Vizio V50P FHDTV10A power problem

[AshC1023]

Ok, so this TV was free but we think it's salvageable.
When you plug it in it turns on with the usual click. Vizio lights up orange, then fades out. The screen is lit up but you cannot access menu, input, anything like that. Side buttons are non functional. The screen stays on the whole time until it either times out/sleep mode or you unplug it. Sub power board has been replaced as we thought it may be faulty.
The back light does not light up even after sub power board replacement.

I cannot seem to find a data sheet or repair manual for this model or by part numbers, even with strong Google-fu.

I tested the "little black things" that the name I can't think of right now, (square, black, 3 pins each) on the main board. They tested as follows with my voltmeter(which doesn't mean much to me without knowing the correct values) also uploaded a pic naming them with the values on it if that's easier to understand:

Far left - bottom mid top
2.07 3.32 5.19
Right 2.03 3.25 5.19


Top Left Mid Right
.54 1.79 3.31

Bottom .54 1.79 3.24


Middle (right of the 4 cluster)
Bottom: 1.25
Mid: 2.49
Top: 5.21

Far right
Bottom: 11.75
Mid: 0
Top: 4.97

I uploaded pictures of all the boards. None of the capacitors seem bulged at all, none have leaked. Any help is appreciated.

[budm]

Re: Vizio V50P FHDTV10A power problem

Far left - bottom mid top
2.07 3.32 5.19
Right 2.03 3.25 5.19

1.25 Vref + 2.07 = Vout 3.28V (+/-2%) = OK

Top Left Mid Right
.54 1.79 3.31

Bottom .54 1.79 3.24
1.25 Vref + 0.54 = Vout 1.79V (+/-2%) = OK

Middle (right of the 4 cluster)
Bottom: 1.25
Mid: 2.49
Top: 5.21

1.25 Vref + 1.25 = Vout 2.50V (+/-2%) = OK

Far right
Bottom: 11.75
Mid: 0
Top: 4.97
5V regulator = OK

[cliff_hootarski]

Re: Vizio V50P FHDTV10A power problem

Make sure you have voltage on both sides of the 3 fuses on the top of the board.
There are also at least 3 other voltage regulators (smaller ones) that you have not
recorded voltages from (located near the farthest to the right big regulator that you
did measure).

[Alastair E]

Re: Vizio V50P FHDTV10A power problem

Thats a Panasonic Chassis. Possibly a PZ80....

[AshC1023]

Re: Vizio V50P FHDTV10A power problem

The three fuses were
3A: -.35 (both sides) ??? seems odd - far left fuse from bottom
3A 11.78 both sides
1.5A 3.62 x 3.65


Other regulators: (Think these were the right ones)
U21 - 0 , 1.24, 2.50
U17 - 2.07, 3.31, 5.24
U22 - 1.65 , 2.64 , 3.62

[AshC1023]

Re: Vizio V50P FHDTV10A power problem

Thats a Panasonic Chassis. Possibly a PZ80....

In a Vizio TV, maybe that's why I can't find anything on repair manuals? Seems that these are interchangeable parts between the two brands.

[Alastair E]

Re: Vizio V50P FHDTV10A power problem

Pity they matched a nice Pan chassis with some cheap Chinese cruddy mainboard...

[cliff_hootarski]

Re: Vizio V50P FHDTV10A power problem

What's the numbers on U22, 2.64v output seems suspect.

[AshC1023]

Re: Vizio V50P FHDTV10A power problem

U22 reading top to bottom

top: 3.60
mid: 2.62
bottom: 1.63

I'll be honest, I don't know much about circuit boards at all so that's about as good as it gets for me, I can test it, but after that...?

[ReeceyBurger123]

Re: Vizio V50P FHDTV10A power problem

Thats a Panasonic Chassis. Possibly a PZ80....

Thats not a PZ70 they are tank lol
Picture of PZ70

Edit: misread that.

[cliff_hootarski]

Re: Vizio V50P FHDTV10A power problem

What are the numbers printed on top of IC itself?

[AshC1023]

Re: Vizio V50P FHDTV10A power problem

There's nothing printed on the top, it's just flat black.

[cliff_hootarski]

Re: Vizio V50P FHDTV10A power problem

What's the model number of the board printed on the white sticker?

[AshC1023]

Re: Vizio V50P FHDTV10A power problem

Printed on the board in white lettering is:

0171-2272-2586

On the sticker with bar code is:

3850-0172-0150 (6B)
05M17585218546B

CSD - 3850-5002-0395

[cliff_hootarski]

Re: Vizio V50P FHDTV10A power problem

I think U22 is a 1117 variable voltage regulator. The difference between pin 1 and pin 2 should be around 1.25v. (add 1.25v to pin 1 voltage for the output voltage pin 2) and in this case should be 2.88v (1.63v + 1.25v), you measured 2.63. I believe tolerance voltage is 3%, so this would be out of tolerance.

Are you sure you can't read any markings on the chip?

Here is a picture from Shopjimmy:

http://assets.shopjimmy.com/media/ca...0150-top_2.jpg

and a listing on eBay for a board like yours:

http://www.ebay.com/itm/VIZIO-3850-0...cAAOSwJcZWfqhl

However, neither board shows the markings for U22.

[cliff_hootarski]

Re: Vizio V50P FHDTV10A power problem

Read this post for more LDO voltage regulator info.

https://www.badcaps.net/forum/showth...999#post300999

[budm]

Re: Vizio V50P FHDTV10A power problem

3.62V input for 2.88 (2.9V) output is not good, the diff between Vin-Vout is <1V, typical is around 1.2V.
So the 3.62V input is too low, or the regulator is bad.

[AshC1023]

Re: Vizio V50P FHDTV10A power problem

It did end up having something etched in it - AMC 1117 F0748F

Now the question really is, is this something that's worth soldering myself, or just best to replace the whole board? I've soldered before, but not circuit boards.

Going by the tutorial, it should be that pin 2 is 2.9v not the 2.64 it reads - which is a 8% difference? Correct this if I did it wrong.

1.65 + 1.25 = 2.9
2.9 - 2.64/ 2.9 = 0.08

[cliff_hootarski]

Re: Vizio V50P FHDTV10A power problem

1117s are cheap. I'd try that first, but even if you successfully soldered a replacement, it still might not explain the no voltage on the 3A fuse. In the mean time, the board on eBay might be gone. Of course the board on eBay might be defective too!

Those 1117s are soldered on the bottom of the chip as well. I guess it just depends on your own assessment of your soldering skills.

[AshC1023]

Re: Vizio V50P FHDTV10A power problem

I solder car electrical, which isn't anywhere near as small or touchy. I ended up ordering a board (not off ebay) for $34 since I had a 50% off coupon and comes with a 6 month warranty on it. Same place I ordered the sub power board (the original had a fuse that read 0 so I figured that wasn't right)
I will give it a shot soldering it after I put a new board in, that way if I botch it really badly, I'm not waiting on a new board. Hopefully this repairs it so I can mess with the other one at a later date. I tried to find those tiny fuses and could only find them on fleabay shipped from China, they're super cheap too but I don't like buying anything from China off Ebay.

An electrician I'm not, my husband is the smart one for that kind of stuff.