Vizio P65Q9-H1 power issue

[EazyBone]

I am learning and trying to repair TVs as a hobby so any help would be great.

Picked up a P65Q9-H1 for $20 and wanted to see what I could do.

TV has no power and no standby light.

Pins from PSU to main board read 16 for the 4 pins as they should and the PSON
Read 3 volts. Now I was hitting the power button and the 3 volts would drop to about .9 if I held it and nothing would happen. No click, nothing. I would let go and it would rise back to 3. After testing many things on the PSU and main I now test PSON and hit the button and now I got zero volts always and never do I have 3 volts again.. oops. Makes me think I may have caused another problem.

Now I have tested the pins from the PSU to the LED backlight board and the voltages are all zero. Whether I hit power (when it worked) or not. Leading me to think it's a PSU problem. But I am no expert and would enjoy some help if you got it.

Any Vizio people think it's the PSU now? And did I screw something up now on the main board as it's no longer sending 3v.

Any help or tests I could run would be helpful. I've searched heavily here before posting so I'm not really sure and don't want to spend $120 trying to fix this if it's not worth much.

[EazyBone]

Re: Vizio P65Q9-H1 power issue

Sorry, learning and here is some pictures

[nomoresonys]

Re: Vizio P65Q9-H1 power issue

So now no voltage anywhere on powerboard, if so check that fuse and probably don't hold down on the power button while it's on, it doesn't seem to like that.

[EazyBone]

Re: Vizio P65Q9-H1 power issue

So now no voltage anywhere on powerboard, if so check that fuse and probably don't hold down on the power button while it's on, it doesn't seem to like that.

There is still 16volt coming from VM at all 4 points from power board to main board. Yes there is voltage on the PSU. Just none goes to the LED lighting and PSON doesn't get voltage anymore.


Update: I was told by the guy who sold it to me, that a new power board and main board were put into the TV. This was supposed to be from a tv repair shop. But there is no power at led still.

Can a bad panel cause all this? I don't necessarily trust the tv shop did its "job" but I don't know. I don't need to fix this thing but it's fun to figure out lol

[nomoresonys]

Re: Vizio P65Q9-H1 power issue

Ah I see, did you by chance get a hold of the original boards and did it ever work after the new boards were put in?

[nomoresonys]

Re: Vizio P65Q9-H1 power issue

If I'm guessing and not all tv repair shops are created equal, lol, might be a problem with the new mainboard communicating with the tcon.

[nomoresonys]

Re: Vizio P65Q9-H1 power issue

Tv's have become much more complicated in the last 7 years or so, needing lots of things to match up in a certain way before they will work correctly. To save lots of trouble with communication problems it's best to buy a mainboard and tcon from the same tv that is compatible with your panel, there's other ways to fix such a problem but involves swapping or reprogramming chips, which isn't real hard but it's harder than easy.

[EazyBone]

Re: Vizio P65Q9-H1 power issue

To save lots of trouble with communication problems it's best to buy a mainboard and tcon from the same tv that is compatible with your panel, there's other ways to fix such a problem but involves swapping or reprogramming chips, which isn't real hard but not real easy either.

Ya I don't know much else about it. Just said PSU and main board were replaced. Not sure if that even happened. But even if what you are saying with the tcon board, wouldn't the backlights come on, or the standby light, or anything at all? Seems like something would at least happen. Just my thoughts. Gotta start learning somewhere lol.

No I don't have original boards. This other guy said he took it in and that they replaced it.

[nomoresonys]

Re: Vizio P65Q9-H1 power issue

For example there's a whole kit, may have to make sure the serials match but of course it won't solve the problem if it's a panel issue: https://www.shopjimmy.com/vizio-p65q...rial-ltyaznmw/

[nomoresonys]

Re: Vizio P65Q9-H1 power issue

I guess the place to start would be to try powering up the powerboard as stand alone but I don't know how it's done with this model. Most start with verifying the powerboard then move on to the other boards, backlights, panel.

[nomoresonys]

Re: Vizio P65Q9-H1 power issue

So tv never worked after alleged board replacements?

[nomoresonys]

Re: Vizio P65Q9-H1 power issue

This seems to be a tv from 2020, not sure if it will work but you could try removing the 2 ribbon cables from tcon to mainboard on mainboard side, then plug tv back into outlet, turn it on see if the optical port on mainboard lights up and stays lit.

[EazyBone]

Re: Vizio P65Q9-H1 power issue

Tv supposedly just shut off one day. Guy took it to repair, they supposedly changed main board/PSU which who knows if that happened. Charged him 250$ and it then never worked. He said it needs a 4k board and that's what they told him. I don't even know what that means but he said the board in the middle lol. I'll try all I can, not sure what I'm gonna do. Found a main board/PSU for $60 but not sure I want to spend it if I can't diagnose it. Appreciate all the responses nomoresonya.

But yes PSU has power. Supplys no power to backlights though, but I've read sometimes it won't supply power until tv turned on, and it won't turn on.

I ordered a backlight testing thing that I will use for this TV and future tvs. Still open to anyones response and experience. Will be messing with it again tonight

[EazyBone]

Re: Vizio P65Q9-H1 power issue

Update***

So I found the cable running from the motherboard to the standby light was damaged. As shown in the pictures. Now I don't know enough about this yet, but would this cause the TV to not turn on? Is this somehow related. Or would it still turn on just never have a light in the first place. Not sure how much control this piece has. Thanks

[EazyBone]

Re: Vizio P65Q9-H1 power issue

Another update, so it appears those pins were shorting out the on. I picked them off and it works good enough that the TV standby light came on. The tv back lights came on and all the voltages to the LED board are now correct and at 28 v. Will update more. I don't think the TV stays on though.

[EazyBone]

Re: Vizio P65Q9-H1 power issue

Last update. Lol

I effin fixed it. Booyah

[nomoresonys]

Re: Vizio P65Q9-H1 power issue

Glad to hear it, nice work, that was a tricky little problem, who expects that cable to be damaged.

[EazyBone]

Re: Vizio P65Q9-H1 power issue

Glad to hear it, nice work, that was a tricky little problem, who expects that cable to be damaged.

Ya no kidding. Repair shop put new stuff in and damaged a cable lol. Now I got a tv I can sell for hopefully like 400 bucks. But yea everything works and have been tested. All is well.
Thanks for the help chiming in. Can't believe it was a $20 tv lol