Vizio no pic

[Stu jaxon]

hi group, i'm working on a Vizio 39 Tesla model..E470va, so it's a 47 inch, I have no picture no audio, I do get the correct voltages from the power supply, I changed the main board, and nada.. when I turn the tv on, with the back cover off, I see a led ON THE INVERTER BOARD turn blue twice then turns off, I am suspecting the tcon board or also called this TQAPT5K00901 TQAPT 5k009 01 LCD PC Board Unit Motherboard. this is a lcd tv, I do have backlights, and a faint glow on the screen from the backlights... any help on this problem, will be taken seriously. Thanks,Stan...

[John-Del]

On Friday, July 12, 2019 at 4:39:38 PM UTC-4, Stu jaxon wrote:
> hi group, i'm working on a Vizio 39 Tesla model..E470va, so it's a 47 inch, I have no picture no audio, I do get the correct voltages from the power supply, I changed the main board, and nada.. when I turn the tv on, with the back cover off, I see a led ON THE INVERTER BOARD turn blue twice then turns off, I am suspecting the tcon board or also called this TQAPT5K00901 TQAPT 5k009 01 LCD PC Board Unit Motherboard. this is a lcd tv, I do have backlights, and a faint glow on the screen from the backlights... any help on this problem, will be taken seriously. Thanks,Stan...

The blue LED on the inverter board will light and extinguish if the inverters are normal.

You could have a bad TCON, a bad display, or still have a bad main. There are no new parts available for these, so any board you buy from *any* supplier is suspect. A legitimate ebay seller who sells a board from a TV with a cracked screen but otherwise verifiable as fully functional is a fair bet, but we still don't know if the donor had a picture, even if it did also have a cracked screen. Other internet board sellers are just recyclers who sell boards without testing, but they offer generous return policies and long warranties.

The way I approach a no-picture issue (with normal backlights) is to scope the differential signals coming out of the main at the LVDS plug to the TCON. These are digital signals and are jibberish, but if they're there, the main is usually good. While scoping, it's helpful to push the TVs menu button and watch for any activity on the differential outputs. If only DC appears on the LVDS output connector, you still have a bad main.

If the differential signals are there, try removing either of the two ribbon connectors going to the display from the TCON and see if you get half a pix. If not, reconnect the ribbon and remove the other. If you get half a picture from either attempt, you've got a bad display. Still no pic? Prob bad TCON.

There is a 12V fuse near the power harness you can check, but if it's open, usually a bad multi layer chip cap has shorted although there could also be a bad IC. If the fuse is good, you can check for DC at various points on the board if marked. If nothing is marked, look for small round inductors that identify the handful of buck converters that normally populate TCONs. There should be DC voltages on them and can vary from 1.2 to 24V depending on design. If any are missing with the output ribbons disconnected, you have a bad TCON.

[Stu jaxon]

thanks for the info.. the fuse tested good.. I hooked up a scope 5v ch1, on dc coupling I got dc differential signals with the menu button pressed on some pins and not data on others same results with ac coupling, if the tcon board was good was i supposed to see an AC siganl.? and with the ribbons removed no pic on either side.. bad tcon board..?

[John-Del]

I should have asked if you checked for 12V on the TCON fuse.

With the scope on AC coupling, set it for 50mv with a 10X probe and maybe .5ms for the horizontal - neither setting is critical. The signals are digital data and not on every pin. What I've found over the years is that any data visible with a known good input source or menu activation (which guarantees *something* should appear on the screen) means the main is good. Of course, those that produce a picture with issues like off colors, pixelization, gamma errors etc. could be the main and it's nearly impossible to tell if the main or the TCON are causing those problems by scoping the signals. But generally, if you have differential signals to the TCON but no picture, the main is good.

So if you have 12V on the TCON fuse, it sounds like you have a bad TCON. Pull the shield off and look for any shorted multi layer capacitors. These are small SMD caps, have no markings, and are invariably brown in color. The ones most suspect are the ones that are side by side in a parallel arrangement. If one of these caps short, the buck regulator in the circuit will shut down. The problem is that one shorted cap may be paralleled by several and up to a dozen, so picking the offending shorted cap out can take some time.

