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Old 03-07-2020, 01:46 PM   #1
x_orange90_x
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Default Vizio E470i-A0 Dark Areas After Replacing Backlights

I just replaced the Backlights in a Vizio E470i-A0 last night and I've noticed the light is not uniform across the panel. There's a patch where you can actually make out a few individual LEDs, the top and bottom of the screen are noticeably darker than the midsection, and the center left is crystal clear. The LEDs I bought were brand new from Amazon.

It was late when I was reassembling it and it had been apart for a few weeks... Did I maybe put the diffusers in the wrong order? That's the only thing I can think would cause this. What's odd though is the section that appears bright and clear which I wouldn't expect to see if the layers were out of order.

Pictures are attached. Any ideas?
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File Type: jpg 20200307_140743.jpg (603.6 KB, 43 views)
File Type: jpg 20200307_141046.jpg (487.3 KB, 24 views)
File Type: jpg 20200307_141055.jpg (455.1 KB, 29 views)

Last edited by x_orange90_x; 03-07-2020 at 01:48 PM..
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Old 03-07-2020, 02:02 PM   #2
budwich
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

the lenses have been "displaced".
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Old 03-07-2020, 02:13 PM   #3
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

Quote:
Originally Posted by budwich View Post
the lenses have been "displaced".
I take it that means I DID put them in the wrong order? I have a picture of the order from when I took it apart, but it's not very helpful because the three thinner layers all look the same color and transparency in my pic.

Any idea what the correct order is? I know for sure that the thick one is correctly placed at the bottom.
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Old 03-07-2020, 04:01 PM   #4
R_J
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

You say you replaced the LED's, Did you actually replace the individual led's? or just replace the complete strips.
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Old 03-07-2020, 07:59 PM   #5
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

Quote:
Originally Posted by R_J View Post
You say you replaced the LED's, Did you actually replace the individual led's? or just replace the complete strips.
Brand new set of strips. Sorry for the confusion.
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Old 03-07-2020, 08:11 PM   #6
neilc6
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

If the standoffs get broken or are missing, the diffuser will sit too close to the LEDs and you will see them. Also if the strips pop up from the chassis. Normally I will power up the tv with the panel disconnected and inspect the backlights before finishing reassembly.

Last edited by neilc6; 03-07-2020 at 08:13 PM..
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Old 03-07-2020, 09:09 PM   #7
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

All of the stand offs fit back into place securely. The strips came with 3M double sided tape already on the backs and seemed to stick very well. I know I'll have to take it apart again to figure out what's wrong.
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Old 03-09-2020, 04:52 AM   #8
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

I took it back apart again last night and carefully studied the order the layers appear to be in in the picture I have. I concluded that they were in fact it of order, so I put them back how I believe they go. After putting it back together the LEDs that were visible are not anymore, however the top and bottom of the screen is still darker than the rest. None of the standoffs are broken or missing either. Before reassembly I checked each strip of LEDs with 9v batteries and they are all working perfectly and bright.

This one's got me confused.. The overall brightness and picture quality is looking like a rear projection with a failing lamp. The areas of the screen that are bright look fine though.

One question about the diffusers, are they reversible, as in, is each side the same or are they supposed to be placed a particular way? Not referring to the order the layers go in, but the orientation of them.
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Old 03-09-2020, 09:14 AM   #9
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

So I've been doing some research online and not turning up to much, but I did however find some asking which order the layers go in and someone else actually replied to them. The person said in LG panels the thick layer typically goes on top just beneath the LCD. This is contrary to the picture I have. BUT, I do seem to remember taking it apart and thinking something odd about the order because it wasn't like my Samsung. I'm guessing it was the fact that the thick layer was on top? If it DOES go on top of the thinner layers, what would support them from sinking into the frame around the standoffs?

It would be great if someone else had a Vizio or an LG that could verify the correct order.
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Old 03-09-2020, 11:26 AM   #10
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

The thick diffuser goes next to the led's, this thcker plastic usually has dimples or a rough surface, which goes toward the led's not toward the lcd. the other thin diffusers go next, and if not correct will effect the uniformaty of the brightness. You should be able to check the led's overall brightness etc. before you reinstall the lcd panel itself.
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Old 03-09-2020, 12:10 PM   #11
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

Quote:
Originally Posted by R_J View Post
The thick diffuser goes next to the led's, this thcker plastic usually has dimples or a rough surface, which goes toward the led's not toward the lcd. the other thin diffusers go next, and if not correct will effect the uniformaty of the brightness. You should be able to check the led's overall brightness etc. before you reinstall the lcd panel itself.
THANK YOU! I will check and make sure that I have the thick diffuser right side up, because I know I placed it on the bottom but could have possibly put it upside down. I'm attaching the picture I took before taking it apart. If you can, please tell me the order YOU think The thinner layers are in.
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File Type: jpg 20200128_143835.jpg (300.0 KB, 20 views)
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Old 03-09-2020, 07:44 PM   #12
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

