"Martik" wrote in message
news:jeIHd.36644$06.34415@clgrps12...
Posted here a while ago broken speed control: Well they sent me a new
one - no charge! but the damn thing still won't work. The motor just hums
in
all positions of the control. I measured 100VDC going to 2 of the 4 wires
to
the motor. The motor bearings and brushes look good. Any ideas what
further
diagnosis I could pursue?



There's 4 wires to the motor? I had assumed the brushes would be in series
with the field coil, you need voltage to both pairs of wires for the motor
to run.