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Old 07-05-2018, 05:34 PM   #1
splinke
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Default Vizio E601i-A3 backlighting problem

I have a Vizio E601i-A3 LCD TV. This morning when I turned it on, I heard sound (coming through the optical audio out port) but could not see video (including the on-screen Vizio logo when first powering up). When shining a flashlight on the screen, I discovered that the video was actually there and seems to be OK. So, I suspect that it is the backlighting that has failed. It is my understanding that this model is edge-lit ("Razor LED"), although I could be wrong.

I have searched this forum, and most of the problems seem to include functional backlighting with no video. However, I found THIS THREAD that describes a problem that sounds exactly like mine (video but no backlighting). I am hoping that the problem is with the Power Supply/LED Board (PN 09-60CAP000-00; 1P-1127800-1010).

I have tested a bunch of things on that board based on the PREVIOUS THREAD, but I am not sure what all of it means, and I am hoping somebody can help me.

CN201 connector from Power Board to Main Board:
Pin__Label_____TV off volts__TV on volts

1____3.3V________3.33__________3.31
2____AC-DET______3.41__________3.39
3____PS-ON_______0.08__________3.28
4____12V-AU______0.60_________12.24
5____GND_________0.00__________0.00
6____GND_________0.00__________0.00
7____GND_________0.00__________0.00
8____12V REG_____0.56_________12.24
9____12V REG_____0.54_________12.24
10___BL-ERR______0.00__________3.26
11___LED-ON______0.00__________3.24
12___LED-BR______0.00__________0.82
13___NC__________0.00__________0.00
14___T2V T CON___0.04_________12.24
15___T CON_ON____0.00__________3.17


Resistance between LED drivers based on letters in photo in old thread:
A/B = 0.6
C/D = 0.6
A/D = 141.3k
B/C = 141.6k
B/E = 1.0
B/F = 141.6k
D/E = 141.3k
D/F = 1.1

Note: E includes capacitor C307 and F includes capacitor C305.


Voltage peaks across capacitors (shown in THIS PHOTO from the previous thread) immediately after power up (all drop back to 0 rapidly):
C308 ~35
C309 ~38
C321 ~33
C332 ~27
---------
C305 0
C307 0

Notes: The spikes are only estimates, because it happened so quickly. I also did capacitors C305 and C307, which never showed any voltage.

CN301 connector from Power Board into panel (LED backlights?):
Pin__Label______Power up voltage peak____TV on volts

1____VLED1-2-__________~+15________________-0.004
2____VLED1-1-_________-0.009_______________-0.009
3____VLED1-2+_________-0.009_______________-0.009
4____VLED1-2-__________~-12________________-0.003
5____VLED2-1+__________~+32________________-0.004
6____VLED2-1-_________-0.009_______________-0.009
7____VLED2-2+_________-0.008_______________-0.008
8____VLED2-2-__________~-17________________-0.004


I saw some CN301 connector voltage readings in ONE OTHER THREAD that make me wonder about my last set of readings. In that thread, pins 1, 4, 5, 8 all show voltages of +83.5 or -83.5. My peak voltages are much lower, and they only briefly spike up upon powering the TV on, and then drop down to very low negative values. It is not clear to me whether these voltages are supposed to stay high, or whether they depend on having a video source hooked up?

If anybody can help me out, I would appreciate it.

Last edited by splinke; 07-05-2018 at 05:56 PM.. Reason: Fixed formatting of "tables" with underscores
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Old 07-06-2018, 01:57 AM   #2
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Default Re: Vizio E601i-A3 backlighting problem

I did several more tests on the CN301 connector on the four pins that briefly showed voltages at initial power up (1, 4, 5, and 8). The peaks seem to vary from about 15 to 45 volts (positive or negative) on the board side, whether the connector is attached or not.

Originally, I was thinking that the power board must be the problem, because the voltages do not stay at reasonable levels to power the LEDs. However, after watching and reading more about this, it seems that some power boards are designed to cut off power when there is not a proper load (i.e., good LEDs), while other power boards will continue to deliver the voltage. If my power board is the type that cuts off the voltage when a proper load is not present, and since the LED power seems to be trying to ramp up briefly at power up, I am now wondering whether it is my LEDs that are bad?

