Vizio E470VA backlight no pic, burned trace on TCON

[symergy]

Hi, I am looking at a Vizio E470VA which I purchased cheap from a lady in the hopes that I could get it running again.

It looks like a repaired or remanufactured unit since there are sharpie markings and notes on the boards and chassis. The TCON board metal cover has been snipped off and is gone.

My current situation is that I have a burned trace on the TCon board with missing components at each end. I think one was a fuse and the other was a bypass capacitor.

I am linking picture of the TCON board and a closer shot of the burned trace. At the top of the burned trace there used to be a capacitor to ground. My theory is that the cap shorted out and drew enough current to obliterate it and the trace and fuse (?). I am not 100% sure that the cratered area at the bottom of the burned trace was a fuse.

I would like to replace the missing components and need some help figuring out what values to use.

Also, I'd like to know if these components indicate some larger problem that I need to investigate before plugging it back in.

[symergy]

Re: Vizio E470VA backlight no pic, burned trace on TCON

Additional: the IC at the top of the burnt trace shows some signs of distress also. It is marked M301 G5795.

[tom66]

Re: Vizio E470VA backlight no pic, burned trace on TCON

That looks like a motion FRC board - for the 120Hz/240Hz functionality - rather than an actual T-con board.

It looks like a serious and persistent fault that was not interrupted by any fuse. Are there signs of damage in the wiring loom going to the T-con board , or on the T-con board?

[symergy]

Re: Vizio E470VA backlight no pic, burned trace on TCON

Here is a picture of the whole board. It has two ribbons going to the LCD panel over the top of the unit.

I don't see any damage to the connectors or wiring. The large connector goes back to what I think is the main controller board. I don't see any obvious damage there.

[symergy]

Re: Vizio E470VA backlight no pic, burned trace on TCON

Close-ups of both ends of the vaporized trace. (poor picture quality, sorry about that.)

On the IC end, I can see through the stereo scope that the IC's ground leg (pin 4) is definitely lifted and detached.

On the connector end, where I think there was a fuse, it is just a crater.

[symergy]

Re: Vizio E470VA backlight no pic, burned trace on TCON

I have ordered a replacement for the G5795 IC off of ebay.

Any guesses on the cap or fuse values? .01 uF ?

[MisterD]

Re: Vizio E470VA backlight no pic, burned trace on TCON

Did it burn clear through the board? Is the other side good? Sometimes circuit traces from one side tie into circuit traces on the other side of the board.
I'm wondering if a liquid may have gotten spilled down the back of the TV, maybe the lady was watering a hanging plant that was right above it. Or rain from an open window.

I suggest you list the part number of the board on here to help find a good picture of same board with components, look on one of the white stickers for 3642-????-????

[mmartell]

Re: Vizio E470VA backlight no pic, burned trace on TCON

From Shopjimmy. Couldn't find your exact board but this looks similar and may help.

[symergy]

Re: Vizio E470VA backlight no pic, burned trace on TCON

Thanks for the picture, that does look the same.

The other side looks fine. There is a connection through from the burned trace to the missing capacitor which goes to the other side and back and that seems to be intact.

FB4401 ? Capacitors are Cxxx Resistors are Rxxx. What is FBxxx ? I see quite a few FBxxx parts on the main controller board. They are just grey colored smt parts.

Found my answer Ferrite Bead in this thread: https://www.badcaps.net/forum/showthread.php?t=39326

It is odd that just the one trace is completely vaporized. With a cap on one end and an inductor on the other end, I wonder if it had some sort of resonance situation ?

I've ordered a new IC by slow boat from china. When that gets here I'm thinking I will put in a .01 uF cap and a piece of wire from the cap
to the remains of the trace by the connector. I'll put a small ferrite bead on the wire at the connector end.

[symergy]

Re: Vizio E470VA backlight no pic, burned trace on TCON

My IC came in today and I did some reconstructive surgery on the TCON board. I think it turned out rather well given the damage.

I got it installed, and no change.

Then I found a smt fuse on the main board, no markings, but it was open. So I took a wild guess (and rummaged through my junkbox) and found a small automotive style 7.5 amp fuse and put that in with some pigtail wires.

