Sanwa Gemini X User manual

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Packaging
The packaging of your Sanwa Gemini X 2.4GHz FHSS-3 radio control system has been specially designed for the safe
transportation and storage of the radio control system's components. After unpacking your radio control system, do not discard
the packaging materials. Save the packaging materials for future use if you ever need to send your radio control system to us
for service, or to store your radio control system if you don't plan on using it for an extended period of time.
TaBLE OF cOnTEnTS
Introduction ......................................................................................................................................................................... Page 3
Safety ............................................................................................................................................................................. Page 3
FCC Compliance Statement ........................................................................................................................................ Page 3
Usage Precautions ............................................................................................................................................................. Page 4
2.4GHz Frequency Band Precautions ......................................................................................................................... Page 4
Transmitter Precautions .............................................................................................................................................. Page 4
Receiver Precautions ................................................................................................................................................... Page 4
Features and Specications .............................................................................................................................................. Page 5
System Features ........................................................................................................................................................... Page 5
System Specications ................................................................................................................................................. Page 5
Servo Recommendations ............................................................................................................................................ Page 5
Features Familiarization .................................................................................................................................................... Page 6
Servo Connectors ......................................................................................................................................................... Page 6
Transmitter Features Diagrams ................................................................................................................................... Page 6
Receiver Features Diagram ......................................................................................................................................... Page 7
Optional Items ............................................................................................................................................................... Page 7
Features Descriptions .................................................................................................................................................. Page 7
Control Stick Spring Tension Adjustment .................................................................................................................. Page 8
Transmitter and Receiver Battery Options ................................................................................................................. Page 9
Transmitter Battery Installation ................................................................................................................................... Page 9
Receiver Connections and Mounting ....................................................................................................................... Page 10
Using Li-Po or Li-Fe Batteries ................................................................................................................................... Page 10
LCD and Programming Keys ............................................................................................................................................Page 11
Multi-Function LCD Overview.................................................................................................................................... Page 12
Programming Key Functions .................................................................................................................................... Page 12
Programming Key Shortcuts ..................................................................................................................................... Page 13
Menu Flow Chart ............................................................................................................................................................... Page 13
Setup Menu ................................................................................................................................................................. Page 13
Programming Menu .................................................................................................................................................... Page 13
Transmitter and Receiver Binding .................................................................................................................................. Page 14
Programming Menu .......................................................................................................................................................... Page 15
Steering Dual Rate ...................................................................................................................................................... Page 15
End Point Adjustment ................................................................................................................................................ Page 16
Exponential ................................................................................................................................................................. Page 19
Servo Speed ................................................................................................................................................................ Page 20
Auxiliary Programming .............................................................................................................................................. Page 22
Fail Safe ....................................................................................................................................................................... Page 32
Servo Sub-Trim ........................................................................................................................................................... Page 34
Servo Reversing ......................................................................................................................................................... Page 36
Model Select ................................................................................................................................................................ Page 37
Setup Menu ....................................................................................................................................................................... Page 38
Modulation Type ......................................................................................................................................................... Page 38
Binding ........................................................................................................................................................................ Page 39
Trim Switch Assign .................................................................................................................................................... Page 40
Trim Step Resolution .................................................................................................................................................. Page 41
Model Naming ............................................................................................................................................................. Page 42
Model Clear ................................................................................................................................................................. Page 44
Audible Key Tone ....................................................................................................................................................... Page 44
Inactivity Alarm ........................................................................................................................................................... Page 45
Battery Cell Count ...................................................................................................................................................... Page 45
Troubleshooting Guide .................................................................................................................................................... Page 47
Glossary of Terms ............................................................................................................................................................ Page 48
Index .................................................................................................................................................................................. Page 51
Notes.................................................................................................................................................................................. Page 55

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inTRODUcTiOn
We appreciate your purchase of the new Sanwa Gemini X 2.4GHz FHSS-3 radio control system. This Operating Manual is
intended to acquaint you with the many unique features of your state of the art radio control system. Please read this operating
manual carefully so that you may obtain maximum success and enjoyment from the operation of your new radio control system.
The Gemini X 2.4GHz FHSS-3 radio control system has been designed for the utmost in comfort and precise control of all types
of model cars and boats. We wish you the best of success and fun with your new purchase.
Additional 2.4GHz receivers can be purchased and paired with the Gemini X transmitter through the Binding operation.
Please note that due to differences in the implementation of 2.4GHz technology among different manufacturers, only
Sanwa and Airtronics brand 2.4GHz FHSS-2 and FHSS-3 surface receivers are compatible with your radio control system.
Please see your local Sanwa or Airtronics dealer for more information.
Fcc cOMPLiancE STaTEMEnT
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC
Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This
equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the operating
instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not
occur in a particular installation.
If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the
equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:
l Reorient or relocate the receiving antenna.
l Increase the separation between the equipment and the receiver.
l Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
l Consult the dealer or an experienced technician for help.
This device complies with Part 15 of the FCC Rules and with RSS-210 of Industry Canada. Operation is subject to the following
two conditions:
1) This device may not cause harmful interference, and....
2) This device must accept any interference received, including interference that may cause undesired operation.
 Changes or modications made to this equipment not expressly approved by Airtronics may void the FCC authorization
to operate this equipment.
RF Exposure Statement
This transmitter has been tested and meets the FCC RF exposure guidelines when used with the Airtronics accessories supplied
or designated for this product, and provided at least 20cm separation between the antenna the user's body is maintained. Use of
other accessories may not ensure compliance with FCC RF exposure guidelines.
l Be certain to read this Operating Manual in its entirety.
l 'Safety First' for yourself, for others, and for your equipment.
l Observe all the rules of the eld, track, or lake where you
operate your radio control equipment.
l If at any time during the operation of your model, should
you feel or observe erratic operation or abnormality, end
your operation as quickly and safely as possible. DO NOT
operate your model again until you are certain the problem
has been corrected. TAKE NO CHANCES.
l Your model can cause serious damage or injury, so please
use caution and courtesy at all times.
l Do not expose the radio control system to water or excessive
moisture.
l Please waterproof the receiver and servos by placing them
in a water-tight radio box when operating R/C model boats.
l If you have little to no experience operating R/C models, we
strongly recommend you seek the assistance of experienced
modelers or your local hobby shop for guidance.
l The Low Voltage Alarm will sound when the transmitter
battery voltage drops to the minimum threshold. If this
occurs, stop using the transmitter as soon as possible,
then replace or recharge the transmitter battery.
SaFETY
This radio control system operates on the 2.4GHz frequency band. The 2.4GHz connection is determined by the transmitter
and receiver pair. Unlike ordinary crystal-based systems, your model can be used without frequency control.
This is a high-output full-range radio control system that should well exceed the range needed for any surface model. For
safety, the user should perform a range test at the area of operation to ensure that the radio control system has complete
control of the model a the farthest reaches of the operational area. Rather than operating the model, we recommend that the user
enlist the help of a fellow modeler to walk the model to the farthest reaches of the track (or for boats, to walk the shore line well in
excess of the operational distance of the boat), then test for proper operation.


