Had a look at this vax tonight, revealed to be knackered arced terminals on the body.
Tested cyclone motor and beater motor with bench power supply and all ok.
If i push cylinder with a bit of man force onto the spine then i get the machine to run ok.
The thumb catch is fine as is the indent that the cylinder locks into on the base.
To be honest i picked it up for next to nowt, was going to refurb and sell on but i dont want any come backs on this one, and in reality i could make more on it for potential spares.
If you want to get to the cyclone motor there's a screw at the back and one hidden under the vax label on the front, flip top off and start/boost pcb / motor are in there.