Visio E470VL won't power on.

[RichWeber]

Hey guys, I've searched these forums before and found solutions to other people's problems that worked for me, so when something happened that I couldn't find a fix for, this was the first place I thought I should ask.

Here's my situation.

I have a Visio E470VL that just powered off in the middle of watching a netflix episode of star trek last night. Obviously panic set in. oh nonono NONONO no NO!

After the initial panic left me, I started observing the symptoms. It's not like other people's problems that I've seen, in which they hear a pop, that preceded it. It just lost power. The amber visio light is not on when powered off, nothing. zero, zip, zilch. It doesn't just power off after a while of power, and won't come back on at all. It doesn't power cycle, just dead. To me this seems like the power board.

I came here to look for some basic troubleshooting procedures to determine if I was right or not, and found a couple things to check. Busted out the old multimeter, Checked fuses, Capacitors, changed outlets, checked power at the cords, everything checked out. Fuses good, 0 ohms. 120v at both sides of the fuse. No bulging, or leaking caps that I can see on the power board or the main board. No sludge, everything is pretty clean.

So from what I see, when plugged in, it has power to the board, but I can't tell how to see if power ever makes it out of the main board.

I'm basically writing to ask what I should check next to determine whether I need the power board, the main board, or both??

I have tried to upload some high res pics of the power board front and back from shopjimmy, but the upload doesn't seem to be working for me in chrome, so here's links to them.

Back:



Front:



Any help is very appreciated.

[Jim1590]

Re: Visio E470VL won't power on.

Can't help too much but can give you next few steps.

Post pics of your board so the experts can review for anything you missed.

Check the output of each clump of wires coming off the power board. Written on the board itself is the expected voltage. Post the results here. Do this for each board coming off of the power board while TV is plugged in and turned on (or what should be on). This will tell you if main and backlight are receiving power and if it is the correct voltage.

[RichWeber]

Re: Visio E470VL won't power on.

Can't help too much but can give you next few steps.

Post pics of your board so the experts can review for anything you missed.

Check the output of each clump of wires coming off the power board. Written on the board itself is the expected voltage. Post the results here. Do this for each board coming off of the power board while TV is plugged in and turned on (or what should be on). This will tell you if main and backlight are receiving power and if it is the correct voltage.

There are embedded pics in my post, can you guys not see them? Or should I post pics of my actual boards?

[Jim1590]

Re: Visio E470VL won't power on.

Post pics of your actual board

[RichWeber]

Re: Visio E470VL won't power on.

Here is the actual board that is in my TV.

Tried to take it a couple different time with different settings. Unfortunately there is some shadow in there that I don't like, but it's still pretty good, high resolution.

[tom66]

Re: Visio E470VL won't power on.

Recommend you test voltages as suggested by Jim.

How to check voltages:
- You need a digital multimeter, an analog one does not do the job.
- Set the meter to the 20V DC range.
- The red probe of the meter goes in the VOLT/OHM jack. Black probe in COM.
- Touch the black test probe on the metal chassis -- a spare screw hole works well.
- Touch the red probe along each pin and compare to the label printed on the board. Report your readings back.

[RichWeber]

Re: Visio E470VL won't power on.

I have tested voltage at all of the 5v, an 12v terminals at the power out from the power board. I pulled the cable and tested voltage to do this.. All read zero volts. I am grounding via the chassis just as I was before. I have tested voltage at the on/off, also 0 volts. in fact, everything was 0 volts at power out. I plugged it back in and hit the power button and nothing. I tested anyway at the other end of the cable, and same thing.. zero volts everywhere. I am using an auto ranging digital multimeter. I have a manual range one that I can try, but I don't really like it.

[tom66]

Re: Visio E470VL won't power on.

Autoranging meter is fine... better in fact.
Anyway, just to confirm, you measured on the power board with the cable from the main disconnected?

[RichWeber]

Re: Visio E470VL won't power on.

Yes, sorry. Going back and reading that it's not exactly clear. I disconnected the power out cable that goes from the power board to the main board, and measured at the posts of the power board. All voltages were 0. I did NOT disconnect the power in to the power board, and then try to measure voltages... LOL. Power in voltages were 120v at the fuse.

