Sharp LC-70C8570U

[nelson6861]

Re: Sharp LC-70C8570U

In post #14

I have 3 regulators reading 0v
Could this be a problem also...

[nelson6861]

Re: Sharp LC-70C8570U

Also i want to add PW1 and PW2 comes from t-con board
And they read .7v PW1 and 0 PW2

[freakaftr8]

Re: Sharp LC-70C8570U

And I'm assuming you tried powering up with all 4 pulled as Well? If so, steady power light but no backlights?

[budwich]

Re: Sharp LC-70C8570U

Since you are "playing" with the set, why don't you try the "standard... disconnect the corner cable test" with the tcon to panel cables all connected to see what happens. Also try it from the other corner. You have nothing to loose and it might help with the "diagnosis"... maybe.

[nelson6861]

Re: Sharp LC-70C8570U

And I'm assuming you tried powering up with all 4 pulled as Well? If so, steady power light but no backlights?

Yess. I connected all four ribbon cables also and same 2/5 blink code

[nelson6861]

Re: Sharp LC-70C8570U

Since you are "playing" with the set, why don't you try the "standard... disconnect the corner cable test" with the tcon to panel cables all connected to see what happens. Also try it from the other corner. You have nothing to loose and it might help with the "diagnosis"... maybe.

Ok...
But the t con board is missing pw1 and pw2 volts to power supply...
I will try it

[nelson6861]

Re: Sharp LC-70C8570U

Ok...
But the t con board is missing pw1 and pw2 volts to power supply...
I will try it

Can you explain what that will do...
Pulling those ribbon cables

[budwich]

Re: Sharp LC-70C8570U

probably nothing but I am having a hard time following what you have done and when. A number of these type of sets have panel issues which "manifest" themselves as 2-5 type problems because of their impact on powering and the limited "code design for errors". Further, depending on the failure, the system shuts down powering accordingly (sometimes fast). Anyways, unless you have something better, it was just a suggestion. I know when I was "playing" with my 70in, it took quite a bit of "playing" before I got anywhere as a comments of "panel problem" was "popular". :-)

Plus... I don't understand "the pw1,pw2 to power supply... come from the tcon to the power supply...." when are you reading / monitoring these? at power up, once code flashing occurs, before code flashing occurs????? Again, reading back your "steps"... sometimes you have 12v and then other times you have 0v.... this tells me that the "process" isn't quite set for consistency. But again just my "eyes" from the internet.

[freakaftr8]

Re: Sharp LC-70C8570U

OK judging that you see 83 volts at each output to the LED drivers And 12 votes going to the tcon tells me that the power filter correction circuit of the power supply has to be going high. Interesting fact that you mention you're getting 83 v to LED drivers. If they were disconnected out of circuit the backlight controller does not allow power to backlights. (Or an open backlight output channel for that reason as well)

And without an actual service manual I would not be open to tell if 83 volts to each channel output is optimal for the backlights to light up. To me that sounds a bit low.

However if you can connect one side of the panel to the point were you do not see the error Flash in the power light stays consistent Look into the screen with a flashlight and see if it has an image without the backlights being lit

[freakaftr8]

Re: Sharp LC-70C8570U

Also I might add that if the panel had indeed failed, Removing the short by disconnecting the shorted side of the LCD panel via the to right or left ribbons, The tcon May already be damaged to the point where it does not allow power supply spool up of led's, When you notice that the 2-5 error goes away by disconnecting the offending side, If you do not have a picture with the flashlight test You could check the inductors on the tcon to see if you're getting other voltages besides just 12 V with the power light on solid.

[nelson6861]

Re: Sharp LC-70C8570U

probably nothing but I am having a hard time following what you have done and when. A number of these type of sets have panel issues which "manifest" themselves as 2-5 type problems because of their impact on powering and the limited "code design for errors". Further, depending on the failure, the system shuts down powering accordingly (sometimes fast). Anyways, unless you have something better, it was just a suggestion. I know when I was "playing" with my 70in, it took quite a bit of "playing"


before I got anywhere as a comments of "panel problem" was "popular". :-)

Plus... I don't understand "the pw1,pw2 to power supply... come from the tcon to the power supply...." when are you reading / monitoring these? at power up, once code flashing occurs, before code flashing occurs????? Again, reading back your "steps"... sometimes you have 12v and then other times you have 0v.... this tells me that the "process" isn't quite set for consistency. But again just my "eyes" from the internet.

The pw1 and pw2 were reading off the power supply

[nelson6861]

Re: Sharp LC-70C8570U

Sorry pwm1 and pwm2 from tcon board to powersupply

[budwich]

Re: Sharp LC-70C8570U

1st of all how did you test the backlights did you remove the LCD panel in physically power the backlights with a dmm?

If you look on this forum you will see many postings about faults with sharp LCD TV's especially the 70 Inch panel. When you 1st power the TV do you get a solid light light before the 2 - 5 Flash? Do you see any indication of the back lights coming on even briefly before shutdown? Also we would watch your monitor voltage to the tcon. you should be getting 12 v to the connector

op... I don't think you "addressed" / answered all of these questions.

Also, what's the history of the set?

Lastly, can you post a picture of the "whole back" so we can see the layout / cabling.

[budwich]

Re: Sharp LC-70C8570U

Sorry pwm1 and pwm2 from tcon board to powersupply

well unless you were looking with a scope, I don't think your meter will show you much for these.

[nelson6861]

Re: Sharp LC-70C8570U

op... I don't think you "addressed" / answered all of these questions.

Also, what's the history of the set?

Lastly, can you post a picture of the "whole back" so we can see the layout / cabling.

Here are those pictures.
Can you see the heat trail on the tcon board. There is a thermal pad on the bottom probably should have been one on the top too

[budwich]

Re: Sharp LC-70C8570U

ok... but again, what is the history of the set? and again, you didn't address the questions that freakaftr8 posted earlier.

potentially, it appears that there is "something" that has happened on the tcon but I wouldn't necessarily say "heating"... more like "moisture marks".

[nelson6861]

Re: Sharp LC-70C8570U

ok... but again, what is the history of the set? and again, you didn't address the questions that freakaftr8 posted earlier.

potentially, it appears that there is "something" that has happened on the tcon but I wouldn't necessarily say "heating"... more like "moisture marks".

I dont know history of tv..
I just know it does not work when i got it from a friend.
I plugged it in and 2/5 fault code. I know this does not help. I have a new t con board coming in tomorrow but i dont think thats goin to help my panel issue. I appreciate your help

[budwich]

Re: Sharp LC-70C8570U

OK. no problem with "unknown history"... that is better than "I won't answer". Again, you still have not answered the questions freakaftr8 asked that I also asked you to clarify.

Hopefully, your replacement tcon will get you there but at this point, I wouldn't necessarily hold my breath.

[nelson6861]

Re: Sharp LC-70C8570U

OK. no problem with "unknown history"... that is better than "I won't answer". Again, you still have not answered the questions freakaftr8 asked that I also asked you to clarify.

Hopefully, your replacement tcon will get you there but at this point, I wouldn't necessarily hold my breath.

What was the post # where freak8 asked the question

[budwich]

Re: Sharp LC-70C8570U

look at my post 33... anyways best of luck with your card replacement.