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USagE PREcaUTiOnS
In addition to the Safety and FCC Compliance sections on the previous page, please observe the following precautions when
installing and using your new Sanwa Gemini X 2.4GHz FHSS-3 radio control system.
l The receiver antenna consists of a coaxial cable and a reception wire (the thin tip at the end of the coaxial cable). When you
mount the receiver antenna, do not bend the reception wire. Reception performance decreases if the reception wire is bent.
l The antenna wire is delicate, therefore, handle with care. Do not pull on the antenna wire with force.
Do not cut or extend the antenna wire.
l The coaxial cable (the thicker portion or the antenna) can be bent into gentle curves, however, do not
bend the coaxial cable acutely, or repeatedly bend it, or the antenna core can be damaged.
l The antenna wire should be installed into a vertical plastic tube per your particular model's assembly
instructions. Keep the receiver antenna as far away from the motor, battery, and ESC as possible.
l There is a danger of runaway operation if connectors shake loose during use. Make sure that the receiver,
servo(s), and switch connectors are securely tted.
l The receiver is susceptible to vibration, shock, and moisture. Take appropriate measures to protect against
vibration and moisture. Failure to take appropriate measures could result in runaway operation or damage to
the receiver. We suggest wrapping the receiver in shock-absorbing foam when installing it into your model.
l When installing the receiver, avoid contact with any carbon or metal chassis components.
l Contact between metal parts mounted on a model can result in electrical noise, which can adversely effect
receiver performance and possibly result in runaway operation or damage to your model.
l With electric-powered models, be sure to t the motor with a noise suppression capacitor. Without a noise suppression
capacitor, excessive electrical noise generation can cause runaway operation and/or result in damage to your model.
l Use rubber anti-vibration absorbers with servos. Direct transmission of engine vibration to servos can cause servo failure and
possibly result in runaway operation with damage to your model.
REcEivER PREcaUTiOnS
2.4gHz FREqUEncY BanD PREcaUTiOnS
l The 2.4GHz frequency band may be used by other devices, or other devices in the immediate area may cause interference on
the same frequency band. Always before use, conduct a bench test to ensure that the servos operate properly. Also, conduct
checks with the transmitter as distant as possible from your model.
l The response speed of the receiver can be affected if used where multiple 2.4GHz radio controllers are being used, therefore,
carefully check the area before use. Also, if response seems slow during use, stop your model immediately and discontinue use.
l If the 2.4GHz frequency band is saturated (too many radio controllers on at once), as a safety precaution, the radio control
system may not bind. This ensures that your radio control system does not get hit by interference. Once the frequencies have
been cleared, or the saturation level has dropped, your radio control system should be able to bind without any problems.
TRanSMiTTER PREcaUTiOnS
l Turn the transmitter ON rst and then turn the receiver ON. After using your model,
turn the receiver OFF rst, then turn the transmitter OFF. It can be dangerous if you
activate the components in reverse order as the servos may start up inadvertently.
l Before use, double-check that the transmitter and receiver batteries have sufcient
power.
l Never touch the transmitter antenna during use. Doing so may cause loss of transmitter output, resulting in loss of signal.
l The transmitter antenna should be rotated and angled so that the antenna is as close to perpendicular to the ground as
possible during use. After use, to prevent any chance of damaging the antenna, the antenna should be rotated and moved into
the horizontal stowed position.
l Do not expose the transmitter or any other components to excessive heat, moisture, fuel, exhaust
residue, etc.
l Do not press the Bind Button during use. The signal is interrupted while the Bind Button is pressed. It may
also require a short time to restore the signal after releasing the Bind Button, which can be dangerous.
l If the outer case becomes dirty, it can be cleaned with a soft dry cloth. If the outer case becomes soiled, it can be cleaned with
a damp cloth and liquid detergent. Do not use any solvents to clean the outer case. Solvents will damage the nish.
Antenna Tube
Coaxial Cable
Antenna
Reception Wire