I can check Monday to see if I have a verified good TCON in the shop.

[Stu jaxon]

if fb401 is a fuse, there is no voltage on either side. i didn't get a chance to further test/scope the tcon board, my truck is in need of repairs. i will post as soon as i can.

[John-Del]

FB nomenclature devices generally are ferrite beads, although they're shaped like any other SMD resistor or capacitor. They tend to be gray in color, have no markings, and should read zero ohms. They may or may not have voltage on them depending on where in the circuit they are.

I just ran your model number through Shop Jimmy to see what the board looks like, and it appears there are two different versions of that TV depending on the display installed. One version has the main board connected directly to the TCON, the other has the main board connected to an FRC board which then feeds the TCON. Both versions use a different TCON.

If you have the smaller TCON, there is a white ceramic surface mount fuse marked 3A which should have 12V on it. You will also have the FRC board which is an equal possibility as the TCON board for causing no pix.

If you have the larger TCON, there is a shield over it that covers most of the components and I'll need to see a picture of the board without the shield to point out the fuse. Follow the leads from connector CN4402 under the shield and you should find the fuse. It might be ceramic like the other one or look like a smd resistor. Most non-ceramic fuses used in these types of boards have a single letter on them indicating current. The larger white ceramic ones have the actual current printed numerically on them.

[Stu jaxon]

couldn't find the fuse, no link to upload a pic.?

[John-Del]

You could upload to a free hosting site (like https://imgur.com/) and post the link, or you could send them to my spam email (which I monitor): ohger1s/at/aol/dot/com

I did find a complete board kit for an E420VA in stock (same TV, smaller screen). The kit I have uses a FRC board and smaller TCON with no shield.

If you have that version, I can walk you through it. If you have the larger TCON with the large shield over the board and no FRC board, then you'll have to remove the shield on the TCON.

[Stu jaxon]

i posted it on imgur, under username...stugots77

[John-Del]

Not found by name.

Open the picture you posted, then cut/paste the URL of the actual picture.

[Stu jaxon]

ok,.. https://imgur.com/hitZFrn

[John-Del]

That's the bigger TCON with the FRC board built in.

That FB near the LVDS connector on the TCON should have 12V on both sides of it when the TV is on. If the 12V is missing, unplug the LVDS and check that FB to ground for resistance. Should read no less than 10K ohms to ground. If the resistance on that FB is showing low ohms, the TCON has a shorted component on it.

U4403 should have something like 1.2V on the tab. If it doesn't, check the input pin for 3.3. That series of tab regulator is a common problem on main boards,FRC boards, and TCONs.

U4402 and u4407 should have something like 3.3 on one, and 1.8 volts on the other (typical Vizio reg voltages) measured at the tabs.

If those voltages are missing, check voltages on CN4402. There should be 12V and 5V on that connector. If either/both are missing, check for shorts to ground as you did with the ferrite bead. If there are no shorts and no voltages, I'd suspect the main.

If the 12 and 5 volt inputs are there on the connector, and the 12 volts is on the ferrite bead, and you can view differential activity on the LVDS connector with a scope, and you can't get a half picture with either display ribbon removed, indications are very strong towards the TCON/FRC board.

[Stu jaxon]

wow, you are a genius, with tv on, no 12v on either side of fb, with lvds disconnected, i got zero ohms, so it's a bad tcon board, that's shorted.. ?

[John-Del]

with tv on, no 12v on either side of fb, with lvds disconnected, i got zero ohms, so it's a bad tcon board, that's shorted.. ?

With the LVDS harness disconnected, run the TV one more time and make sure you have 12V on the harness. Most of the time, a shorted TCON will cause the 12V supply that feeds it to shut down, but there's a chance the 12V source could have been damaged as well. If there's no 12V, check the main for an open surface mount fuse (these are generally white on Vizios with a letter on them).

