TV repair issue

[Hattie]

Hi guys I was feeling good after repairing phones for a little while, and bought a westinghouse DWM40F3G1 tv. the seller said that they had gone to church, and came back home, and the TV had no picture but had sound. I went to youtube and the internet for ways to fix it the main board looks good, I'm not sure what's causing the problem, thus how to fix it.  So I was hoping that the internet would come to the rescue. I'll post some pictures, OH and also I was thinking about maybe just replacing the one board? what do you guys think... I also did the flashlight test and I could see the westing house logo. All help is appreciated.

[Donut417]

18 hours ago, Hattie said:

I also did the flashlight test and I could see the westing house logo.

As in there was a picture but it was dark? If so it could be an issues with the back lighting. Newer TV's use LED's so I could be an issues with what ever controls them. If this is an old school LCD tv then it would use actually bulbs, and that might be a pain to fix. 

 

Be careful poking around. The PSU in that TV probably has power in the caps, one wrong move means someone could end up in the ER or in a pine box in the ground. 

[Hattie]

4 hours ago, Donut417 said:

As in there was a picture but it was dark? If so it could be an issues with the back lighting. Newer TV's use LED's so I could be an issues with what ever controls them. If this is an old school LCD tv then it would use actually bulbs, and that might be a pain to fix. 

 

Be careful poking around. The PSU in that TV probably has power in the caps, one wrong move means someone could end up in the ER or in a pine box in the ground. 

Ye I know what you're saying with the power caps when I have to test something which requires power I don't get close to the board, and yes the picture was there but really really dark but I couldn't see it without the flashlight.

[Donut417]

13 minutes ago, Hattie said:

Ye I know what you're saying with the power caps when I have to test something which requires power I don't get close to the board, and yes the picture was there but really really dark but I couldn't see it without the flashlight.

That narrows it to a back light issue. Could be PSU related but it could also be what ever controls the back light. So changing the board may or may not work. Not sure if there is any documentation on how the back lights are wired in to the TV, but thats what I would want to see. 

[Hattie]

9 hours ago, Donut417 said:

That narrows it to a back light issue. Could be PSU related but it could also be what ever controls the back light. So changing the board may or may not work. Not sure if there is any documentation on how the back lights are wired in to the TV, but thats what I would want to see. 

I know this has some images regarding the wiring of just the whole thing if not I can take the whole back panel off to show you 

http://westinghouseelectronics.com/wp-content/uploads/2014/11/DWM40F3G1_UM.pdf

[Hattie]

On 9/15/2018 at 11:57 PM, Donut417 said:

That narrows it to a back light issue. Could be PSU related but it could also be what ever controls the back light. So changing the board may or may not work. Not sure if there is any documentation on how the back lights are wired in to the TV, but thats what I would want to see. 

Why would It be a PSU issue, the TV still powers on as well as has sound. I think it is the back light is replacing the motherboard my best bet?

[Donut417]

42 minutes ago, Hattie said:

Why would It be a PSU issue, the TV still powers on as well as has sound. I think it is the back light is replacing the motherboard my best bet?

How is the back light powered? We dont know. No regular documentation is going to show that. You have to find the back light circuit and trace it back to power and figure out why its not getting power. This is a little out side my wheel house, this is some EEVBlog/8-bit guy territory we are getting in to. 

[Hattie]

12 minutes ago, Donut417 said:

How is the back light powered? We dont know. No regular documentation is going to show that. You have to find the back light circuit and trace it back to power and figure out why its not getting power. This is a little out side my wheel house, this is some EEVBlog/8-bit guy territory we are getting in to. 

Ok means a lot you really were a lot more helpful than a lot of people.