Vizio VP50 Smoked

[aheliason]

Hello Badcaps moderator & members. I am back with a new problem. My VP50 has lost all raster and shortly thereafter, there was the acrid smell of burned resistor(s). After careful inspection, the only burned components seem to be R5000, R5010, and possibly D5000 on the board in the left center (from the rear view) which has three large heat sinks. The two resistors appear to be 1 watt and are located at the left center of the card beneath an electrolytic and a ceramic cap.

To get started, can anyone with access to schematics tell me if this looks like a real bad situation or if I may have a shot at repairing this set? Question two is where to get those schematics?

Thanks in advance.
Andy E.

[tom66]

Re: Vizio VP50 Smoked

Can you post a picture of where the resistors were burned, and one of the overall chassis of the TV? If the resistors are on the Y-main, then the Y-buffer may be bad too.

[tw2005]

Re: Vizio VP50 Smoked

Sounds like the samsung based model potentially with a ymain similar to this in between the 2 buffer connectors??

[tw2005]

Re: Vizio VP50 Smoked

There's over 15 hits for search VP50, some of which have the Samsung Panel S50HW-YD02 . Common shorted upper buffer and blown ymain, might find some good info amongst them as well.

[aheliason]

Re: Vizio VP50 Smoked

Per the request of Tom66, here are photos of the back. It sounds as if he understood which board correctly. This will be my first try at posting photos so if I fail, please bear with me!

[aheliason]

Re: Vizio VP50 Smoked

Larger image.

[aheliason]

Re: Vizio VP50 Smoked

TW2005, yes,exactly, I have just posted two photos.

[aheliason]

Re: Vizio VP50 Smoked

I am ready to remove the Y main card from the upper and lower drivers (buffers). The Tyco edge connectors seem very tight. Is there a release method or should I just pry harder? By the way, I have reviewed several of the repair videos and think this is certainly worth a try, given that I have more spare time than spare money..

[tom66]

Re: Vizio VP50 Smoked

Pry harder -- make sure to disconnect orange panel ribbons first and unscrew boards. Then they come off quite easily usually.

[aheliason]

Re: Vizio VP50 Smoked

Tom, Success. I had not noticed the positioning ferruls on the inside set of stand-offs. Lifted first one end of the board then the other and it seemed free, but when I let go of the board one or the other of the screw holes caught on the post. Live and learn..

[ben7]

Re: Vizio VP50 Smoked

Those resistors look ok. (Some are made of a black ceramic like material) If they were burned, the paint stripes would be browned/non-existent.

The solder joint on one resistor doesn't look ok! It probably was a crack which arced, and heated up...

[aheliason]

Re: Vizio VP50 Smoked

Update. The two 10 ohm resistors R5600 & R5610 were intact but the pcb runs to them were totally gone and the board quite blackened beneath where the runs had been. It's no wonder it smelled so bad! To my surprise, the diode D5600 is good. I have yet to find a schematic of the Samsung Y Main and the buffer cards so if anyone can help with that, please post a link.

[tom66]

Re: Vizio VP50 Smoked

Samsung do not publish any schematics for y-main, y-buffer etc. Only power supply and main board.

[aheliason]

Re: Vizio VP50 Smoked

I have used the diode fwd/rev method to check all the semiconductors on the Y-main. Nothing seems out of the ordinary. Note that two of the devices on the longer heatsink look like transistors, but are dual diodes. The top Y buffer measures bad with very low resistance in both directions across V+ to Gnd. I plan to rebuild the burned runs and replace the two parallel 10 ohm resistors, then reassemble and power up, briefly, with the top buffer removed. If I get any raster and the resistors stay relatively cool then I'll probably just replace the top buffer board. If not, hmmm, don't know.
If anyone can think of something else I should do, please post!

[tw2005]

Re: Vizio VP50 Smoked

As far as I know the panel won't fire up without working top buffer.

[aheliason]

Re: Vizio VP50 Smoked

Hi TW, A few days ago I found a video in which someone used that method. In fact, he started with the same set of resistors cooked as I have. Sorry to say that I can't seem to find the video again. I can not recall if it was the top or bottom board that the person was testing but he did show the set on with just half the screen active with one board out, so I'll give it a shot. If anyone has tried this then please comment. Thanks

[aheliason]

Re: Vizio VP50 Smoked

https://www.youtube.com/watch?v=WB23...e_gdata_player

It worked for me, too. Repaired the runs and replaced the resistors. I have raster over the bottom half of the screen. Tomorrow, I'll try to get some signal to it. Anyone got a top buffer for sale?

[tw2005]

Re: Vizio VP50 Smoked

That's the video I thought you may have seen where he removed the short on the upper by removing the cooked chips and fired it up. So did it run with no upper and only lower board installed? Maybe I did something dopey and tried it with a dead ymain, whatever it was I had no luck with bottom board only.

The upper is hard to find and generally expensive, they were virtually run out when I last did one about a year ago. I did get an earlier model board to work instead of the original.

https://www.badcaps.net/forum/showthread.php?t=21637

[chuckup]

Re: Vizio VP50 Smoked

aheliason,

Sent you a PM

[aheliason]

Re: Vizio VP50 Smoked

Update: Thanks to help from you members I now have what I think is a repaired Y-Main a set of buffer cards on order. I will check back in after they arrive and let you all know how the job is progressing. If all is well, I would like to do a video at that time outlining what I have learmed. I believe YouTube is probably the best place to post that with a link to it here. In the meantime, feel free to add any comments to this thread. Andy E (Old Sea Dog)