Turntable belt problem Thorens TD 280 MK IV

[EYEREX]

Hello all i was just given my Thorens TD 280 MK IV a spring clean and for some reason the belt won't stay on, it's not slack or anything but for some reason it keeps coming off

Anyone got any ideas as i need to get my 80's Electro vibe on

 

[Sinopa]

A worn belt that is too slack perhaps.

Are you trying it with the platter on? Sometimes these things behave differently when the mass of the platter is missing.

A temp cure that might prove if the belt is worn is to put the belt in boiling water for a few minutes. If it works after that I'd say the belt needs replacing.