vizio sv470xvt1a no light or power

[manofllama]

A friend gave me a Vizio sv470xvt1a that gets no power at all. The vizio light doesn't even turn on. The friend said that he was watching, then a small pop, then no power. I have some pictures of the boards, I could not get the metal covers off of one of them. Any help is great.

Thanks,
manofllama

[budm]

Re: vizio sv470xvt1a no light or power

If there is no indicator light at all, first place to look will be the main fuse, it should be close to where the power cord is connected to, it is usually marked with Fxxx.
Second thing to do will be the close inspection with magnifying glass to see if you located any burnt parts.

[manofllama]

Re: vizio sv470xvt1a no light or power

I'm not sure where the main fuse is. Could you point it out on one of my uploaded pictures? Thanks.

[budm]

Re: vizio sv470xvt1a no light or power

It should be at the bottom left of the board under the heatsink, you can see the AC input white connector with two black wires on it.

[manofllama]

Re: vizio sv470xvt1a no light or power

Is it this white cylinder? The white rectangle with the three prongs is the power connector (I disconnected it for now.) If that is the fuse, it's not see-through like most I've seen. And I'm not sure how to remove it.

[budm]

Re: vizio sv470xvt1a no light or power

Yes, the white cylinder, it is called Ceramic body fuse, they use this so when it's exposed to really bad shorted out circuit, the body will not crack or explode like the glass body fuse. You will need an Ohm meter to test it. It is soldered in, so just test it with the meter first.

[manofllama]

Re: vizio sv470xvt1a no light or power

Thanks for all your help, I'll test it tomorrow, I have to get a meter from my office.

EDIT: I found my multimeter. I tested the fuse with current running through, it measures about 120V coming out. I also tested the Ohms while the circuit did not have power, it measured 0.5 Ohms for the fuse. This maybe a little inaccurate, as my meter is rather cheap. If I recall correctly (been a while since I played with many circuits) the resistance on the fuse means it is out, right?

[tom66]

Re: vizio sv470xvt1a no light or power

0.5 ohms sounds okay.

Next step: Are there any labels on or near the connectors on the right side of this picture? If so, is there one labelled STB5V, ST5V, STBY or similar?

https://www.badcaps.net/forum/attach...6&d=1342490840

[manofllama]

Re: vizio sv470xvt1a no light or power

These are close ups. The only kinda similar label I found was 5VSB.

[selldoor]

Re: vizio sv470xvt1a no light or power

Thats great - with it all on and powered up put your meter on 200vDC and with the black lead on a ground screw check if you get any voltage on the 5Vsb the 12 v and the 24v
pins. Sometimes easier to put the red lead into the side of the socket if the pins are too fat. although these are low voltages remember parts of the boards will be at high lethal voltage.

[selldoor]

Re: vizio sv470xvt1a no light or power

Can you also look at the areas marked in this pic and advise if there looks to be a problem- What is the brown marks and is the cap punctured?
I see that caps are TEAPO which are considered poor and may all need replacing. Check them all for damage including the bases blowing out.

[manofllama]

Re: vizio sv470xvt1a no light or power

The connectors on the right side of that big board do not have any voltage. I'm not sure if that one cap is punctured, hard to tell. I'm not sure what that brown mark is. I have a question, should the marked cover on the big board have voltage running through it? Because it does.

[tom66]

Re: vizio sv470xvt1a no light or power

Nothing on 5VSB?

[manofllama]

Re: vizio sv470xvt1a no light or power

I didn't get any reading on any of the pins on those connectors while the tv was plugged in.

[tom66]

Re: vizio sv470xvt1a no light or power

Okay, so the first place to check would be the standby supply as this is required for before everything else can power up.

Can you get a picture of under the PSU (green side)?