Re: VIZIO VT420M back light/no picture
Here are the measurements you suggested I make. Please let me know if there's anything else I can do.
Thanks again,
mike
[ATTACH]181988[/ATTACH]
ps Not sure the attachment feature worked but I have attempted to attach a pdf file with the measurement information.Re: VIZIO VT420M back light/no picture
Here are the measurements you suggested I make. Please let me know if there's anything else I can do.
Thanks again,
mike
[ATTACH]181988[/ATTACH]
...
mpbarber
Member
Last Activity: 08-30-2018, 08:13 PM
Joined: 09-07-2017
Location: alpena/michigan
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Re: VIZIO VT420M back light/no picture
Great! Thank you! I'll get the measurements today.....Leave a comment:
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Re: VIZIO VT420M back light/no picture
I took a closer look at my photos and realized that by using the macro setting on my camera it focused on the surfaces that were close to the lens and blurred those that were further away.
My main objective here is to see if I can identify one particular board that should be replaced.
Any further help/advice would be appreciated.Leave a comment:
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Re: VIZIO VT420M back light/no picture
Here are more pics.
I don't know what "SMD works" is.
I can get close up pics if you can tell me where.... I don't know much about the names of the electronic components....Leave a comment:
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Re: VIZIO VT420M back light/no picture
Sorry... try these....Leave a comment:
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Re: VIZIO VT420M back light/no picture
Hello, Sorry, I'm not being very thorough reading the responses. I've attached some pics of what I believe to be the main board along with some close ups but not sure I've captured what you are asking for.
Please let me know if you want additional pics.
Again, I really appreciate your help and your patience while I try to give you the information you require....Leave a comment:
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Re: VIZIO VT420M back light/no picture
Hello,
I measured 0.91 - 1.01 volts on both ends of the fuse. Shouldn't it be 12 volts?...Leave a comment:
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Re: VIZIO VT420M back light/no picture
I must have missed this. I plugged in the power cord, turned on the TV, got a temporary blue light on the board with the fuse. Measured each end of the fuse to ground and got 0.91 - 1.01 on both ends.
That would indicate that I'm not getting 12 volts to the fuse?
thanks...Leave a comment:
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Re: VIZIO VT420M back light/no picture
Hi Dick,
With power to the TV and the power switch turned on, the back light and a blue light on the board that has the fuse, cycles twice. I measure .045 to .051 @2K ohms setting on the meter. I also noticed that the screen flashes a blue/white horizontal stripe pattern across the screen which eventually stops.
Thank you for trying to help. I'm hoping that I can perhaps find that one of the boards is bad and it is a simple replacement, if I can find the board.
thanks again,
mikeLeave a comment:
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Re: VIZIO VT420M back light/no picture
New measurements.............. O/F 4.98, PDIM 3.30, 12VDC 11.41, 12VDC 11.41, GND 0, GND 0, GND 0, 24VDC 23.8, 24 VDC 23.8 PS-ON 4.97, 5VDC 5.14, 5VDC 5.14 F1 125V/3.0A .02 - .03 to ground both ends of the fuse
thanks in advance for any suggestions....+Leave a comment:
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Re: VIZIO VT420M back light/no picture
Thank you... as my kids used to say..... DUH!...Leave a comment:
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Re: VIZIO VT420M back light/no picture
THANKS! Yes, all measurements were done with with black probe to a chassis screw. So can I test the main board or should I just replace it?
I made all measurements using the same chassis screw for ground.... I have the unit face down on a blanket on a table so I just plugged in the power cord and did not actually "turn on" the TV.
Could that explain the reading errors and would it help if I turned the TV on and then make the measurements?Leave a comment:
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Re: VIZIO VT420M back light/no picture
OK, so I finally got back to this problem.... it's my bedroom TV so no rush.
I plugged in the TV and measured the voltage of the multi-collored connection on the power board, see attached pics.
I listed the voltage readings per pin, again, see pics. That seems OK.
But when I measured both sides of the fuse, I got zero volts. I tried to take a close up picture of that fuse. Not sure this is my problem, but "no volts" is probably not a good thing....
thanks again,
...Leave a comment:
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Re: VIZIO VT420M back light/no picture
OK Got it to work... Is that a fuse in pic 2 (F1 125V/3.0A) and if it is how do determine if it's bad?...Leave a comment:
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Re: VIZIO VT420M back light/no picture
Thanks. I would but I'm not sure where to check or what the values should be....Leave a comment:
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Re: VIZIO VT420M back light/no picture
OK... I took the cover off took pictures but.....
I can't add the pics.... there is a dropdown arrowhead just to the left of "Undo Redo" and to the right of the dropdown that shows "Smilies" which shows "Attachments" when I put the cursor on it but when I click on it nothing happens.
When I click on the Insert Image icon it displays.... Please enter the URL of your image.......Leave a comment:
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Re: VIZIO VT420M back light/no picture
Sorry. There is no picture or sound but I have the back light. It started out as fuzzy picture that kind of jumped... It would go away after about 5 minutes but then after about a month of that the picture and sound quit.
I'll need some help identifying exactly where to get the readings. Would I be measuring voltage to ground from various wires on the ps to main, or voltages from the ps wires to the main wires? I have a multi-meter....Leave a comment:
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Re: VIZIO VT420M back light/no picture
Thanks to both.... I will work on this and get back to you. I thought I'd get an email when someone responded but I did not. Is there something I can do to get emails?Leave a comment:
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VIZIO VT420M back light/no picture
Tried to do this yesterday but didn't seem to work so this may be a duplicate...
looked at a lot of posts regarding this problem but am having trouble understanding the suggested repairs.
I'm going to put some pictures on here hoping that someone can help me identify the names of the various cicuirt boards and what things I can try to fix this TV.
Thanks in advance for your help....Last edited by mpbarber; 09-10-2017, 12:07 PM. -
Hello. I attempted to post a new question but my computer took a long time processing it. Should I have gotten a message if it was successful? If it was, how long should it take for it to show up in "All posts by mpbarber"?
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