This machine suddenly started going at full speed only. I looked inside the foot control and there were signs of charring on the coil where the contacts touched it and no continuity measured on meter across it. Got replacement universal foot control, wired this in as per instructions, but same problem. Foot control supplier tested the control and found no fault. Any suggestions? Are these foot controls variable resistance or varaible transformers? I have had a suggestion that a capacitor inside the machine has burnt out, but v. hard to get in there to check. Is there any test I can do from outside?

Peter, July 2009

Thanks. It is very difficult to actually get this capacitor out, as it is attached to the motor, which is not accessible without significantly dismantling the machine, but I have been able to cut the two leads coming out of it. I hoped that it was wired across the motor to reduce rf interference, and so not vital to the operation. However, when plugged back in, the motor still goes full speed, whatever the depression of the foot control (the old Elna foot control). Any other suggestions?

Peter, July 2009

Hello Peter,
It will definitely be a capacitor and if it is not in the foot control it will be either inside the motor or alongside the motor and you will need to take it out, if it is wired into the motor you may need to wire a new one in.

drivewithken, July 2009