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FEaTURES anD SPEciFicaTiOnS
SYSTEM FEaTURES
SYSTEM SPEciFicaTiOnS
l 3-Channel 2-Stick 2.4GHz Computer Radio with Advanced Programming for Competition Cars, Trucks, and Boats
l Compatible with All Current Sanwa and Airtronics 2.4GHz FHSS-3 and FHSS-2 Surface Receivers
l High-Power FHSS-3 Technology Provides the Best Reception and Connectivity, Giving Racers Added Assurance
l 4 Cell Dry Cell Battery for Lighter Weight - Also Accepts 2 Cell Li-Po or Li-Fe
Transmitter
Model: Gemini X
Output Power: 100mW
Nominal Input Voltage: 4.8v ~ 7.4v
Power Supply: 4 Cell 'AA' Alkaline/Ni-Cd/Ni-MH*
Weight: 632gr (with 4 Cell 'AA' Alkalines)
Frequency: 2.4GHz FHSS-3
Receiver
Model: RX-451 (92744)
Frequency: 2.4GHz FHSS-3
Nominal Input Voltage: 4.8v ~ 7.4v
Weight: 0.3oz (8.5gr)
Dimensions: 1.43 x 0.94 x 0.59in (36.5 x 24.0 x 15.0mm)
Fail Safe Limit: 3.8v Default / 3.5v ~ 5.0v Adjustable
Both analog and digital servos will work with your Gemini X 2.4GHz FHSS-3 radio control system. To get the most out of
your experience, we recommend the use of digital servos.
l Model Naming
l Model Select
l Model Clear
l Servo Sub-Trim
l Modulation Type (FH2/FH3/FH3F/DS2)
l Audible Key Tone
l Low Voltage and Inactivity Alarms
l Battery Type Selectable (4 Cell or 6 Cell)
l Battery Voltage Monitor
l 18 Model Memory
l Servo Reversing
l Steering Dual Rate
l End Point Adjustment
l Exponential
l Adjustable Servo Speed
l Four Wheel Steering Mixing
l Dual Throttle Mixing w/Dig & Burn
l Brake Mixing with Brake Hold
l Auxiliary Channel 3 ON-OFF
l Step Auxiliary
l Point Auxiliary
l Auxiliary Mixing (ST>CH3, TH>CH3)
l Programmable Fail Safe
l Receiver Battery Voltage Fail Safe
l Digital Trims
l Programmable Trim Switch
l Adjustable Control Stick Tension
Although most current brand servos will work with your Gemini X 2.4GHz FHSS-3 radio control system, we recommend using
Sanwa and Airtronics brand servos. For pricing, availability, and more selection, please visit your local Sanwa or Airtronics dealer
or our website at http://www.sanwa-denshi.co.jp or http://www.airtronics.net.
SERvO REcOMMEnDaTiOnS
Torque: 225oz/in (16.2kg/cm @ 6.0v)
285oz/in (20.5kg/cm @ 7.4v)
Speed: 0.12 sec/60º @ 6.0v
0.10 sec/60º @ 7.4v
Dimensions: 1.59 x 0.83 x 1.50in
(40.5 x 21.0 x 38mm)
Weight: 2.22oz (63gr)
Torque: 50oz/in (3.6kg/cm @ 4.8v)
61oz/in (4.4kg/cm @ 6.0v)
Speed: 0.17 sec/60º @ 4.8v
0.14 sec/60º @ 6.0v
Dimensions: 1.54 x 0.79 x 1.42in
(39.1 x 20.0 x 36.0mm)
Weight: 1.55oz (43.9gr)

Torque: 361oz/in (26.0kg/cm @ 4.8v)
423oz/in (30.5kg/cm @ 6.0v)
Speed: 0.19 sec/60º @ 4.8v
0.15 sec/60º @ 6.0v
Dimensions: 1.60 x 0.83 x 1.50in
(40.6 x 21.1 x 38.1mm)
Weight: 2.33oz (66gr)


Torque: 124oz/in (8.9kg/cm @ 4.8v)
151oz/in (10.9kg/cm @ 6.0v)
Speed: 0.17 sec/60º @ 4.8v
0.13 sec/60º @ 6.0v
Dimensions: 1.54 x 0.78 x 1.50in
(39.0 x 20.0 x 37.4mm)
Weight: 1.93oz (56gr)

*For additional battery options, see page 9.


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FEaTURES FaMiLiaRizaTiOn
Antenna
Power Indicator
Light
Auxiliary Switch
(Channel 3)
Multi-Function
LCD
FROnT
Power Switch
TRanSMiTTER FEaTURES DiagRaMS
Use the diagrams below to familiarize yourself with the basic features of your Gemini X 2.4GHz FHSS-3 transmitter. Descriptions
of these features can be found on pages 7 and 8.
The transmitter antenna is adjustable. It should be adjusted so that when you're holding the transmitter during use, the
antenna is orientated as close to perpendicular to the ground as possible at all times. This provides the best signal between
the transmitter and the receiver. You should never point the antenna directly at your model, as this results in a weakened signal.
Throttle
Control Stick Steering
Control Stick
Throttle
Trim Switch
Steering
Trim Switch
Neck Strap Anchor
Programmable
Trim Switch
Programming Keys
Handle
Programming
Toggle Switch
Programming
Toggle Switch
The RX-451 4-Channel receiver included with your Gemini X 2.4GHz FHSS-3 radio control system uses universal 'Z' connectors
which are electronically compatible with the servos of other radio control system manufacturers. The connectors are rugged, but
should be handled with care.
When unplugging the servo connector, it's best not to pull on the servo
wire itself. This could result in damage to the servo wire pins in the plastic
plug. Always grasp the plastic connector itself.
SERvO cOnnEcTORS
- = Negative (Black)
+ = Positive (Red)
S = Signal (Blue)

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FEaTURES FaMiLiaRizaTiOn
Back
Use the diagram at right to familiarize yourself with
the RX-451 4-Channel receiver included with your
Gemini X 2.4GHz FHSS-3 radio control system.
Descriptions of these features can be found below
and continued on page 8.
REcEivER FEaTURES DiagRaM
Bind Button
Bind LED Coaxial Cable
Antenna
Reception Wire
Batt
Auxiliary 2 CH 4 (Not Used)
Auxiliary 1 CH 3
Throttle CH 2
Steering CH 1
= Signal = Positive = Negative
OPTiOnaL iTEMS
The following optional items (available separately) can be used with your Gemini X 2.4GHz FHSS-3 radio control system.
For pricing and availability, please visit your local Sanwa or Airtronics dealer or our website at http://www.sanwa-denshi.co.jp or
http://www.airtronics.net.
99103 Adjustable Neck Strap 92451 Sanwa RX-451R SSR FHSS-3 Receiver
TRanSMiTTER FEaTURES DiagRaMS, cOnTinUED....
Battery
Compartment
Programming
Toggle Switch
Programming
Toggle Switch
Charging Jack
 Transmits the signal from the transmitter to the receiver in the model. The Antenna should be pivoted into the vertical
position during use. When not in use, the Antenna should be collapsed into the horizontal position to prevent damage during
handling and transport.
 The portion of the antenna that receives the transmitter signal. The Antenna Reception Wire should
never be bent or it could be damaged and limit the range of your model.
FEaTURES DEScRiPTiOnS


