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DS390 Digital Precision Micro Metal Gear Servo

Key Features

  • Thin and lightweight
  • Ultra-precision electronics
  • Class-lleading torque and speed
  • Ideal for performance electrics, sailplanes and pylon models
  • Durable metal gear train

Overview

The DS390 digital precison micro metal gear servo offers class-leading holding torque, zero deadband and the legendary high resolution of JR® servos in a package that's ideal for high-performance sailplanes and electrics. By re-engineering certain internal components, the JR brand has improved upon the precision of the previous generation DS388 servo to give the DS390 servo the performance advantage JR customers demand.

Bearing: Dual
Bushing Or Bearing: Bearing
Gear Type: Metal
Servo Type: Digital
Servo Voltage: 4.8–6.0V
Speed: 0.16 sec/60 deg @ 4.8V; 0.13 sec/60 deg @ 6.0V
Torque: 60 oz-in (4.3 kg-cm) @ 4.8V; 75 oz-in (5.4 kg-cm) @ 6.0V

FAQs

What's the difference between digital and analog servos?

Digital and analog servos have very similar construction and components. They both use the same type of motors, gears, cases, and have a potentiometer. A digital servo is different in the way it processes the incoming signal and converts that signal into servo movement. 

An analog servo when it receives a command to move, takes that signal and sends pulses to the servo motor at about 50 cycles per second, which in turn moves the motor to its required position determined by the potentiometer.

A digital servo has a micro-processor that receives the signal and then adjusts the pulse length and amount of power to the servo motor to achieve optimum servo performance and precision. A digital servo sends these pulses to the motor at a much higher frequency which is around 300 cycles per second. This helps eliminate deadband, provides a faster response to the servo motor, smoother motor movement, and has higher resolution and holding power than an analog servo.

There are some disadvantages to digital servos, but the disadvantages are not in any way close to out weighing the advantages. A digital servo will have a higher power consumption (Around 10 to 15 mAh per servo at idle) than an analog servo due to its higher pulse frequency, so larger capacity battery packs are recommended. Digital servos also are more expensive than analog servos which can get very costly in applications that require many servos.

What grease should I use on my servo gear train?

For JR servos we recommend Tamiya ceramic grease (TAM87025).

Why doesn't my servo center properly?

There are several scenarios which may attribute to this problem. 

1. The servo arm fit on the output spline may be loose.

2. There may be slop or wear in the gear train.

3. There may be slop or binding in the linkages.

4. You may have a faulty servo saver.

5 The push rods may be too flexible.

6. Improperly mounted servo (screws too tight, mounting rail too tight against the servo)

7. Faulty extention, damaged lead or dirty connector.

8. Worn or dirty pot.

Can I use a JR servo with a Futaba receiver?

Yes

Why can't you use the JR 8700G servo with FM?

The frequency on operation is so high that it feeds back with FM receivers.

Product Support Tips

Product Support

Technical questions about this JR product should be directed to JR AMERICAS Support Department:

Horizon Hobby, LLC no longer provides service for JR products. For service needs please contact JR AMERICAS at 217-352-7959 or by email at customerservice@jramericas.com

Sales Support

If you would like to purchase this product, please go to the Store Locator or contact the Horizon Hobby Consumer Sales Department:

Horizon Hobby, LLC.
ATTN: Consumer Sales

4105 Fieldstone Road
Champaign, IL 61822
Email: Sales Phone:(800) 338-4639
Fax:(217) 355-1552