Sustained beeping at startup

My Ender 3 v2 was working perfectly. I shut her down for the night, and the next morning when I started her up, I just got sustained beeping and a blank screen. From online searches, I am thinking the power on created a surge. I’m seeing things about perhaps updating the firmware to fix this, but wondering if there are other recommendations here. (I will be checking out the post here on how to update firmware, if that’ll fix it.)

Also, I am now thinking I should never shut down my machines. They are on surge protectors, but this seems to be a “surge” from startup, not from my house electricity line. Is there any way to avoid this happening in the future besides just leaving my machines on all the time?

Let’s start with the easiest test you can do that doesn’t involve unplugging or unscrewing anything:

With the printer turned on, plug it’s USB port into your computer. Open a communications terminal program (NOT a command prompt) like Putty or the Arduino IDE.

In the terminal program, select whichever COM/TTY/Serial port is applicable (you may have to experiment to find it)

Set the Baud rate to 115200, the printers default speed.

In the SEND bar/window, type M503 and, of course, .

The printer should then reports it’s current settings.

You don’t care about the settings, you just care that the controller board is alive and talking to you.


Step 2: If the terminal test fails, turn the power off and unplug all the stepper motors, the bed heater and the hot-end heater and fans.

Turn the power on. If it started, one of your devices is overloading the controller board. Power off, plug things in one or two at a time and restart. Rinse and repeat until you find the one that causes the failure.

Step 3: If unplugging everything did NOT fix the problem, you’ll have to unscrew the bottom of the printer and access the power supply. If you aren’t familiar with working with electricity, beware that the power supply has 120V exposed on the terminal strip. Use a voltmeter, turn the power on, and read the voltage between any of the three terminals marked “+” and any of the three terminal marked “-”. It should read 24V. If it does read 24V and your controller board is not communicating with nothing attached to it other than the USB cable (previous post), then the controller board needs to be replaced. If it does not read 24V, move to the next step.

Step 4: If it doesn’t read 24V, unplug the power and remove all the leads on the “+” and “-” terminals, leaving only the 120V and Ground leads connected. Turn on the power and measure the voltage between “+” and “-”. It should read 24V. If not, the power supply is dead. If it does, the controller board has an internal short and needs to be replaced.


A very nice hardware troubleshooting summary.

Wow! I love your response - it is so thorough!!! Unfortunately, it’s over my head for some of these things, so I’ll bring it into the store to fix. But I will slowly learn, especially with this kind of detailed response. Thank you so much!!

Don’t give up so easily.
Take it slowly and focus on each step to avoid getting intimidated by the whole possible process.
You may have to buy a multimeter but that is a useful tool to have around the house even if you only use it to check batteries.
A cheap item and a lot less than the cost of getting a tech to even talk to you!

If you get to a step with which you are having trouble, ask a question.

Don’t think about all the steps just do the first one and see where that gets you…

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So try the steps that are not over your head. Ask for clarification on things that are. It’s really not difficult to do once you break it down into manageable steps plus you learn more and gain more confidence along the way. Then, if all else fails, bring it to the store. You’ll end up paying the same anyway.

Thank you for this.

It ended up that by reloading the firmware, the beeping stopped. (Yay!) However, now when I “auto home”, nothing moves, so I have a feeling it’s the firmware for the bl-touch (which I don’t have), so I’m going to try reinstalling the firmware and trying to make sure it’s the right one.

Thanks again for all of the help!!!