Denon Receiver Turns Off and Blinks Red Quick Fixes

Norvan Martin
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 Denon receivers are excellent devices for improving your home entertainment experience. However, even modern Denon receivers may develop a problem where they turn off and blink red. Keep reading for details about what this means and how to fix it.

The Denon receiver red light is known as the Protection Mode Light. The light comes on when:

  • Current sensors detect unusual conditions.
  • Heat sensors notice potential dangers.
  • The device is restarting to attempt to resolve the issue.

Let’s get into more detail about what the Denon protection mode is and how to fix it

Quick Fix

If your Denon Receiver continually shuts off and displays a red blinking light:

  1. Unplug all the speakers from the receiver and then turn it on.
  2. If the issue persists, there’s likely an issue with the receiver itself.
  3. If the problem stops, plug in one speaker and turn the receiver on.
  4. If everything’s fine, plug in another speaker and power up again.
  5. Continue this process, adding one speaker at a time. If the receiver shuts off at any point, the last speaker or wire connected could be the culprit.

If your Denon receiver turns off and then blinks red, it indicates that it is in “protect” mode. In other words, your receiver has detected a problem and shuts down to prevent further damage.

It blinks red to advise you to fix the issue as quickly as possible before attempting to reuse it. This can happen if there is a current surge or if the device is overheating.

For example, the Denon 4306 often shuts off at high volume if it is being driven too hard and overheating or there is an overcurrent issue. 

How Do You Fix a Blinking Red Light on a Denon Receiver?

If you want to fix your Denon receiver that keeps turning off and blinking red, we recommend that you do the following:

1. Increase Ventilation

Consider increasing ventilation since it’s one of the most common culprits. It’s easy to fix. Follow the steps below to achieve your goal.

  1. Remove physical objects near the receiver (Ensure the room is spacious enough)
  2. Give a few minutes of cooling time (Wait for the protection light to go out)
  3. Try powering on the receiver

denon receiver overheating


You can use an AV receiver cooling fan like the AC Infinity AIRCOM S6, Quiet Cooling Fan or a laptop cooler like shown in the image above to help you cool the device faster. A good choice for this purpose is the TeckNet Laptop Cooling Pad, 6-Fan Notebook Laptop Cooler Cooling Pad with LED Lights, Dual 2.0 USB Ports, Suitable for 12-19 Inch Laptops.
Note: The circuitry will reset automatically during the cooling time. Once everything is fine, the protection light will go out.

2. Check Your Speaker Connections

When your connections don’t allow the seamless transmission of electric signals or current, your Denon receiver will experience this problem. You should do the following to fix it:

  1. Turn off the receiver
  2. Check all the wire connections
  3. Ensure the wires are firmly connected
  4. Turn on the receiver
  5. If the protection light turns on immediately, disconnect your speaker wires at the side of the receiver
  6. Reconnect the speaker wires one by one to try to detect the faulty one and replace it
  7. Ensure all the speaker connectors are set up correctly and not damaged. 

3. Fix any Impedance Issues

If you follow the above step and the protection light turns on after a while or when you increase the volume, your speaker impedance could be lower than required.4 ohm speakers and receiver

Confirm whether this is the case by reading the ohm values indicated on the receiver and the speakers.

Remember that if the speaker resistance is too low, it will pull too much current from the receiver. In this case, the receiver might turn off almost immediately. For example, if you use a 4 ohm speaker with your receiver, you should keep the volume low, or the receiver will go into protect mode, and you will risk damaging it. However, there are some receivers that support 4 ohm speakers

What should I do if lower speaker impedance is the issue? You have two options. These are:

  1. Match the impedance: This involves buying modern speakers that match your Denon receiver. Check the manual, but in most cases, 8 ohm speakers are a good choice. If you don’t want to spend on this for any reason, you can opt for the following method.
  2. Use Series Connection: Series connection allows you to increase your speaker impedance quickly by using multiple speakers. The impedance will equal the sum of the resistors since you are connecting your speakers end-to-end.

