Do you know why I had readings on the previous t-con I had in before damaging it?
Do you know how to get into the service mode on the tv if there is one and or if theres any type of interface software to troubleshoot the unit from a laptop? If you know of any such software? I do happen to have a contact that can get his hands, that on just about any software out there. If there is and I can get it, I'd be happy to pass it on. Also if not do you know if theres any way of independantly testing the panel to rule it out? Can you pass on where I can purchase the COXA transistor or the SOT N-channel mosfet with the specs you gave me (I could not find it anywhere online) and the silver capacitor?
Again, thanks for all your help-
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Old 10-11-2015, 09:08 PM   #32
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Default Re: e701i-a3 no picture but backlights

I have a question about the red lines you had seen where they spanning vertically or horizontally accross the screen?
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Old 10-12-2015, 07:04 AM   #33
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Default Re: e701i-a3 no picture but backlights

Hi no the thin red lines were making up part of the 'V' logo. I'm attatching a picture I edited to describe it. The real image I saw on the screen was much more faint and not as pronounced.
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Old 10-12-2015, 07:47 AM   #34
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Default Re: e701i-a3 no picture but backlights

So when you did the previous test (and in the "recent past"), you no longer see or get any code flashing at any time? Not sure about a Vizio but the corresponding sharp panel displays "SHARP" BUT not all the time. That gets only displayed during some form of "reboot" / "initialization" which isn't necessarily tied to just unplugging / plugging because there is some "retention" power.


Further, I think that perhaps there is some misunderstanding of the observations (maybe mine). Freakaftr8.... how are error codes flashed on the vizio?

Last edited by budwich; 10-12-2015 at 08:11 AM..
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Old 10-12-2015, 08:02 AM   #35
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Default Re: e701i-a3 no picture but backlights

Ok here is how I found the glitch from the beginning. My TV came in to me with the same typical symptoms. I replaced the tcon board thinking it was an easy fix to find out that the one I got was already failed from eBay so I ordered another one to find out that one was also already failed from eBay. I found out the second one was bad by just connecting the LVDS cable and not connecting the ribbon cables to the panel. I was not able to achieve any voltages from that board studying the board and reading what others have posted about the board I found out that in the component repair kit they offer an EPROM a couple transistors and a four Channel voltage regulator. There were absolutely no problems with any of the components on any of my boards except for the small Coxa transistor shorting. I noticed that the two boards that I received already had a bad Coxa transistor. The way I found that out is using a digital voltmeter in ohms load and probing the black tip to the center pin the red tip to each individual other pin on the other side of that transistor a good transistor should read about 500 ohms between center pin to one of the ending pins. If you're getting near zero on that transistor shorts when there is a panel problem. The reason I found the specs on that transistor by researching it on the internet I came across a suitable replacement that I had mentioned earlier. This replacement I had found was often old tcon board to a Sony. It was the only thing that I had in my stash that was even close to an equivalent transistor and when I replaced that transistor it obviously had a little more meat to it per say it could handle the surge that the panel was giving it for a few more seconds just enough to be able to turn on the TV and see the actual symptom. What I saw was a really messed up right side picture with a lot of lines going through it very dark and flickering like crazy. I instantaneously knew that there was a problem on one of those side tab driver boards on the right side. So to my findings that is when I disconnected the right hand ribbon driver to the right panel driver boards. When I powered it up the next time I no longer had a flickering red right side but a dim and blurry right side which I was pretty sure that that was going to be like that when I powered it up because there's no power going to those tab drivers any longer but also I was presented with some really nice bright horizontal lines in the picture like you saw in my previous post. The next thing I did was remove the metal framing to expose the side tab drivers and when I pushed on the driver in the suspected problem area the lines started disappearing in and getting bigger. That's when I decided that since the screen has two drivers one on each side I had nothing to lose except for to pull those drivers off since they were causing an issue. That's how I got a perfect picture. The dark lines in the Vizio emblem I don't know what to tell you about but you drew those as if they were on the left side of the screen. The only other thing that I could offer as help would be to attempt to either Repair one of your tcon boards because I seriously doubt you want to go buy another one or purchase another one disconnect both side driver cables on each side of the screen and then power it up if you do not blow that t-con board then you know that it obviously is the left side causing the problem not the right. Then I would focus my efforts on those drivers and then reconnect the right side. This is all trial and error and can be a very expensive process. I just took the expense part out of it by finding my own equivalent transistor replacements instead of constantly buying another t-con board to try to find out how to repair the symptoms. If you are in anyway having extra board laying around your house from previous repairs it wouldn't hurt to Google search some of the small transistors on those boards and try to find an equivalent close to the specs that I provided for the transistor if it's somewhere even close you can try soldering one on and giving it a shot.

