My Tecra S1 suddenly stopped booting, and I was getting the Beep codes 2short 1 long, followed by 3 short. I mamaged to obtain a used board on E-Bay, that was advertised as working. Swapped out the boards, and now, the CPU fan spins up, HDD spins up, and DVD drive operates, but I have no display output, either from the Monitor, or the External Monitor connection. Before I either give up or source another board, could there be any other cause to this, such as a failed CPU, although I am suspecting the GPU.