Vizio P502ui-B1 has no video or sound

[ksuper]

I have a Vizio P502ui-B1 4K Led TV.

It was working fine until one day the picture went out. When the picture first went out, it had some sporadic sound.

Now when you try to power it on, the power light comes on and fades away but that is it. There is no picture or sound.

I tried the flashlight test, but didn't see anything.

I opened up the case, but didn't find anything of interest. The boards all look to be in good condition, the fuse on the power board looks ok (when researching there were references to other fuses, but I only saw the one fuse), no bulging capacitors, etc.

I also unplugged and replugged the connectors to the various boards, but nothing changed.

Any ideas for a next step?

[budm]

Re: Vizio P502ui-B1 has no video or sound

Show us good clear pictures of the whole backside of the TV so we can see how the boards are connected together, that will be a start so we can see what we are dealing with.
What Voltage testing have you done so far?

[R_J]

Re: Vizio P502ui-B1 has no video or sound

Search your model number, there are a few threads on this same model, like this one: https://www.badcaps.net/forum/showth...ight=P502ui-B1

[ksuper]

Re: Vizio P502ui-B1 has no video or sound

I've got some pics up now. There is one of the full layout and a little closer pictures of the individual boards

I just did the basic checks that I mentioned before. I haven't done any voltage testing.

[budwich]

Re: Vizio P502ui-B1 has no video or sound

the tcon is under the plate at the bottom. You need to try disconnecting the cables going from it to the panel (one at a time, with power off) to see if anything changes.

[Storyteller12]

Re: Vizio P502ui-B1 has no video or sound

I’ve had a few of these TVs. Always seems to be the Main chips connected to the heat sink. . It needs to be reflowed or really reballed. You can check by heating the heat sink for 1-3 minutes.

Tv should turn on then to confirm. Unfortunately it’s short lived without reballing it. Reflowing is just a temp solution

[ksuper]

Re: Vizio P502ui-B1 has no video or sound

the tcon is under the plate at the bottom. You need to try disconnecting the cables going from it to the panel (one at a time, with power off) to see if anything changes.

I disconnected the right cable and nothing changed.

With the left cable disconnected, when I power on, I thought I saw the screen flash slightly. I waited a bit, but nothing happened.

I powered off and back on again to see if it would flash again, but nothing happened on the power on. I waited a bit and then the screen came on with the "no signal" sign on the left side of the screen and all white on the right side.

I was trying to get the cable box to power up to see what it would look like with a video input, but since there was no signal, the tv turned off and when I powered it back on, it was back to no activity at all (except for the power light). I tried powering off and on several times, but there was no activity except for that one time.

[ksuper]

Re: Vizio P502ui-B1 has no video or sound

Besides that one blip, I guess I should just say there was no difference when trying to run the TV with each of the tcon connectors disconnected.

Any ideas? Should I try something else? Replace the tcon?

[budwich]

Re: Vizio P502ui-B1 has no video or sound

Your "one blip" appears to indicate a problem with / near the panel... maybe (withstanding the suggestion of reflowing the main board). The disconnected side (on most sets) will show up as white while the connected side may show a picture IF it is functional. You need to ensure that the cabling has seated properly during the tests otherwise your results maybe erratic. Having said that, if the "blip" is "valid", you might need to start checking some of the components on the bottom edge boards, especially the capacitors for being shorted. It is a common problem and lots of post on this forum with this type of problem. Some have fixed by replacing the shorted cap CAREFULLY with good soldering efforts. You could get lucky.

As suggested earlier, good pictures of the boards especially focus around the labelling of voltages will help as then certain voltage checks can be suggested / done.

With respect to the main boards, some have done some "baking" to see if it helps the situation which then would certainly point to a main board issue. Again, numerous posts about "board baking"... carefully.

[ksuper]

Re: Vizio P502ui-B1 has no video or sound

Ok. I'll check and retest the cable cable connections to see what the results are and update.

I'll also take some pics of the voltage labels.

[ksuper]

Re: Vizio P502ui-B1 has no video or sound

Here is the update from adjusting the cables, along with the pictures of the boards.

I disconnected and reconnected the cables from the panel. Upon trying to turn the tv on with the remote, I saw the same slight flash that I saw before and then nothing further on the screen. After powering off and then on again, just like last time, the tv turned on with some image.

As you will note in the picture, the right screen is still not working and is distorted. But now the left side has a vertical line going through it and where the no input sign is, it is distorted, whereas last time it was a normal display.

I'm guessing the distortions are a problem with the cables or the cables not getting the proper connections?

[ksuper]

Re: Vizio P502ui-B1 has no video or sound

After adjusting all the panel cables on both ends, I tried powering up, with no success. I didn't see the flash and I tried powering off and on many times, but no video ever showed.

I checked and reconnected the cables a second time and tried to power up several times, but still no video or sound at all.

Any ideas where to look? I would like to be able to just get it down to the component (tcon, power, etc.) that is failing and replace it so I can get the tv up and running again. The user would like to use their tv again soon.

I put some pictures of the boards up in the previous post, but if something else or more specific is needed, let me know.

[Storyteller12]

Re: Vizio P502ui-B1 has no video or sound

I already mentioned it’s most likely the BGA chip on the main board failing. It’s the ones attached to the heatsink.
You never responded if you tried to heat it up with hot air to see if it worked or not.

Don’t ask for help if you can’t follow directions.

[frannyjunk]

Re: Vizio P502ui-B1 has no video or sound

I already mentioned it's most likely the BGA chip on the main board failing. It's the ones attached to the heatsink.
You never responded if you tried to heat it up with hot air to see if it worked or not.

Don't ask for help if you can't follow directions.

There are a couple of chips under the heat sink. Which one is typically the culprit?

[ksuper]

Re: Vizio P502ui-B1 has no video or sound

I already mentioned it's most likely the BGA chip on the main board failing. It's the ones attached to the heatsink.
You never responded if you tried to heat it up with hot air to see if it worked or not.

Don't ask for help if you can't follow directions.

The actions posted are what have been done.

Indeed, I can follow directions and that is what was being done. The others had listed some steps of things to try and report the results back to narrow down the problem area(s). What was offered by you was a potential cause and a suggestion on a way to alleviate it. While you may be correct in your assessment, I do not believe we had narrowed the problem area enough to implement your suggestion quite yet.

With that being said, there are two mentions of the main board being a potential area. But budwich mentioned something about the "bottom edge boards." Does that mean the boards connected to the tcon? (The ones at the bottom connected to the panel?) If so, I'm pretty sure there are no capacitors on those boards on this unit.