The layers appears to be in the right order. Make sure the background (the white thing with holes for the LEDs) is clean, flat everywhere and not touching the LEDs lenses. Use double sided tape if necessary, especially on the angled edges. Also try clean all the lenses so they are perfectly clear (no fingerprints on them).
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Old 03-09-2020, 08:24 PM   #13
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Wink Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

Quote:
Originally Posted by guix View Post
The layers appears to be in the right order. Make sure the background (the white thing with holes for the LEDs) is clean, flat everywhere and not touching the LEDs lenses. Use double sided tape if necessary, especially on the angled edges. Also try clean all the lenses so they are perfectly clear (no fingerprints on them).
Thanks for your reply!

I did just recheck the order of the layers and even tried some things. I've determined that whether there thick diffuser layer is first or last, it doesn't affect the quality of the picture. I did however flip the diffuser over (because the rougher side was up), and it helped quite a bit. The only area of the screen that is darker is the bottom now. By darker I mean white logos and lettering appear more greyish, and colors are less vivid than the rest of the screen.

A strange thing I've encountered several times now that I can't chalk up to being random or something I had done.. But a few times now that I've "put" the panel back together to test, I will get Backlights and osd until a source starts rendering video, then the Backlights go out but I can still the image. If the channel is changed or signal interrupted, the Backlights will come back on for the osd but go back out when the source is displayed.

Is this a coincidence or a hint that something else is wrong? If it were a power supply issue of some sort, do they ever cause dimming/irregularity like I'm getting?
Attached Images
File Type: jpg 20200309_213521.jpg (275.8 KB, 18 views)
File Type: jpg 20200309_213519.jpg (363.3 KB, 16 views)

Last edited by x_orange90_x; 03-09-2020 at 08:26 PM..
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Old 03-10-2020, 07:31 AM   #14
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

I read a success story on Shopjimmy that specified intermittent backlights and the guy replaced the power supply. Is it likely that mine is failing, or that something else is happening? Backlights on when no source, but off with source?
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Old 03-10-2020, 09:28 PM   #15
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

Update:

Turned out to be something really simple causing the Backlights to go out. I was thinking about the mere fact of it going out only when watching a video source... Then I thought of the most rediculous but predictable cause... Ambient lost sensor. I wasn't reconnecting the wires to the front bezel every time I disassembled it. So I guess it looks for the sensor when displaying video and not seeing it causes ZERO Backlight?

As for the darker area toward the bottom of the screen... I've tried everything I can think of to resolve it but to no avail. I will use it as is because it's a nice size Smart display for my sunroom. The image isn't really bad, it's obviously darker at the bottom but not a deal breaker for me.
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File Type: jpg 20200310_215549.jpg (213.9 KB, 18 views)
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Old 03-11-2020, 05:10 AM   #16
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

Almost looks like there's a strip out on the top and bottom.
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Old 03-11-2020, 06:50 AM   #17
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

Quote:
Originally Posted by nomoresonys View Post
Almost looks like there's a strip out on the top and bottom.
I know, however they're all brand new strips and I tested each row with a series of 9v batteries. I even went through and rechecked them just to verify that they didn't burn out. They all illuminate the same; very bright.

Would it be possible that the power supply is sending a lower voltage to just those two rows? The led arrangement in this TV is as follows:

L2/R2
L1/R1
L2/R2
L1/R1
L2/R2
L1/R1
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File Type: jpg 20200306_221820.jpg (318.6 KB, 14 views)

Last edited by x_orange90_x; 03-11-2020 at 06:52 AM..
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Old 03-11-2020, 09:10 AM   #18
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

what led voltages your getting when the sets running are any lower?
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Old 03-11-2020, 09:24 AM   #19
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

Quote:
Originally Posted by vinceroger69 View Post
what led voltages your getting when the sets running are any lower?
Do you mean the voltages on the main board led plug? I haven't checked that. If you mean the voltages of each individual row I couldn't tell you that if I wanted to. I can't get backlights without the panel connected for some reason. Unplugging the main board from power supply also doesn't turn the Backlights on.

Last edited by x_orange90_x; 03-11-2020 at 09:54 AM..
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Old 03-11-2020, 10:28 AM   #20
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Default Re: Vizio E470i-A0 Dark Areas After Replacing Backlights

if you can test the voltages on the mainboard led plug it may show if you have two lower voltage readings hence the black areas on the lcd
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