Page 8
 The Auxiliary Switch controls different options, depending on your programming preferences. In
the default conguration, the Auxiliary Switch controls Auxiliary Channel 3. In addition, the Auxiliary Switch is used to program
and control the different Mixes that are available.
 Houses the 4 'AA' Alkaline cells that power the transmitter.
 Used in the process of Binding the transmitter and receiver.
 Used for onboard charging of the optional Ni-Cd or Ni-MH batteries. For more information, see page 9.
 The portion of the antenna that extends the Antenna Reception Wire. The Coaxial Cable can be bent into gentle
curves, however, do not bend the Coaxial Cable acutely, or repeatedly bend it, or the antenna core can be damaged. The Coaxial
Cable should be installed through a nylon tube (antenna tube) in the vertical position for the best reception.
 The Handle provides a comfortable way to carry your transmitter. It also provides a comfortable angle to program the
transmitter when the transmitter is laid on its back on a at surface.
 The heart of the programming and display features of the transmitter. All programming and transmitter
display functions are shown on the Multi-Function LCD.
 Used to attach your neck strap (available separately) to the transmitter.
 Flashes slowly when the transmitter is turned ON and transmitting a signal. Flashes in rapid succession
indicating that Mixing is Active. The Power Indicator Light is also used during the Binding process.
 Turns the transmitter ON and OFF.
 Controls the steering function of your model. The Steering Control Stick spring tension is adjustable to
suit your preference. For more information, see the Control Stick Spring Tension Adjustment section below.
 Used to adjust the center trim of the steering servo.
 Controls the Throttle and Brake (if equipped) functions of your model. The Throttle Control Stick spring
tension is adjustable to suit your preference. For more information, see the Control Stick Spring Tension Adjustment section below.
 Used to adjust the center trim of the throttle servo.
 The Programming Keys are used to facilitate transmitter programming. The four Programming Keys
consist of two MENU Keys (Right and Left), one +/INC (Increase) Key, and one DEC/- (Decrease) Key.
 The TRM Switch controls different options, depending on your programming preferences. In the
default conguration, the TRM Switch controls the Steering Dual Rate adjustment. The TRM Switch can also control Throttle High
EPA, Throttle Brake EPA, Auxiliary Channel 3 High EPA, Auxiliary Channel 3 Low EPA, and more.
 The two Toggle Switches perform the same functions as the four Programming Keys. The Toggle
Switches make it easy to make programming changes during use. For example, to change the Steering Dual Rate percentage value
or Activate the Dig and Burn functions while your driving. For more information, see page 11.
FEaTURES FaMiLiaRizaTiOn
FEaTURES DEScRiPTiOnS, cOnTinUED....
cOnTROL STick SPRing TEnSiOn aDjUSTMEnT
The spring tension of the control sticks can be adjusted to suit your preference. Some
drivers prefer a rmer feel and some drivers prefer a softer feel.
1) Remove the battery cover on the back of the transmitter by pushing down rmly on
the two tabs in the top of the battery cover and pulling the battery cover out.
2) Unplug the battery from the transmitter and remove it. Set the battery aside for now.
3) Remove the eight Phillips head screws from the back of the transmitter, then very
carefully pull the back half of the transmitter off.
Pull the back half of the transmitter straight off to avoid bending or damaging the
battery pins.

Page 9
FEaTURES FaMiLiaRizaTiOn
When reinstalling the back half of the transmitter, be very careful that you don't bend or otherwise damage the battery
pins. These long battery pins should be carefully slid through the matching holes in the back half of the transmitter before
pushing it down into place.
cOnTROL STick SPRing TEnSiOn aDjUSTMEnT, cOnTinUED....
6) Reinstall the transmitter battery and plug it back in. The
battery connector is polarized and can therefore be plugged
in only one way. A A
4) To increase the spring tension of the control sticks, tighten
(turn clockwise) the adjustment screws (A). To decrease the
spring tension of the control sticks, loosen (turn counter-
clockwise) the adjustment screws (A).
5) When satised with the results, carefully reinstall the back
half of the transmitter.
In the default conguration, the spring tension is preset to
a soft feel.
The Gemini X 2.4GHz FHSS-3 transmitter's Nominal Input Voltage is 4.8v ~ 7.4v. This means that the transmitter can be used
with several different battery types, depending on your preference.
The Gemini X 2.4GHz FHSS-3 transmitter features a Charging Jack, which can be used with a 4 cell overnight charger to
recharge the optional Ni-Cd or Ni-MH the batteries without removing them from the transmitter. For more information, please visit
your local Sanwa or Airtronics dealer or our website at http://www.sanwa-denshi.co.jp or http://www.airtronics.net.
 In the default conguration, the transmitter is designed to be powered using 4 'AA' Alkaline batteries (not included).
This results in a transmitter that is lightweight and well-balanced for unmatched comfort.
 Rechargeable batteries (available separately) can be used. Using rechargeable batteries will provide longer
usage time and reduced cost in the long run, since you won't need to continuously purchase new Alkaline batteries.
 A 2 cell Li-Po battery or a 2 cell Li-Fe (battery (available separately) can be used to power the transmitter.
Please see the Using Li-Po or Li-Fe Batteries section at the bottom of page 10 if you decide to use one of these types of batteries.
TRanSMiTTER anD REcEivER BaTTERY OPTiOnS
IMPORTANT In the default conguration, the transmitter is programmed to use 4 'AA' Alkaline cells. If you're using a 2
cell Li-Po or 2 cell Li-Fe battery, the Battery Cell Count must be changed in the SETUP menu from 4 Cell to 6 Cell. For more
information, see page 45.
Transmitter power output, range, and speed is the same, regardless of the battery type/cell count used.
WARNING An after-market peak-detection charger, cycler, or fast charger should NOT be used to charge Ni-Cd or Ni-MH
rechargeable batteries through the transmitter. The circuitry within the transmitter can interfere with the peak-detection
charger's normal operation, resulting in over-charging and damaging the batteries, and possibly the transmitter itself.
In addition, a fast charger can damage the transmitter's circuitry. These chargers can be used, but ONLY if the batteries are
charged outside of the transmitter.
1) Remove the battery cover on the back of the transmitter by pushing down rmly on the two tabs in the top of the battery cover
and pulling the battery cover out.
2) Remove the battery holder, then
install four fresh 'AA' Alkaline
batteries into the battery holder,
making sure that the polarity is
correct. The direction that each battery should be installed is molded into the battery holder (+ Positive and - Negative).
3) Push the battery holder back into place, making sure that it's centered, then set the bottom of the battery cover back onto the
transmitter and push it rmly until it 'clicks' closed.
TRanSMiTTER BaTTERY inSTaLLaTiOn


