DMR-203 Troubleshooting

Troubleshooting tips for the DMR-203

The output is always zero?

• Is there power to both the motor controller and receiver? The DMR-203 does not supply power to the receiver – this will require its own battery.
• Are the connections correct?
• Is the receiver supply voltage too high or too low? (This can cause invalid inputs)
• Is the motor controller supply voltage/current too low? (Both the interface & motor controller have under voltage protection)
• Is the ignition switched on?
• Try testing the radio by connecting a servo to the receiver.
• Is pulse repetition frequency from the receiver between 40Hz and 70Hz? Some cheaper Chinese sets are different, and some more expensive sets can be adjusted.

No Reverse?

• Is the receiver input calibrated properly? Does the controller give zero speed on stick centre? If not, adjust the offset.
• Does the controller operate correctly with manual reverse input? If so, then the reverse driver in the DMR may be damaged.

The unit works but will not give maximum speed?

• Has the motor controller gain been adjusted to give full output with full stick displacement in BOTH forward and reverse directions?
• Is the supply voltage/current low?

The output dithers between two speeds or rises in steps?

• This is normal and a product of using a microprocessor to sample the RC input signal. You can minimise this by ensuring the gain is adjusted to give full output at full stick displacement.
• “Stair-Casing” may be more noticeable on high speed motors or motors operating beyond their intended voltage rating.

The output is not symmetrical (forward and reverse peak)

• Is the transmitter signal symmetrical? Adjust the controller gain to give maximum output when the transmitter gives its lowest output for the full stick displacement.
• Is the motor controller set to half speed reverse mode?
• Is the motor controller operating correctly?

The output is either Full Speed or Zero Speed?

• Are the jumper settings correct?
• Is the Controller “Gain” set to an excessively high value