Toshiba 55g300u. Picture goes on and off but sounds remains

[skienstein]

I just bought an used toshiba 55g300u. when i went to buy it there were no issues. i haven't really used it much, but it just started making a high pitch sound and the picture comes on and off in no particular sequence.

i have tried to use the different hdmi and cable inputs and it happens to all. the picture goes on and off but the sound remains. if i tap on the back cover the picture comes back or turns off. if you are on the menu and the picture goes off, you don't see the menu either.

i just need a general idea if the tv is toast, or if its an inverter, a bad backlight tube, power issue, or connection issue?

[tom66]

Re: Toshiba 55g300u. Picture goes on and off but sounds remains

When in a dark room, when the screen flickers, can you see a glow from the screen or not?

[skienstein]

Re: Toshiba 55g300u. Picture goes on and off but sounds remains

Thanks tom66 for your quick reply. I don't know. I'm going to have to wait until tonight when its dark. I will post my findings then.
I really appreciate your help! Have a great day

[aaronwt6]

Re: Toshiba 55g300u. Picture goes on and off but sounds remains

I would immediately pull the back off and check all of the connections between the inverter boards. These things have connections issues that cause arcing / noises like you just described and lead to burned out inverter boards and wires. I've fixed 1 that I caught in time by just reseating connectors and another that needed inverter boards replaced. I've also sold two sets of inverters out of some with broken screens to people that had the exact same issue. Anyway, I'd check that out before you even turn it on again. Every time it flickers you are 1 step closer to needing parts.

[skienstein]

Re: Toshiba 55g300u. Picture goes on and off but sounds remains

tom66 there is a glow on the screen so it does not turn completely black as when you turn off the tv. when the picture goes off, there are like 3 spots that start from the top and turn into lines as they go down on the screen. sorry, a bit hard to explain.
aaron, i will open the back and check out the connections.
i appreciate the help!!!

[skienstein]

Re: Toshiba 55g300u. Picture goes on and off but sounds remains

Hello Again. I'm sorry I've haven't had the time to resolve this issue earlier. aaronwt6, i opened the back of the tv and did reseat all of the connections on the inverter board on the left side. I've attached some pictures for your reference. The inverter board i checked is to the left side. I also reseated the connections to the tcon board shown on the top part of the lcd.

To the right of the lcd, there is also what i think looks like an inverter board underneath the main board. I have not found any diagrams online to explain what everything is, and since i'm a lcd repair amateur, i didn't know and did not check that side of the lcd (the high pitch noise comes from this area)
I also found that this tv has been worked on before. There is a piece of foam that was "secured" with electrical tape on top of the main board (shown on pics 31 through 34)

I also recorded a short 1 minutre video I uploaded to youtube that shows from the moment I powered the tv. I move the tv and tap the back just a bit, and you can see were the picture goes off and some lines appear to move on a downward direction. At the end of the video I placed the camera on the back of the tv and you can hear the high pitch sound coming from the right of the tv.

Here is the link to the video: http://www.youtube.com/watch?v=_i-l6...ature=youtu.be

Is this something you think I can repair and would be worth it? I'm already $400 into this tv and in my area would be hard to sell for parts on craigslist.

I appreaciate in advance your time and all your help!!

[tom66]

Re: Toshiba 55g300u. Picture goes on and off but sounds remains

Oh dear, it looks like the previous owner has tried to apply pressure to the video processor to keep it from breaking off the board (not physically but the electrical connections) - like similar problem in Xbox360/PS3. The best fix is going to be to replace the main board if that is what is causing the problem; I don't see any obvious burning on the inverter connections.

[skienstein]

Re: Toshiba 55g300u. Picture goes on and off but sounds remains

wow, thank you so much tom66 for taking the time to look over my issues. its exactly the kind of lead i needed the proceed. god bless you!!
have a wonderful weekend and i will keep you guys posted.