Repair X-Sustain Buffer Board P/N: NA18106-5008 for Hitachi 42EDT41A?

I have a Hitachi 42edt4a that develops a 1'' to 1/2'' black bar down the middle of the screen after about 1 hour of operation. The bar happens quicker in a setting where the TV is exposed to more heat, and less ventilation. As opposed to replacing the X-sustain buffer board (P/N: NA18106-5008) completely, is there any way I can demount the heat sinks, replace the thermal grease, and mount a cooling fan into the existing circuitry to fix this problem. I guess what I'm asking is, is this a bad buffer board, or the effect of a board getting too hot and shorting out temporarily? Come on super-scientists, make my day :)