Page 10
FEaTURES FaMiLiaRizaTiOn
USing Li-PO OR Li-FE BaTTERiES
l Use  a 2 Cell Li-Po or Li-Fe battery pack of desired capacity. 
or the transmitter and/or receiver will be damaged.
l Do NOT charge your battery through the transmitter using the Charging Jack. It  be removed from the transmitter for
charging or the transmitter could be damaged.
l Use a charger specically designed to charge Li-Po or Li-Fe batteries.
lWhen changing the connector on your battery to match the battery power plug in the transmitter (or
on the receiver switch harness), please observe correct polarity. Connecting with reverse polarity
will damage the transmitter and/or receiver.
l Observe all safety precautions provided with your Li-Po or Li-Fe battery before and during use, and during the charging process.
l Damage to the transmitter and/or receiver caused by improper use, wrong battery type, or reverse polarity will not be covered
under warranty.
- = Negative (Black)
+ = Positive (Red)
REcEivER cOnnEcTiOnS anD MOUnTing
l We suggest Binding the transmitter and receiver, and setting the Throttle Fail Safe position, prior to mounting your receiver in
your model.
l The receiver should be mounted as far away from any electrical components as possible.
l Route the receiver antenna up through a plastic tube so that it is in the vertical position.
l To protect the receiver from vibration and other damage, we recommend wrapping the receiver in shock absorbing foam when
installing it in your model.
WARNING The receiver is NOT equipped with BEC circuitry. DO NOT use a receiver battery with a nominal voltage greater
than 7.4 volts to power the receiver. When using an ESC, it should feature a BEC circuit that lowers the voltage to the receiver
to between 4.8 volts and 7.4 volts.
Set your model on a stand so the wheels are off the ground before turning on your radio control system or connecting
your motor for the rst time.
Use the diagram below to make the connections to the RX-451 4-Channel receiver.
The RX-451 receiver's Nominal Input Voltage is 4.8v ~ 7.4v. This means that a 2 cell Li-Po or 2 cell Li-Fe battery can safely
be used to power the receiver without the use of a voltage regulator
WARNING If you are using a 7.4 volt receiver battery, you MUST also use 7.4 volt-rated servos. Using 6.0 volt servos with a
7.4 volt receiver battery can result in damage to your servos and will not be covered under warranty.
1) Install four fresh 'AA' Alkaline batteries into the battery holder, making sure that the polarity is correct. The direction that each
battery should be installed is molded into the battery holder (+ Positive and - Negative).
'AA' Dry Cell Battery Holder
or 4.8 volt to 7.4v Ni-Cd, Ni-MH, Li-Po, or Li-Fe

Page 11
LcD anD PROgRaMMing kEYS
The Gemini X 2.4GHz FHSS-3 transmitter features four Programming Keys and two Toggle Switches that are used to facilitate
transmitter programming. The four Programming Keys consist of two MENU Keys (Right and Left), one +/INC (Increase) Key,
and one DEC/- (Decrease) Key. This section summarizes the functions of each of the 4 Programming Keys and the two Toggle
Switches, in addition to describing the main areas of the Multi-Function LCD.
Because certain areas of the LCD are printed onto the display, the PROGRAMMING menu selections displayed will NOT
change when cycling through the various SETUP menu options. This is normal because those areas of the LCD are printed
onto the display. For example, when you enter the SETUP menu and highlight D/R, MOD will be displayed in the Programming
Window, when you highlight EXP, TRM will be displayed in the Programming Window, etc.
Scrolls left (backward) through the individual
functions assigned to the currently highlighted
menu. In addition, when held down while turning
the transmitter ON, enters the SETUP menu.
Scrolls right (forward) through the individual
functions assigned to the currently highlighted
menu.
  
+/INC Key (Increase)
Increases number values in the Programming
Window and is used to make programming
selections.
DEC/- Key (Decrease)
Decreases number values in the Programming
Window and is used to make programming
selections.
Left MENU Key
Right MENU Key
PROgRaMMing kEY FUncTiOnS
MULTi-FUncTiOn LcD OvERviEw
Programming
Window
Model Number
Battery
Indicator
PROGRAMMING Menu / SETUP Menu Functions
Digital Voltage
Indicator
Steering Trim Display
Throttle Trim
Display
Setup Menu Icon
(SETUP Menu Only)
Top Menu Icon
(SETUP Menu Only)
or
or
or
or
The two Toggle Switches perform the same functions as the four Programming Keys, as described below. The Toggle
Switches make it easy to make programming changes during use. For example, to change the Steering Dual Rate percentage
value or Activate the Dig and Burn functions while your driving.


Page 12
+
+
PROgRaMMing kEY anD TOggLE SwiTcH SHORTcUTS
LcD anD PROgRaMMing kEYS
The Programming Keys and Toggle Switches can be used to change important information displayed in the Programming
Window. The information that can be displayed will vary depending on what menu you're currently in and/or what is currently
displayed in the Programming Window.

While within a PROGRAMMING menu, pressing the Right
MENU key and the Left MENU key at the same time, or
pushing the two Toggle Switches forward at the same
time, will display the Digital Voltage Indicator.

