Thanks
I had picked that figure up,and will probably try both 470 ohm and 560 ohm. My supply is a nominal 9volt, but it uses Pulse width Modulation, so the requirements may be different to that from a standard DC, smoothed or unsmoothed supply. There is some suggestion that a zener diode may be more effective, but again I would need to know the wattage required. For this it will be useful to know the resistance and current draw of the Portram motor.
Ron