Originally Posted by
ArchaicArcane
That's not normal at all. In fact, I think the "shorting bars" have been assembled upside down. Someone has definitely been in there playing without knowing what they were doing.
If you look at the copper pieces that are just to the right of the tape in your photos, compare it to the pictures on this page:
http://www.archaicarcane.com/singerattheraces/
They look upside down to me, which might cause them to short unexpectedly, causing someone to put an insulator between them?
After seeing ArchaicArcane's post, I looked at my older controller (which ran much too slow, incidentally).
The copper strips are the shorting bars and are supposed to do nothing (they do not make contact with anything) until the pedal is fully pressed. When you 'floor it', the copper strips touch the metal plate (which is attached to the long screw down the middle), and current flows without resistance along the copper and plate, causing the motor to run at full speed (which it would have done anyway, but the carbon pile would get hot). If you take away that electrical tape, you'll find that yours will make contact and thus run at full speed if you *don't* press it at all, because someone has put it in wrong.
As a side note, I disassembled my rheostat and cleaned every one of the carbon discs as per ArchaicArcane's blog post (although I rubbed the excess carbon onto clean paper, instead of with a pencil eraser) and the foot now works much, much better (thanks). One of the copper strips was also broken, though, and I'll make a new one now I know how it all works.
Mike
EDIT: Oops! Took too long to post. Good you got it all sorted out. I'll leave my post anyway in case someone else finds it helpful (like me, when I forget it in six months).