Last edited by splinke; 07-06-2018 at 01:58 AM..
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Old 07-06-2018, 03:51 AM   #3
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Default Re: Vizio E601i-A3 backlighting problem

I may be going about this the wrong way but here's my thoughts.

Shopjimmy says that there are two strips with 68 leds per strip. There appears from the thread you point to that there are 4 voltages at the connector in the region of +/-85V but further down says the problem was with the leds.

It each led bar was split into two then with 34 leds @ 3V per led I would expect the voltage to be closer to +/-102V. That is if they are 3V leds.

This is where a meter with min/max function proves extremely useful for catching the peak voltage.
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Old 07-06-2018, 11:05 AM   #4
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Default Re: Vizio E601i-A3 backlighting problem

Quote:
Originally Posted by dick_barton View Post
I may be going about this the wrong way but here's my thoughts.

Shopjimmy says that there are two strips with 68 leds per strip. There appears from the thread you point to that there are 4 voltages at the connector in the region of +/-85V but further down says the problem was with the leds.

It each led bar was split into two then with 34 leds @ 3V per led I would expect the voltage to be closer to +/-102V. That is if they are 3V leds.

This is where a meter with min/max function proves extremely useful for catching the peak voltage.
Thanks for that information, and it all sounds reasonable. Unfortunately, my multimeter does not have a min/max function, and I am not sure whether it is worth investing in one for this one project--or whether the additional information I could get would help solve my problem.

I assume that the previously reported +83.5 and -83.5 voltages at the CN301 LED power connector were steady voltages, as opposed to peaks on power up. Since the LEDs were apparently bad in that TV, that could suggest that the power board in this model is designed to continuously output relatively high voltage regardless of LED condition. I am hoping that is the case, because that would indicate that the lack of voltage at the LED power connector in my TV is due to a bad power board, which is easily replaced.

On the other hand, if the power board in this model is designed to shut off power to the LEDs when they are not functioning, then it would be a waste of time and money to replace the power board, because the problem is likely with the LEDs. Perhaps an assumption is wrong, or perhaps the LED problem reported previously was only a partial failure, while mine is complete failure?

It is not unlikely that the voltages in my TV spike up higher on power up than the ~45 volts I can see on my digital multimeter (e.g., up to a more expected voltage between 85 and 100), but I am not sure whether I could use that information--unless it spikes up really high to trigger a shutdown, which may indicate a bad power board.

Does anybody know what voltages the power board in a Vizio E601i-A3 should output over the CN301 LED power connector, and whether it outputs those voltages continuously, regardless of the condition of the LEDs?

Last edited by splinke; 07-06-2018 at 11:06 AM..
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Old 07-08-2018, 12:51 AM   #5
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Default Re: Vizio E601i-A3 backlighting problem

I was hoping somebody here would know whether the brief power-on spike in voltages at the LED power connector on the power board provided any hint on whether the failed backlight was the result of bad LEDs or a bad power board. In the end, I concluded that the voltage spike and immediate drop to virtually zero must be an overvoltage protection circuit kicking in, and that the problem is more likely with the LEDs than the power board. I was prepared to replace the power board, but I think the LEDs are a different order of difficulty, and I have not even found anywhere that I could even buy them.

So, I just bought a new TV, and it is off to the landfill with the Vizio. I had the bad chip that was in the Vizio security bulletin when I first bought the TV, and then I had about half a dozen horizontal black lines that appeared a couple of years ago (I could make them temporarily go away be squeezing the frame of the TV or pressing the screen near the frame), and now the backlight went out completely, so I guess this TV was destined for the landfill, and it will be difficult for me not to smash it to tiny bits with a hammer first.

This also follows a Sony rear projection HDTV that cost around $3,000 back around 2004 that developed the blue blob syndrome after just a few years. It seems that TVs are a real crapshoot and should not be expected to last very long.

