Samsung un46d6000sf now has no picture/ no sound backlights are on. had sound, placed tape on ribbons with left improving then when applied to right lost all, removed tape still nothing???

Your pictures IC is bad ir your the board it's self is damage

There have been many posts on this series TV, it's not a bad tcon board making the lamps come on, you have a shorted panel and unhooking the tcon takes the power away from the panel and makes the backlights come on. If you unhook one of the flat ribbon connectors and power the set up it will come on with half a picture, if you hook the ribbon connector back up the set will come on and work like it's supposed to tell you shut it off, but it won't come back on. There are some vids on youtube on using a piece of tape and taping off some of the connectors and the set will work again. Its time consuming finding the right pins to tape off, I've did this on a number of this model set with good luck.

I have the same problem, I mean the exact same sinario. I just ordered and replaced both boards and the cords and ribbon that came with the order and the problem continues. Following

Without getting all technical your LED backlights are bad, the part of unhooking one ribbon cable and not having the repeated cycle would be normal in this model set.

The model(s) that use this T-con board have a history of LED panel failure. If this board does not fix the TV, it's likely that the TV has a bad panel/screen.

If you wish to get some details; check the site linked here. Pull up older posts.
http://electro-medical.blogspot.com/
http://electronicshelponline.blogspot.com/

T-con is not the problem. The main board is.

can be tcon, inverter or main board, have to troubleshoot it, schedule a google helpout, use code paul51p for free helpout.
https://helpouts.google.com/109162147223399593709/ls/b77b1f21705865ca?authuser=0

This guy is an expert! Hope this helps!

I’m happy to help further over the phone at https://www.6ya.com/expert/charles_6bf94c079488b145

Only thing left is the back light control board.

Changing the Correction Tape

1) Move the print carrier to the center of the platen using the SPACE or BS key.

2) To replace the correction tape, lift out the typing ribbon cassette (see Changing The Ribbon Cassette) and remove the two spools of the lift off tape by pulling them outwards.

3) Place the empty spool of new tape on the left pin so that the tape winds clockwise. Place the tape around the left guide. Pull the tape around the right

guide and place the loaded spool on the right pin so that the tape unwinds counter-clockwise.

Note: Make sure the sticky side of the tape is facing the platen.

4) Manually turn the left-hand spool in the clockwise direction, tightening the tape until resistance is felt.

5) Replace the typing ribbon cassette.
6) Press the CODE + = (SETTING) key.

Changing the Ribbon Cassette

1) Move the print carrier to the center of the platen using the SPACE or BS key.

2) Hold the ribbon cassette on both sides and lift up the front portion (where the ribbon is exposed) to remove the cassette.

3) To insert a new cassette, place the back end of the cassette on the cassette

holder on the carrier and gently press down on the front of the cassette unit it clicks into place.

4) Turn the ribbon feed knob counter-clockwise again to take up any slack in the ribbon.
5) Presss the CODE + = (SETTING) key.

Good Luck!