Good evening Drigongilbert
I used the Solton MS40 for the ball and tea dances, and unfortunately like you I knew this problem which occurred ... when I did not expect it.in this case, I turned off the module and after a few minutes I put it back on the mains, there the problem was solved.then I bought the XD3 and now I use the Audya 4, a wonder.
As for the French manual of the Ms 40, it is the same as for the MS 50, 60 and 100 keyboards.
I may still have this manual in my old boxes .... and I could send it to you if I find it, having of course your email address (for the contact section) good evening. Jodi