Last edited by splinke; 07-08-2018 at 12:54 AM..
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Old 10-20-2018, 04:53 AM   #6
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Default Re: Vizio E601i-A3 backlighting problem

I am resurrecting my own thread in the hope that somebody can still help. I figured before sending the TV to the landfill, as I indicated in my last post, I might as well finish tearing down the TV to get at the LED strips to see if they were working...not caring whether I destroyed anything in the process.

I removed the LCD and light diffusion panels, exposing two LED strips along the bottom edge of the TV. Each strip has two sets of wires going to it with the LEDs seemingly divided into four sets of 17 LEDs, labeled 1-1 through 1-17, 2-1 through 2-17, 3-1 through 3-17, and 4-1 through 4-17. So, there is a total of 68 LEDs per strip (136 LEDs for the whole TV).

At first, it seemed like all of the LEDs were bad, because none of them lit up when I individually applied 3.0 to 3.5 volts to them (the typical voltage range I have read these types of LEDs require). It seemed unlikely that they all suddenly went bad, though. And when I increased the voltage to 5.0 volts (for the individual LEDs), all 136 of them lit up. So, now I am back to thinking that my problem is with the Power Supply/LED Board.

I am hoping that somebody has some insight into the readings I posted in my original post in the context of the readings reported in the two other posts I linked in that post. My main questions again are: (1) whether the initial power-on voltage spikes with rapid decrease to zero after at the LED power output connector indicates a bad power board, or whether something else could be causing those voltages to go back to zero, and (2) whether the 3.3 volts on the BL-ERR pin (presumably "backlight error") at the connector to the main board means anything.

Regarding the individual LED voltages, I found a YouTube video of somebody testing the LED power voltages at the connector on the related Vizio E701i-A3 (a 70" version of my 60" TV). That TV appears to have three LED strips, each seemingly with two sets of 32 LEDs--so 64 LEDs per strip (with only one set of wires going to each strip from the LED power board). That is 192 total LEDs in the TV. In any event, the YouTube video shows the three outputs at 164 volts. Assuming the sets of 32 LEDs are what is relevant for the voltage, that is 5.1 volts per LED. That seems to be consistent with the other report on the E601i-A3 of LED outputs running at 85 volts, assuming the sets of 17 LEDs are what is relevant (5.0 volts each). All of this seem logical to me, but I may be completely wrong about all of it.
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Old 10-20-2018, 07:47 AM   #7
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Default Re: Vizio E601i-A3 backlighting problem

The led's appear to be 3V led's so 5V may well overdrive and damage the leds while testing. The other problem is that it only needs one led to fail and like fairy lights all the leds in that string go off. There are normally some resistors that monitor the current flow through the led string which control the led driver circuit and if no current flows due to an open circuit led or if the current increases due to a short circuit led(s) then the driver is shut down.
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Old 10-20-2018, 09:15 AM   #8
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Default Re: Vizio E601i-A3 backlighting problem

Quote:
Originally Posted by dick_barton View Post
The led's appear to be 3V led's so 5V may well overdrive and damage the leds while testing. The other problem is that it only needs one led to fail and like fairy lights all the leds in that string go off. There are normally some resistors that monitor the current flow through the led string which control the led driver circuit and if no current flows due to an open circuit led or if the current increases due to a short circuit led(s) then the driver is shut down.
I am wondering how it can be determined that they are 3-volt LEDs, rather than 5-volt. I borrowed a DC power supply to check each of the individual LEDs. None of them lit up with 3 volts, but all 136 of them lit up with 5 volts. However, I did not know what amperage setting to use, so I chose a very small number--20 mA. Could they all light up with 5 volts if some or all of them had failed due to an open circuit or short circuit?

Also, I was also able to make adjacent pairs of LEDs light up when applying 10 volts, but not less than 10 volts. Is there a better way to check the LEDs? My borrowed power supply has a 30-volt limit.
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Old 10-20-2018, 09:28 AM   #9
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Default Re: Vizio E601i-A3 backlighting problem

Led's appear to available only in either 3V or 6V packages.
The 6V have a double led (3V x 2) integrated into a single package.

