Every now and then my WK-3800 freezes. By that I mean that it keeps on playing the same tempo, rhythm, tone, etc., and is unresponsive to pressing any of the keys or buttons, including the Power button. The only way to get it to function properly again is to unplug the power cord and re-plug it. I suspect that it occurs due to some very short power change (surge or drop). I've tried using a power conditioner, albeit a cheap one, but the problem still occurs once in a while. Has anyone else experienced this? Any thoughts on other possible causes? Solutions? Thanks.