Vizio M261VP Not Turning On

[CapLeaker]

Re: Vizio M261VP Not Turning On

I checked all of the LEDs in diode mode and they all lit up with my multimeter.

Okay, so I measured the voltage regulators and what was labeled as U10 did not look like U9. See image:

https://dl.dropboxusercontent.com/u/...69/Circuit.jpg

-U9 to carry about .25V
-U10 to carry nothing, based on the pins I measured.
-U8 carried 18.5 V

I couldn't quite read the #U8 correctly from the other pic. That's why clear pics are important. I was thinking on U8. However, one of them, U8, U9 or U10and maybe the one to the right of U9 (is it U6?) isn't working correctly. But I would check those regulators U8 and U10 first. Also have a look at these little surface mount caps and see that they are not shorted.

Kind of looks like there are 2 power supplies, one supplies the left side and the other the right side of the LED's. Great! now you got something to compare, if components are the same. Now a schematic would be nice!

[budm]

Re: Vizio M261VP Not Turning On

You may want to read these threads:
https://www.badcaps.net/forum/showth...t=Vizio+M261VP

https://www.badcaps.net/forum/showth...t=Vizio+M261VP

https://www.badcaps.net/forum/showth...t=Vizio+M261VP

[CapLeaker]

Re: Vizio M261VP Not Turning On

Oh well... there you go! there were already cases with the same problem before...
Anyway... then I can shut up now and keep quiet.

[SBlevins]

Re: Vizio M261VP Not Turning On

You may want to read these threads:
https://www.badcaps.net/forum/showth...t=Vizio+M261VP

https://www.badcaps.net/forum/showth...t=Vizio+M261VP

https://www.badcaps.net/forum/showth...t=Vizio+M261VP

I found all of those threads and I read them all before hand.

https://www.badcaps.net/forum/showth...t=Vizio+M261VP

The first one would turn on and mine will not. Also I got confused when XmouseX stated 405 regulator in post #44, but then I understand it to be 540. It was also not stated that he found a replacement, and then the rest was related to the LED strips which I quoted in post #1 of this thread.

Do you know if there was a replacement to the regulator 540N budm?

https://www.badcaps.net/forum/showth...t=Vizio+M261VP

The second one addresses the same problem, and I PM'ed the OP who said he had narrowed the issue to a power source issue on the main board and would let me know if he figured it out.

https://www.badcaps.net/forum/showth...t=Vizio+M261VP

The third one allows for the TV to turn on, but mine does not, and the "symptoms" are not the same.

[CapLeaker]

Re: Vizio M261VP Not Turning On

have you figured out yet, why U10 hasn't been proper powering up? See if there is input voltage, if not you havta trace it.

[SBlevins]

Re: Vizio M261VP Not Turning On

have you figured out yet, why U10 hasn't been proper powering up? See if there is input voltage, if not you havta trace it.

It leads to a resistor and then it leads to U8 which is the one that was stated to be bad in one of the forums posted by budm. (#1 I think?)

I traced the ground of U10 and it looks like it leads to an electrolytic capacitor (CE36)? I am not 100% sure of what I am looking at. Here is a "clearer" image of the board quadrant I was looking at: https://dl.dropboxusercontent.com/u/...228_093410.jpg

[CapLeaker]

Re: Vizio M261VP Not Turning On

Turn the tv on and measure u8 and u10. Put the negative lead on the GND pin on each individual regulator and measure the dc voltage. See if there is a difference between U8 and and U10. You need to figure out if there is any input voltage to the regulator. GND (left pin) middle pin is output of the regulator and the right pin is the input voltage. The tab of the regulator and the middle pin have the same connection. The difference between the input voltage and the output voltage is 1.25V. If that isn't within 1%, the regulator is bad.

[SBlevins]

Re: Vizio M261VP Not Turning On

Turn the tv on and measure u8 and u10. Put the negative lead on the GND pin on each individual regulator and measure the dc voltage. See if there is a difference between U8 and and U10. You need to figure out if there is any input voltage to the regulator. GND (left pin) middle pin is output of the regulator and the right pin is the input voltage. The tab of the regulator and the middle pin have the same connection. The difference between the input voltage and the output voltage is 1.25V. If that isn't within 1%, the regulator is bad.

Are you sure that the pins you have listed are not reversed? The right pins have a small "O" next to them and I thought that it meant output.
Okay here are my results:

U8
Middle Pin (Output) = 0.23 V
Right Pin (Input) = fluctuates between 0.01 V and 0.09 V

U10
Middle Pin (Output) = 18.91 V
Right Pin (Input) = 0.00 V

That seems reversed to me from what you said, but it looks like they are both bad? Your help is much appreciated.

[CapLeaker]

Re: Vizio M261VP Not Turning On

Well, there is for sure no backlight then when u8 doesn't get any input voltage on regulator. What is the part number on u8? Now we need a schematic to find out why one regulator (U10) has power and the other one (U8)has not. My bad on the pin switch on the regulators, O is output and middle pin or tab is the input on these.

[budm]

Re: Vizio M261VP Not Turning On

"The difference between the input voltage and the output voltage is 1.25V. If that isn't within 1%, the regulator is bad."
Please make the correction, the ADJUSTABLE REG IC (1117 series) will have 1.25V (+/-2~3%) between the ADJ pin and the output pin, it cannot have 1.25 between input and output otherwise it will not regulate the output voltage.
OP, it is important that you also provide P/N of the ICs as shown in the thread on how to test the Voltage regulator.
Some of these regulators may not have input voltage until all the power supplies are turned on.