One of the problems with led's is that they don't always go into fault condition until the current increases and they heat up. 20mA is a very small current. Your power supply circuit board may give the voltage supplied to the led string and the expected current flow through each in the string. Check the silkscreen information on the topside of the power supply circuit board.

Last edited by dick_barton; 10-20-2018 at 09:29 AM..
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Old 10-20-2018, 11:19 PM   #10
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Unhappy Re: Vizio E601i-A3 backlighting problem

Quote:
Originally Posted by dick_barton View Post
Led's appear to available only in either 3V or 6V packages.
The 6V have a double led (3V x 2) integrated into a single package.

One of the problems with led's is that they don't always go into fault condition until the current increases and they heat up. 20mA is a very small current. Your power supply circuit board may give the voltage supplied to the led string and the expected current flow through each in the string. Check the silkscreen information on the topside of the power supply circuit board.
Yeah, the photo of the replacement LED strips on ShopJimmy suggest that the individual LEDs are "LG Innotek 7030PKG," and I was able to find an LG brochure that includes an entry for a "7030 series" that look the same. The information in the brochure indicates a voltage range of 2.8 to 3.2 volts, a normal current of 200 mA, and a maximum current of 280 mA for the LEDs. I am not 100% sure this is what I have, but it probably is.

All of my individual LEDs begin to light up and show current at around 4.5 volts, and they continue to get brighter through 5.0 volts (I have not pushed the voltage higher to prevent damaging them, although that is probably a moot point at this stage). However, the current never seems to even reach 1 mA (more like 0.4 mA), and the LED does not get very bright.

I can light a pair of adjacent LEDs at 10 volts, three adjacent LEDs at 15 volts, and so on, up to six adjacent LEDs at 30 volts (as long as I stay within the groups of 17 LEDs). However, with the voltage any lower, they do not light.

I have seen many postings on the Internet showing strips of LEDs in which a few individual LEDs are either very dim or completely burnt out, but I have never seen anything like my case where none of them light up with the rated voltage, but all of them light up at a slightly higher voltage. It seems like the morning we turned on the TV and saw no backlight (after everything was fine the night before), all 136 LEDs simultaneously short-circuited to an extent that they still work dimly at the slightly higher voltage.

I guess I am back to the landfill plan for my TV.
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Old 10-20-2018, 11:30 PM   #11
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Default Re: Vizio E601i-A3 backlighting problem

3V LED will light up with applied Voltage of 2.8V at 30mA, if your LED has to reach 5V before it lights up that means it is 6V LED.
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Old 10-21-2018, 12:41 AM   #12
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Default Re: Vizio E601i-A3 backlighting problem

Quote:
Originally Posted by budm View Post
3V LED will light up with applied Voltage of 2.8V at 30mA, if your LED has to reach 5V before it lights up that means it is 6V LED.
Your post emboldened me to increase the voltage, and when I ramped up from 5 volts to 6 volts, the LEDs rapidly got super bright, as I would expect from a TV backlight, and the current ramped up to about 35 mA! So, now I am back to thinking that all of the LEDs are fine (and that they are 6-volt LEDs).

If you look at the power supply board data I put in my original post, is there anything there that would definitively identify that board as the problem. As I have mentioned, the voltages at the four positive LED driver outputs rapidly rise and then immediately fall to zero (in less than a second). [Note that Pin 1 of the CN301 connector that goes to the LED strips is mislabeled VLED1-2- on the Rev 1.0 power supply board in my TV (and in my post), and that it was re-labeled to the expected VLED1-1+ on the Rev 1.1 board they sell at ShopJimmy.]

Thanks!
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Old 10-21-2018, 09:02 AM   #13
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Default Re: Vizio E601i-A3 backlighting problem

IF you disconnect the led connector and monitor the voltage there at power up, does it jump to the same / similar value that you see with them connected? what's the values? what kind of meter are you using... can you select a range as opposed to "auto"?

