the saw's electric brake doesn't seem to work, blade spins for a long time after i let go of the trigger.

Diagnosis

The Makita XSR01Z utilizes a sophisticated electronic braking system that relies on the motor's back-EMF (electromotive force) to rapidly decelerate the blade upon trigger release. Unlike mechanical brakes that use a physical friction pad, this system works by reversing the polarity or shorting the motor windings to create a counter-torque. When the blade continues to coast for several seconds after the trigger is released, it indicates a failure in the electronic braking circuit, typically localized within the motor controller or the trigger switch assembly. This failure is often caused by carbon dust buildup inside the switch housing or a failure in the capacitors within the control board that manage the braking current. If the switch does not return to its "neutral" position fully or if the internal contacts are pitted, the signal to engage the brake is never sent to the controller. You can confirm this by observing the blade speed: a functioning brake should stop a 7-1/4" blade almost instantly; if it takes more than 2 seconds to stop, the electronic brake is definitively non-operational.

How to Fix It

To resolve this issue, you must first ensure the electrical signal is reaching the controller and then inspect the internal switch mechanism for debris. Follow these steps precisely:

1. Power Isolation: Remove both 18V batteries from the XSR01Z to ensure there is no residual current in the system.
2. Case Disassembly: Using a T20 Torx driver, remove the screws securing the plastic housing. Carefully lift the upper shell, being mindful of the wiring harness connecting the trigger to the main control board.
3. Switch Cleaning: Locate the trigger switch assembly. Use a can of high-pressure electronic contact cleaner (such as QD Contact Cleaner). Spray the cleaner directly into the trigger mechanism and the micro-switches. Rapidly pull the trigger 20-30 times to work the solvent into the contacts and clear out any sawdust or metallic shavings.
4. Connection Check: Inspect the wiring harness connecting the trigger to the motor controller. Look for any pinched wires or loose spade connectors. If a wire is frayed, strip the end and re-crimp it using a 0.25-inch female spade connector.
5. Control Board Inspection: Visually inspect the PCB for any "burnt" smell or blackened capacitors. If the board looks clean, use a soft brush to remove any conductive dust that may be bridging the braking circuit.
6. Reassembly and Test: Reinstall the housing and screws. Insert two fully charged 5.0Ah or 6.0Ah LXT batteries. Perform a "dry run" without a blade first to see if the motor stops abruptly, then test with a blade installed.

If That Didn't Work

• Replace the Trigger Switch Assembly: If cleaning doesn't work, the internal micro-switch responsible for the braking signal has likely failed. You will need to replace the entire trigger assembly. Ensure you order the specific part for the XSR01Z, as the switches for the front-handle models are not interchangeable.
• Replace the Motor Controller Board: If the trigger is functioning but the blade still coasts, the MOSFETs on the electronic control board have likely blown. This requires a full replacement of the PCB. This is a common failure point if the saw has been used heavily in extremely high-temperature environments without adequate cooling.
• Check Battery Communication: The XSR01Z requires synchronized power from both batteries. If one battery has a failing cell or a damaged terminal, the voltage drop during the braking phase can prevent the brake from engaging. Test the saw with a completely different set of known-good 18V batteries to rule out power delivery issues.

Heads Up

• Safety Warning: Never attempt to test the electronic brake without the guard in place. A malfunctioning brake can lead to dangerous "kick-back" if the blade doesn't stop before you move the tool.
• Dust Prevention: The XSR01Z is a high-performance tool, but sawdust is its enemy. Periodically blow out the trigger area and motor vents with compressed air every 10-15 hours of use to prevent the braking circuit from clogging.
• Battery Matching: Always use two batteries of the same capacity (e.g., two 5.0Ah) and the same charge level. Mismatched batteries can cause erratic behavior in the electronic braking and speed control systems.
• Blade Choice: Be aware that extremely heavy-duty, high-tooth-count blades have more rotational inertia, which puts more strain on the electronic brake. Ensure your blade is sharp; a dull blade creates more drag, which can actually mask a failing brake.