The other thing I should have mentioned: The wiring insulation typically doesn't melt on its own, unless it's been sitting in a shed in Arizona. What I've found on the three machines I acquired that had these dreaded black streaks is that all of them had been over-oiled, and in one case actually had oil dumped directly into the brush tubes. Needless to say that's bad news
When someone over-oils a machine, that oil can get onto the wiring insulation, and over time the combination melts the wiring insulation and makes a real mess.
Now I know that when I see the black streaks, the machine's motor in particular may have been ruined due to someone improperly oiling it.
Last edited by Vintage.Singers.NYC; 09-16-2012 at 10:55 AM.