This has been a very informative thread!
I just want to assure you, Sheri, taking the tensioner apart, cleaning it and then putting it back in again will be a confidence booster.
I'm from a generation of Home Ec students that grew up thinking it was against the law to so much as 'think' of touching that tension dial!!!!! Lol God bless our Home Ec teachers. It must have been a nightmare to have to adjust the tension on all those machines after every class.
Anyway, once you have done a couple of them you will see that they aren't so scary after all. I take pictures as I take each piece off and lay the pieces out, in order, in an egg carton so they don't get lost or mixed up. Good luck!