Hey guys i got this new old stock wm-f18 recently and im having an issue where the speed of the motor keeps changing by it self, when im listening to a cassette it would sound normal and slowly it would slow down (not too much but its noticable) and after a while it would go back to sounding normal. Anyone has come across this before and can give me a tip on how i can fix it. (Ive tried 2 different belts 1 thick and 1 thin) i found one capacator that was leaky so i replaced it but the problem is still there. it was working mint for maybe a week and then all of a sudden it started playing up and i think its called fluttering. any help appreciated