RC10Talk - The Net's Largest Vintage R/C Community

I have a few old KO servos at home. Those with the blue wire that goes to the ESC, but not even one seems to work.
May this be because the blue wire has to be connected?
Around early 90' I was too young to spend more than a 100 bucks on a servo, so I used cheap standard ones without this blue wire. so I have no idea.

Any help is appreciated.

the blue wire is supposed to be tied to battery voltage though an inductor isn't it? I don't think they will work without it connected, it is what is used to power the servo drive motor, and the benefit is that the motor gets almost full battery voltage, not 4.8 or 6v.

Thank you guys.
Umm.. it seems that I can only see wether they work or not checking them with a LRP ICS I have. This is the only ESC I have with this blue wire.

Jose' you'll find that the blue wire from the servo can be connected directly to the positive side of the battery. You may need a 'choke' between them though.

Also be aware that early KO servos had the positive and negative wires reversed in the servo plug when compared to Futaba, JR etc systems..

This is fine if you are using an early KO radio/receiver, but if your using Futaba, JR, Hitec or just about any modern RC gear, then you may have to switch these two wires in the servo plug to get them to work....

What is the 'choke'? It looks like a resistor on the scan...

it's an inductor. probably like a 1 microHenry (uH)

Here's a couple of FET servo chokes in their packs, by both Mtronics and Team OzCharge. The Mtronics ones are 4.7uH (micro Henry), but the OZcharge one is unmarked, so will have to get the books out and confirm by the coloured bands.
Hope this helps....

Alex

if I am seeing the colors right it's brown brown orange is 1.1uH (silver band is tolerance)