Hi Beaky:

Is the problem the same with both keyboards? I'm assuming you have identical MICs hooked to each S910. Could be just a warm-up problem (don't know if there may be a trim-pot to adjust on the motherboard) but if you have already paid for the extended warranty, sounds like a good idea to have it checked out. If you think about it, when the smoke and dust have cleared away on this problem, please let us know what you found out... or the final result. Good luck!

Dave Rice