Probs dust in the switch they tend to with age i just take the cover off clean the contacts put it back together and it's good as the day it was purchased
some cool machines there!😁 WOW the yellow NRV's cable is well long!🤣🤣 Btw I've got a few spare hose cuffs knocking around if you wanna swap one for the one off of the RSV, save you having to get a brand new one (I'll drop ya a message on insta)