I then plugged the power out cable back into the power board, hit the on/off button and tested the other side at the metal legs of the socket of the power in on the main board. All zero volts.

[Jim1590]

Re: Visio E470VL won't power on.

You can measure with the cable hooked up. I almost always do. Just cram the tip into the fitting. Probably safer that way as well since it is harder to cross two posts.

Looks like it is narrowed down to the power board. Did you get all 0's at the power going to all of the boards or just one?

Check the power cable to main, backlight, tcon etc... heck may as well do the sound board as well.

[RichWeber]

Re: Visio E470VL won't power on.

I'll go back and check again with it plugged in. And no, I didn't measure all the outs. I can check the backlight power out, and the LCD power out. I see those. Not sure what TCON is, and I think the sound board is integrated to the main board. Thanks for your help guys.

[RichWeber]

Re: Visio E470VL won't power on.

I'll go back and check again with it plugged in. And no, I didn't measure all the outs. I can check the backlight power out, and the LCD power out. I see those. Not sure what TCON is, and I think the sound board is integrated to the main board. Thanks for your help guys.

Confirmed. 0 volts on all outputs. Can't figure out which component failed without a circuit diagram, I don't think, but I get 71 volts at most of the transistor blocks, and pieces of jumper wire that I tested, and 34 volts at another transistor block, but there's no power to the transformers for the backlight, or the lcd, and no power at the outputs. Seems like maybe a smoothing cap shared by the various outputs failed, even though they all appear fine. I've pulled the board and looked at solder joints, and they look ok.

So you guys think a power board would be a safe purchase?

[munirutech]

Re: Visio E470VL won't power on.

i think your power board is faulty do have any electronics baground ? if yes then start checking the stage of your power

[tom66]

Re: Visio E470VL won't power on.

We can probably give repairing the power board a good try, but yes most likely a power board would fix it.

[RichWeber]

Re: Visio E470VL won't power on.

i think your power board is faulty do have any electronics baground ? if yes then start checking the stage of your power

Nothing beyond simple repairs, and no formal training. I can solder and replace components and test a little to find a bad part, but I couldn't design a circuit to save my life. I have no idea how to check the stage of my power. I know a little about simple components and what they do, but that's about it.

I did find a transformer that has power to one side, but nothing on the other.. That seemed strange to me. It's the one with the yellow tape across the top sort of close to the power outs.

I don't really know what I'm doing though. I'll probably pull the board, and lean everything against a wall, and buy the replacement when I get paid.

[RichWeber]

Re: Visio E470VL won't power on.

We can probably give repairing the power board a good try, but yes most likely a power board would fix it.

I'm all ears! If I can save a buck, I'm all for it!

[tom66]

Re: Visio E470VL won't power on.

OK, I presume you've tested the fuse on the input?
For the red points, in the image, test the voltage between here, expect around 160 to 170V DC.
For the blue devices, check the voltage across them on DC volts.

[RichWeber]

Re: Visio E470VL won't power on.

OK, I presume you've tested the fuse on the input?
For the red points, in the image, test the voltage between here, expect around 160 to 170V DC.
For the blue devices, check the voltage across them on DC volts.

Yes, I've tested the input fuse. It read 0 ohms resistance, and when power is plugged in I tested 120v on it's output. Ok, I got ~70v (not 170) on both the red spots. The center legs read .3v, and full 120, incase you are interested. ~60v dc on both the blue.

[tom66]

Re: Visio E470VL won't power on.

For the red and blue, you need to measure across the device, not from one lead to chassis. These components are on the primary side so for safety are isolated from the chassis.

[RichWeber]

Re: Visio E470VL won't power on.

For the red and blue, you need to measure across the device, not from one lead to chassis. These components are on the primary side so for safety are isolated from the chassis.

Whoops, OK. On the red points - I measured across them. I had my multimeter set to ACV, and it just didn't know what to make of it. I measured it in DC and I got 166v, which is pretty close to what you predicted, so I'm assuming that's what I was supposed to be doing?

For the caps (blue), on one I got 4.45v, on the other I got 33v. Measured DC as directed.