While the Digital Voltage Indicator is displayed, pressing
and HOLDING the +/INC key, or pulling and HOLDING
the left Toggle Switch, will display the current Modulation
Type in use.

While the Digital Voltage Indicator is displayed, pressing
and HOLDING the DEC/- key, or pulling and HOLDING
the right Toggle Switch, will display the current function
assigned to the TRM switch.

While within a PROGRAMMING menu, pressing and
HOLDING the +/INC key and the DEC/- key at the same
time, or pulling and HOLDING both Toggle Switches, will
reset the Programming Value to the default value.
All SETUP menu options displayed are indicated by
the Setup Menu icon in the lower left corner of
the LCD. The icon indicates that you are at the top level
of that specic menu.

To enter the SETUP menu, press and HOLD the Left
MENU key and turn the transmitter ON or push and
HOLD the left Toggle Switch and turn the transmitter ON.

Page 13
The Menu Flow Chart shows the different menus that are available for programming your transmitter. The default setting when
the transmitter is turned ON the very rst time is the PROGRAMMING menu with the Digital Voltage Indicator displayed. When
the transmitter is subsequently turned ON, the last screen displayed when the transmitter was turned OFF will be displayed.
Pressing either the Right MENU key or the Left MENU key scrolls through the individual functions assigned to the currently
highlighted menu. For example, press the Right MENU key to highlight the EPA menu. The EPA menu will be highlighted and ST
will be displayed in the Programming Window. Pressing the Right MENU key again will move the selection to TH and so on until
the EXP menu is highlighted.
MEnU FLOw cHaRT
PROgRaMMing MEnU
SETUP MEnU
       
To enter the SETUP menu, press and HOLD the Left MENU key and turn the transmitter ON or push and HOLD the left
Toggle Switch and turn the transmitter ON. For more information, see page 12 or 38.
  
D/R
EPA
EXP
SPEED
AUX
F/S
SUB-T
REV
MODEL
Steering Dual rate
enD Point aDjuStment
exPonential
Servo SPeeD
auxiliary FunctionS
Fail SaFe
Servo Sub-trim
Servo reverSing
moDel Select
aDjuSt Steering Dual rate
aDjuSt Steering, throttle, anD auxiliary enD Point aDjuStmentS
aDjuSt Steering anD throttle exPonential
aDjuSt Steering anD throttle Servo tranSit SPeeD
change anD aDjuSt auxiliary FunctionS anD channel mixing
Program tranSmitter Fail SaFe FunctionS
aDjuSt Steering anD throttle Servo centering
aDjuSt Steering, throttle, anD auxiliary Servo reverSing
Select SaveD moDelS
  
MOD
BIND
TRM
STEP
NAME
M_CLR
BEEP
ALRM
BATT
moDulation tyPe
binDing
trim Switch aSSign
trim SteP reSolution
moDel naming
moDel clear
auDible Key tone
inactivity alarm
battery cell count
change the tranSmitter moDulation tyPe
binD the tranSmitter anD receiver
aSSign variouS auxiliary FunctionS to the trm Switch
aDjuSt the reSolution oF the Steering anD throttle trim SwitcheS
name each oF your inDiviDual moDelS
reSet moDel-SPeciFic Programming Data to the DeFault valueS
turn auDible Key toneS on or oFF
turn the inactivity alarm on or oFF
uSeD to enSure correct oPeration oF the low voltage alarm







 






























Page 14
TRanSMiTTER anD REcEivER BinDing
The Binding function allows you to 'Bind' the transmitter and receiver pair. When new, it is necessary to
pair the transmitter and receiver to prevent interference from transmitters operated by other users. This
operation is referred to as 'Binding'. Once the Binding process is complete, the setting is remembered even
when the transmitter and receiver are turned OFF. Therefore, this procedure usually only needs to be done
once. Under some circumstances, the receiver may not operate after turning the transmitter and receiver
ON. If this occurs, perform the Binding procedure again.
Before beginning the Binding procedure, connect your servos and battery to the receiver, using the diagram on page 10.
Make sure that the receiver is turned OFF and that the transmitter is turned ON and in the SETUP menu.
3) While holding down the Bind Button on the receiver, turn the receiver
ON. The Bind LED on the receiver will ash slowly. After approximately
2 seconds, release the Bind Button. The Bind LED on the receiver
will continue to ash slowly.
Use the tip of a pencil or a 1.5mm hex wrench to reach the Bind Button on the receiver.

1) Enter the SETUP menu by following the procedures described on page 12 or 38.
2) Press the Right MENU key to highlight the EPA menu. BIND will be displayed in the Programming
Window.
4) Press the +/INC key on the transmitter. PUSH INC will ash in the Programming
Window.
After releasing the Bind Button, you must press the +/INC key quickly (within a
couple of seconds). If you take too much time, you may need to restart the Binding
procedure.
The Gemini X 2.4GHz FHSS-3 radio control system uses FHSS-3 technology, however, the transmitter is compatible with
both FHSS-3 and FHSS-2 Sanwa and Airtronics 2.4GHz surface receivers. To bind the transmitter to an FHSS-2 2.4GHz
receiver (available separately), the transmitter Modulation Type must rst be changed to FH2. For more information, see page 38.
When the Binding procedure is successful, the Bind LED will stay solid blue and the Power Indicator Light will ash slowly
when both the transmitter and receiver are turned ON. If the Bind LED on the receiver is ashing rapidly, the transmitter and
receiver are not paired. In this case, turn both the transmitter and receiver OFF, then repeat the Binding procedure.
6) After verifying that the Binding process is complete (solid blue Bind LED on the receiver) and the servos operating normally,
press either the Right MENU key or the Left MENU key to return to the BIND menu.
5) Press the +/INC key a second time.
PUSH DEC will ash. Press the DEC/-
key once. BIND will be displayed in the
Programming Window, the LCD and the
Power Indicator Light will ash, then the
Bind LED on the receiver will turn solid
indicating the Binding process is complete.

