Sharp LC-70C8570U

[nelson6861]

Re: Sharp LC-70C8570U

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

Ok.
When i plug tv in i get v light lit then i hit power button and get 2/5 blink code...
I get no backlights at anytime

[nelson6861]

Re: Sharp LC-70C8570U

Ok.
When i plug tv in i get v light lit then i hit power button and get 2/5 blink code...
I get no backlights at anytime

I get 12v on tcon board also

[nelson6861]

Re: Sharp LC-70C8570U

Ok.
When i plug tv in i get v light lit then i hit power button and get 2/5 blink code...
I get no backlights at anytime

I had removed the panel and tested all led backlights.
I used my led backlight tester.
All leds lit up bright

[budwich]

Re: Sharp LC-70C8570U

OK. well, i would do the "disconnect the corner cable" as suggested earlier and see what the results are from doing that... this "test" is done with all tcon cables connected.

[nelson6861]

Re: Sharp LC-70C8570U

OK. well, i would do the "disconnect the corner cable" as suggested earlier and see what the results are from doing that... this "test" is done with all tcon cables connected.

Ok disconnected the left corner and nothing.
V light lit up
Did not have flash fault code re-appear.
Im thinkin maybe backlight led issues...
I took some measurement with dmm with leds connected and power on.
Might have power board issues or whats preventing leds from coming on...

[budm]

Re: Sharp LC-70C8570U

PWM signals from the T-CON are used for controlling the brightness of the backlights base on the scene of the video for dimming control so they can claim fake high contrast ratio, no PWM = no backlights. You have 3 sets of edge-lit LEDs, thus 3 LED drivers circuits.
What do happen if you disconnect just that cable from the T-CON? Also test the PWM pins too without the cable in place.
Those 83 V LED voltage reading are made against chassis GND?
STB = BL-ON, that siganl will be locked out if ERROR pin is HIGH.
You are 100% sure that PNL-12V is present and not drops out afetr seconds or two?
Sharp RUNTKA935WJQZ (DPS-171CP A) Power Supply / LED Board.

[nelson6861]

Re: Sharp LC-70C8570U

PWM signals from the T-CON are used for controlling the brightness of the backlights base on the scene of the video for dimming control so they can claim fake high contrast ratio, no PWM = no backlights. You have 3 sets of edge-lit LEDs, thus 3 LED drivers circuits.
What do happen if you disconnect just that cable from the T-CON? Also test the PWM pins too without the cable in place.
Those 83 V LED voltage reading are made against chassis GND?
STB = BL-ON, that siganl will be locked out if ERROR pin is HIGH.
You are 100% sure that PNL-12V is present and not drops out afetr seconds or two?
Sharp RUNTKA935WJQZ (DPS-171CP A) Power Supply / LED Board.

Ok
The 83 volts for led is against chasis ground.
Pnl-12 is pin 16 reads 3v
Error voltage is reads 0v
I have a new tcon coming

[budm]

Re: Sharp LC-70C8570U

PNL_POW PIN 16 (3V =ON) is the command signal to turn on switched 12V to feed the PNL-12V pin on the other connector that goes to the T-CON board.
So do you have 12VDC at PNL-12V or not for sure?

[nelson6861]

Re: Sharp LC-70C8570U

PNL_POW PIN 16 (3V =ON) is the command signal to turn on switched 12V to feed the PNL-12V pin on the other connector that goes to the T-CON board.
So do you have 12VDC at PNL-12V or not for sure?

I get 12v on tcon connector to the board... but i think tcon board is back... i will see when i get new tcon board

[budm]

Re: Sharp LC-70C8570U

So the 2/5 error did not shutdown the PNL-12V supply.

[nelson6861]

Re: Sharp LC-70C8570U

So the 2/5 error did not shutdown the PNL-12V supply.

No...

[budm]

Re: Sharp LC-70C8570U

the 2/5 error detect if the PNL-12V is present (or loaded down too much by bad T-CON) or not, so we just have to wait for the new T-CON to see what happen.

[lonewolf55]

Re: Sharp LC-70C8570U

I know this is an old Thread, I have been searching the forums for RUNTKA935WJQZ information myself.

I have similar issue with an LC-70LE847U .... I see the OP ordered a T-CON but then the thread goes Dead... my guess is this did not fix the issue and that the issue is most likely a Dead LCD Panel.

the symptoms I have are:
No Backlight
No Video (Picture) when using the old Flash light method
with the 4 white Panel cables disconnected, there is still no Backlight
all LED strips were tested with SID-GJ2C 0-300v tester and no defects.
I notice when I touch the metal frame there is presence of Voltage (about 10VAC leakage from Chassis to GND) <<=== this is gone when the PSU Board is Isolated from the Chassis.