If you get 12V on the disconnected LVDS connector, then just a TCON should get you going. If you have the time, you can check for shorted chip caps. These are brown, about the size of that ferrite bead, and have no markings. One way is to feed a current regulated supply set to 2 amps right at that ferrite bead to force feed the TCON to see what gets hot. A frost covering from a can of freeze spray will often give you a visual of what's drawing the current (whatever thaws first).

[Stu jaxon]

if your talking about the harness connector cn702, I get 11.97v on green wire, 11.98 v on the yellow wire. nothing on the red and orange wires. 5v on brown wire. and just for your info I got a little anxious and ordered the tcon board arrive yesterday, got nothing no pic... the main board is recently purchased also from ebay .. I think i got both from electroparts..

[John-Del]

Did you try your original main board back in with the new TCON? You may have added a problem where none existed before.

There are two 12V inputs going to that TCON/FRC board. The CN702 four wire connector (which will have 12V , 5V, and ground) and the larger LVDS harness CN4404 where the ferrite bead smd component is.

So on CN 702, you have the 12V and 5V, so that's OK.

On the ferrite bead near the LVDS, you should have 12v as well. I don't know if they're sourced from the same 12V supply or not, but you should have 12V on that ferrite bead. Your earlier post said you did not have 12V on that ferrite bead and were reading a short to ground. Is this correct? If you unplug the LVDS harness, the short on the ferrite bead to the TCON ground will either go away or remain. If it goes away, the problem is on the main. If it stays, the short is on the TCON.

Be aware that fair percentage of boards bought on-line are defective regardless of where they're purchased. There are no new parts available for these, so any part you buy is from a recycled donor, and none of these mass parts sellers check them. They strip the carcass of it's boards, sell them, and replace or refund the money if they get a complaint. If the donor TV failed with the same defective board you have, you'll have the same issue.

This is why we go through several tests before estimating the job for the customer, and why we repair about 95 percent of the boards we see.

There are several guys in our association that sell parts on ebay, but these guys are technicians who will only sell verified boards.

The good news is that Electroparts is a good company and they'll replace or refund without question.

[Stu jaxon]

the short is still there, with the lvds cable removed. just bought the tcon board.? I now noticed that the backlights go off off after a minute or two, high voltage shut down..? I put the original main board back in, and got two 12v & 5v inputs to the tcon on cn702..

[John-Del]

You're confusing me. Are you saying that both the original TCON board and the one you just bought are showing a low ohm short to ground as read on that ferrite bead near the LVDS cable?

>I put the original main board back in, and got two 12v & 5v inputs to the tcon on cn702..

Again, see if there is any 12DC voltage on the LVDS connector when it is disconnected from the TCON. IIRC, the CN702 connector goes to the power supply, not the main. Is there 12V on the LVDS connector when it is lifted off the TCON?

[Stu jaxon]

yes, both the original TCON boards fb are shorted. no 12v when lvds is disconnected.

[Fox's Mercantile]

Do either of you know how to use an editor?


--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

[Stu jaxon]

OK, I miss read your post, I measured the fb on v scale, now i measured on ohms scale and with the tv on I get OL with the backlights on, when the backlights go out the fb reads lights a cap starts high 320k on both sides, this is with the new board recently purchased from ebay.. and what wire am i supposed to get 12v on at lvds connector when i pull it, there's 20-30 wires..?

[Stu jaxon]

> OK, I miss read your post, I measured the fb on v scale, now i measured on ohms scale and with the tv on I get OL with the backlights on, when the backlights go out the fb reads like a cap, starts high 320k on both sides, this is with the new board recently purchased from ebay.. and what wire am i supposed to get 12v on at lvds connector when i pull it, there's 20-30 wires..?

