The Blade 120 S2 tail motor not working problem is one of the most common reasons this micro helicopter becomes hard to control.
Because the tail system is responsible for yaw stability, even a small failure in the motor, wiring, or flight controller can make the model spin or drift uncontrollably.
This guide explains the most likely causes, how to test each component, and what to replace before you spend money on unnecessary parts.
What the tail motor does on the Blade 120 S2
The Blade 120 S2 uses a small brushed tail motor to counter the torque created by the main rotor.
When the motor spins correctly, the helicopter holds heading and responds predictably to rudder input from the transmitter.
If the tail motor stops working, you may notice one or more of these symptoms:
- The helicopter spins continuously in one direction
- Tail output is weak or intermittent
- The motor does not respond at all when throttle is raised
- Yaw control works briefly and then fails
- The motor feels hot, jerky, or noisy before stopping
Most common reasons the Blade 120 S2 tail motor stops working
On a micro helicopter like the Blade 120 S2, tail problems usually come from one of five areas: the motor itself, the tail wiring, connector damage, the main board, or drivetrain-related binding that overloads the motor.
1. Worn-out tail motor
Brushed tail motors have limited service life.
Over time, the internal brushes and commutator wear down, reducing output until the motor fails completely.
This is the most common failure if the helicopter has many flights or has been crashed often.
2. Broken or loose wiring
The tail motor wires are thin and can break internally near the motor leads, along the boom, or where the wire enters the frame.
A wire may look intact from the outside but still fail under vibration or movement.
3. Damaged connector or solder joint
If the connector is oxidized, bent, or partially unplugged, the motor may receive inconsistent power.
Cold solder joints can also interrupt current flow, especially after a hard landing.
4. Faulty main control board
The Blade 120 S2’s flight controller supplies power to the tail motor.
If the output transistor or motor driver circuit on the board fails, the motor may not run even when the motor itself is good.
5. Binding or excessive load
If the tail rotor shaft, gears, or tail assembly is rubbing, the motor may draw too much current and fail early.
Mechanical drag can look like an electrical problem, so it should always be checked first.
How to diagnose the problem step by step
Use a structured process so you can isolate the fault before replacing parts.
A simple bench test often reveals whether the issue is electrical, mechanical, or related to the flight controller.
Check for visible damage first
Inspect the tail boom, motor leads, connector, and tail rotor blades under bright light.
Look for cuts, pinched insulation, melted plastic, or signs of impact.
Also make sure the tail rotor can spin freely by hand without scraping.
Test the tail motor at low throttle
Power on the helicopter and slowly advance the throttle.
Watch whether the tail motor starts consistently.
If it does not move, then suddenly flickers, the issue is likely a poor connection, failing motor, or board output problem.
Swap or test the motor directly
If you have a known-good replacement motor, swap it in temporarily.
If the replacement runs normally, the original motor is faulty.
If the replacement also fails, the issue is more likely in wiring or the main board.
Inspect continuity with a multimeter
A multimeter set to continuity or resistance can help identify broken wires.
Test from the motor leads back to the board connector.
An open circuit usually means a broken wire or failed solder connection.
Check for drivetrain drag
Spin the tail rotor assembly and feel for resistance.
Even slight rubbing can force a small brushed motor to work harder than intended.
Remove dirt, hair, or debris wrapped around the shaft or rotor hub.
How to fix a Blade 120 S2 tail motor not working
The correct fix depends on what the diagnosis reveals.
In many cases, replacing the motor is the fastest and most reliable repair, but some problems can be solved with simple rework.
Replace the tail motor
If the motor is worn, intermittent, or dead, install a compatible replacement designed for the Blade 120 S2.
Match the connector type and motor size carefully.
A quality OEM-style replacement usually provides the best fit and performance.
Resolder damaged connections
If a wire has pulled free or the solder joint looks cracked, resolder it with a fine-tip iron and minimal heat.
Use care not to overheat the motor tabs or nearby plastic parts.
Secure the repair so vibration does not break it again.
Repair or replace the tail wiring
If the wire is broken internally, patching the outer jacket is not enough.
Replace the damaged section or the full wire run if possible.
Thin stranded wire with flexible insulation is preferred for micro helicopter repairs.
Inspect or replace the flight controller
If a known-good motor still does not run, the board may have failed.
On many micro helicopters, the tail output circuit is not separately serviceable, so replacing the entire flight control board is often the practical option.
Remove mechanical binding
Clean the tail shaft, check alignment, and replace any bent parts.
A bent boom, rubbing blade, or damaged tail hub can make the motor appear weak when the real issue is excess friction.
Signs the motor is failing before it stops completely
Recognizing early failure can prevent a crash.
Watch for reduced tail authority, delayed rudder response, short bursts of normal operation followed by loss of control, or a motor that becomes unusually warm after a short flight.
These warning signs usually indicate wear in the brushes, increased friction, or a loose electrical connection that is worsening over time.
What parts are worth replacing together?
When the tail motor fails, it is often efficient to replace several related parts at once, especially after a crash or heavy use.
This can reduce repeat repairs and help restore stable flight faster.
- Tail motor
- Tail rotor blades or hub if damaged
- Tail boom if bent or cracked
- Wiring harness if frayed or pinched
- Flight controller only if motor and wiring test good
How to prevent future tail motor failure
Prevention on the Blade 120 S2 is mostly about reducing mechanical load and avoiding electrical stress.
Small brushed systems are sensitive to wear, so maintenance matters.
- Avoid flying with bent tail parts or rubbing blades
- Inspect wiring after every crash
- Do not hold the throttle up while the rotor is blocked
- Keep the tail assembly clean and free of debris
- Replace worn motors before they fail in flight
- Store batteries properly to reduce unnecessary strain on electronics
When replacement is better than repair
For micro helicopters, repair time can quickly exceed the value of the part if the motor, wiring, and board are all questionable.
If the motor is old, the wire is damaged in multiple places, or the board output is uncertain, replacing the full tail motor assembly and testing again is usually the most practical path.
If the helicopter still has no tail response after motor replacement and wiring inspection, the flight controller is the most likely remaining cause.
At that point, board-level diagnosis or a full board swap becomes the next logical step.