3 Steps How To Fix a Shredder That Won’t Turn Off

Is your paper shredder running constantly or won’t turn off? Learn how to clean blocked sensors, clear stuck paper, and reset the motor to fix a shredder that won’t stop.

Quick Fix: Shredder Won’t Stop Running?

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If your paper shredder continues to run even after the paper has passed through, it is usually caused by the sensor. Try these three steps to stop the motor:

Sensor Clear (Most Common): Unplug the shredder and use a can of compressed air or a soft cotton swab to clean the small glass eye (infrared sensor) located in the center of the paper feed slot. Dust or a tiny scrap of paper is likely trickling the sensor into thinking there is still a document in the throat.
Reverse Flush: Plug the unit back in and switch it to REVERSE for 5 seconds. This can often dislodge a microscopic sliver of paper that is hanging directly over the sensor.
Power Cycle: Switch the unit to OFF and leave it unplugged for 1 minute. This allows the internal logic board to reset if a temporary electronic glitch is keeping the “Run” command active.

Safety Warning: If the shredder is hot to the touch or smells like burning electronics, leave it unplugged. The internal “auto-on” switch may have failed mechanically, and the motor needs to cool down to prevent damage.

Paper Shredder With Sensor Issues

A shredder that keeps running has sensor-related issues. This usually does not indicate mechanical or electronic problems. Wipe away dust or debris from the sensors.

Infrared (IR) Sensors. About 90% of the time, a shredder that won’t turn off is simply blinded by a piece of paper dust covering the sensor, making it think there is always paper in the feeder.

Types of Shredder Sensors

The auto-start/stop sensor
A bin/bag sensor
An overload sensor
A load indicator sensor

Mechanical Sensor Auto Start/Stop

This type of sensor consists of a metallic part that is depressed once a paper is fit into the tray. This signals the machine to start shredding. Once the document’s weight disappears from the tray, the sensor returns to its position and the shredder stops.

This type of sensor is disadvantaged as its sensitivity reduces over time and is the main reason for the dysfunction in these types of shredders.

Photo Sensor Auto Start/Stop

This sensor is more reliable than the mechanical subtype as it covers almost the entire tray. It consists of a detector and a light source easily identifiable by a color marking. A photo sensor malfunctions mainly due to damage caused by dust.

Photo sensors have a protective mechanism and should never be disabled to prevent exposure to dangerous accidents and consequences.

Where Is the Sensor Located?

shredder that won't turn off. sensor location

Identifying and locating the sensor is the first step in troubleshooting your shredder. Most shredders, including models from Fellowes, MBM, GBC, Martin Yale, HSM, and Dahle, have sensors placed near various parts. After turning off the machine, you can use a flashlight to locate the sensor.

The sensor location is identified using the user manual. The mechanical type of sensor is located at the top of the shredder. In contrast, the photosensor can be found in the center of the paper entry throat.

Suppose your model has safety flaps over its cutters, in that case, you will have to remove them before the sensor can be located safely.

How To Clean a Shredder Sensor?

Once the sensor has been successfully located using a flashlight, it can be cleaned using a variety of objects. A cotton swab, straw, or soft fiber cloth can easily clean the sensor. However, the exact method to clean it will be different for both the photo and mechanical sensor.

This YouTube video will give you a fundamental understanding of how to clean your shredder sensor:

How to Clean a Photo Sensor?

To clean a photo sensor do the following:

Unplug and remove your device from the power source.
Locate the sensor.
Dip the cotton swab or the soft fiber cloth in isopropyl alcohol or propanol (it should be damp, not dripping).
Clean all sensor parts carefully, removing the dust, oil, and debris, without damaging any sensor part.

However, accessing the sensor in some shredding machines might be challenging. After unplugging and removing the appliance from the source, you should take the paper catch bin out and turn the shredder upside down. Then, use a screwdriver to unscrew the machine, flip the unit with the right side facing up and the top piece held firmly.

One side of the top piece will be looser than the other end thus you can carefully remove it without damaging any parts.The shredder sensor should not be easily visible.

