here ya go. try squirting a load of mechanic in a can (gt85) into the cable hole first then try this:-
take off all plastic casings. do not undo anything that looks remotely like a hex bolt. allen keys are ok anything requiring a spanner leave well alone
check all the little springs have the ends in the groves they fit in.
to clean, spray with degreaser, the poor over boiling water, then spray with some sort of oil, gt-85, 3 in one but not wd40 as it has no lube in it.
check with a bit of old cable in the hole under tension
re-assemble and activate smug mode.