[nomoresonys]

Re: Vizio M261VP Not Turning On

read a post by tom66, think it was yesterday when I read it, he said a barely audible click meant something, cant remember exactly but I think it was to do with an IC, I could be wrong about if he said IC but it had to do with a very faint click issue. in reference to post #5

[CapLeaker]

Re: Vizio M261VP Not Turning On

"The difference between the input voltage and the output voltage is 1.25V. If that isn't within 1%, the regulator is bad."
Please make the correction, the ADJUSTABLE REG IC (1117 series) will have 1.25V (+/-2~3%) between the ADJ pin and the output pin, it cannot have 1.25 between input and output otherwise it will not regulate the output voltage.
OP, it is important that you also provide P/N of the ICs as shown in the thread on how to test the Voltage regulator.
Some of these regulators may not have input voltage until all the power supplies are turned on.

There is no schematic that I can find for that board. I haven't got a clue what numbers that regulator has as I can't read the numbers of it from the pic. Is it fixed or variable, dunno. Both regulators feed one side of the LEDs. One has input power, the other one has not, does not make any sense.

[budm]

Re: Vizio M261VP Not Turning On

OP needs to get the P/N to look up the spec sheet and application notes on the application circuits.
Variable regulator will have two resistors connected to the ADJ pin, see more details I provided on the how to test voltage regulators.

[nomoresonys]

Re: Vizio M261VP Not Turning On

OP needs to get the P/N to look up the spec sheet and application notes on the application circuits.
Variable regulator will have two resistors connected to the ADJ pin, see more details I provided on the how to test voltage regulators.

thats post #20.

[SBlevins]

Re: Vizio M261VP Not Turning On

OP needs to get the P/N to look up the spec sheet and application notes on the application circuits.
Variable regulator will have two resistors connected to the ADJ pin, see more details I provided on the how to test voltage regulators.

So here is what I have (post #28 has mismatched values):

U8
P/N: 540N 05S5G
Middle Pin (Input) = 18.91 V
Right Pin (Output) = 0.00 V

U10
P/N: SM260F 10100DF1
Middle Pin (Input) = 0.23 V
Right Pin (Output) = fluctuates between 0.01 V and 0.09 V

High RES: https://dl.dropboxusercontent.com/u/...228_132020.jpg

read a post by tom66, think it was yesterday when I read it, he said a barely audible click meant something, cant remember exactly but I think it was to do with an IC, I could be wrong about if he said IC but it had to do with a very faint click issue. in reference to post #5

I was thinking about that and it seems likely.

[CapLeaker]

Re: Vizio M261VP Not Turning On

Dunno what a sm260f is, but see what feeds the tab of it.

[budm]

Re: Vizio M261VP Not Turning On

OK, those two regulators (now we know they are not 1117 series since we see what they look like now)
U6 and U9 are probably the SMPS IC or LED drivers. I cannot tell. Can you take larger area to see more parts in that area?
I cannot read U6, U9 P/N. If we can get the spec of these two ICs then we may have some idea how this circuit works.

The more I looked at those U8 looks like power MOSFET for driving the inductor boost regulator circuit.
The GND pin looks to be Gate pin which is driven by U6 pin 13 through resistor R25.
the O pin looks to be the Source pin.


https://cdn.badcaps-static.com/pdfs/...23be5e315f.pdf

U10 GND pin and O pin seem to be connected to the same ground plain. Can you check the resistance between GND and O pin?
I think U10 is a Diode (Common Cathode at the big tab) which is connected to the + of the filter cap CE11.
You can verify U10 by using Diode mode, the big Tab i Cathode, the two legs are the Anodes.

[SBlevins]

Re: Vizio M261VP Not Turning On

OK, those two regulators (now we know they are not 1117 series since we see what they look like now)
U6 and U9 are probably the SMPS IC or LED drivers. I cannot tell. Can you take larger area to see more parts in that area?
I cannot read U6, U9 P/N. If we can get the spec of these two ICs then we may have some idea how this circuit works.

See attached. See Dropbox link for High Res: https://dl.dropboxusercontent.com/u/...9/DSC_0322.JPG

The more I looked at those U8 looks like power MOSFET for driving the inductor boost regulator circuit.
The GND pin looks to be Gate pin which is driven by U6 pin 13 through resistor R25.
the O pin looks to be the Source pin.


https://cdn.badcaps-static.com/pdfs/...23be5e315f.pdf

U10 GND pin and O pin seem to be connected to the same ground plain. Can you check the resistance between GND and O pin?
I think U10 is a Diode (Common Cathode at the big tab) which is connected to the + of the filter cap CE11.
You can verify U10 by using Diode mode, the big Tab i Cathode, the two legs are the Anodes.

I can confirm that the resistance between the GND and O pins on U10 is almost 0 ohms, and they seem connected.

For U10, the big tab (cathode) and the GND and O pins (Anode) gave me a diode value of 0.343 and 0.324.

[budm]

Re: Vizio M261VP Not Turning On

So at this point you cannot trust the prints on the board, U10 is Diode.
So what are the P/N of U6, U9?

[nomoresonys]

Re: Vizio M261VP Not Turning On

So here is what I have (post #28 has mismatched values):

U8
P/N: 540N 05S5G
Middle Pin (Input) = 18.91 V
Right Pin (Output) = 0.00 V

U10
P/N: SM260F 10100DF1
Middle Pin (Input) = 0.23 V
Right Pin (Output) = fluctuates between 0.01 V and 0.09 V

High RES: https://dl.dropboxusercontent.com/u/...228_132020.jpg



I was thinking about that and it seems likely.

read the post again and it was a diode not an IC that was causing the faint click.