I'll post PD voltages but they look Normal at this point IAW the SM.

I suspect the LCD Panel is most likely Dead, and right now I'm building a simple test fixture to try turn on the Backlight section of the supply.

There are no V flash codes, so I'm not Positive what I have yet.

[lonewolf55]

Re: Sharp LC-70C8570U

Ahhh I see now all voltages are good, but PWM-1 signal not happening, so I removed the Pin 17 and then after powering the set up I jumped pin 17 to pin 15 which is BUSY @5.05v. <<<== EDIT: Just to be clear, the PD Connector is what I jumpered the PWM1 Line that I removed comes from the Main Board and it was left hanging loose so as not to damage things by Arbitrarily shorting things out.

Low and behold we have full Backlighting, so this means the Main Board is not giving PWM-1 signal.

So now a question, what function tells the Main Board to turn on PWM-1 ?
probably comes from the T-CON .... sucks to have to Reverse engineer all these boards as I cannot find a Schematic

[lonewolf55]

Re: Sharp LC-70C8570U

BTW there is no such TV as the LC-70C8570U ... I think the OP meant LC-70C8470U anyway really same as the LC-70LE847U

Maybe I should have made a new Thread my Bad

[nomoresonys]

Re: Sharp LC-70C8570U

I know this is an old Thread, I have been searching the forums for RUNTKA935WJQZ information myself.

I have similar issue with an LC-70LE847U .... I see the OP ordered a T-CON but then the thread goes Dead... my guess is this did not fix the issue and that the issue is most likely a Dead LCD Panel.

the symptoms I have are:
No Backlight
No Video (Picture) when using the old Flash light method
with the 4 white Panel cables disconnected, there is still no Backlight
all LED strips were tested with SID-GJ2C 0-300v tester and no defects.
I notice when I touch the metal frame there is presence of Voltage (about 10VAC leakage from Chassis to GND) <<=== this is gone when the PSU Board is Isolated from the Chassis.

I'll post PD voltages but they look Normal at this point IAW the SM.

I suspect the LCD Panel is most likely Dead, and right now I'm building a simple test fixture to try turn on the Backlight section of the supply.

There are no V flash codes, so I'm not Positive what I have yet.

It's very possible that the tcon did fix the issue, some people just don't bother themselves to report back, just another eternal mystery, sucks but happens frequently.

[lonewolf55]

Re: Sharp LC-70C8570U

I think I might have a Main Board issue DKEYMF953FM01 (KF953, QPWBXF953WJN1)

Problem is I don't have one to substitute and all I see for sale are Used NOT WORKING for parts only @ around 150 Bux, I guess fine but the parts I need are most likely what failed on the boards all those folks are selling LMAO

Looks like this one might go in the Dumpster.

I don't have an LVDS cable that will fit my Panel tester for this one either (it's a 41 Pin Cable) Maybe I can make one.

[lonewolf55]

Re: Sharp LC-70C8570U

OK found it PWM1 comes off the T-CON and just passes thru the Main Board.

As I suspected earlier, so now it's down to T-CON or the Panel, most likely the Panel.

Love it when I answer my own Questions


Well, it could still be Main Board need to check PNL ENABLE and a few other things

[budwich]

Re: Sharp LC-70C8570U

you checked that you have 12v at the tcon?
instead of disconnecting all of the tcon to panel cables, you can try one at a time and also a "disconnect of the small corner cable" at the bottom of the panel... interconnecting the bottom edge board to the side... this is done with all other cables in place. that might tell you more.... maybe.

[lonewolf55]

Re: Sharp LC-70C8570U

yes I have 12V to the 4 pin connector it is GND GND 12V 12V and all good.

I don't see "Corner Cable Connectors" on this Sharp LC-70LE847U TV, maybe one needs to remove the panel to get to them.

The T-Con board is Duntkf961fm01

on the LVDS test points I have no PWM1 signal out (this turns on Backlight inverters) so I just finished checking PNL_EN this is Pin 3 of the 41 Pin LVDS connector and I see a toggle at power up and Power Down so looks like it works....

I thought that the Backlight should turn on with the 4 T-Con ribbons removed, I'm not sure but most tell me it should. That being the case with those 4 removed the Panel is out of the equation. <<== at least for now, was my thinking


BTW the History of the set is........ it was working fine then was powered off over night, then when it was powered back up, it turned on and only the V LED under the Sharp name was lit up solid, not flashing any code and there was no Backlight and no Picture seen on the screen, even when looking with the old Flashlight, But there is sound.