The key to trial and error on this TV is to keep your hand on the power cord if the V emblem doesn't come up with in a few seconds or you see something flickering it doesn't look right immediately unplug it so it doesn't damage the board because if it doesn't look right from the get go then it's not going to be right.

This TV uses the Sharp LCD panel. To my knowledge only one other member has been able to successfully repair a sharp model TV the same time I was working on mine.
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Old 10-12-2015, 08:29 AM   #36
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Default Re: e701i-a3 no picture but backlights

Quote:
Originally Posted by budwich View Post
So when you did the previous test (and in the "recent past"), you no longer see or get any code flashing at any time? Not sure about a Vizio but the corresponding sharp panel displays "SHARP" BUT not all the time. That gets only displayed during some form of "reboot" / "initialization" which isn't necessarily tied to just unplugging / plugging because there is some "retention" power.


Further, I think that perhaps there is some misunderstanding of the observations (maybe mine). Freakaftr8.... how are error codes flashed on the vizio?

There are no error codes on a Vizio. Sharp has reluctantly put in a shutdown overcurrent protection system into their circuitry. Vizio has not so when there's a short it just blows up the t-con board instead of shutting down into an error code. That's why this is a completely different beast but the same at the same time.

So therefore there is no reboot or troubleshoot procedure. Like Eminem said you only get one shot. Unfortunately
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Old 10-12-2015, 08:46 AM   #37
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Default Re: e701i-a3 no picture but backlights

ok.... another question.... maybe more general but
IF you pull both right and left side driver cables, will the panel still be able to display somethings... ie lines ... as in vertical ones?

for instance on my sharp, with the one side disconnected even at the tcon, I could run my fingers gently across the lower tab bonded flex cables at the bottom of the panel / edge boards and cause a display of vertical lines.

Last edited by budwich; 10-12-2015 at 08:47 AM..
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Old 10-12-2015, 09:19 AM   #38
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Default Re: e701i-a3 no picture but backlights

I don't believe the panel will technically show anything if both driver boards are disconnected. at least one side must be connected in order to display the trailing horizontal lines that a control. Due to the fact that this effect is not built into the vertical drivers like other panels
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Old 10-12-2015, 04:58 PM   #39
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Default Re: e701i-a3 no picture but backlights

Quote:
Originally Posted by budwich View Post
So when you did the previous test (and in the "recent past"), you no longer see or get any code flashing at any time? Not sure about a Vizio but the corresponding sharp panel displays "SHARP" BUT not all the time. That gets only displayed during some form of "reboot" / "initialization" which isn't necessarily tied to just unplugging / plugging because there is some "retention" power.


Further, I think that perhaps there is some misunderstanding of the observations (maybe mine). Freakaftr8.... how are error codes flashed on the vizio?
I've never seen any codes since theres no display only backlights. When I hit menu while the tv is on, the backlights only get brighter. I read of a way to get into service mode but doubt it will work since there is no display.

TO ENTER SERVICE MODE TO VIZIO TV
Method 1

Turn the Vizio TV off.
Press and hold the CH + & CH buttons on the TV.
Then press and release the POWER button on the TV Vizio.
Release the CH+ & CH- buttons.
Press the MENU button on the remote.
You should get your regular menu up, but with a F in the bottom right corner of the menu (This if for factory reset).
Press and hold the MENU button for few seconds.
The Service Menu will be displayed.
Method 2
Turn off th Vizio TV.
Press and hold the CH+ & CH- buttons on the TV Vizio.
Then press and hold the POWER button on the TV.
Keep all three buttons pressed for few seconds.
Press the MENU button on the remote.
You should get your regular menu up, but with a F in the bottom right corner of the menu (This if for factory reset).
Press and hold the MENU button for few seconds.
Service Menu will be displayed.

I did not see any service input on the main board like Samsung has. Do you know of any way to get the tv to display onto another screen? Obviously all the usb's and hdmi's etc. are all in, but do you know of a way out?
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Old 10-12-2015, 05:10 PM   #40
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Default Re: e701i-a3 no picture but backlights

Quote:
Originally Posted by budwich View Post
ok.... another question.... maybe more general but
IF you pull both right and left side driver cables, will the panel still be able to display somethings... ie lines ... as in vertical ones?

for instance on my sharp, with the one side disconnected even at the tcon, I could run my fingers gently across the lower tab bonded flex cables at the bottom of the panel / edge boards and cause a display of vertical lines.
With no gate drivers there is no gate signal ergo no lines are selected and none light up, you need approx +25V to drive the gates and get the lines to light up.
Running your fingers along the lines is probably providing the drivers with something that looks like data causing them to go into various incorrect modes.
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