I got it all put back together and it blew that fuse. That doesn't sound so good to me. Would the main board of a 47" TV use more than 7.5 amps? Sounds like maybe something is shorted. But... I'm willing to try a bigger fuse if you all think that 7.5 isn't enough.

Otherwise, I'm down to putting in a bigger fuse to cause a real fire, or look at buying boards, or toss the thing.

I get backlighting. The Visio logo is dim white and then comes on bright when I push the power button. The backlight comes up bright for a few seconds then goes dark for a bit and then comes up bright again. I see no menu and hear no sound.

I think my voltages coming out of the power board look ok.

That's about all I know.

[MisterD]

Re: Vizio E470VA backlight no pic, burned trace on TCON

Can you post a picture of the mainboard and show the fuse that's open? You probably have other shorted components on the board that you replaced the IC on and most likely that's why the fuse is blowing, I believe it's a processor/t-con combination board all in one.
Please show clear pictures of all the boards in the tv and clear pictures of the white barcode sticker so part numbers of these boards can be read.

[symergy]

Re: Vizio E470VA backlight no pic, burned trace on TCON

Overall picture of the back of the set (4 boards): http://w0ep.us/vizioE470VArepair/GEDC0347.JPG

Main board (on the lower right of the set, has all input connectors on it): http://w0ep.us/vizioE470VArepair/GEDC0348.JPG
The bad fuse was already marked with a sharpie black arrow on the connector on upper left of the board. Same fuse. This TV has been worked on before (?).

Main board - zoom in on white barcode label: http://w0ep.us/vizioE470VArepair/GEDC0351.JPG

Main board - zoom in on my jury-rigged fuse and the board number: http://w0ep.us/vizioE470VArepair/GEDC0358.JPG

T-con board (the board at the top-center of the back, the board which had the burned trace) zoom in on white barcode: http://w0ep.us/vizioE470VArepair/GEDC0355.JPG

T-con board zoom in on upper part of the board with board number and another barcode: http://w0ep.us/vizioE470VArepair/GEDC0356.JPG

[symergy]

Re: Vizio E470VA backlight no pic, burned trace on TCON

For completeness here's the

barcode from power supply board: http://w0ep.us/vizioE470VArepair/GEDC0359.JPG
barcode from the inverter board:
http://w0ep.us/vizioE470VArepair/GEDC0361.JPG

There are various black sharpie markings on the unit, it looks like someone ticked off as they checked voltages and electrolytic caps. Anything you see in the pics was done by someone else, I have not marked anything.

[adamgaudreau]

Re: Vizio E470VA backlight no pic, burned trace on TCON

Can someone please help me test my power board. I didn't see any problems with the multimeter. Which pins do I jump to test the board and backlight? My board has the pins
21 22
GND B15V
B5V B5V
GND B5V
PS_ON B15V
GND A5V
VA VA
5V 5V
GND GND
DS-RESET VS_ON
XG VS_CON
XS DRV-RESET

The tv (Samsung PN43F4500AF PLasma) led on front just flashes red and there is no picture or sound. All the caps look fine.

[tom66]

Re: Vizio E470VA backlight no pic, burned trace on TCON

Adam, post your question in a new thread.

[MisterD]

Re: Vizio E470VA backlight no pic, burned trace on TCON

If I was working on that same TV set, I would use your meter on the ohm scale for continuity purposes see if you can determine which wire on the large connector (one with drawn on arrow) on the main board is directly connected to that blown fuse.

leaving enough wire so it can be spliced back together cut the wire on the connector that goes to the fuse that goes back to the T-Con/processor board that had the burnt trace, jump in another fuse, probably a 2 to 5 amp, power on the set and see if the fuse still blows, most likely your board with the burnt trace is causing that fuse to blow due to shorted components or carbon tracking from the burned pc board, you can splice the wire back together once you are done with this test. Shopjimmy is out of stock on that board but here is the link. http://www.shopjimmy.com/vizio-cbpft...1-pc-board.htm you may have to replace the board instead of trying to repair it.

Maybe others will chime in with some suggestions on what to do next.