KO PS-87Z fet servo
 

last time i ran one of these (many years ago) a choke had to be fitted in the power lead between the speedo and the fet box,does anyone know the value of the choke`s and where i can get some?.

the servo that you mean is these? between the speedo and the fet box it is nothing.I have PS-87 and PS-88Z.

i have a ps87z and a ps302 both with the seperate fet box, and am pretty sure that if they were run without a `choke` in the power lead, then there was a good chance of interference from the speedo. i have found one now and will try the servo with and without the choke to see what happens.

there were problems with interference generated by the pulses caused by the speed control drive frequency if i remember correctly, was worse with certain speed controls, especially the ones of the era that sported 'regenerative' braking. even modern 4 wire fet servo's still require a choke and they are quite cheap and easy to come by, nick adams at demon products will help you out if you have any trouble getting them. i have 2 ps87 still in cars and both going strong, not quite as fast as the modern ones but they still work after all these years, will the modern ones!

anyone got one for sale? i would like to own one :)