[John-Del]

> > Again, see if there is any 12DC voltage on the LVDS connector when it is disconnected from the TCON. IIRC, the CN702 connector goes to the power supply, not the main. Is there 12V on the LVDS connector when it is lifted off the TCON?
>
> OK, I miss read your post, I measured the fb on v scale, now i measured on ohms scale and with the tv on I get OL with the backlights on, when the backlights go out the fb reads lights a cap starts high 320k on both sides, this is with the new board recently purchased from ebay.. and what wire am i supposed to get 12v on at lvds connector when i pull it, there's 20-30 wires..?

OK, let's go back one step at a time...

With the TV off and your meter on ohms, what is the resistance at the fb to ground?

With the TV still off and the LVDS harness unplugged from the TCON and your meter on ohms, what is the resistance on the fb to ground?

With the TV on and your meter now set to DC volts, what voltage are you reading at the fb?


Do not attempt to read ohms with the TV running!

If you are getting 12V on the fb, you don't need to look for the voltage at the LVDS harness. But if there is no voltage at the fb, then we want to look for it with the TCON disconnected by reading it at the unplugged LVDS harness.

With the LVDS harness unplugged, you should be able to read 12V on several pins. The correct pins will be physically close to the fb, in other words, the first couple of pins at the side of the harness that would be close to the fb.

Perform all those tests using your original TCON and your replacement board. If there is a difference between them, then answer for both.

[Stu jaxon]

with the new tcon board installed, ON FB to ground both sides are .3-4m ohms. with lvds unplugged 400k one side other 300k ohms.. TV on testing pins closest to FB the highest was 1.4v - 0v..

Old Tcon board... .4 ohms both sides,.. lvds unplugged .3 ohms... TV on .2mv on FB TV lvds unplgged pins closest to FB 2v- .3 mv.. hope i covered everything...

[Stu jaxon]

On Saturday, July 20, 2019 at 7:53:56 PM UTC-4, Stu jaxon wrote:
> On Saturday, July 20, 2019 at 6:37:17 PM UTC-4, John-Del wrote:
> > > > Again, see if there is any 12DC voltage on the LVDS connector when it is disconnected from the TCON. IIRC, the CN702 connector goes to the power supply, not the main. Is there 12V on the LVDS connector when it is lifted off the TCON?
> > >
> > > OK, I miss read your post, I measured the fb on v scale, now i measured on ohms scale and with the tv on I get OL with the backlights on, when the backlights go out the fb reads lights a cap starts high 320k on both sides, this is with the new board recently purchased from ebay.. and what wire am i supposed to get 12v on at lvds connector when i pull it, there's 20-30 wires..?
> >
> >
> > OK, let's go back one step at a time...
> >
> > With the TV off and your meter on ohms, what is the resistance at the fb to ground?
> >
> > With the TV still off and the LVDS harness unplugged from the TCON and your meter on ohms, what is the resistance on the fb to ground?
> >
> > With the TV on and your meter now set to DC volts, what voltage are you reading at the fb?
> >
> >
> > Do not attempt to read ohms with the TV running!
> >
> > If you are getting 12V on the fb, you don't need to look for the voltage at the LVDS harness. But if there is no voltage at the fb, then we want to look for it with the TCON disconnected by reading it at the unplugged LVDS harness.
> >
> > With the LVDS harness unplugged, you should be able to read 12V on several pins. The correct pins will be physically close to the fb, in other words, the first couple of pins at the side of the harness that would be close to the fb.
> >
> > Perform all those tests using your original TCON and your replacement board. If there is a difference between them, then answer for both.
>

> with the new tcon board installed, tv off FB to ground both sides are .3-4m ohms. with lvds unplugged 400k one side other 300k ohms.. TV on testing pins closest to FB the highest was 1.4v - 0v..
>
> Old Tcon board... .4 ohms both sides,.. lvds unplugged .3 ohms... TV on .2mv on FB TV on lvds unplgged pins closest to FB 2v- .3 mv.. hope i covered everything...

