tl;dr: Can a non-responsive touch-key be mended?
I purchased a purportedly "new" MP Original from a private seller (as well as a new MP Mini from the official store). On the Original, when connected to USB, it displays "Welcome [...] Touch a lit key to begin!" and at this point all six keys are lit blue and it will move to the next screen if I touch on any of the four quadrant keys or the left-hand key, but not the right-hand key. After proceeding to the next screen, which says "Touch accept to continue..." I can't make it continue any further because touches on the right-hand key do nothing. The blue light is lit but doesn't go off when I put my finger on it, unlike the left key where the light does go off when I put my finger on it.
Is this a known failure mode with some Originals? Is there any way I might be able to fix it? Or am I perhaps just doing something wrong? (I have not used one before.)
Thanks,
- Julian