Vizio E552VLE Schematics needed! [no power on]

[Holes Flow]

Experts,

Like other posters, I cannot get this behemoth to turn on, nor does the Vizio "off light" illuminate. Bought anther power board-no change.

I have no voltages on any of the connectors where voltage levels are indicated. I have voltage on one side of the isolation transformer, and nothing on the other side-on both boards.

Its becoming obvious that the controller board needs power to send a signal back to the power board, but no juice at ALL gets to the control board. REALLY need a schematic...

trying this way... vBulletin can be finnicky...

https://drive.google.com/file/d/1xBJ...ew?usp=sharing

https://drive.google.com/file/d/1wrX...ew?usp=sharing

https://drive.google.com/file/d/1wr1...ew?usp=sharing

https://drive.google.com/open?id=1wk...s&usp=drive_fs

https://drive.google.com/open?id=1wk...s&usp=drive_fs

https://drive.google.com/open?id=1wi...s&usp=drive_fs

...hope the above links work...

TIA!

[Holes Flow]

Re: Vizio E552VLE Schematics needed! [no power on]

The message you have entered is too short. Please lengthen your message to at least 1 characters."

Where is the message I wrote?

attaching 6 pis here as the forum said it failed to make the links to the image on GDocs...

basics: E552VLE no power on, no light, no power at ALL from power board, so nothing to control board.

Thanks

[Holes Flow]

Re: Vizio E552VLE Schematics needed! [no power on]

I've since removed the PS and controller boards, keeping the interconnections, and brought to bench.

I could trace everything a lot easier with a schematic, but I guess I have to start drawing the circuits by hand... joy...

[dskall]

Re: Vizio E552VLE Schematics needed! [no power on]

Need to see picture of connector legend to mainboard. Probably have a bad mainboard.

[Holes Flow]

Re: Vizio E552VLE Schematics needed! [no power on]

I see the signal for on on the silk screen of the power board, that is, the signal is coming from the control board. But the controller board isn't getting any power whatsoever, there is no power on any of the pins of any of the two connectors that send power over from the power board to the controller.

But still, I'm curious if the signal on that pin is supposed to be a short to ground or go high to a certain voltage.

If anybody has links to any schematics even schematics in this general series which are probably going to be similar control boards, I would really love to hear from you...

TIA!

[R_J]

Re: Vizio E552VLE Schematics needed! [no power on]

Do you have 5.1 volts on CN2 of the power supply board?

I have no voltages on any of the connectors where voltage levels are indicated. I have voltage on one side of the isolation transformer, and nothing on the other side-on both boards.

What isolation transformer are you talking about? You do know that the primary side uses hot ground which is different from the secondary side ground.

[Holes Flow]

Re: Vizio E552VLE Schematics needed! [no power on]

Yay! @R_J I have 5.1V on CN2! I have the board completely removed on bench, no connectors to the main/control board.

Without the controller board, the 5.1VDC is present continuously on pins 1, 2, 3 of CN2. However, as soon as it powers up with CN2 and CN5 connected, the 5VDC is only present for 4-5 seconds on powerup.

Unplugging CN5 (+18V) from the power board allows the 5.1VDC to continue on power up. After a few tries w/out CN5. 5.1VDC goes away after only 1 second now... Ain't it great when symptoms change?! :-(

Progress!

P.S. I have been over the boards with a microscope, and have tried a different power board, and no change in symptoms. Am I taking the $130+ plunge on a controller board, or does anyone have a schematic so I can t-shoot at component level?

[Holes Flow]

Re: Vizio E552VLE Schematics needed! [no power on]

@R_J,

"What isolation transformer are you talking about? You do know that the primary side uses hot ground which is different from the secondary side ground."

There are 2 transformers on the power board, crossing the primary-secondary line. I cannot find them by part number in the Interwebs...

[Holes Flow]

Re: Vizio E552VLE Schematics needed! [no power on]

Looks like everything on CN2 (JP2 on CTRL board) & CN5 (JP3) is shorted to ground. Everything around those two jacks is less than 1 Ohm to GND. I'm talking about no cables connecting the CTRL board to any others.

[captainKKK]

Re: Vizio E552VLE Schematics needed! [no power on]

Check the U801 and all the Schottky around it for short to ground

[Holes Flow]

Re: Vizio E552VLE Schematics needed! [no power on]

Check the U801 and all the Schottky around it for short to ground

Thanks for the tip! Every bloody thing shows a short! And I have no IR camera, but do have a variac... Hoping it wouldn't come to that...

Thanks again!

will update.

[dskall]

Re: Vizio E552VLE Schematics needed! [no power on]

You can always use alcohol.

[Holes Flow]

Re: Vizio E552VLE Schematics needed! [no power on]

Check the U801 and all the Schottky around it for short to ground

I cannot locate this IC, and the numbering doesn't look like the rest. Here are 4 shots, with the 4 and 14 conductor cables being the power ones from the power board...




I think this is a link to the folder: link