BEC
The Battery Eliminator Circuit is used to supply 5V to the R/C receiver. The Scorpion XL
comes from the factory with this enabled. To disable the BEC simply clip the wire
jumper located above the R/C wires on the circuit board. We recommend a single cut
and bending the wires apart to allow the BEC to be easily re-connected later if desired.
Mode Setting
The operating modes of the Scorpion XL are as follows:
Mode M Jumper T Jumper R/C Cables
1 Mix OFF OFF Left & Right required
2 Mirror/Mix Right OFF ON Left & Right required
3 Mirror/Mix Left ON OFF Left & Right required
4 Tank ON ON Left & Right attached
5 Mirror no mix ON ON Left only or Right only
Detection of the operating mode is done at startup. If a mode is selected that requires
both Left and Right R/C channels the unit will remain in radio detection mode until
signals are received on both Left and Right channels. Note, the behavior of the
Scorpion XL in Mode 4/5 depends on which R/C channels are connected. The mode
jumpers are located on the male header on the opposite side of the unit from the R/C
wires. Small white lines and letters on the PCB show were the jumpers are placed. The
Scorpion XL ships from the factory with the jumpers attached to one pin of the header.
These may fall off in a high-vibration environment so jumpers that are intended to be
OFF should be removed and stored in a location where they won’t be lost.
Exponential Steering
A jumper may be placed on the indicated pins on the ISP header to select exponential
steering response. This mode gives a wide gentle dead band around the center point
and rapidly increases in response at the ends of stick travel. Many drivers using hand-
held radios prefer this mode as it is less sensitive near the center point which makes it
easier to drive straight ahead and yet still allows rapid turns or spinning in place if
needed. At Robot Power we always leave this jumper on when driving a “skid steer”
drive configuration.
HV Jumper
The Scorpion XL is equipped with a jumper labled HV. This is used when the battery
voltage is above 16V. If the rated battery voltage is above 16V clip this wire.
Reconnect to use with a lower voltage battery.
Radio Calibration
Different radio systems have slightly different center points and travel ranges. To adjust
the Scorpion XL to your radio a jumper is located on the ENC header on the circuit board
to activate the radio calibration function. To calibrate the Scorpion XL to your radio
systems set all your trims to center and place a jumper on the two pins indicated in the