Last edited by budwich; 10-21-2018 at 09:05 AM..
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Old 10-21-2018, 12:08 PM   #14
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Default Re: Vizio E601i-A3 backlighting problem

Quote:
Originally Posted by budwich View Post
IF you disconnect the led connector and monitor the voltage there at power up, does it jump to the same / similar value that you see with them connected? what's the values? what kind of meter are you using... can you select a range as opposed to "auto"?
Whether the LED power connector at CN301 is inserted or not, I get similar results (quick voltage spike up and down immediately at power up). Sorry, I have a very basic multimeter that does not measure min/max or set any sort of range.

I have also tested continuity between the disconnected connector and the 8 test points on the LED strips (2 positive and 2 negative on each strip), as well as the metal chassis. For each of the 8 "pins" on the connector, I only get continuity to the single expected test point. So, I think all of the LEDs, as well as the path back to the power supply board should be OK.
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Old 10-21-2018, 02:00 PM   #15
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Default Re: Vizio E601i-A3 backlighting problem

Can we see the pictures of the whole back side of the TV showing all the boards?
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Old 10-22-2018, 01:51 AM   #16
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Default Re: Vizio E601i-A3 backlighting problem

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Originally Posted by budm View Post
Can we see the pictures of the whole back side of the TV showing all the boards?
In partial answer to your question, I would refer you to THIS VIDEO on ShopJimmy, which shows the power supply board, main board, and T-CON board at about 25 seconds in.

That said, the story on this TV gets a bit crazy. After putting the light diffuser sheets, LCD panel, and frame back on the TV, I powered it back up to do some more voltage testing. Lo and behold, all of the backlighting was working again! I was happy about that, but I was also concerned that I may have only temporarily "fixed" the problem by doing so much fiddling with the LED strips while doing my testing on them--and that they might soon fail again under usage/heat. Time may tell on that, except that...

I went ahead and put everything back together. Unfortunately, when powering it up again, I now get a bunch of variously colored vertical lines, suggesting that I damaged something or did something wrong on re-assembly. These are NOT the bright, static, colored vertical lines that run the entire height in specific areas of a panel, whicc I see in many troubleshooting posts.

They are a bit difficult to describe. They are more subtle in color and "dance" around depending on the color and size of objects that are being displayed. For example, if there is a very light person's head in the image, and they are moving their head around, subtle colored vertical lines will sort of follow the head around. They are pretty much everywhere over the whole screen, but, from a distance or angle, they are more difficult to see. They are there no matter what input is being used, including appearing in the TV's menu system.

The whole panel seems to be working, and the backlighting seems to cover the entire area. I am just so disappointed that this new issue came up. I thought I was being very careful, but these things are fragile. Maybe one of the cable is not fully engaged or is damaged? I can make a video of what the lines look like, and I can get better photos of the boards if/when I open the TV back up.

Thanks so much for everybody's help on this.

Last edited by splinke; 10-22-2018 at 02:21 AM..
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Old 10-22-2018, 02:06 AM   #17
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Default Re: Vizio E601i-A3 backlighting problem

Here are some rather poor photos I took before putting the TV back together:
  • SANY6574 = Main board with part of power supply board and T-CON covered by metal plate
  • SANY6576 = Partial main board and power supply board with T-CON covered by metal plate
  • SANY6577 = Part of power supply board and T-CON covered by metal plate
  • SANY6578 = Main board (dark picture)
  • SANY6580 = Control panel and IR area
Attached Images
File Type: jpg SANY6574.jpg (762.4 KB, 28 views)
File Type: jpg SANY6576.jpg (636.7 KB, 26 views)
File Type: jpg SANY6577.jpg (684.3 KB, 23 views)
File Type: jpg SANY6578.jpg (656.0 KB, 22 views)
File Type: jpg SANY6580.jpg (657.0 KB, 24 views)

Last edited by splinke; 10-22-2018 at 02:11 AM..
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Old 10-22-2018, 03:05 AM   #18
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Default Re: Vizio E601i-A3 backlighting problem

Try reseating your tcon cables taking notice that they are perfectly aligned. If that doesn't work remove the cable from one side and power on and report what you see. Do the same for the other side.

