Re: Vizio LED Backlight Issue? Dark areas
I think the LCD panel is 705TXES235200X, see picture.
Let me know what to probe and if it is anymore difficult than just getting dc voltage....
roundbox52
Member
Last Activity: 09-15-2017, 04:58 AM
Joined: 08-18-2017
Location: Buffalo, NY
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Re: Vizio LED Backlight Issue? Dark areas
Great. See attached photos for part numbers.
Are we thinking these two components are bad and giving poor voltage to some of the leds?...Leave a comment:
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Re: Vizio LED Backlight Issue? Dark areas
Sorry for my ignorance but is P/N stand for Possitive/Negative?
I found Q801 (which has test points labeled 1-7) and U801, but would be unsure of how to test U801. Any chance you can elaborate on what I should be checking?...Leave a comment:
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Re: Vizio LED Backlight Issue? Dark areas
cn801
Pin# / On / Settled
1 / 19.69 / 30.07
2 / 19.75 / 30.08
3 / 19.71 / 30.09
4 / 19.75 / 30.09
5 not used
6 not used
7 / 11.15 / .607
8 / 11.44 / 11.49
9 / 10.95 / 11.26
10 / 11.49 / 11.49
11 / 11.65 / 11.35
12 / 11.65 / 11.62
13 / 10.80 / 11.36
14 / 11.37 / 11.41
15 / 11.44 / 11.46
16 / 11.36 / 11.41
17 / 11.36 / 11.38
18/ 11.52 / 11.54
19 / 11.42 / 11.43
20 / 11.46 / 11.48
...Leave a comment:
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Re: Vizio LED Backlight Issue? Dark areas
Anyone?
Anyone know what is going on or what I should check next?Leave a comment:
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Re: Vizio LED Backlight Issue? Dark areas
I measured the voltages at the cn804 on the driver board, not the psu.
Pin# / On / Settled
1 / 20.11 / 19.49
2 / 19.99 / 19.48
3 / 20.15 / 19.48
4 / 19.99 / 19.48
5 / .7mv / .4mv
6 / .7mv / .4mv
7 / .7mv / .4mv
8 / .7mv / .4mv...Leave a comment:
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Re: Vizio M502i-B1 Issues
Well I ordered a main board and the initial issue seems to be fixed. I do however have a back light issue where I either have dark areas or bright areas. I've started a new thread about this specific issue.
Any help in diagnosing would be greatly appreciated.
[url]https://www.badcaps.net/forum/showthread.php?p=767526#[/url]Re: Vizio M502i-B1 Issues<br /> <br.... I've startedLeave a comment:
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Re: Vizio LED Backlight Issue? Dark areas
Before diagnosing the main board issue I don't recall having back lights, however once I created a short on the 1 & 3 pin of cn701 of the main board, the upper left back lights came on but no others. I'm wondering if I sent too much voltage to those leds somehow and they remained on or at least brighter than normal.
I'm thinking instead of having dark spots I really have bright spots. Would any of this make logical sense?
This picture is from tonight after turning the tv on. Typically, when everything is...Leave a comment:
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Re: Vizio LED Backlight Issue? Dark areas
Yes it is the exact # as the previous board. Did a different board solve you're issue?...Leave a comment:
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Vizio LED Backlight Issue? Dark areas
I just replaced the main board on my 50" Vizio LED, M502i-b1 which fixed my original issues. I now have an issue with dark areas on the screen, see picture. The image fills the entire screen it is just darker in some areas than others, like the lower right, lower left, center top...
I do recall when diagnosing the main board issue I created a spark on the main board at the power supply connector. This did cause the backlight to flash and partially remain on.
Any help on diagnosing this issue?... -
Re: Vizio M502i-B1 Issues
Interestingly when I plugged the tv in tonight I can see some led's are on, just the left top. I can't see anything on the tv though other than the lights. The power button still does not change voltages on the power supply board.
Any chance we think this can be narrowed down?
I took readings on the led driver board for the two connectors which work their way directly to the tv, I'm assuming these are for all the led's. For the connector for the left side of the tv I had (4) 30v readings and quite a few 11v readings however...Leave a comment:
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Re: Vizio M502i-B1 Issues
Well looks like I'm just going to buy a new tv. Not sure what board is an issue so rather than guess and buy and guess again, I'd rather just put down another $200 and get a new tv, which will also have issues in a few years!
Isn't anything made with quality parts anymore?Leave a comment:
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Re: Vizio M502i-B1 Issues
I originally thought my probes were too fat to not ruin the connector when probing from the entrance of the wire. I though wrong. Here are the corrected values for the right side of cn9101 in [B]bold[/B]:
16/5v/5.17v
14/12v/[B]11.66v[/B]
12/12v/slowly builds to 400mv then starts over at 0 (no wire is connected to this terminal)
10/24v/[B]20.03v[/B]
8/GND/[B]7.1mv[/B]
6/GND/[B]7.1mv[/B]
4/NC/runs to +400 mv then starts over at 0 (no wire is connected to this terminal)
2/ON-OFF/[B]1.342v[/B]...Leave a comment:
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Re: Vizio M502i-B1 Issues
I'm assuming I do this with power supplied to the tv and doesn't matter if I press the manual on/off button.
[U][B]Connector cn9102[/B][/U]
Pin #/Name/Pin Voltage
1/24v/20.04v
2/24v/20.04v
3/24v/20.04v
4/24v/20.04v
5/NC/runs to -400mv then starts over at 0 (no wire is connected to this terminal)
6/NC/runs to -400mv then starts over at 0 (no wire is connected to this terminal)
7/GND/-1.3mv
8/GND/-1.3mv
9/GND/-1.3mv
10/GND/-1.3mv
11/12v/11.67v (no wire is connected...Leave a comment:
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Vizio M502i-B1 Issues
My Vizio M502i-B1 (serial #LTYWRLAQ...) failed to turn completely on yesterday. Pressing power on the remote made the white light appear briefly however nothing showed on the tv. The tv was then unresponsive to the remote or the power button on the back side.
If I plug the tv in the white light now stays on. There is no screen image or backlight.
Some previous history:
I did have the main board replaced under warranty in 2015.
The sound stopped working 6 months ago so I rigged the tv speakers directly to an external receiver (wasn't a problem with the... -
Re: New Members - please post your introductions here
Hello everyone! Newbie here to the forums, wish I had gotten into electrical engineering. I love breaking electronics down but don't understand much about them and circuits...
Hope to learn a lot from everyone here!Leave a comment:
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