[Stu jaxon]

On Saturday, July 20, 2019 at 8:16:51 PM UTC-4, Stu jaxon wrote:
> On Saturday, July 20, 2019 at 7:53:56 PM UTC-4, Stu jaxon wrote:
> > On Saturday, July 20, 2019 at 6:37:17 PM UTC-4, John-Del wrote:
> > > > > Again, see if there is any 12DC voltage on the LVDS connector when it is disconnected from the TCON. IIRC, the CN702 connector goes to the power supply, not the main. Is there 12V on the LVDS connector when it is lifted off the TCON?
> > > >
> > > > OK, I miss read your post, I measured the fb on v scale, now i measured on ohms scale and with the tv on I get OL with the backlights on, when the backlights go out the fb reads lights a cap starts high 320k on both sides, this is with the new board recently purchased from ebay.. and what wire am i supposed to get 12v on at lvds connector when i pull it, there's 20-30 wires..?
> > >
> > >
> > > OK, let's go back one step at a time...
> > >
> > > With the TV off and your meter on ohms, what is the resistance at the fb to ground?
> > >
> > > With the TV still off and the LVDS harness unplugged from the TCON and your meter on ohms, what is the resistance on the fb to ground?
> > >
> > > With the TV on and your meter now set to DC volts, what voltage are you reading at the fb?
> > >
> > >
> > > Do not attempt to read ohms with the TV running!
> > >
> > > If you are getting 12V on the fb, you don't need to look for the voltage at the LVDS harness. But if there is no voltage at the fb, then we want to look for it with the TCON disconnected by reading it at the unplugged LVDS harness.
> > >
> > > With the LVDS harness unplugged, you should be able to read 12V on several pins. The correct pins will be physically close to the fb, in other words, the first couple of pins at the side of the harness that would be close to the fb.
> > >
> > > Perform all those tests using your original TCON and your replacement board. If there is a difference between them, then answer for both.
> >

> > with the new tcon board installed, tv off FB to ground both sides are .3-.4m ohms. with lvds unplugged 400k one side other 300k ohms.. TV on testing pins closest to FB the highest was 1.4v - 0v..

[Stu jaxon]

> > Old Tcon board... .4 ohms both sides of fb,.. lvds unplugged .3 ohms... TV on .2mv on FB TV on lvds unplgged pins closest to FB 2v- .3 mv.. hope i covered everything...

[John-Del]

Standby till Monday. I have a donor set of boards for that model but it's for the version with a separate TCON and FRC, so I don't have the combo TCON that you do. Still, the voltages from the main should be the same on the LVDS harness. I'll put the boards together and get some voltage readings.

[Stu jaxon]

I found both fuses on the main boards are open f701,.. circled in yellow, the fuses are next to cn701 harness from the power supply. https://imgur.com/a/yf8cz7v

[str0...@aol.com]

> > >
> > > Old Tcon board... .4 ohms both sides,.. lvds unplugged .3 ohms... TV on .2mv on FB TV lvds unplgged pins closest to FB 2v- .3 mv.. hope i covered everything...
> >
> > Standby till Monday. I have a donor set of boards for that model but it's for the version with a separate TCON and FRC, so I don't have the combo TCON that you do. Still, the voltages from the main should be the same on the LVDS harness. I'll put the boards together and get some voltage readings.
>
> I found both fuses on the main boards are open f701,.. circled in yellow, the fuses are next to cn701 harness from the power supply. https://imgur.com/a/yf8cz7v

Stan, you have two original boards and two replacement boards. It's important to identify if any particular voltage or resistance is on the original, the replacement, or both!

I have a main for a similar model that I was able to power up. With the TV ON, at fuse F701 there should be 12V on both sides of the fuse if the fuse is good.. F702 should have 24V, same conditions.

Near the LVDS output harness on the main is a ferrite bead smd FB416. There should be 12V on that.

With the TV powered down, the main disconnected from the TV, and enough time gone by to make sure voltage is bled off the main, there should be a resistance of no less than several thousand ohms.

