Vizio P652ui-B2

[Goznu]

Hello,

My sister's tv stopped working a couple months ago and I told her that I could look at it. It seemed to be turning it self off right about 5 minutes after turning on. You wouldn't see any video or anything. I took it apart and unhooked the power button to eliminate that. I was able to get audio briefly on most hdmi source inputs but #5. I figured that it had to be the main board, because I wasn't getting backlights, or image and it would continually shut off and turn on. I ordered a main board and installed it and I now have backlights, but still no image. I ordered a T-con board and it didn't help. I'm unsure about the quality of this main board. I get backlights and audio but no menu screen or video at all, the only thing I see is slight changes of brightness in areas on the tv where there may be something moving if there were an image there. My voltages out of my power supply board seem to be right in line with what is labeled. My first main board and this main board as well both had good fuses (1) that I could see. The fuse on the T-con board seems good as well. I had heard about disconnecting a ribbon cable from the main board to T-con, I did one and then the other and I saw no change in the actual image, or lack of image. Not sure if that's a good thing or a bad thing.

[Goznu]

Re: Vizio P652ui-B2

I did notice some odd voltages on the connector between the LED driver board and the Main board. The original main board had all 0 volts on each wire at the connector. On the replacement main board I read .017,1.65,3.1,.117,2.2,.07, and 0 volts, top to bottom. Most of these readings seem really fishy to me. I believe this is connector CN2003.

[budm]

Re: Vizio P652ui-B2

Can we see the WHOLE back side of the TV showing all the boards?

[Goznu]

Re: Vizio P652ui-B2

Posting 2 more pics.

[Goznu]

Re: Vizio P652ui-B2

After scratching my head on this, it seems like t would have to be the main board. I believe I did the T-con diagnosis properly to signify that the panel was still good. All voltages off PS board are good and i think that's all that I am left with.

[Goznu]

Re: Vizio P652ui-B2

I would think that the LED driver board in the top middle would be for backlights and thats it. Through each of the fuses (8), I read 33 volts and I would guess that's what it's supposed to be. From everything that I have noticed, it seems like the main board and t-con board are responsible for the actual image, unless the panel happened to go out. Am I wrong?

[Goznu]

Re: Vizio P652ui-B2

It appears that I may have the wrong main board after all. I misread a digit on the main board, so I guess I'm back to square one. The tv will get stuck in a loop of turning itself off and on numerous times. I don't have backlights or an image, but I do have audio while it is in the brief on state. The CN2003 connector has zero volts on every wire at that connector. This connector goes from the main board to the LED driver board. I have been trying to find a replacement board, but that is very, very hard to come by, so I may have to try to fix this on a component level.

[kca]

Re: Vizio P652ui-B2

Goznu ~

Did you ever have any luck fixing this 65” Vizio set of yours? I picked up the exact same model today and it has all of the exact same symptoms as you describe above.

Was it the Main Board, and the Main Board only that needed to be repaired or replaced? Or, in the end, was it some other culprit?

Any insight you could provide to would be extremely helpful.

~ kca

[Goznu]

Re: Vizio P652ui-B2

I'm still struggling with it. I get back to it every few months. I did find a supposedly new main board on eBay and that didn't change a thing. I didn't really want to do this, but I think I'm down to checking the LEDs. I guess I could have had a bad main board from Ebay and that could be the problem all along, but they are hard to come by. It is kind of odd that when I used the wrong main board from a 55" that I got backlights and a very blurry image in the middle, which I believe was the Vizio logo. But since I had the wrong board, I haven't been able to come close to that kind of progress. Which leads me to believe that it isn't the LEDs, and I may have another bad main board.

[budwich]

Re: Vizio P652ui-B2

I don't think you did the "tcon / panel" test correctly... the cables that need to be disconnected are going from the tcon to the panel not tcon to main (which only potentially activate the backlighting...maybe). Disconnect one tcon to panel cable (far right or left), see what happens, repeat doing the test with the other one.

[Goznu]

Re: Vizio P652ui-B2

I disconnected the panel to tcon on left side and no change to anything. Still doing the same thing it has always done.

[budwich]

Re: Vizio P652ui-B2

there are four cables... do the ones on either ends / side... not just one test of one side. are you sure about what cables we are discussing? Further, when a tcon to panel cable is disconnected, that half of the screen normally goes white. If you aren't seeing that, there is some problem for sure.

IF you have a panel issue, it is possible that it took out the TCON card... not the fuse but a fet that is used to drive the panel. You might have to check the appropriate fet on the tcon to determine if it is bad.... replacing a tcon with a bad panel on a vizio will take out the fet again.... hence you need to try determine what's up before going too far.

Since after replacing the main, you indicate you are getting backlighting, then it would appear the problem is more in the signal domain / panel.

[Goznu]

Re: Vizio P652ui-B2

When I disconnected the panel from the tcon on the left side, I removed both small ribbon cables. I put those back in and just took out the ribbon cables on the right side. Still no change.

[Goznu]

Re: Vizio P652ui-B2

I only had backlighting last year when I replaced the main board with a board from a 55" same type model. I thought it was the same number and interchangeable. That is the only time that I had backlighting. After going through it again this time around, nothing has really changed. I think I did read that a while back that if there is a problem with the panel that it could do just that, take out the tcon.

[Goznu]

Re: Vizio P652ui-B2

I am also hooking up a portable blu ray player to this that has a screen built into it. I have tried cycling through the inputs but it doesn't seem to matter. I can hook up to any of the 5 hdmi inputs and 1-4 will make the screen turn off then back on while the tv is cycling. Input #5 does nothing to the screen of my player. Even though I've tried cycling through the inputs, it always stays at 5. Or it appears to stay there. Same response from my player.

[budwich]

Re: Vizio P652ui-B2

how many cables are there between the tcon and panel?

OK... I re-read your previous posts... now with a different main board, you have no backlights? So you have two main boards and neither give any backlights.

You might have to get "dirty with a meter". You need to read (with a meter) all the pins labeled on the power board leaving towards the tcon or main board. If you post those with the pin description, you might find further direction.

[Goznu]

Re: Vizio P652ui-B2

There are 4. 2 for each side.

[Goznu]

Re: Vizio P652ui-B2

They are about 1.5 inches long.

[budwich]

Re: Vizio P652ui-B2

OK.... so we are "in sync". What happened to the "wrong main card"?

[Goznu]

Re: Vizio P652ui-B2

I sent it back to the seller on Ebay. He told me that those boards aren't interchangeable. The board number was super hard to read, so I ordered the wrong one, thinking it would work.