How to Clean a Mechanical Sensor?

Unfortunately, a mechanical sensor doesn’t have as simple a fix as cleaning it with a piece of cotton. This is because, in most cases, the issue lies in the sensitivity of the tray that signals the machine to start/stop shredding.

A mechanical sensor that won’t stop after shredding might have dust, food, or a definite article forcing down the tray. Paper parts are commonly found forcing down the sensor in this type of shredder. You need to carefully examine the paper tray in your device, and if stuck, disassemble and then reassemble it.

You can also try inserting a pointed object (a toothpick or needle) into the sensor’s hole to see if there is any difference in the machine’s behavior. Finally, if all else fails, replace the part.

Video Instructions

This YouTube video does well in explaining how to fix a paper shredder that won’t stop:

Prevention of Sensor Malfunction

Sensors are subject to wear and tear like all electrical and mechanical equipment. Simple maintenance is the easiest way to prevent these issues:

Clean the auto-start/off sensor and related parts thoroughly in case of a photo sensor.
A mechanical sensor is rarely fixed by simply cleaning it. However, it can be repaired or replaced.
Clean the paper detection sensors.
Ensure that the shredder is not placed directly under excessive sunlight; this can easily damage the sensors.
Make sure to maintain your shredder thoroughly and regularly.
Use soft cloths, vacuum, and cotton swabs dampened with alcohol for cleaning.
The shredder blades work by cutting the paper. The dust eventually builds up, which wears them down. Thus you should regularly oil the blades as instructed in the manual.
In case of any issues, place a service call or contact your manufacturer’s customer support.

Document Dynamix has also provided an online guide to troubleshooting problems related to your shredder machine.

How Long Can You Run a Paper Shredder?

The most important factor in shredder longevity is the “Duty Cycle”—the maximum time a motor can run before it risks permanent heat damage.

The Run-Time Reality: Most standard home shredders are designed for “intermittent use,” meaning they can only run continuously for 2 to 10 minutes before the thermal safety switch kicks in and shuts the machine down.
The Cool-Down Wait: Once a shredder overheats, the cool-down period is almost always significantly longer than the run time. A basic model that shreds for 3 minutes may require a 30 to 40-minute break to reach a safe operating temperature.
Performance Tiers:
Pro-Tip for Longevity: To extend the life of the motor, avoid “maxing out” the sheet capacity. Feeding 5 sheets into an 8-sheet capacity shredder reduces strain and friction, keeping the motor cooler for longer.
Maintenance Matters: Friction is the primary cause of heat. Regular oiling of the blades (using dedicated shredder oil) ensures the motor doesn’t have to work as hard, which can slightly extend your active run time per session.

How to Use a Paper Shredder

Follow these easy steps to use your new paper shredder.

Unpackage the shredder completely, being careful to remove all of the packaging components around the blades and trash drawer.
Review the user manual for tips and limitations on the machine.
Plug in the shredder and turn it on.
Carefully insert dry, clean documents that are free of staples, paper clips or more.
Turn of the machine when not in use and empty the paper tray often.
Keep the shredder in a well-ventilated place and avoid overheating.

A Few Safety Tips

Here are a few safety tips to get you started before using your paper shredder. These will make sure to stop any silly mistakes that could be made during the paper shredding process:

Always inspect your shredder for damage just before use. This could stop any accidents from occurring before they have even happened.
Keep the power cord away from foot traffic areas, as this could cause tripping hazards for any passers-by.
Keep the location of the shredder away from a wall to stop any chance of overheating.
Always have your full and undivided attention on the shredder; this will stop any chance of mistakes from a lack of awareness.
Don’t ever put anything in the shredder except for paper. Each shredder has a limit, so don’t put more than it can handle at once.
Push the paper gently through the shredder one sheet at a time. This will allow the shredder to do its job properly.
If you feel the machine getting too hot, turn it off immediately. Allow the shredder to cool down before turning it back on.
Always turn the machine off and unplug it after use.