Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

[Matt C]

It seems that a lot of folks are having trouble with this Vizio model SV422XVT. I love the TV but it went right out on me. The "VIZIO" logo lights orange when it is plugged in but it does not turn white when the power button is hit. Just a black screen, no sound. Before giving up the ghost it did scew the picture a couple of times (like when the channel signal wasn't quite right on an old school tv for those of you that can remember that far back). I'm new to this site and to diagnosing TVs any help would be greatly appreciated. I am a technical guy and write electrical schematics for automobiles for a living, just need a little guidance. I have it apart and have inspected it for obvious damage but found none. I have checked what I believe to be all of the fuses and all check good.

[budm]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

Is this the same main board as yours as shown in this thread?
https://www.badcaps.net/forum/showth...light=SV422XVT
https://www.badcaps.net/forum/showth...light=SV422XVT
There are two fuses and 3-pin voltage regulator ICs that need to be checked and report the result as shown in this thread:
https://www.badcaps.net/forum/showth...999#post300999

[Matt C]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

Yes that was me. Sorry. This is actually my first time on a forum and I'm sure that there will be plenty of "teachable moments". Thanks for the response I will review the information that you've provided and respond with my findings. I have attached some pictures of the board. It may take me a few days to test since I'm doing this all in the evenings when I have the time. Who knows, maybe the solution is provided within the context of the information that you've already given. Excited to say the least!!

[Gghs1226]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

I'm having the same problem with my VO47L. About 2 1/2 years ago while it was still under warranty they replaced what they called the Master & Slave Inverter(s) because image had dimmed way down but was stillviewable.

Monday everything was working fine. Shut it off went and ran some errands. Came back turned it on & nothing but black screen. After closer examination could see image with flashlight on screen. It was apparent that the problem was with the light source similar as before only worse. This time it is not viewable at all. I have been having trouble locating someone to work on it. I'm in the Springfield, Illinois area. Any help much appreciated.

[Matt C]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

If you call Vizio they can schedule a service person to come to your home for repair. This will be done for a fixed price. Or since you found this forum you could have a run at fixing it yourself. Lots of talented people out there to help you through

[Jester11]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

I had a similiar problem and ordered replacement parts (I'm not skilled enough to replace capacitors yet). Was very easy to do, and saved a ton of money. I'm confident that I'll find the right answers here with the issues on my new TV. Good luck!

[Matt C]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

You had a similar problem? What did you replace?

[Matt C]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

OK a small update. I have reviewed most of the data that was supplied by budm and was blown away. To be hones I'm a bit overwhelmed. I did do some testing with the the TV plugged in (something that I wasn't so sure I should do before reading the documents). I took some photos that I'll use to help tell my story. Because of my symptom "TV has power but won't turn on" I decided to try and isolate the problem to either the power supply side or the control side. In the picture "Overall layout of boards" I'm calling the left side white board the "power supply" and I'm calling the right side green board the "control side". As I stated, I plugged in the TV and tested the fuses for power (as opposed to just checking them for open). In the picture "power supply with Fuses highlighted" the Fuse marked "Fuse A" had a good 120V. The fuse marked "Fuse B" only had about half that; coming in at about 60V. This doesn't seem right to me; am I on to something here? Also I was going to try to test for the "on signal" from the power supply to the control but couldn't find the right pin to check. I though that I'd find the "PSON" pin. I have included a picture of the available pins to check in a photo called "power supply with connections highlighted". Would you be so kind as to give me some advise?

[mmartell]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

Hmm that's interesting I see no such pin. Perhaps a similar shot of the main board connectors may help.

[budm]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

CN201 STANBY PIN is the same as PS_ON pin, when TV is turn off it should be <1VDC, when TV is turn on, it should be >2VDC.

" The fuse marked "Fuse B" only had about half that; coming in at about 60V" You get that reading due to using the wrong ground ref point for the PRIMARY (HOT, DEADLY SIDE) side of the crcuit, the Negative leg of the 450VDC Main filter cap is the ground ref point for the PRIMARY side, the SECONADRY (COLD) side ground ref point is the chassis which is tied the Ground of the SECONDARY side on the circuit board or some time through the board mounting screws.
We know that the 5VSTBY power supply is working , otherwise you will not be getting the orange LED, but must be checked to make sure it is stable at 5VDC.
Did you check the two fuses on the main board (where you have those input connectors) and the voltage regulator ICs as requested in post 2 yet?

