Massey 5S pto

[Bloders]

Hello
Got a massey 5S.135
Today it's started dropping out of pto all the while especially when loaded a bit
Watching the pto speed and it is fluctuating, including above the set speed. I think therefore the speed sensor is dud. It cannot be slipping as the speed indicated goes above set speed?

Can anyone confirm my diagnosis before I get the wallet out please
And also confirm it's plugged in right at the back, reading the notches on the pto shaft?

Thank you

 

[Timbo]

Pull sensor out n check for anything stuck to rhe end of it- they are magnetic check the plug n pins. Otherwise likely sensor dying.