As for the backlighting you may have had a poor connection at one of the led strips which you inadvertently remedied by going inside and mucking about.
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Old 10-22-2018, 07:17 PM   #19
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Default Re: Vizio E601i-A3 backlighting problem

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Originally Posted by mmartell View Post
Try reseating your tcon cables taking notice that they are perfectly aligned. If that doesn't work remove the cable from one side and power on and report what you see. Do the same for the other side.

As for the backlighting you may have had a poor connection at one of the led strips which you inadvertently remedied by going inside and mucking about.
OK, I took the back cover back off the TV and disconnected and reconnected the various ribbon cables, and now the image is back to normal, and the backlight still works. So, I guess I have revived my TV--at least for now. Thanks to everybody for all of your help!

Here are some things I learned:

1. Pin 10 of connector CN201 (Power Board to Main Board) labeled "BL-ERR" most likely stands for "Backlight Error," and, in my experience, it read ~3.3 volts when my backlight was not working and 0.0 volts when the backlight started working again.

2. Pin 12 of connector CN201 (Power Board to Main Board) labeled "LED-BR" most likely stands for "LED Brightness," and, in my experience it read ~0.4 volts when the Backlight setting on the TV was set to "0," and it read ~2.5 volts when the Backlight setting on the TV was set to "100." I did not check any more, but presumably it varies between 0.4 and 2.5 volts as the Backlight setting is increased.

3. The CN301 connector on the Power Board, which provides power to the LED strips was outputting about 85 volts when the TV LED Brightness was set to "0," and about 97 volts when set to "100". Details:

Pin__Label______LED Brightness=0_______LED Brightness=100
1____VLED1-1+__________+85________________+97
2____VLED1-1-__________0.0_________________0.0
3____VLED1-2+__________0.0_________________0.0
4____VLED1-2-__________-85________________-97
5____VLED2-1+__________+85________________+97
6____VLED2-1-__________0.0_________________0.0
7____VLED2-2+__________0.0_________________0.0
8____VLED2-2-__________-85________________-97


4. The 85-97 volts makes some sense when considering the LED strips appear to be configured in multiple sets of 17 LEDs in series. A possibly over-simplistic calculation results in a 5.0 to 5.7 volt range per LED, which is consistent with 6-volt individual LEDs. The reality of the voltages here may be a bit different, because I am not an electrical expert. There are four sets of 17 LEDs on each of the two strips, and 4 sets of +/- pins (two for each strip), so each set of +/- outputs on the power board likely feeds two 17-LED series' in parallel. In contrast, the 70" version of this TV (the E701i-A3) has three LED strips, each with two sets of 32 LEDs, and the power board has only three +/- outputs (one for each strip).

5. Pin 1 on the CN301 connector seems to be mislabeled VLED1-2- on my Rev 1.0 of the Power Board. It is correctly labeled VLED1-1+ on the Rev 1.1 replacement Power Boards.

6. It seems that the power board turns the LED power off (as tested at the CN301 connector) when the LEDs are not working properly--at least under some circumstances. So, simply finding no voltage there does not necessarily mean that there is a problem with the power board--it may be an issue downstream at the LEDs?

Last edited by splinke; 10-22-2018 at 07:33 PM..
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Old 10-22-2018, 07:23 PM   #20
splinke
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Default Re: Vizio E601i-A3 backlighting problem

And here are better pictures of the boards in the TV:
SANY6609 = Entire back of TV with cover removed
SANY6612 = Power Board
SANY6615 = Power Board (closeup of LED power connector area)
SANY6617 = Main Board
SANY6618 = T-Con Board (covered by small protective frame/heat sink)
SANY6621 = Small Keypad and IR Boards
Attached Images
File Type: jpg SANY6609.jpg (532.8 KB, 20 views)
File Type: jpg SANY6612.jpg (618.0 KB, 21 views)
File Type: jpg SANY6615.jpg (521.8 KB, 17 views)
File Type: jpg SANY6617.jpg (651.0 KB, 15 views)
File Type: jpg SANY6618.jpg (494.5 KB, 15 views)
File Type: jpg SANY6621.jpg (449.8 KB, 15 views)
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