"Here, sweetheart, give me something to hammer on it with." Thus spake the ~60-ish helpful dude at the crossroads, upon our mutual discovery that the positive connection had popped plumb off due to not being quite tight enough. "The vice-grips will do."

He's working now, and I got some new terminal clamps (plus jump-start cables, because mine were MISSING) against any UNTOWARD HAPPENINGS.