Washing Machine Spinning at Too High a RPM

Hi,

My mom's Kenmore Elite 700 Series (Kenmore elite 796.4219) spin speed is going too high during spin mode. When it first happened, she heard a strange noise, like a buzzing. During wash mode it is fine. I found the manual on scribd and used the test mode to confirm. During the wash rpm test (test 1), it stays within rpm range, but test drain and low spin test (test 2), it just keeps rising in rpm past the rpm range.

In the service manual, I don't see any mention of a rotational speed sensor (it's a direct drive unit). Is it possible it's just a bad board somewhere in the unit? I've replaced the UI board on dryer previously, so I have some experience with that. Or is it possible that it's an issue with the motor? We don't mind having a service rep come out to diagnose the issue, but I'd like a better idea of what it could be before then.

Thanks in advance