This document contains general servo information and frequently asked questions regarding the use and care of Hitec servos. Please note that modifying your servo will void the warranty.

All Hitec servos require 3-5V peak to peak square wave pulse. Pulse duration is from 0.9mS to 2.1mS with 1.5mS as center. The pulse refreshes at 50Hz (20mS).

All Hitec Servos can be operated within a 4.8V-6V. range. Only the HS-50 operates exclusively with 4 Nicad cells ( 4.8 volt ).

All RC servos turn Clockwise direction ( CW ).

1. Servos are rated for Speed and Torque. In many cases, manufacturers  will create one servo and then gear it for speed and sacrifice torque, then create its twin, geared for torque at the sacrifice of speed, i.e. 525/545, 625/645, 925/945.

2. If you are not sure, it is better to have more torque than you need, as torque is your friend.

3. When in doubt ask your peers about servo application questions. Look at what others are using in comparable applications. Usually the kit manufacturer will suggest a servo of a certain physical size and torque value specification in the aircraft, car or boat plans. It is wise to follow their guidelines.

The digital micro processor sends out signals five times faster than analog servos. This results in much quicker response.

There are many more steps in the digital format compared to the conventional analog version. This means the servo is capable of finer adjustments.

The standing torque of the digital servos is 3 times that of the analog counterpart. Check it out, try moving the transmitter stick or wheel and at the same time hold the servo horn to keep it from twisting. You will not be able to prevent the horn from turning.

Hitec is the first servo manufacturer to include metal horns as a standard accessory for our digital servo line. Not just any metal horn but thier own design super horn. Hitec engineers were not satisfied with the traditional plastic or composite servo arms as they would flex and fail long before the servo reaches its maximum torque capability. Just another very unique feature of Hitec digital servos.

Hitec offers gear sets for all our servos and these are available from your local hobby shop or from a mail order retailer. To replace the gears on any servo, carefully lay out the new gears on a clean work surface to have them available for re-assembly. You will also need a supply of servo gear lubricant. We suggest the Hitec lube part # 58450. Loosen or remove the screws located on the bottom of the servo case enough to pop the upper case off and expose the gears. If any gears or shafts are stuck in the upper case, remove them and plug them back into position on the lower case. Now carefully remove the gears while placing them in approximate order on your work surface in front of you. The Hitec AM, model HAS-02MB, HAS-03MB and HP-2RNB receivers are built with a BEC or battery eliminator circuit built into the battery port of the receiver. This will limit the amount of power some of the larger servos can draw from the receiver. It is suggested that using these receivers with large power consumption servos like the HS-805BB, HS-815BB or the high end, premium coreless motor servos and digital servos, a "Y" harness be used to connect the receiver battery / switch harness and servo to the receiver. Typically this is done by connecting one of the upper "Y" connectors to the servo, the other upper connector to the switch harness and the lower "Y" connector

into receiver port 1,2 or 3, depending on what channel you wish the servo to operate. This will allow the BEC to be bypassed, your large servo will always have power and the rest of the servos and the receiver will be powered from the port you plug the "Y" into. Modern coreless and digital servos have impressive torque values. This takes a lot of power. Receivers are capable of delivering only so much power to the servos plugged into it before the voltage draw down caused by the servo power consumption falls below what the receiver requires to "hear" the signal from the transmitter. When this occurs a "glitch" will result from loss of signal to the receiver. Large aircraft can easily use 6 or more powerful servos with some 1/3rd scale planes having multiple servos per control surface. There are several answers to this issue. Many modelers choose to use two receivers and others power the servos with a separate battery from that of the receiver. The point here is to be cautious when "Y" harnessing or "ganging" powerful servos together. Using larger capacity Nicad batteries as well as Heavy Duty switch harnesses are highly recommended in these applications. Use only specially designated servo grease when replacing servo gears. Using other type of grease not intended for servo gears may produce gas when used in sealed cases which may coat a nasty film on the motor brush that could stop the servo operation. We would like to strongly discourage you from ever working on the coreless motors. Unlike conventional cored motors, the brush base of the coreless motors is extremely fragile and can be easily separated from the Printed Circuit Board. This is best left to authorized service technicians with the proper equipment.

Too Many Servos

Servo Grease

Coreless Motor Care