Jones 1681 and brother xl2620 ?

Hello I don't know if you could help me, but I have two machines and both have broken at the same time. My oldest about 30 years old Jones 1681 has a problem with the bobbin winder and the handwheel. The bobbin winder wont work and the handwheel has to be pushed at the same time as the foot controller is depressed to get it going. Its my best friend so can't send it to the scrap heap. My newer one from Argos Brother XL2620 just lost all power although the light works so theres power getting there. Do you think its just the foot controller? I use these machines every day so please I hope they are not dead!!! I can't afford another one. I would like to learn to strip them down if I could.
Thank you so much for reading this.