My yamaha RX-V596 receiver refuses to disply any video signal on my TV. No matter what source I select, DVD, VCR or computer, there is only audio signal output. No video or s-video signal at all. It worked flawlessly before untill a rainy day with thunder storm. Could it be lightening shock? The manual says the micro-computer could be frozen after a electrical shock. So I tried the solution for the stated problem, but no use at all. Anybody can give me any hints on this problem? Many thanks.