Vizio VP50 HDTV20A no picture or sound

[loukin]

I just got a Vizio VP50 HDTV20A that has no picture or sound but just the green light. The guy I got it from said it was working before he moved and now it only works intermittently. So I got it home and turned it on and it worked. I turned it off and the next few days tried to use it and never would show picture or sound just a green light. I took the back off to check for bad caps but didn't see any caps that looked bad. This is the Samsung version of the Vizio. Here are some pictures. Can someone help me please.

[tom66]

Re: Vizio VP50 HDTV20A no picture or sound

Common to get bad solder joints on the transistors of the power supply.
https://www.badcaps.net/forum/attach...9&d=1370731206

I suggest you remove the board and resolder all the transistors attached to the heatsinks.

[loukin]

Re: Vizio VP50 HDTV20A no picture or sound

I will try that right now.

[loukin]

Re: Vizio VP50 HDTV20A no picture or sound

Okay I took the board off and re-soldered the transistors and put the board back in the tv but now it's doesn't have a stand-by light and doesn't turn on. Did I burn a fuse out maybe?

[loukin]

Re: Vizio VP50 HDTV20A no picture or sound

I just checked all the fuses they are fine.

[loukin]

Re: Vizio VP50 HDTV20A no picture or sound

I was reading that transistors can burn out very easily and I was think I might have burn one out. Can I test the transistor while they are still attached to the board? Is there a way to see if it's something other then having to check every transistor?

[tom66]

Re: Vizio VP50 HDTV20A no picture or sound

You should still have a standby light unless you got a "bang" when installing the new board. Check your soldering for bridges/accidental shorts, and double check all connectors are installed. Reflowing joints should not make a problem any worse.

[loukin]

Re: Vizio VP50 HDTV20A no picture or sound

Thank you for your help. I didn't get a bang or anything all it does now is nothing. I will check it for bridged connections now.

[loukin]

Re: Vizio VP50 HDTV20A no picture or sound

I checked all Transistors and verified there are no bridged connections and put it back together and still nothing. Even though the tv would not turn on with sound or picture when plugging it in and turning it on I would at least hear a click and now nothing happens at all. I have a multimeter is there a way I can check what's wrong with it plugged in?

[tom66]

Re: Vizio VP50 HDTV20A no picture or sound

Yes, on the main board connector there should be pins marked either: "5V", "5V1", "5V2", "5V3", "5V4", "5VS", "STBY5V". You should have 5V approximately on that pin, do you? (Red probe on pin, black probe on chassis of TV.)

[loukin]

Re: Vizio VP50 HDTV20A no picture or sound

I have a very cheap multimeter from ebay I bought and I am not sure what to set it to, to see if I am getting 5v coming from the pin. Here is a picture of the multimeter and you let me know which setting I need to set it too?

[attainteddragon]

Re: Vizio VP50 HDTV20A no picture or sound

set it to 20 dcv and your good to go. as long as you have it set higher than your testing voltage, your all good. black probe on fixing screw or chassis and red probe on pin to be measured.

[retiredcaps]

Re: Vizio VP50 HDTV20A no picture or sound

let me know which setting I need to set it too?

http://www.sparkfun.com/tutorials/202

[loukin]

Re: Vizio VP50 HDTV20A no picture or sound

Yes, on the main board connector there should be pins marked either: "5V", "5V1", "5V2", "5V3", "5V4", "5VS", "STBY5V". You should have 5V approximately on that pin, do you? (Red probe on pin, black probe on chassis of TV.)

Well I checked the D5V and 5VSB pin and they come back 0 with my multimeter.

[tom66]

Re: Vizio VP50 HDTV20A no picture or sound

I thought you had a power LED?

[loukin]

Re: Vizio VP50 HDTV20A no picture or sound

http://www.sparkfun.com/tutorials/202

Thank you for the link for the multimeter tut. I am reading through the Troubleshooting guide now and will post better pictures after.

[loukin]

Re: Vizio VP50 HDTV20A no picture or sound

I thought you had a power LED?

I did until I re-soldered the Transistors and then when I put it back together I didn't get a green light or a stand-by light and not even the 2 clicking noises. That is why I ask if maybe I burn out a transistor.

[tom66]

Re: Vizio VP50 HDTV20A no picture or sound

Since you have no 5VSB, the first place to check is around here: look for cracked solder joints, shorted points, etc. And can you get a close up of the area?

[loukin]

Re: Vizio VP50 HDTV20A no picture or sound

Here are some close ups I don't see anything wrong.

[loukin]

Re: Vizio VP50 HDTV20A no picture or sound

Since you have no 5VSB, the first place to check is around here: look for cracked solder joints, shorted points, etc. And can you get a close up of the area?

Here are closeup pictures of this area. I looked at it and it looks find is there a way to check these components?