I got an old Janome 663 machine. The foot pedal seems to have only 2 speeds, full power and stop, no matter how delicately I press it.
Should there be more control in the foot pedal (I would expect that)?
Is something broken in it, or this is how it operates?
I think that you need to take your machine to a sewing machine technician. I've never known of a machine to have a foot controller that only has a fast or stop. As they are on the floor dust gets in and it probably just needs to be cleaned out.
Saskatoon, Saskatchewan Canada Janome 15000, 12000, 4120, 760, 1200D Serger, Huskylock 926, Cover Pro 1000 & a few older sewing machines; my favourite computer games of DigitizerMBX v.4.5 with Cutwork, Floriani Total Control, & EQ7