THIS!!!!! If there is no support during the warranty period then send the keyboard back and get a non-Korg keyboard. I purchased my Kurzweil back in 2011 and Jean (technical) from Kurzweil will usually respond within 24 hours with questions to this day. World class support......
The sad thing Dave is that the customer support varies considerably.
I have repeatedly seen Korg USA being abysmal with no support at all.
Yet here in the UK I have had top class support and Saulo of Korg Italy has been great.
Yet others in the EU have also received none or poor service from Korg.
What is the answer?
Buy from a local dealer who knows the product if at all possible, there is one near me who offers lifetime support and help foc on all keyboards bought from them.
In the case of this SV the Op should still test out the keyboard with a tuner app to determine the extent of the problem.