Samsung un40c5000qf black screen - tcon?

[jasonbay13]

Neighbors tv is no work: plug in and press power button it makes the startup sound and the backlight comes on but the screen is black. i am not sure if someone has touched it before as the tcon board connector from the main board had the pull clip broke on one side.

i could not find anything with a look by my own eyes.
i am getting 12.8v on both sides of the fuse at the tcon board.
connections appear to be good, re-did connection to be sure.

so, am i right in thinking t-con board or could it be the main board not sending signal, and how would i test?

part number off t-con board is "CPWBX RUNTK DUNTK 4414tp ZZ"
https://www.shopjimmy.com/sharp-cpwb...con-board.htm#
not in stock and expensive :/


~thanks

[budm]

Re: Samsung un40c5000qf black screen - tcon?

We need to see the pictures so we can see what we are dealing with.
If the T-CON has two ribbons between T-con and the LCD panel then try having one ribbon cable connected one at time to see what you see on the screen.
There are also Voltage test points on the T-CON that should be checked.

[jasonbay13]

Re: Samsung un40c5000qf black screen - tcon?

dont have the bottom side of the main board or power board since i have not removed them from the panel. i can if needed.

[jasonbay13]

Re: Samsung un40c5000qf black screen - tcon?

i just tried one side of the panel at a time. when i pull the left one out the left side goes mostly gray (except left edge it fades to black). right side is black except it says "nal cable." i assume the first part would be "check pa" nal cable.

when i reverse and have the left in and the right out it stays all black

[budwich]

Re: Samsung un40c5000qf black screen - tcon?

In lots of cases, when a cable from the tcon to panel is disconnected, that side is "all white" while the remaining side shows a picture... which is partly your result... if you fed in a signal instead of the set showing a message. However, the non-white display seems to indicate a problem and further, in the reverse, no picture is shown and no white "half".

Still further, the message is likely "check signal cable" as in you have selected an input that has no cable connected and hence the set is "complaining" accordingly.

Lastly, if the LVDS cable (main to tcon) has an issue, then this will cause a problem there after. This connection / connectors are very important and need to have "full integrity".

[jasonbay13]

Re: Samsung un40c5000qf black screen - tcon?

so i was looking around and found this post: https://www.badcaps.net/forum/showthread.php?t=44635

in tom66 says "if you get half a good picture with one half unplugged usually it means there is a short on one side of the panel (i.e. Bad panel.)"

probably a bad idea, but it looked like the two halves of the tcon are the same so i tried putting the right (one that shows an image) and connecting to the left side of panel. i got all black screen. and when i connected the left of tcon to right of panel i got vertical lines. is this conclusive that i have a bad t-con or bad panel or bad mainboard/lvds? i do have an oscope that i know how to turn on, if that can be useful.
considering that i can only get white or black on the left side no matter what and either signal or black on the right side (no white) i'm leaning towards bad panel but i have little experience around these things.

thanks for all the help

[budwich]

Re: Samsung un40c5000qf black screen - tcon?

I don't think "crossing cabling" is a good idea... :-( it is likely to cause tcon issues as though the circuit looks that same, the signal / voltages on various pins may not be.

you would probably be wiser checking voltages as printed at various points on the tcon and compare those to ones that should show up somewhere thru the cabling on either side of the panel / edge boards.... assuming that you can get an image still on one side.

[nomoresonys]

Re: Samsung un40c5000qf black screen - tcon?

Neighbors tv is no work: plug in and press power button it makes the startup sound and the backlight comes on but the screen is black. i am not sure if someone has touched it before as the tcon board connector from the main board had the pull clip broke on one side.

i could not find anything with a look by my own eyes.
i am getting 12.8v on both sides of the fuse at the tcon board.
connections appear to be good, re-did connection to be sure.

so, am i right in thinking t-con board or could it be the main board not sending signal, and how would i test?

part number off t-con board is "CPWBX RUNTK DUNTK 4414tp ZZ"
https://www.shopjimmy.com/sharp-cpwb...con-board.htm#
not in stock and expensive :/


~thanks

This appears to be a match, as always triple check if you buy it: https://www.ebay.com/itm/Sharp-CPWBX...s4YO:rk:1:pf:0

[budm]

Re: Samsung un40c5000qf black screen - tcon?

i just tried one side of the panel at a time. when i pull the left one out the left side goes mostly gray (except left edge it fades to black). right side is black except it says "nal cable." i assume the first part would be "check pa" nal cable.

when i reverse and have the left in and the right out it stays all black

So at this point you can no longer get the display back to this condition? You should use the Video source so you can get better ideas if the working half of the screen is really OK or not. You can also check the Voltages on the T-CON with both cables connected and with just one working cable connected to see what the differences are.

[jasonbay13]

Re: Samsung un40c5000qf black screen - tcon?

So at this point you can no longer get the display back to this condition? You should use the Video source so you can get better ideas if the working half of the screen is really OK or not. You can also check the Voltages on the T-CON with both cables connected and with just one working cable connected to see what the differences are.

no. it seems to be the same as when i started.

[jasonbay13]

Re: Samsung un40c5000qf black screen - tcon?

do you mean the supply voltages at the fuse?

i plugged in my laptop to it and it shows up, though very near the center it started getting discolored, could have been bleed from the white half?

[jasonbay13]

Re: Samsung un40c5000qf black screen - tcon?

i have an update: i got the new t-con just in case since it really wasnt that expensive. no change.

i have checked the voltage at c105 and c102 and at the fuse. the fuse voltage always stays at 12v (while on)
the c102 and c105 voltage with just the working side plugged in is 15.5v on the meter and when both or just the non working side is plugged it goes to 1.5v

[budm]

Re: Samsung un40c5000qf black screen - tcon?

https://www.badcaps.net/forum/attach...4&d=1551019052
It is too bad that there is no Voltage test points names on that T-CON board.
may be look up the spec sheet for the IC300 (LCD bias power supply IC) to get the pin out and the application circuit so you can do Voltage testing that way.

[nomoresonys]

Re: Samsung un40c5000qf black screen - tcon?

Have a real close look at the lvds cable and test it for integrity as mentioned.