93 marathon resistor arching at 2nd speed post

[steele]

I installed new board and contacts,new brush. Now when I push pedal on it is dead on 1st speed . I think I seen a small spark from inside resistor case the first time I pushed the pedal. MY real question is Would 1st speed resistor being open cause a bad arching when it goes to the 2nd speed post on the board but not on the others. After looking close at old parts. That 2nd speed post is what fried on original board as well as brush.I carefully watched and ran the brush up and down the board after assembly and brush was tight against each contact .I checked with ohm meter and micro sw goes closed after brush is completely on post. Thanks; Rick