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View Full Version : KO PS-87Z fet servo


brian s
25-01-2011, 08:03 PM
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?.

lllyf
28-01-2011, 05:34 AM
the servo that you mean is these? between the speedo and the fet box it is nothing.I have PS-87 and PS-88Z.

brian s
31-01-2011, 09:12 PM
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.

dodgydiy
31-01-2011, 09:23 PM
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!

93works
03-02-2011, 11:48 PM
anyone got one for sale? i would like to own one :)