This set started having problems with tiling when cold, going green with patterns of lines, and other patterns of distorted images. It would clear up when run for a couple of hours. At the time, the digital board was on backorder, and in order to get the client up and running, I pulled the digital board from my personal set and installed it. This worked, assuring me that the digital board was the problem. I transferred the bad board to my set, and it had the same issues. After using it a while longer, it began having other symptoms, including locking up with no pix and turning off. Eventually, the set would start the lamp, never have any video nor any sound, then shut down after about a minute. It remained that way for a couple of months while I waited on a board.
Along the way, I have heard from a couple of sites, including Jason1976 here, that the problem may be connections on the DNIE chip on the digital board, near the DVI connector at the back side of the board. Apparently people were having success applying pressure to this chip. It is a BGA type (Ball Grid Array) that has pins underneath that contact points on the board. This is becoming common with high density ICs where external pin connections require larger size chips, tighter spacing, and geometries that are not efficient for the design of the chip. There are good reasons to use BGA, but they can be difficult to solder properly. Apparently, Samsung has had some issues with this chip.
One solution is to try to re-flow the slder. I don't suggest this for anyone without the right equipment. It is very easy to heat the wrong parts or overheat the chip, board, or related parts.
So I decided to experiment. I received the new board that had been on backorder, but figured I would play with the bad one as an experiment. The board is encased in a metal housing with holes. I looked in my shop for something that might fit between the chip and housing to put some pressure on the chip. I found a small bolt that happened to be just a litte too long to fit between the chip and the metal housing above it. I fitted it in, then pushed the edges of the housing down to where I could put the screws holding it all together back in. There was significant tension on the bolt, with the larger hex head end standing on the chip and the tip of the screw fitting against the metal housing (bolt standing on its head on top of the chip). It took a little pressure to get the screws back in, which was good, as it used the housing like a large spring pushing down on the bolt, which put a great deal of pressure on the chip. Simple solution if this is the problem.
The result is that the set fired up the first time and has run fine since. I don't know how long it will work, but I will run it and see. I have the other board, if anyone needs one. Keeping it will cost me an extra $50 on top of its cost, as it does have a core value and we normally send them back for credit. It will be worth it to have a new board on hand if my solution fails, or if another client needs one.
The part number for the digital board for this set is BP94-02084A. This is for the HLR6167WAX/XAA, L64C chassis type. You need to verify all of the suffixes on the service model and the chassis number to get the right board for Samsung sets, particularly these. There were many production changes and versions of these sets and some differences in the boards. Some even reportedly need to have the analog and digital boards changed together for some reason, but this one does not.
onder:chip. Without that nasty DNIE processing. 
