Understanding a Holy Stone HS720 Motor Not Spinning After Crash
If your Holy Stone HS720 motor is not spinning after a crash, the problem may be minor, such as a bent propeller or a loose connector, or it may involve the ESC, motor shaft, or arm wiring.
The fastest fix depends on identifying whether the issue is mechanical, electrical, or a safety lock triggered by impact.
The HS720 uses brushless motors, a flight controller, and electronic speed controllers to keep each arm responsive.
After a hard landing, one motor may stop responding while the others still start normally, which makes the fault easier to isolate if you follow a structured check.
Common Reasons a HS720 Motor Stops Spinning
Crashes can affect more than the propeller.
On the Holy Stone HS720, the most common causes of one motor not spinning are physical damage, blocked rotation, wiring failure, or a damaged motor control component.
- Propeller damage: A cracked, warped, or jammed propeller can prevent the motor from starting properly.
- Motor shaft bend: Impact can slightly bend the shaft, causing friction or rubbing inside the motor housing.
- Loose wire or connector: A dislodged connection inside the arm can interrupt power delivery.
- Damaged ESC channel: The electronic speed controller for one motor may fail after impact or overheating.
- Foreign debris: Dirt, grass, sand, or broken plastic can block the motor bell or propeller hub.
- Flight controller response issue: Less common, but the aircraft may no longer command that motor correctly.
First Checks to Perform Before Disassembly
Before opening the drone, check the simplest causes.
These steps can save time and help you avoid unnecessary repairs.
Inspect the propeller and motor by hand
Remove the propeller from the affected arm and gently rotate the motor bell or shaft by hand.
It should move smoothly without grinding, resistance, or clicking.
If it feels rough or stuck, the motor may have internal damage or debris inside the arm.
Compare the damaged arm with the other motors
Rotate the other motors to compare resistance and smoothness.
If only one motor feels abnormal, the fault is likely localized to that arm rather than the whole drone system.
Check for visible impact damage
Look closely at the arm, motor mount, and propeller hub.
Cracks, gaps, or a tilted motor indicate mechanical damage that can affect spinning even if the drone powers on normally.
Test the drone without props
For safety, remove all propellers before powering on the HS720.
Arm the drone and watch whether the affected motor tries to start.
If it twitch-starts, stutters, or stays dead while others spin, that behavior helps narrow the fault to the motor, ESC, or wiring.
How to Diagnose the Fault Step by Step
A methodical diagnosis is the most reliable way to fix a Holy Stone HS720 motor not spinning after crash.
Work from the outside in, starting with parts you can inspect quickly.
1. Confirm the battery and power output
Low battery voltage can exaggerate startup issues.
Fully charge the battery and test the drone on a stable surface.
If the issue appears only at low charge, the battery may be the real limitation rather than a failed motor.
2. Remove the propeller and check for friction
With the propeller off, spin the motor gently.
If it binds, the crash may have bent the shaft or damaged the bearings.
A motor that spins freely by hand but fails under power often points to an electrical fault instead of a mechanical one.
3. Inspect the arm wiring
If you are comfortable opening the frame, examine the wiring inside the affected arm.
Look for pinched insulation, a disconnected lead, or a wire pulled loose from a solder joint.
Even a partial break can cause intermittent spinning or complete failure.
4. Compare the motor resistance
Using a multimeter, compare the resistance of the three motor phase connections if accessible.
A reading that differs significantly from the other motors may indicate a short or open coil winding.
If you do not have the right tools, this is a good point to stop and seek repair help.
5. Check whether the ESC channel responds
If the motor is physically fine but still never starts, the ESC may be damaged.
In many drones, the ESC is integrated or closely tied to the flight control system, so a failed channel can mimic a dead motor.
Signs include no startup twitch, no response at throttle increase, or repeated failure after resets.
Mechanical Fixes That Often Work
Some crash-related motor issues are purely mechanical and can be repaired without replacing electronics.
- Replace the propeller: Use a matching Holy Stone HS720-compatible propeller and ensure correct orientation.
- Clear debris: Remove dirt, fibers, or broken plastic from the motor and arm area.
- Realign the motor mount: If the mount shifted slightly, carefully reseat or replace the damaged arm section.
- Replace a bent motor: If the shaft is visibly warped or the motor feels gritty, replacement is usually more practical than repair.
Mechanical fixes are most effective when the motor still produces some movement by hand and there is visible evidence of impact on the propeller or arm.
When the Problem Is Electrical
If the motor is physically free but still does not spin after a crash, the issue is often electrical.
Brushless motors depend on correctly timed signals from the ESC, and impact can damage wiring, solder joints, or controller components.
Electrical failure is more likely if the drone powers on, the app or remote links normally, and the other motors behave correctly while one motor remains silent.
In that case, the fault may be a bad motor winding, damaged phase wire, or a failed ESC output.
Typical signs of electrical damage include:
- one motor never twitching at startup
- intermittent spinning followed by cutout
- burning smell near the arm or controller area
- visible scarring or overheated components
Should You Replace the Motor or the Arm Assembly?
Replacement choice depends on the severity of the crash and your repair experience.
If the HS720 motor is directly damaged, replacing the motor may be enough.
If the arm housing, wiring, or mount is cracked, replacing the entire arm assembly can be more efficient.
Choose a full arm replacement when:
- the arm is cracked or bent
- wiring is damaged deep inside the frame
- the motor mount will not hold alignment
- multiple components were hit in the crash
Choose motor-only replacement when:
- the arm is intact
- the motor shaft is bent or the bearings are rough
- the wiring and mount are still secure
- the fault is clearly isolated to the motor itself
Repair Tips to Avoid Making the Damage Worse
Crash repairs can become more expensive if the drone is tested repeatedly with a damaged part.
A few precautions help protect the rest of the HS720.
- Always remove propellers before powered testing.
- Do not force a stiff motor to spin.
- Avoid over-tightening screws into plastic mounts.
- Use the correct replacement part, not a near-match propeller or motor.
- Test after each repair step instead of changing multiple parts at once.
If a replacement motor is installed, make sure the wire routing matches the original layout and that nothing rubs against the rotating parts.
Poor routing can recreate the same failure after takeoff.
When to Stop Troubleshooting and Get Professional Help
Some HS720 motor failures are not practical to fix at home, especially if the drone has hidden board damage.
If the motor still does not spin after propeller replacement, wiring inspection, and battery checks, the issue may be in the ESC or flight controller.
Professional repair is the better choice if you see burned components, broken solder points, or damage that requires board-level work.
That is especially true if the drone is under warranty or if replacing multiple parts would cost nearly as much as a replacement aircraft.
Preventing Motor Failure After Future Crashes
Once repaired, reduce the chance of repeat motor problems by inspecting the HS720 after every hard landing.
Small issues caught early are much easier to fix than a motor that has been forced through multiple flights with hidden damage.
- Check propellers for chips and replace them immediately if damaged.
- Inspect each motor for smooth rotation before the next flight.
- Keep the drone clean so debris does not enter the motor area.
- Use controlled takeoffs and avoid flying close to hard obstacles.
- Land before the battery gets too low, since weak voltage can amplify crash-related issues.
For pilots dealing with a Holy Stone HS720 motor not spinning after crash, the key is to separate mechanical damage from electrical failure as quickly as possible.
That approach leads to faster repairs, fewer replacement mistakes, and a better chance of getting the drone back in the air.