Vizio SV422XVT no backlight, photos and details inside

[tom66]

Re: Vizio SV422XVT no backlight, photos and details inside

The part is a 5N50 which indicates a generic 5A, 500V MOSFET.

The package is DPAK, not D2PAK, so make sure to get that right when ordering.

[gustagen]

Re: Vizio SV422XVT no backlight, photos and details inside

Looks like I'll be ordering two of these from Digikey.

A big __THANKS__ to everyone who posted in this thread! I really appreciate the time you all dedicate to helping strangers on the internet!

I'll report back in a few days when the parts arrive and I've installed them. Keep those fingers crossed!

[budm]

Re: Vizio SV422XVT no backlight, photos and details inside

I would get at least 8 of them. I usually replace them in a set.

[gustagen]

Re: Vizio SV422XVT no backlight, photos and details inside

Will do, thanks for the advice. You caught me just before checkout!

[retiredcaps]

Re: Vizio SV422XVT no backlight, photos and details inside

I would get at least 8 of them. I usually replace them in a set.

Yes, I was going to suggest that as well. No point going "cheap" on a 42 inch TV.

[gustagen]

Re: Vizio SV422XVT no backlight, photos and details inside

S U C C E S S ! ! !

I replaced Q708 and Q709 as well as the fusible resistor and the TV fired right up. Thanks to everyone who contributed, we really appreciate the help!

[retiredcaps]

Re: Vizio SV422XVT no backlight, photos and details inside

Good job on the repair and following through. Thanks for reporting back as the feedback helps others in the future.

@budm, tom66, selldoor, only 46 posts to a fixed solution.

[tom66]

Re: Vizio SV422XVT no backlight, photos and details inside

Nice one! Another TV saved from inevitable landfill...

[budm]

Re: Vizio SV422XVT no backlight, photos and details inside

Thanks for the repair feedback.

[Matt C]

Re: Vizio SV422XVT no backlight, photos and details inside

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.

[kfkboys]

Re: Vizio SV422XVT no backlight, photos and details inside

I too am having trouble with this television. From the previous posts, I've inspected all fuses on the power board tested good, even the white variable fuse, the mosfets which all measure pin 1-2: 9M ohms | pin 1-3: 321 ohms | pin 2-3: 9M ohms | these seem low in comparison to the previous posts... I'm not sure where to begin checking anything else, upon inspection there are no blown or bloated caps, and no visible damage / burn markings or smells. What should I attempt next? I've already purchased another video board and power board, however I can get the backlight to turn on regardless of power board. The video board I purchased will not allow the backlight to turn on regardless of power being pressed. The only board I have yet to replace is the tcon board, but I'm not sure if I even need to. I'm looking for some guidance and some hope.

In addition, on the original video board I have checked the 3 fuses on the video board, all are good, I have checked the that the 5VSTBY power supply is working the orange light is on, however the backlight will power off once powered on for more than 30 seconds.

[dholley]

Re: Vizio SV422XVT no backlight, photos and details inside

Hello, I hope you can help me. I have read all pages of this post. It is very similar to the problem I have with my TV. No standby voltage. TV will not power on. As early in this post the ICP 250 4A SMT fuse is open / blown. My power board is E-IPB47 PLHH-A945A.
I believe have the same MOSFETS as Gustagen, KF5N50, but mine or through hole not surface mounted. I did a resistance tested on all 4 of the MOSFETS as instructed above, assuming that the gate is Pin 1, Drain Pin 2 and Source is Pin 3, Pin 1 (the gate) would be to on my right.
The readings were similar to Gustagen, except on all readings 2 -3 , drain to source all showed OL. Am i doing something wrong in testing or is this an identification that the MOSFET is bad? Your help is greatly appreciated