Note: Choosing a parallel connection won’t help you in this case since it reduces speaker impedance. To calculate the speaker impedance, you multiply the value of your resistors and then divide the result by the sum of their values. Since this connection reduces the speaker impedance, it could worsen the situation.

4. Reset the Receiver/Initialize the Microprocessor

If none of the above steps work for you, initialize your receiver’s microprocessor. In simple language, reset the receiver.

  • The process is simple, and you’ll hardly require more than a minute, though it’s highly effective.
  • Once you are done, your receiver might be as good as new.
  • Check the owner’s manual for the correct procedure for your Denon receiver model.

Note: Reset your Denon receiver as a last resort. This process will delete all the setup configurations, meaning you’ll need to set up your system again once you’re done.

5. Call an Authorized Repair Expert

If you have tried everything within your means and everything fails, or you can’t reset the receiver yourself, take the machine to an authorized Denon repair center.

  • They’ll use advanced tools to diagnose the nature of repairs that the device requires.
  • Remember that you’ll need an authorized Denon repair expert if you believe that the device has malfunctioned.
  • In some cases, as you troubleshoot, you might discover that you have electrical issues. Maybe the power outlet is defective. In this case, call a certified and experienced electrician instead.

Why Does My Denon Receiver Keep Turning Off?

Suppose you allow the receiver to sit for a while, but when you turn it on, it keeps turning off. Your Denon receiver could be turning off and blinking red for the following reasons:

1. Hardware Issues

Hardware or physical problems can cause your Denon receiver to keep turning off and blinking red. A short or bad speaker will likely cause this. Generally, any issue with your connections can lead to this problem.

2. Software Bugs

Software-related bugs in the microprocessor can also send incorrect signals, triggering the device to turn off and blink red. Some of these problems might go away on their own after a while. In some instances, if you power on the device again, it may work perfectly.

If this problem starts after a firmware update, check out our guide on how to update your Denon receiver firmware and how to fix firmware update issues.

3. Lack of Ventilation

A lack of proper ventilation is another common reason your Denon might turn off and then blink red. The circuitry typically produces a lot of heat.

However, it cannot operate effectively in a hot environment. So, when your receiver overheats, it shuts off to prevent damage to your audio system.

4. Low-Speaker Impedance

Low speaker impedance is a common cause of this issue that many people often overlook because they don’t understand the consequences.

If your speaker or speakers have low impedance, it means they require more power than your receiver can supply. An impedance mismatch can cause the receiver to overheat and damage your speakers and other devices.

If you use a low-impedance speaker at a low volume, you might not experience this issue. Remember, the amount of current speakers need often increases as the volume goes up.

In conclusion, if your receiver keeps turning off, consider overheating due to impedance mismatch and lack of ventilation as primary culprits. This advice is relevant unless you have reason to believe otherwise.

How Do You Reset A Denon Receiver?

If you’ve tried all the tips we’ve shared here without success, consider resetting your Denon receiver. This method reboots the receiver’s microprocessor to restore normal operations. Consult your user’s manual for the proper steps to follow.

To reset your AVR-S510BT Denon receiver, make sure the receiver’s power is off. Then, press and hold the “SOUND MODE,” “TUNER PRESET CH+,” and “POWER” buttons simultaneously until the display starts flashing at approximately one-second intervals.


Modern Denon receivers are designed to turn off and blink red when they detect potential damage. Understanding these issues can help reduce stress if your Denon receiver starts behaving this way. This article has covered the essentials to help you identify the root causes of problems and how to address

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Norvan Martin is the founder of He is a professional Electronics Engineer and is passionate about home theater systems and AV electronics. BoomSpeaker was created as an online hub to share his knowledge and experiences as it relates to home theaters and home audio electronics. My email: [email protected]  Connect on Pinterest and Linkedin