Page 15
[[PROgRaMMing MEnU
D/R - STEERing DUaL RaTE
The Steering Dual Rate function is used to change the amount of steering servo travel compared to the
amount of physical movement of the steering control stick. For example, by increasing the Steering Dual
Rate percentage value, you can make the steering servo travel more which might prevent your model
from pushing during turns. If your model oversteers during turns, you can reduce the Steering Dual Rate
percentage rate.
3) Move the steering control stick right and left to full. Adjust the Dual Rate percentage
value to decrease (DEC/-) or increase (+/INC) the amount of steering to reach
the steering stops without binding. For more information, see the next page.
WARNING The Steering Dual Rate percentage value should not be increased
to the point where your steering linkage and servo bind when the steering control
stick is moved all the way to the right or left. Binding will cause the steering servo to
'buzz', resulting in a quicker loss of battery power and eventual damage to the servo.
To enter the PROGRAMMING menu, turn the transmitter ON. when the transmitter is turned ON
the very rst time is the PROGRAMMING menu with the Digital Voltage Indicator displayed. When
the transmitter is subsequently turned ON, the last screen displayed when the transmitter was
turned OFF will be displayed.
The following PROGRAMMING menus are available by repeatedly pressing the Right MENU key or the Left MENU key:
Steering Dual Rate End Point Adjustment Exponential Servo Speed Auxiliary Functions
Fail SafeServo Sub-TrimServo ReversingModel Select
2) Attach the steering linkage to the servo horn per your model's assembly manual, then install the servo horn onto the steering
servo, making sure it's as close to being centered as possible. Use the Servo Sub-Trim function to center the servo arm
exactly, then mechanically adjust both wheels to point straight ahead. For more information, see page 34.

1) Set the Steering Trim to '0' using the Steering Trim switch. Press the Steering Trim
switch right to increase Steering Trim toward the right and press the Steering Trim
switch left to increase Steering Trim toward the left. The current amount of Steering
Trim is indicated on the LCD in both digital format in the Programming Window
and in scaled format along the bottom of the display.


Page 16
EPa - EnD POinT aDjUSTMEnT
The End Point Adjustment function is used to adjust the desired amount of servo travel in both directions
independently. This makes it possible to balance servo travel in both directions. The End Point Adjustment
function can be adjusted for the Steering channel (Right and Left), the Throttle channel (Throttle High and
Throttle Brake), and Auxiliary channel 3 (High and Low).
WARNING End Point Adjustment percentage values should not be increased to the point where your linkages and servos
bind when moved all the way to the right or left. Binding will cause the servos to 'buzz', resulting in a quicker loss of battery
power and eventual damage to the servos.
Before making Steering End Point Adjustments, you must make sure that the servo horn is centered. Install the servo horn
onto the steering servo, making sure it's as close to being centered as possible, then us the Servo Sub-Trim function to
center the servo arm exactly. For more information, see page 34.

Your model’s turning radius can differ from left to right because of variations in linkage, suspension balance, tire diameter, or
weight distribution. In such cases, Left Steering servo travel and Right Steering servo travel are adjustable using the End Point
Adjustment function.
[[PROgRaMMing MEnU

1) Press the Right or Left MENU key to highlight the D/R menu. ST 100% will be displayed in the
Programming Window.
D/R ST setting range is 0% to 100%. The default setting is 100%.
2) Press the +/INC or DEC/- keys to increase or decrease the Steering Dual Rate percentage
value. When the Steering Dual Rate percentage value is decreased, steering servo travel is
decreased. When the Steering Dual Rate percentage value is increased, steering servo travel
is increased.
TRM Switch
3) After the Steering Dual Rate percentage value has been set, adjust the independent left and right End Points using the End
Point Adjustment function. For information, see the next page.

1) In the default conguration, the TRM switch is used to change the Dual Rate
percentage value without accessing the Programming Menu. This allows you to
adjust the Dual Rate percentage value easily during use. Press the TRM switch
up to increase the percentage value in 5% increments and press the TRM switch
down to decrease the percentage value in 5% increments. The increment percentage
value that the TRM switch adjusts the Steering Dual Rate can be changed to suit
your preference. For more information, see page 41.

Page 17
[[PROgRaMMing MEnU
EPA ST R setting range is 0% to 150%. The default setting is 100%.
2) To set the Right Steering End Point Adjustment percentage value, push and the steering
control stick to the right. R 100% will be displayed. Press the +/INC or DEC/- keys to increase
or decrease the amount of steering servo travel in that direction.
3) To set the Left Steering End Point Adjustment percentage value, push the steering control
stick to the left. L 100% will be displayed. Press the +/INC or DEC/- keys to increase or
decrease the amount of steering servo travel in that direction.
EPA ST L setting range is 0% to 150%. The default setting is 100%.

Your model's carburetor may not open completely, or it may open too much and cause the throttle servo to bind. If you're using an
Electronic Speed Control, the Electronic Speed Control may not command full power, or the brake may not engage adequately.
In such cases, Throttle High servo travel and Throttle Brake servo travel are adjustable using the End Point Adjustment function.

1) Press the Right or Left MENU key to highlight the EPA menu. ST L 100% or ST R 100% will
be displayed in the Programming Window depending on the last position of the steering
control stick.
EPA TH H setting range is 0%to 140%. The default setting is 100%.
2) To set the Throttle High End Point Adjustment percentage value, push the throttle control stick
forward. H 100% will be displayed. Press the +/INC or DEC/- keys to increase or decrease the
amount of throttle servo travel in the High throttle direction.
1) From within the EPA menu, press the Right MENU key to display TH. TH H 100% or TH B
100% will be displayed in the Programming Window depending on the last position of the
throttle control stick.
If you're using an Electronic Speed Control, the Throttle High and the Throttle Brake End
Point Adjustment percentage values are both generally set to 100%, although the Throttle
High direction may need to be increased to achieve full power. In some cases the End Point
Adjustments can also be set directly via the Electronic Speed Control.


