Toshiba 55ZV650U REGZA sound but no picture

[eztiger12]

I will try to give you as much information as possible in order to figure out the issue I have presently.

Like the tilt says its a Toshiba 55ZV650U REGZA.
Manufactured October 2009 in mint condition.

The problem: I got sound but no picture!

I would have to open and close the TV once or twice in order to get a picture and the TV worked normal.
Later.... the on and off became 5 - 6 time and then nothing at all......no picture no matter how many time I turn it on or off.

I can turn on the TV now ...the TOSHIBA sign lights up, the sound comes on but still no pictures.

I have done the flash light test in a dark room but I still cannot see a picture.

I can see light when I have the back cover off when TV turned on and I can see the front screen go front pitch black to lighter black or very dark grey.

I have been doing a lot of reading but I m just getting more confused on what it might be.
I dont want to change pieces just for the sake of it.

Thanks

I would really appreciate it..........

[CapLeaker]

Re: Toshiba 55ZV650U REGZA sound but no picture

I dont want to change pieces just for the sake of it.

In order to get around that, you would have to provide clear, high res, straight shot pictures of your PSU and main board. Then you need a digital multi meter, so we can measure things and determent the fault.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

Ok will do.......I ll try to get that done as soon as possible. If anyone else wants to kick in feel free.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

I have taken several picture and attached them to this post to help solve the problem. I thought I had this one solved and replaced the T-com but nothing doing. I does the exact same thing no change.

What I have checked so far was the standby light lights up in front of the TV.
Standby volts is at 5 volts on the multimeter.
There is 24 volts coming go of the board to the backlight. (I can see the light go on as well once the back cover is off).

I checked the rectifier output and its at 106.5 steady ( saw on youtube that maybe it should be at 160V but not sure if he was working on the same model).

Rectifier output for the a/c is 117.8

I am really hope for everyone input so I can solve this issue.
I also checked the fuses and they look fine.

Anxious to get some replies.

Thanks in advance.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

If any other pictures are needed please let me know.

[dick_barton]

Re: Toshiba 55ZV650U REGZA sound but no picture

The set looks as though it's been worked on before looking at the amount of heatsink compound around some of the components.

What voltage do you have on both sides of the white ceramic fuse on the Tcon board
What volatge do you have on the 12VLCD pins.

[dick_barton]

Re: Toshiba 55ZV650U REGZA sound but no picture

The mains does seem low. Is one of the large caps (C821) starting to bow on top?
What is the dc voltage across the legs of C820 & C821 which are rated at 450V dc.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture (Pix of boards added)

Just wanted to in the title that I have added pictures of my boards in order to get some help......sorry and Thanks

[Diah]

Re: Toshiba 55ZV650U REGZA sound but no picture

let your room dark and use light torch on the screen and tell us if you can see some effect of picture or Menu any els

[CapLeaker]

Re: Toshiba 55ZV650U REGZA sound but no picture

are the back lights on and no picture, or you got no picture because the back lights are off?

[budm]

Re: Toshiba 55ZV650U REGZA sound but no picture

"I checked the rectifier output and its at 106.5 steady ( saw on youtube that maybe it should be at 160V but not sure if he was working on the same model)."
Where did you put the black probe of the meter, the chassis or at the negative leg of the cap? It looks like you are using the chassis as the GND.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

To answer Dick Barton ......

if you refer to the 4th picture you can see C821 and I noticed an ever so slight bow compared to the other large ones. But like I said minimal.
How do I check this ...."the voltage across the legs of C820 & C821 which are rated at 450V dc."

Budm
I put a probe on each leg.

Capleaker / Diah
Backlights are on but there is no picture.

Dick Barton
help me out here plz....

Where do I check the voltage on both sides of the white ceramic fuse on the Tcon board. Where is or which is the ceramic fuse?

where do i check the voltage on the 12VLCD pins.

Please guide me and Ill supply the results ......I am not a pro but I manage to do a lot with instructions, youtube, the internet and a lot of reading on this forum.....lol

Thanks guys for the input so far.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

"I checked the rectifier output and its at 106.5 steady ( saw on youtube that maybe it should be at 160V but not sure if he was working on the same model)."
Where did you put the black probe of the meter, the chassis or at the negative leg of the cap? It looks like you are using the chassis as the GND.

If you enlarge image 6 or 8 on the rectifier, I got that reading by putting a probe on each of the squiggle lines ......a probe on each one of those interior legs.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

The set looks as though it's been worked on before looking at the amount of heatsink compound around some of the components.

What voltage do you have on both sides of the white ceramic fuse on the Tcon board
What volatge do you have on the 12VLCD pins.

Just wanted to add that the TV was bought brand new in a sealed box and never had an issue with it until now. Not sure if that changes anything.

[budm]

Re: Toshiba 55ZV650U REGZA sound but no picture

The ~ pins are the Line and Neutral AC input pins for the bridge rectifier and it should show 120VAC.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

The ~ pins are the Line and Neutral AC input pins for the bridge rectifier and it should show 120VAC.

Sorry ....my bad...your totally right. I get a reading of 117.8 on those pins.
But I get a reading of 106.5 on the pins just on the outside of those that are identified with a "-" and "+" signs.

Sorry about that.

[CapLeaker]

Re: Toshiba 55ZV650U REGZA sound but no picture

For those you did set the meter to measure DC volage? 120x1.414=169.68V

[budm]

Re: Toshiba 55ZV650U REGZA sound but no picture

You should measure right between the +/- legs of the main filter cap.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

For those you did set the meter to measure DC volage? 120x1.414=169.68V

Yes sir I did .........but I will double check tomorrow but Im 99 percent sure.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

You should measure right between the +/- legs of the main filter cap.

Budm.........you got to help me out here. I am not sure what exactly you want me to check. Can to guide me please. I would like to more tests on it tomorrow morning even though its Mothers day........not sure if the wife will aprouve lol