Samsung sp42w5hfx rear projection tv

You have a problem with the STK convergence modules. They're on the center circuit board attached to an aluminum heat sink that's about 8" long and 6" tall. You may be able to recreate the problem (hour glass effect) by gently moving the heat sink (which the modules are connected to). This gives the hour glass effect on the picture and the advanced convergence screen. This is an indication that the modules pins aren't solidly connected (meaning soldered) properly. Remove the circuit board and clean the old solder off & resolder the modules pins to the circuit board reconnected the board and then retest by again pushing on the heat sink. The "factory" job was good enough for 3-4 years but the heat (and these modules do create a lot of heat) and stress created from repeated use eventually takes it's toll, weakens the pin connections and our problem occurs. take the appropriate cautions working around the high voltage of the set & use a non-conducting piece of wood to push the heat sink when doing tests.
If soldering doesn't help, then the modules have died and need replacing. Don't buy the $10 cheap ones. Most of them have an upgraded version that is stronger. Also look for any burned resistors in the vicinity of the modules.
Best of luck, hope ya fix it.