Vizio P652ui-B2

[budwich]

Re: Vizio P652ui-B2

Well... at least it worked to turn on the backlights... :-) which if it didn't cause them to burn out (doubt)... would likely mean they are OK... maybe.

anyways, check the voltages.... look at the tcon to see if it is getting the required 12v... especially to and from the fuse. Note: you need to watch for it right at "power up" as the system may shut it down quickly.

[Goznu]

Re: Vizio P652ui-B2

Sorry it took so long. It's a pain in the ass to take the stand off and get to the tcon board and doing most of it myself with being an inconvenience to my son to help a little. I hooked everything back up and at no point does the voltage ever get higher than .082 VDC. It drops during the cycle then comes back to .082. I'm guessing main board gives it 12v?

[budwich]

Re: Vizio P652ui-B2

depending on the design / layout... some sets have direct 12v wiring from the power supply to the tcon but others have a "switching fet" in the main that controls the 12v going to the tcon from the main. the labelling at the connectors will tell you what to see where.

[Goznu]

Re: Vizio P652ui-B2

I went back and scrounged through my stuff to find the "replacement" main board that was supposedly new from Ebay that I bought last December. That one gives me .135v to the Tcon. I suspected that one was bad but they said it was new. I have had bad luck with main boards for this stupid thing. The original one, I ordered another one, it was bad, then the 55" which kinda worked, and then this one. I know I probably kind of confused you about the boards.

[Goznu]

Re: Vizio P652ui-B2

Oh, and yes, the fuse on the tcon is good. I checked that first thing.

[budwich]

Re: Vizio P652ui-B2

the 12v is not made any where but the power board. So even if the track can be switched, the 12v has to be somewhere at the power board first.

[Goznu]

Re: Vizio P652ui-B2

I checked all my voltages at the power board and all seemed to be correct. I had the 5v standby and 12 volts and all seemed to be correct connecting to the main board.

[Goznu]

Re: Vizio P652ui-B2

I just checked again. All 5v standby, 12v, 24v, and 32v are all made.

[Goznu]

Re: Vizio P652ui-B2

The Tcon board only has 6 ribbon cables running to it. The 4 from the panel and 2 from the main board. Nothing coming from the power board.

[budwich]

Re: Vizio P652ui-B2

If there is no 12v at the tcon then the main isn't switching it since you say you are getting it produced at the power board.

As suggested, check / state all the voltages / conditions as listed / labeled on the cards. This should be done for "standby" and as well as "power on". This may help point to the issue (ie. change of state).

[Goznu]

Re: Vizio P652ui-B2

No voltages listed for the main board, only the power board. I'm unsure what those are supposed to be. I can check the voltages and post on here and maybe they can be deciphered.

[budwich]

Re: Vizio P652ui-B2

the "legend" for the connectors either leaving the power board (or at the "other end") should be printed on the board. Most / all the pins will have some sort of designated description. Post a closeup of the power board / legend for better comments.

some of the pins are control pins while others are "straight up voltages". As suggested post the list of pins, their "names" and the value -> at standby, at power up. the test / reading will take a bit as you need to read / monitor them (one at a time) in some cases as they may disappear quickly if the control changes / shuts down.

Further, since the cable goes from the power board to main, you can then trace what wire the 12v (and others... 5v, etc) are going to the main and thus also know where to look on the main. Common issue on sets is the "switching fet" is bad or its control is missing (ie. possibly capacitor or other component) such that the switch never occurs.

[sukaht]

Re: Vizio P652ui-B2

Hello,
I am new here, and need advice from all the expert here.
I just picked up the same TV P652ui-B2, the owner said it was working until a week ago, no picture and no back light. When I tested, the power supply's relay making clicking sound 2x (like failing to stay on). And this relay clicking keeps doing it every 20 seconds.
Is this mean I have a bad main board, if yes which component need to be replaced?
The mainboard seems to be so expensive, however there are a few people on Ebay can fix the mainboard, so do you know what part that they replace? Perhaps I can do it my self.
Thank you in advance for your help here.