Re: Vizio XVT3D474SV: power but no video, suspected t-con failure
Yes. I ended up replacing the T-Con board and it works beautifully now. They're tough to find though, probably because this is a common issue. Keep an eye on eBay. They pop up every now and then.
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Re: Vizio XVT3D474SV: power but no video, suspected t-con failure
So I tried baking the T-Con board to reflow the BGAs. Figured I had nothing to loose. It didn't fix it but it does something different now. The backlight comes on and it shows what looks like a test pattern. White screen with 3 vertical black bars dividing the screen into quarters.
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Re: Vizio XVT3D474SV: power but no video, suspected t-con failure
Boroth's TV would be getting firmware updates automatically over wifi.
I tried scoping the LVDS signals but its really hard because the pins are so tiny and I have a crappy scope. Some of the lines do change voltage when the TV turns on (looks like about 3V), but I havn't found anything that looks like a signal. Can you tell me a little more about what I'm looking for? What frequency and any pins in particular?
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Re: Vizio XVT3D474SV: power but no video, suspected t-con failure
Yes. Normally this would indicate the motherboard but I am still leaning towards t-con for a couple reasons. First, I confirmed with my friend that the technician replaced the motherboard already. Second, even when the backlight comes on there is still no image. Finally, the threads I linked to in my original post describe identical symptoms and the solution was to replace the t-con.
I'm getting 6.6 ohms across both of those capacitors....
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Re: Vizio XVT3D474SV: power but no video, suspected t-con failure
The backlight seems to be working more consistently today. Not sure why. I tried hitting the motherboard with my heat gun, but it had no effect. Warming up the tcon also did nothing.
Heres an updated voltage chart with measurements from when the backlight turns on. Sometimes it flickers while it is running. Still no image under any circumstances.
[CODE]
Standby On (no backlight) On (with backlight)
5V SB 5.10 5.07 5.09
REMOTE ON/OFF 0.00 3.29 3.29
LD ON/OFF...Last edited by unlimitedbacon; 08-16-2014, 02:09 PM.
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Re: Vizio XVT3D474SV: power but no video, suspected t-con failure
Heres the signals you asked for and a few extra. There is nothing here labeled PS_ON but REMOTE ON/OFF seems to serve the same function. I'm not sure what LD ON/OFF does.
[CODE]
Standby On (not functional)
5V SB 5.10 5.07
REMOTE ON/OFF 0.00 3.29
LD ON/OFF 0.00 0.06
BL ON/OFF 0.00 0.01
12V 0.00 11.79
18V 0.00 18.73
[/CODE]Code:Re: Vizio XVT3D474SV: power but no video, suspected t-con failure Heres the signals you asked
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Re: Vizio XVT3D474SV: power but no video, suspected t-con failure
I was also thinking of trying to reflow the BGA chips, but I don't really want to do anything until I have a better idea of whats wrong with it. Does anyone have any advice? I have a crappy oscilloscope if that will help for anything.
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Vizio XVT3D474SV: power but no video, suspected t-con failure
Hi everyone,
I just picked up a broken Vizio VXT3D474SV from a friend. Reportedly, they had a technician come out and replace 1 or more of the circuit boards but the TV still did not work and it was declared dead. On bringing it home, I cleaned it up and powered it on. Amazingly, it worked absolutely fine for about 20 minutes. Then, as I was flipping through channels, the screen became garbled. I tried to reboot the TV but it does not want to power back on.
[B]Symptoms:[/B]
* After plugging in power, TV goes through normal boot sequence (LED logo blinks amber/white...
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Re: New Members - please post your introductions here
Hi everyone. I replaced the caps on a motherboard a few years ago. It was scary doing surgery on it, but it worked. Now I'm back because this seems to be the best place for learning the long lost art of diagnosing and fixing things.
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