VIZIO VO47L FHDTV10A - Voltage Regulator Input

[gethooked]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

I am brand new to reading circuits bud. I don't know how to read it.

I've attached an image to see if you can help me decipher it.

[budm]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

So does the resistance show <1 Ohms when measure between the input pin of U3 to either end of the DIODE?
Same for the resistance reading for the fuse for 12V and either end of the diode?

[gethooked]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

See Image.

Thanks budm

[budm]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

At this point I am not so sure what Q27 is, it may be transistor or regulator. The resistance readings do not look right since the O (Out) pin is the same as the bib tab pin on top which is also connected to the Cathode of the Diode, the resistance between the Cathode and fuse is 1.2 Ohms, that cannot be right sine the center pin is the output pin, then it cannot be connected to the 12V fuse.

[gethooked]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

Q27 is a transistor according to norcal in this video.

http://www.youtube.com/watch?v=jR2UZhoDC2c

I am just going to order another board. I have spent enough time on it. Once I install the new board, I am still going to see if I can repair this one. It would be a good learning tool.

The TV is working and the only issue is that there is only audio @ the optical output. The TV speakers do not function (just buzzing), nor does the RCA audio out. So I will just use the optical for now. I'm guessing this is because I am only receiving 1.02V out of that regulator. The picture looks almost perfect. Im sure with the correct voltage, I will improve a little more.

One of the main reasons I'm throwing in the towel is I cannot desolder the 7805. That tab wont budge at all. No matter how much heat I throw at it. I do not want to burn the board while I wait on a new one to become available.

Thanks again, bud! I sure appreciate your time and advice. I have learned a lot and hope to learn more in the future.

[budm]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

We can ask PO of this thread to make some measurement for us:
https://www.badcaps.net/forum/showth...619#post492619
to see what the resistance will be between the input and the FUSE for the 12V. I will look and see if I have the same TV at the recycle place today.
You will need 50~60W Iron with wide tip and you need to add flux and solder to the pad to remove it.

[gethooked]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

Thanks bud! I appreciate you taking a look. Hopefully you can find one that you could test.

I will head over and ask the PO of that thread to see if they would be willing to measure for us.

My iron is only 40W, with an old tip, so I'm sure the heat transfer was not sufficient at all.

[VaBeachTennis]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

Q27 is a transistor according to norcal in this video.

http://www.youtube.com/watch?v=jR2UZhoDC2c

I am just going to order another board. I have spent enough time on it. Once I install the new board, I am still going to see if I can repair this one. It would be a good learning tool.

The TV is working and the only issue is that there is only audio @ the optical output. The TV speakers do not function (just buzzing), nor does the RCA audio out. So I will just use the optical for now. I'm guessing this is because I am only receiving 1.02V out of that regulator. The picture looks almost perfect. Im sure with the correct voltage, I will improve a little more.

One of the main reasons I'm throwing in the towel is I cannot desolder the 7805. That tab wont budge at all. No matter how much heat I throw at it. I do not want to burn the board while I wait on a new one to become available.

Thanks again, bud! I sure appreciate your time and advice. I have learned a lot and hope to learn more in the future.

I'm sorry that I am resurrecting an old thread but this thread came up when I used the search engine to try to solve my problem. I am having the same exact problem as the poster above. It's the same voltage regulator and so far I am having no luck being able to remove the tab that is attached to the PCB. It seems to be secured by heat sink compound.
Is there a proper technique to remove this tab from the PCB? Thanks!

[R_J]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

I would suspect the tab is soldered to the pc board. apply some flux and use enough heat to release it.

[budm]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

I cut the two legs and then use flux and ADD solder to that big tab using at least 45~50W iron with wide tip.

[VaBeachTennis]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

I cut the two legs and then use flux and ADD solder to that big tab using at least 45~50W iron with wide tip.

Thanks. I was using a thin tip with 60 watts but no flux and solder. It wasn't doing a damn thing!!! I looked up Youtube video after Youtube video and couldn't find someone taking these things out. The tab looks like it's held on with heatsink compound instead of solder, so it confused me. I will use your technique tomorrow morning and report back. Thanks again.

[VaBeachTennis]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

I would suspect the tab is soldered to the pc board. apply some flux and use enough heat to release it.

I'm going to try it tomorrow morning. The thing that confused me was that it looks like it is connected by a heat sink compound.

[budm]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

I did not read the whole thread again, but do do you get at the input and output of that 7805 regulator U3 you are trying to replace?

[VaBeachTennis]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

I did not read the whole thread again, but do do you get at the input and output of that 7805 regulator U3 you are trying to replace?

My apologies for not posting a photo. Mine is at U11 and the tab seems to be secured by a heat sink compound, Here is the photo :


https://www.badcaps.net/forum/attach...1&d=1513820880

[VaBeachTennis]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

Here's another photo of the U11 on a Vizio 0420e, it's right above the 0171-2271-3060 number:

https://www.badcaps.net/forum/attach...1&d=1513821250

[budm]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

The tab is just soldered to the copper plane.
I would check the Voltages on all 3 pins first.
What are the number as printed on the body?

[VaBeachTennis]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

The tab is just soldered to the copper plane.
I would check the Voltages on all 3 pins first.
What are the number as printed on the body?

The voltages on the pins equal 0v.

The numbers are:

LM-7805-CT

[budm]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

If you get all 0V on all the pins than it not likely to be the bad regulator unless the input pin has dead short to GND.

[VaBeachTennis]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

If you get all 0V on all the pins than it not likely to be the bad regulator unless the input pin has dead short to GND.

Thank you, I am embarrassed to say that I think that I shorted it out when I was taking the readings. There was a spark when I accidentally touched pin 2 to pin 1 or 3, after that I was getting the 0V on all of the pins.

It's pretty much easy for me to replace the boards (after troubleshooting) but I am trying to learn more and advance to replacing the components on the PCB's. Hopefully it will be more cost effective. Luckily for this project, I have another of the same board to practice on before I go and work on the other board.

[R_J]

Re: VIZIO VO47L FHDTV10A - Voltage Regulator Input

On the original posters pictures there are two white fuses, have you checked them? you may have blown one of them when you shorted the regulator