| Fault | Analysis | Solution |
| No reaction after connecting the battery | The connection of motor or battery is abnormal | Please use brushed 480 motor andbattery which the voltage is higher than7.4V ， make sure battery and motor is functional，reconnect motor to make surethe circuit is closed then test the DTUwith battery |
| Only pre-loading function works | 1.The connection of motor is abnormal 2. Fault of motor | Please confirm motor and gearbox arefunctional，reconnect motor then test theDTU with battery |
| Magazine keeps feeding after it is attached | For DTU with pre-loading function ， circuit for pre-loading function maybe overload For DTU without pre-loading function， negative of magazine could be connected improperly |
1.Automatic pre-loading function is disabled, please return it to retailer for repair 2.For DTU without pre-loading function, the negative wire of magazine shouldbeconnected to negative of motor insteadof negative of battery |
| Magazine cannot feed gel/BB | Fault of magazine Fault of gearbox Diameter of gel is improper Power supply wire of magazine anomaly | Please reconnect terminals for magazine, make sure the connection betweenmagazine power supply and DTUis functional, then do troubleshooting for magazine/gearbox/ diameter of gel suchexternal factors. |
| 1 long ‘beep’ following by 3 short ‘beeps’ after battery is connected, no reaction after the trigger is pulled | One long ‘beep’ following by 3 short ‘beeps’ indicate that DTU is entering ‘quick’ model, it means trigger is pulled while selector plate is at ‘semi’ position. If trigger is not pulled ， it means trigger cannot block sensor while it is released ，DTU detects that trigger is pulled. | Trigger sensor is pulled is because it is pressed by wires or other things andit cannot reset. Please disassemble gearbox to check |
| Only 3 short ‘beeps’ after battery is connected, no reaction after trigger is pulled | 3 short ‘beep’ means the DTU has Entered shooting mode successfully, it means initialization of DTU is successful. No reaction after the trigger is pulled might be caused by that trigger sensor is blocked by wires or other things or the travel of trigger is not enough to reach the trigger senso or the end of trigger is too far away from the switch of trigger | Please investigate wires of gearbox；Sincetravel of trigger might not be enough，it is needed to modify the trigger limit of trigger on gearbox to make thetrigger is able to reach the trigger sensor；If the trigger cannot reach theswitch, please thicken the end of trigger until it can reach the switch |
| 4 short ‘beep’ | 4 short ‘beep’ is the warning for low voltage warning ， it means battery is out or the setting for battery protection is wrong. | Fully charge battery ，then set the first term to 5 before testing with battery |
| ‘semi’ mode only | There is a ‘beep’ while changing Mode, if there is not, it means selector switch cannot detect selector plate at ‘auto’ position , it means the width of selector palate is not enough | Please make sure the linkage betweenselector plate and selector is normal andselector can move freely on gearbox. Thicken selector plate properly to makesure that it can press the selector switchwell at ‘auto’ position |
| ‘auto’ mode only | There is a ‘beep’ while changing Mode, if there is not, it means selector switch cannot detect selector plate at ‘semi’ position, it means the selector plate is too wide and it press the selector switch at this position | Please make sure the linkage betweenselector plate and selector is normal, selector plate can move freely ongearbox. Then cut the selector plateproperly to ensure that selector switchcannot be blocked by selector plate at ‘semi’ position |
| ‘semi’ or ‘auto’ mode is unclear | The position of selector plate is inaccurate, it is located in between ‘auto’ and ‘semi’ position. It is shifting between 2 modes due to vibration or the loose of circuit cause the contact of gear switch and sector gear is insufficient or the contact of trigger and trigger switch is insufficient so it cannot press the trigger switch well which leads to the sensor is pressed repeatedly and multiple shots | Please make sure the linkage betweenselector plate and selector is normal, selector plate can move freely ongearbox. Modify the selector plateproperly, so the selector plate can press selector switch well at ‘auto’ position; Based on actual situation, extend or shorten the cam of sector gear to ensurethe cam can trigger the switch once for rotating a round；Alter the angle anddistance of trigger and trigger switch，place shim properly on trigger to adjust the distance between trigger and trigger switch |
| Long ‘Beep’ after Motor rotates few rounds |
Long ‘beep’ is the alarm for motor stall ， DTU detect gears are not rotating, it could be: 1. Motor does not drive gears rotating 2. Gear sensor is close to gear which it cannot reset smoothly 3. Gear sensor is down |
Disassemble gearbox and check the gear switch can reset smoothly then enter thequick testing mode to check the reactionof gear switch. If the reaction of theswitch is normal, it is recommendedtomodify gear or gear switch. If the lever of the gear switch is too long, it is suggestedto cut the lever off for 1mmthen test it again. If the lever is short, use clue andplastic piece to lengthen the lever |
| Motor heating | Frequent motor heating is mainly caused by high start and shut current and frequent shut. Active Brake of DTU needs to transfer the kinetic energy to heat energy for brake. It is related to the performance of motor; heating of motor is normal phenomenon, and it is unavoidable | Set the position of piston to 4 or higher inprogramming model can reduce or closeactive brake function to reduce motor heating. In addition, change the motor tohigh torque and low RPMones can alsoreduce motor heating. |
| Battery heating | Critical battery heating is mainly caused by that the torque of motor is not enough for load or load is too large. Normally, it is because gears are too tight or the main spring is too strong；it could also be caused by discharge of battery is not enough or it is at overloading status for a long time | Battery with higher discharge rate andcapacity is recommended. In addition, connector for battery, it is recommendedto use XT30 or mini-Tamiya connector. Investigate the tightness of gears, thestrength of main spring and smoothness of gearbox. Change the motor toahigh-torque one can relieve this issue |
| Critical wire heating | Critical heating of wire is because torque of motor is not enough for load or the load is too much (Gears are too tight or main spring is too strong)；It could also be the discharge rate of battery is not enough or the battery is at overload situation for a long time | Battery with higher discharge rate andcapacity is recommended. In addition, for connectors of battery, it is recommendedto use XT30 or mini-Tamiya connector. Investigate the tightness of gears, thestrength of main spring and smoothness of gearbox. Change the motor toahigh-torque one can relieve this issue |
| Firing instantly after battery is connected | FET chip has damaged | Please investigate battery connectors andmotor connectors are reversal or not. Please check is there a short circuit or damage on wires or circuit boards，Pleasecontact after-sales for solution |
| DTU burn down instantly after battery is connected | Battery is connected reversely | Please check the connector of battery is Reversal or not，Please contact after-sales for solution |
| DTU burn down instantly after trigger is pulled | Polarities of motor (Gearbox) are connected reversely Short circuit occurs on the wire that connects motor | Please check connector of motor is reversal or not, is there a short circuit or damage in wire，Please contact after sales for solution. |
| Influent single Shot but the ‘auto’ mode is normal | Gear is too close to gear sensor or the circuit board is loose. | Please fix the circuit board on gearbox and modify the lever on the gear switchbased on actual situation thenreassemble the DTU to test |
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