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**budm** · 10-11-2012, 12:44 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

So the resistance reading of 97 Ohms is correct at middle pin., I would get the new regulator. According to my calculation, the output should be about 1.30V

**MisterD** · 10-11-2012, 12:50 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

Originally posted by budm View Post

That is OK, at this point I think it is pretty safe to say that U7 is bad since the output voltage cannot not be less than 1.25V.

So do you think U9 is okay? I think they could be the same type made by different manufacturers.

**budm** · 10-11-2012, 12:52 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

U9 is a fixed 1.5V regulator. It is OK
U7 is an adjustable regulator.
They are 1117 series. I myself stock both fiexd regulator and adjustable regulator for my spare parts.
You can get them from DIGIKEY.

**MisterD** · 10-11-2012, 01:05 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

Do you think this one will work?

http://www.ebay.com/sch/i.html?_trks...at=0&_from=R40

**MisterD** · 10-11-2012, 01:12 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

I'm having trouble finding from DIGIKEY

**MisterD** · 10-11-2012, 01:20 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

Originally posted by budm View Post

U9 is a fixed 1.5V regulator. It is OK
U7 is an adjustable regulator.
They are 1117 series. I myself stock both fiexd regulator and adjustable regulator for my spare parts.
You can get them from DIGIKEY.

This is the best place I have ever been for troubleshooting and Bud you have been a lot of help as well as others here, Thank You All Very Very Much!!!

I will get this part ordered and hope to have it up and working again,will keep you posted.

**budm** · 10-11-2012, 01:58 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

http://www.digikey.com/product-detai...SCT-ND/1967218.
See Examples.
You may want to order 5 each incase other values go out later.

Attached Files

**MisterD** · 10-11-2012, 02:06 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

Sorry but I'm confused don't know which one to order. Thanks!

**budm** · 10-11-2012, 02:22 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

This one for U7:
http://www.digikey.com/product-detai...SCT-ND/1967218

This one for 1.5V fixed:
http://www.digikey.com/product-detai...SCT-ND/2121241

This one for 1.8V fixed:
http://www.digikey.com/product-detai...SCT-ND/1967216

This one is for 2.5V fixed:
http://www.digikey.com/product-detai...SCT-ND/2121243

This one is for 3.3V fixed:
http://www.digikey.com/product-detai...OSCT-ND/660708

**MisterD** · 10-11-2012, 02:22 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

I see that U 33 is the exact same one, does anyone have that part number from DIGIKEY?

Part # stamped on regulator is AMC1117 F0722F

Thanks!

**MisterD** · 10-11-2012, 02:24 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

Originally posted by MisterD View Post

I see that U 33 is the exact same one, does anyone have that part number from DIGIKEY?

Part # stamped on regulator is AMC1117 F0722F

Thanks!

Never mind Bud has posted it. Thanks!

**MisterD** · 10-14-2012, 07:41 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

Originally posted by budm View Post

"but U7 and U9 have 3.3 v input but zero v output on one and only .01v output " Can we see the pictures and the P/N?

I posted wrong info: U7 had 3.3v input and only .8v output
U9 had 3.3 input and 2 v output.

**MisterD** · 10-15-2012, 07:15 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

Originally posted by budm View Post

So the resistance reading of 97 Ohms is correct at middle pin., I would get the new regulator. According to my calculation, the output should be about 1.30V

I replaced U7 (checked bad) and went ahead and replaced U33 (common failure part) although it checked good, now it turns on and works great, the output voltage on U7 is now 1.27 Volts. I want to thank everyone that posted comments they were all a lot of help, I would probably still be trying to diagnose it if it wasn't for you guys helping, you are greatly appreciated..

Thanks again!!! Thanks Bud!!!

**budm** · 10-15-2012, 09:09 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

I am glad that was all it needs, and glad that my calculation is correct.
Here is the calculator.

Attached Files

1117 LDO calculator_BudM.xls (24.5 KB, 51 views)

**Derrick8265** · 12-18-2015, 03:04 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

Hello - I'm having similar trouble. TV will simply not power up and turn logo white.

I'm in need of some help finding a schematic for my Vizio model VW42LHDTV10A. I'm not getting the proper voltages at the 13 pin connector at the top of the main board:

pins 2-5 should be 12v, but they are 1) none, and 2-5 are 5.1v. Also, 9-11 should be 5v, but I have no voltage there. So, I replaced the PSU, but no change in symptoms or meter readings.

Symptoms are: orange logo lights up, but will not power on.

Apparently, it's a common main board issue to not be able to power off, but I'm not having that problem specifically. I suspect the main board as the cause, but can't be sure without a schematic.

I also read the left side (bigger single leg) of U33, U7-9, and U2:
U7 is .9, U9 is .52, U33 is 3.29, U8 is 3.31, and U2 is 3.33v.
Most of these are offered in a repair kit online, but can't determine what these voltages should read when good. I don't know any more than that as to how to trouble-shoot this issue or how to go on from this point.
I appreciate any advice, thanks!

**budm** · 12-18-2015, 03:10 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

The 12V from power supply will not be present until the main board is working and sends out PS-ON command to turn on the rest of the power supply.
You need to report the reading of ALL 3 pins of the LDO regulator IC.
Report in the format as shown in this link, it will make it much easier for us to tell you which one is bad. BTW, there are more than one version of the main board so we need the pictures of your main board.
https://www.badcaps.net/forum/showth...999#post300999

'I also read the left side (bigger single leg) of U33, U7-9, and U2:' Do you mean the big tab on top? Se the spec sheet of the IC to get the pin out for you to report the proper readings.

**Derrick8265** · 12-18-2015, 03:13 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

PS: I also tested main board fuse F1 and F2. F1 is 5.1v and F2 is nothing. However, F1 and F1 both read 1.2 ohms with power cord out. (?)

**budm** · 12-18-2015, 03:14 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

F2 is for the switched 12V supply.

**Derrick8265** · 12-18-2015, 03:20 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

Thank you for your reply budm! I am working with my father-n-law on this repair. I know virtually nothing about this, but he was an IT in the Navy, so he will understand what you're saying and/or asking for. He's out plowing snow right now, but I will get back to you tomorrow with pics and more info. By the way, the board is:
0171 2272 2293
3642 0102 0150

Sorry to say, but I don't know how to post a pic on this forum

**Derrick8265** · 12-18-2015, 03:22 PM

Re: Vizio 42" LCD VW42LHDTV10A Will Not Turn On

Bud - apparently my posts are a bit out of sync, but thanks for the info about F2 - that makes sense.

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