If those resistances are OK, plug the main back into the TCON. If the resistance drops anywhere to the tens of ohms or lower, the TCON is bad.

Make sure you runs these tests on all boards in every combination.

[Stu jaxon]

I changed the fuse f701 on the main board before you posted. I installed the original tcon board, and powered on the tv, and got no pic, no audio, and the backlights went on and then off, no blown fuse. so, i installed the new tcon board recently purchased from ebay, and the fuse f701 blew. I should have removed the ribbon cables, I tested some caps on the original and found that three metal cylindrical caps are shorted. I know it makes no sense. but anyways, I returned the new board back to ebay, and am going to purchase a new one. I want to make the tests you mentioned but am out of fuses, so how i can i find the ratings on them, it's a smd white fuse with a number 5 on it, any ideas..?

[Jeff Urban]

I don't know if it works on all of them today, but if you take your fingers and bounce them kinda hard and you see glimpses of light the backlight is working. You might be missing power to the Tcon or have a bad Tcon. Unfortunately I do not recommend putting any money into this new junk.

Best course of action now is to always save the box and get he longest FACTORY warranty they have after you buy a new one.

Only other thing is to look for bad caps. Either the bulge or not but I got other ways of testing them.

[Stu jaxon]

I did bounce the ribbon cables around, no flicker, than again the main board fuse f701 is blown, no 12v on either side fb401. how do i find the fuse ratings for the main board, and you said you have other ways of testing the caps on the tcon..?

[John-Del]

>
> I changed the fuse f701 on the main board before you posted. I installed the original tcon board, and powered on the tv, and got no pic, no audio, and the backlights went on and then off, no blown fuse. so, i installed the new tcon board recently purchased from ebay, and the fuse f701 blew. I should have removed the ribbon cables, I tested some caps on the original and found that three metal cylindrical caps are shorted. I know it makes no sense. but anyways, I returned the new board back to ebay, and am going to purchase a new one. I want to make the tests you mentioned but am out of fuses, so how i can i find the ratings on them, it's a smd white fuse with a number 5 on it, any ideas..?

The two fuses on the main are marked with a T. According to my notes, that makes them 5A 32V.

Again, you're not differentiating what boards are what.

Did you blow fuses on both mains?

One more time: replace the fuses on one of the mains and install the complete set of boards. Do not turn the TV on. Read the resistance of the fuses on the main and FB416 near the LVDS connector on the main to ground.

They should have no less than several thousand ohms on any of those points. If you get a low reading, disconnect the TCON. If the short goes away, your TCON is shorted. Install you second TCON and read again. If the short reappears, your second TCON is shorted.

If you get a low ohm condition to ground on the fuses or the FB, you'll blow fuses every time you plug it in.

Those caps are bypass filters to ground and will read short if the source they're on is feeding a shorted device. Those larger caps might also be bypassed by low value low ESR ceramic caps, any of which will present a short across any of the parts paralleled in the circuit.

[Stu jaxon]

I'm outta fuses, any idea where i can find them..?, the Length is about.1/4 in, or 6.25mm. i searched and searched all I can find is the small ones.

[Stu jaxon]

On Saturday, July 27, 2019 at 1:58:24 PM UTC-4, John-Del wrote:
> >

oops, the length on the fuse is 2/8 or 6.25mm.

[Stu jaxon]

On Saturday, July 27, 2019 at 1:58:24 PM UTC-4, John-Del wrote:
> >

I tested FB416 near the lvds cable both sides to ground on the main board, a short on both sides, .6 ohms. removed the lvds cable from the Tcon board short went away. is there anyway to test the panel for a short.?

[John-Del]

It's unlikely the panel is causing the problem. The only TV I know of that would blow the TCON because of a shorted display is the Vizio E701i-A3.

You need to acquire another TCON, and *before* you power the TV up, measure the resistances of the fuses and ferrite bead to ground with all the boards connected. If you pick up the short, you bought another bad TCON.

