I mean, Doc brown did tell Marty the neccessary parts to repair wouldn't be invented until the 1950's at the start of the film, but maybe he just gave up too quickly because he enjoyed living in the past? Mrs. Clara and her desire for adventure could well have encouraged him to give it another go.
There is one little problem though. The tme machine could only be repaired in the 1950's because the time curcuits were powered by Mr. Fusion which was still working. How did the doc generate the 1.21 gigawatts neccessary to power the time circuit in the train? Not with steam power!
ztc - 2009-12-15 Is there any other kind of dwarf?
Charles - 2009-12-19 I was ready to mark this down for that bullshit editing but now I'm genuinely disturbed by this perverse little albino dwarf-child with downs and a libido like a goddamned panther.
ez - 2010-04-19 So with this and Teen Wolf, you have 2 movies involving Michael J. Fox in which at the very end there is something weird going on in the background with somebody's crotch...