[Matt C]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

Thanks budm. I'll recheck the fuse. Your statement "Did you check the two fuses on the main board (where you have those input connectors)" is something I'm not clear on. I know that the White board has two fuses and I have checked those. The green board has three very small fuses. I checked them for open but obviously could not get a voltage reading because I have no power to that board that I'm aware of. And voltage regulator ICs I have checked...I think. I checked everything that looked like the pictures within the post but to be honest I'm really not sure which ones to check and even if I'm doing it correctly. :0( Any Idea based on the photos which ones I should be focusing on?

[budm]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

OK, the pictures were not clear enough, I see three fuses now.

[Matt C]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

OK I have confirmed my voltage regulator measurements (VR). I have included a better picture of the logic board with the measurments indicated on each VR right on the photo (I will also include the measuremnets belowwithin the body of this post). Also on the photo I have indicated my ground point. As a point to note I have not been able to find the Negative leg of the 450VDC Main filter cap for properly reading voltage accross the fuse maked "FUSE B" in the photo "power supply with Fuses highlighted" (posted above). I did move my negative lead around the board to different mounting screws to test my reading but ended up with the same results. Below are my VR readings:

U5
L373
0117
PIN1 (ADJ) = .287
PIN2 (OUT) = .460
PIN3 (IN) = .007

U7
L373
0117
PIN1 (ADJ) = .008
PIN2 (OUT) = .016
PIN3 (IN) = .007

U71
L373
0117
PIN1 (ADJ) = .000
PIN2 (OUT) = .000
PIN3 (IN) = .034

U88
L373
0117
PIN1 (ADJ) = .036
PIN2 (OUT) = .058
PIN3 (IN) = .000

It seems that I am not getting the desired reading on any of them. Would you agree? And if so what would you recomend next? Thank you so much for you help!!

[Matt C]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

Anybody know where the Negative leg of the 450VDC Main filter cap is?

[tom66]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

You can see the two "K" capacitors. Just near "Fuse B".
https://www.badcaps.net/forum/attach...6&d=1392945402

There's a blank space for an additional capacitor not installed on this model, the left hand pin is positive, right hand is negative. That's your 450V cap negative.

[budm]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

When you work in the secondary side of the circuits, in this case, the main board, you will use chassis as the Ground ref. point for you meter. You use the negative leg of the main filter cap in the primary side when you are working in the primary side of the circuit.
So take the readings again on the main board.
One of the 3 fuses on the main board should at least show 5V which is from 5VSTBY of the power supply board, the other two fuses, one of them will be for switched 12VDC.

[Matt C]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

Thanks everyone. When I measured voltage using the 450V cap hole on the main board I got a reading of 37.6ACV on Fuse A (Red stripe) and a reading of 17.47ACV on Fuse B (Yellow stripe). This to me seems suspect in that I am not getting a 120ACV on any fuse now. To take the reading using the 450V cap I just jammed a lead to my meter in the hole of the cap as described by "tom66". The symbol that was where I probed for ground using the 450V cap negative (and no capacitor was present) had this symbol: (- near it. Is this the correct spot? I also measured voltage at the 5VSTBY pin and came up with a reading of only .351ACV. I did try it on a couple of other pins (marked 12V or 18V) and got the same reading. The 3 fuses on the control board still read nothing. Now I'm confused and not entirely sure that I'm testing correctly because my readings do not seem to make sense to me. But I really have no idea what I'm doing anyway which is why I'm so dependent on the good advice here. :0)
Any tips advice?

[Matt C]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

Can I include some different information that would make it easier to guide me through the diagnosis? Or is anyone aware of the main part(s) that would cause this malfunction? I'm not opposed to replacing an entire board if that is what it takes.

[Matt C]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

guess that I'll call Vizio and have them come out to repair...

[Matt C]

Re: Vizio model SV422XVT "VIZIO" logo lights orange but won't turn on

Follow up for anyone looking to do repair themselves. The repair ended up being the control board (green circuit board). Because the Vizio logo lit up but did not change when the power button was pressed the repair man deemed it the control board. He ordered and replaced the board, synchronized the remote and all work well.