If there are no shorts at this point, power up the TV with the two ribbons disconnected from the display. If the backlights stay on and the TV runs for 10 minutes or so, unplug the TV and reconnect the ribbons to the display and try again. If the TCON shorts with the ribbons reconnected, then you have a bad display taking out the TCON. I would suspect Windex Syndrome (cleaning solution sprayed on the screen in such a volume that it drips below the front mask and attacks the bonded address boards).

[Stu jaxon]

OK, Thanks for all your help. now I have to order a new tcon board and fuses. and there are no tcon boards available for this tv that i found.

[Stu jaxon]

On Sunday, July 28, 2019 at 7:21:38 PM UTC-4, Stu jaxon wrote:
> On Sunday, July 28, 2019 at 6:55:54 PM UTC-4, John-Del wrote:
> > On Sunday, July 28, 2019 at 6:30:03 PM UTC-4, Stu jaxon wrote:
> > > On Saturday, July 27, 2019 at 1:58:24 PM UTC-4, John-Del wrote:
> > > > >
> > > > > I changed the fuse f701 on the main board before you posted. I installed the original tcon board, and powered on the tv, and got no pic, no audio, and the backlights went on and then off, no blown fuse. so, i installed the new tcon board recently purchased from ebay, and the fuse f701 blew. I should have removed the ribbon cables, I tested some caps on the original and found that three metal cylindrical caps are shorted. I know it makes no sense. but anyways, I returned the new board back to ebay, and am going to purchase a new one. I want to make the tests you mentioned but am out of fuses, so how i can i find the ratings on them, it's a smd white fuse with a number 5 on it, any ideas..?
> > > >
> > > > The two fuses on the main are marked with a T. According to my notes, that makes them 5A 32V.
> > > >
> > > > Again, you're not differentiating what boards are what.
> > > >
> > > > Did you blow fuses on both mains?
> > > >
> > > > One more time: replace the fuses on one of the mains and install the complete set of boards. Do not turn the TV on. Read the resistance of the fuses on the main and FB416 near the LVDS connector on the main to ground.
> > > >
> > > > They should have no less than several thousand ohms on any of those points. If you get a low reading, disconnect the TCON. If the short goes away, your TCON is shorted. Install you second TCON and read again. If the short reappears, your second TCON is shorted.
> > > >
> > > > If you get a low ohm condition to ground on the fuses or the FB, you'll blow fuses every time you plug it in.
> > > >
> > > > Those caps are bypass filters to ground and will read short if the source they're on is feeding a shorted device. Those larger caps might also be bypassed by low value low ESR ceramic caps, any of which will present a short across any of the parts paralleled in the circuit.
> > >
> > > I tested FB416 near the lvds cable both sides to ground on the main board, a short on both sides, .6 ohms. removed the lvds cable from the Tcon board short went away. is there anyway to test the panel for a short.?
> >
> > It's unlikely the panel is causing the problem. The only TV I know of that would blow the TCON because of a shorted display is the Vizio E701i-A3.
> >
> > You need to acquire another TCON, and *before* you power the TV up, measure the resistances of the fuses and ferrite bead to ground with all the boards connected. If you pick up the short, you bought another bad TCON.
> >

> > If there are no shorts at this point, power up the TV with the two ribbons disconnected from the display. If the back-lights stay on and the TV runs for 10 minutes or so, unplug the TV and reconnect the ribbons to the display and try again. If the TCON shorts with the ribbons reconnected, then you have a bad display taking out the TCON. I would suspect Windex Syndrome (cleaning solution sprayed on the screen in such a volume that it drips below the front mask and attacks the bonded address boards).

>
> OK, Thanks for all your help. now I have to order a new tcon board and fuses. and there are no tcon boards available for this tv that i found.

I installed the new tcon board along with the fuse on the main board,I took measurements, no shorts. with the ribbons disconnected, I powered up the tv, back-lights stayed on a little longer, but went out... I took measurements again still no shorts..

[Stu jaxon]

TV is working, thanks again for all your help, i learned a lot.