Samsung no pic

Might help.

Peter Wieck Melrose Park, PA

ound. Power supply has all the normal voltages,. I changed the Tcon board a nd main logic board, still no pic. I have 12v on both sides of fuse on the Tcon board, still no pic, there are three blue led's lit on the Tcon board. i disconnected the ribbons to the panel one side at a time.. nothing. is t he panel bad.???

Unless you bought these boards *brand new* directly from Samsung, you don't know what you're dealing with. Every ebay seller says the board came from a broken screen TV, and that may be true, but a lot of screens are broken when the TV craps and someone throws the remote at it, or simply breaks the screen tossing it on the street or in the recycle pile.

All late model Samsungs are experiencing high failure rates of display scre ens. Depending on configuration, some will run with half the display conne cted and some wont, so splitting the screen doesn't always work as a troubl eshooting method, although it usually does on the older models that don't u sually suffer display failures. Oh, the irony. Check the small brown smd capacitors on the display's address board(s) for shorts. If you find one, you may find a bunch more as they're often massively paralleled. If so, re moving the shorted cap will usually restore normal operation. If there is a bunch wired in parallel, look under a bright light and eye loop for one t hat looks a bit darker than the others. Otherwise, you need to disconnect the ribbons and feed a limited voltage and current into the shorted line an d see which cap is warmer than the others. A bit of freeze spray frost lay er is helpful.

If no shorts are found, the only way to figure this out is with a scope. Y ou need to check LVDS harness from the main for signals going into the TCON and then out to the ribbons at the display. This is the best method but e ven that's not foolproof. Some Sony's won't output a signal to the TCON if the TCON doesn't answer the main board's ping on boot...