The Dewalt DCS391 circular saw is a renowned power tool, lauded for its durability and precision in the woodworking community.
However, even a stalwart can sometimes show signs of failure. If you’re encountering issues with your DCS391 not working correctly, don’t fret.
This post is your troubleshooter’s guide, covering seven common fixes for a Dewalt DCS391 that has lost its sawdust-chewing charm.
Why is the Dewalt DCS391 Not Working?
Before diving into the possible solutions, it’s essential to understand why your Dewalt DCS391 is having problems in the first place. The most common reasons behind a circular saw not working are:
- Lack of power supply: If your saw doesn’t turn on at all, it could be due to a faulty power outlet or cord.
- Malfunctioning blade: A dull or damaged blade can hinder the saw’s performance and cause it to overheat.
- Loose connections: Vibrations from regular use can cause wires and components to loosen, resulting in a malfunctioning saw.
- Clogged dust port: Sawdust buildup in the dust port can obstruct airflow, leading to overheating and stalling of the motor.
7 Fixes for a Dewalt DCS391 Not Working
Now that you’ve identified the potential causes, here are seven solutions to get your Dewalt DCS391 back up and running:
1. Check the Power Supply
The most obvious solution can often be the most overlooked one. Before launching into more complex repairs, check if your saw is getting the power it needs.
Here are some steps to ensure you’re not dealing with a simple power issue:
- Test the outlet by plugging in another gadget to see if it’s working.
- Inspect the power cord for any visible damage or wear. If present, replace the cord immediately.
- If your saw is cordless, ensure the battery is charged and properly inserted. Test the battery in another tool, if possible, to verify its condition.
By methodically eliminating each potential issue, you are likely to find the root of the problem and be back to cutting in no time.
2. Examine the Safety Mechanisms
Circular saws, including the Dewalt DCS391, are equipped with multiple safety features that can prevent the saw from operating if not properly set. Here’s what to look out for:
- Trigger safety: Many saws have a two-step process where you need to engage a secondary lever before pulling the trigger. Ensure you’re following the correct sequence and that the safety isn’t locked into place.
- Blade guard: If the blade guard is stuck, it can prevent the blade from spinning. Check for debris or damage that could be causing it to malfunction.
Always operate your saw while adhering to the recommended safety guidelines outlined in the manual.
3. The Brushes and Motor
The motor brushes on your circular saw transfer electricity to the spinning armature. Over time, these brushes can wear out, leading to motor failure. You can inspect and replace the brushes using the following steps:
- Unscrew the motor housing and carefully remove it.
- Look for the brushes on either side of the motor. If they are less than ¼ inch long, it’s time to replace them.
- Obtain the correct replacement brushes from Dewalt and gently insert them into their respective housings.
Motor issues can be more challenging to troubleshoot and solve, but examining and replacing the brushes is a critical step in the process.
4. Assess the Trigger Mechanism
The trigger on your saw may have become faulty, preventing it from sending the necessary signals to the motor. To check and possibly repair the trigger:
- Disassemble the handle to access the trigger mechanism.
- Use a multimeter to test if the trigger is sending the appropriate amount of electricity to the motor when pulled.
- If you notice a problem or the trigger fails to function, you may need to replace it. Order a new trigger from Dewalt and follow the provided instructions for installation.
The trigger is a common failure point in many power tools, so a swap-out might be a simple fix to your saw not working.
5. Blade and Spindle Issues
A dull blade or issues with the spindle can lead to operational problems with your saw. Perform the following checks:
- Blade sharpness: A dull blade can cause the saw to seize up. Replace or sharpen the blade according to the manufacturer’s recommendations.
- Spindle play: With the saw unplugged, try moving the spindle left and right. If there is excessive play, the spindle bearings may be damaged and require replacement.
Maintaining a sharp blade and ensuring the spindle is in good condition is important for the efficient and safe operation of your circular saw.
6. The Switch and Wiring
The power switch on your saw functions similarly to the trigger and can also deteriorate over time. To troubleshoot the switch:
- Disassemble the handle and locate the switch.
- Use a multimeter to check for continuity when turning the switch on and off.
- If there is no continuity, or if the multimeter reading fluctuates, the switch is likely faulty and should be replaced.
Additionally, inspect the wiring for any signs of fraying or disconnection. Reconnect wires as needed or replace them with new ones if damaged.
7. Drive Train Problems
Issues with the gears or belt that comprise the drive train can lead to operational difficulties. Here’s how to investigate:
- Remove the motor housing and inspect the gears for damage.
- If the gears are stripped or show significant wear, you will need to order and install a gear assembly replacement from Dewalt.
- Check the drive belt for tightness and signs of wear. Replace the belt if it is damaged and ensure it is properly tensioned upon reassembly.
The drive train transfers power from the motor to the blade, so any issues with its components can cause your saw to malfunction.
8. Replace the battery:
If you have a cordless Dewalt DCS391, another potential cause for your saw not working could be a faulty battery.
If you’ve exhausted all other troubleshooting methods and the problem persists, try replacing the battery with a new one.
This is especially important if your saw has been in use for a long time and the battery may be reaching the end of its lifespan.
here’s how to replace the battery:
- Turn off and unplug the saw.
- Press the release button on the battery to remove it from the tool.
- Insert a new fully charged battery into the slot until it clicks into place.
9. Contact Dewalt Directly
If you’ve gone through all of the above steps and your Dewalt DCS391 circular saw still isn’t working, it may be time to contact Dewalt directly for further assistance.
You can contact Dewalt’s customer service at 800-433-9258 or You can email your problem at support.dewalt@sbdinc.com.
They have a team of experts who can help troubleshoot and provide guidance on how to resolve any issues with their tools. Additionally, if your saw is still under warranty, they may be able to provide a repair or replacement.
Conclusion:
While it can be frustrating when your circular saw stops working, troubleshooting the issue and finding a solution can save you time and money in the long run.
By following these steps and properly maintaining your saw, you can ensure smooth operation for all your DIY projects.
Always prioritize safety when handling power tools and consult a professional if you are unsure of how to proceed with repairs. Invest in a quality circular saw like the Dewalt DCS391 and take care of it, and it will serve you well for years to come.