Page 18
3) To set the Throttle Brake End Point Adjustment percentage value, pull the throttle control stick
back. B 100% will be displayed. Press the +/INC or DEC/- keys to increase or decrease the
amount of throttle servo travel in the Brake direction.
EPA TH B setting range is 0% to 160%. The default setting is 100%.

Auxiliary Channel 3 can be used for a number of different uses. One of the more common uses would be for the reverse function
in a glow-powered monster truck. Often, the transmission only requires a small amount of throw, but the servo binds because
of too much travel. In such a case, Auxiliary High servo travel and Auxiliary Low servo travel are adjustable using the End Point
Adjustment function.
1) From within the EPA menu, press the Right MENU key to display AUX. AUX H 100% or AUX L
100% will be displayed in the Programming Window depending on the current position of the
Auxiliary Switch.
[[PROgRaMMing MEnU


1) The TRM switch can be programmed to adjust Steering, Throttle, or Auxiliary End
Point Adjustment percentage values without accessing the Programming Menu.
This allows you to adjust the End Point Adjustment percentage values for one of
these functions easily during use. Press the TRM switch up to increase the
percentage value and press the TRM switch down to decrease the percentage
value. For more information, see page 40.
EPA-AUX H setting range is 0% to 150%. The default setting is 100%.
2) To set the Auxiliary High End Point Adjustment percentage value, move the Auxiliary Switch
UP. HIGH will be displayed momentarily in the Programming Window, then H 100% will be
displayed. Press the +/INC or DEC/- keys to increase or decrease the amount of channel 3
servo travel in the High auxiliary direction.
EPA-AUX L setting range is 0% to 150%. The default setting is 100%.
3) To set the Auxiliary Low End Point Adjustment percentage value, move the Auxiliary Switch
DOWN. LOW will be displayed momentarily in the Programming Window, then L 100% will be
displayed. Press the +/INC or DEC/- keys to increase or decrease the amount of channel 3
servo travel in the Low auxiliary direction.
TRM Switch

Page 19
[[PROgRaMMing MEnU
EXP-ST setting range is -100% (Mild) to 100% (Quick). The default setting is 0% (Linear).
2) Press the +/INC or DEC/- keys to increase or decrease the Steering Exponential percentage
value. Decreasing the Steering Exponential percentage value will make the steering less
sensitive around neutral and increasing the Steering Exponential percentage value will make
the steering more sensitive around neutral.
Changes to the steering Exponential percentage value affects both right-hand and left-hand
steering equally.
1) Press the Right or Left MENU key to highlight the EXP menu. ST 0% will be displayed in the
Programming Window.
EXP - EXPOnEnTiaL
The Exponential function allows you to vary the amount of servo travel in relation to the movement of the
steering control stick and the throttle control stick near the neutral positions to change the way the steering,
throttle, and brake react to control movement. Increasing the Exponential percentage value will soften the
control feel around neutral and decreasing the Exponential percentage value will heighten the control feel
around neutral. Using a lower negative value allows for smoother control. Using a higher positive value
may result in more 'twitchy' control response.

Steering Exponential can be variably adjusted from Mild through Linear to Quick to allow you to set the most effective steering
response for your model. Generally, if your model over-steers, reduce the Exponential percentage value, and if your model
under-steers, increase the Exponential percentage value.

Throttle High Exponential can be adjusted from Mild, Linear and Quick. In general, reduce the Exponential percentage value on a
slippery track or with a model that has a higher-torque motor or engine. Increase the Exponential percentage value on a high-grip
track or with a model that has a lower-torque motor or engine.
1) From within the EXP menu, press the Right MENU key to display TH. TH H 0% will be displayed
in the Programming Window.

Amount of steering control stick operation on
the 'L' side or the amount of throttle control stick
operation on the 'H' side.
Amount of steering control stick operation on
the 'R' side or the amount of throttle control
stick operation on the 'B' side.

Page 20
Throttle High Exponential affects throttle control only from the neutral position to the full throttle position (throttle control
stick pushed forward). It does not affect the Throttle Brake side. That is adjusted separately below.
EXP-TH B setting range is -100% (Mild) to 100% (Quick). The default setting is 0% (Linear).
2) Press the +/INC or DEC/- keys to increase or decrease the Throttle Brake side Exponential
percentage value. Decreasing the Throttle Brake Exponential percentage value will make the
brakes less sensitive around neutral and increasing the Throttle Brake Exponential percentage
value will make the brakes more sensitive around neutral.
Throttle Brake Exponential affects brake control only from the neutral position to the full
brake position (throttle control stick pulled back). It does not affect the Throttle High side.
[[PROgRaMMing MEnU
EXP-TH H setting range is -100% (Mild) to 100% (Quick). The default setting is 0% (Linear).

2) Press the +/INC or DEC/- keys to increase or decrease the Throttle High side Exponential
percentage value. Decreasing the Throttle High Exponential percentage value will make the
throttle less sensitive around neutral and increasing the Throttle High Exponential percentage
value will make the throttle more sensitive around neutral.

Throttle Brake Exponential can be adjusted from Mild, Linear and Quick. In general, reduce the Exponential percentage value
on a slippery track or Increase the Exponential percentage value on a high-grip track. Decreasing the Exponential value can aid
traction during braking, helping to prevent your model from skidding or sliding out from wheel lock.
1) From within the EXP menu, press the Right MENU key to display TH B. TH B 0% will be
displayed in the Programming Window.
SPEED - SERvO SPEED
The Servo Speed function allows you to slow down the transit speed of the steering and throttle servos.
Servo transit speed can be slowed in both the Forward and the Return to Center directions independently.
When driving your model, proper steering and throttle control are vital. For example, lowering the transmit
speed of the steering servo can help to limit excessive steering, which will enable you to achieve smoother
cornering. In addition, lowering the throttle servo speed can help to ensure smooth throttle control.

The transit speed of the steering servo can be slowed in both the Forward and the Return to
Center directions independently, giving you a broad range for improving steering control.
1) Press the Right or Left MENU key to highlight the SPEED menu. ST F 0% will be displayed in
the Programming Window.