This Zycle training bicycle was flashing its status light red. No amount of restarting fixed the problem, eventually it was a simple mechanical fix.

The Zycle is not cheap but looks very sturdy, simple and well built.

After removing the cranks and the plastic covers, measuring the +12V, +5V, VCC (+3V) test points on the main PCB confirmed that all voltages were OK.

On power up I notice a very faint sound an barely noticable vibration of the small motor:

The motor looks to be a stepper motor. I removed the small PCB to find an optical sensor. When I obstructed the optical path, I noticed that the status ligt was going green when powered on. So we are on to something…

I removed the assembly from the bicycle. It consists of a stepper motor, some slidy in/out bit that has two big magnets mounted on the end. The position of the magnets relative to the wheel induce more or less “friction” because of eddy currents.

After loosening the screws and the stepper motor, it was clear that the coupling of the motor and the axle was loose. So the stepper motor was turning, but the axle was not!

The motor pulled off without any effort:

After some cleanup of the motor axle and the grub screw hole, time to re-assemble. Make sure to align the flat part of the motor axle to the hole:

Add some thread locking to the grub screw before fixing the motor axle with it:

Time to mount the motor to the sliding assembly:

After reconnecting the cables and turning the bycicle on, the motor started running and the black lip moved from the right to the left. Arriving at the left (blocking the light path in the sensor), the motor stopped and the status light turned green! Pushing the buttons on the handlebars turns the motor a bit and changes the position of the magnets. Fixed!