<p>I have had the same Issue with my Maker select prusa printer, the way I found that best combats this is to attach the printer to a UPS and avoid attaching any High draw devices from the same circuit. Every Time i'd switch something on, My TV, my lights, etc. The same would happen. Hope this helps!</p>

CC BY-SA 3.0
2017-02-02T18:32:51.033Z
2017-02-02T18:32:51.033Z
Collin Willson
<p>I am running the SeeMeCNC customized version of <a href="https://github.com/seemecnc/Firmware" rel="nofollow noreferrer">Repetier</a> on a Rostock Max V2. I have experienced this problem with both the stock configuration along with an E3D The Chimera. Sometimes, when I am printing and connect a mains device, my printer will fail in some way. The first time this happened I was printing with ABS, so I connected my fume sucker (A ~25-50W fan) to an outlet. However, when I connected it, the LCD showed garbled characters and my software (MatterControl) reported an error. Restarting the printer returned it to the previous state. I had a ~15 foot (coiled) extension cord connected to a 3-way splitter.</p>

<p>Today, I connected a hot glue gun, and MatterControl reported that Repetier had switched to "Printer set into dry run mode until restart!" (no heat or extrusions). Looking at the firmware, this seems to be caused by a thermistor failure. I had everything plugged into the same setup as before, except for a surge protector at the end. The circuit that it is connected to has a 20A circuit breaker, with probably ~3A of it constantly used.</p>

<p>My theory for this is that an additional device causes a slight fluctuation in the thermistor wires, causing an error to occur. However, the Rostock Max is designed so that wires are inside of aluminum tubes, which I think would provide EMF protection. The power supply is a generic 12V 30A power supply that was included in the kit, usually seen in LED strips. Both of these occurred while printing. I have ordered a UPS for the printer: would its under/over-voltage detection help? Are there any other solutions for this?</p>

CC BY-SA 3.0
2017-01-29T08:00:19.163Z
You have a 5 m extension cord to which both your printer and the fan are connected? Or is the printer connected directly to an outlet and the device is connected to the cord? And this extension cord is largely coiled up?
Tom van der Zanden
CC BY-SA 3.0
2017-01-29T13:27:45.413Z
Currently, I have a short but thick extension cord, connected to the long extension cord (coiled), and then to a surge protector. I don't have many outlets near my printer, so I have to do that. Is that too long (and I replace the coiled extension cord with several short ones), or does coiling cause EMF, even with twisted pairs? Furthermore, I should mention that both cords and extension cords are from reputable sources, rated for 15A each.
lights0123
<electronics><switching-power-supply><repetier>
Print failing when connecting mains loads
lights0123
# Print failing when connecting mains loads

(Asked by: username_0 on 2017-01-29)

I am running the SeeMeCNC customized version of [Repetier](https://github.com/seemecnc/Firmware) on a Rostock Max V2. I have experienced this problem with both the stock configuration along with an E3D The Chimera. Sometimes, when I am printing and connect a mains device, my printer will fail in some way. The first time this happened I was printing with ABS, so I connected my fume sucker (A ~25-50W fan) to an outlet. However, when I connected it, the LCD showed garbled characters and my software (MatterControl) reported an error. Restarting the printer returned it to the previous state. I had a ~15 foot (coiled) extension cord connected to a 3-way splitter.

Today, I connected a hot glue gun, and MatterControl reported that Repetier had switched to "Printer set into dry run mode until restart!" (no heat or extrusions). Looking at the firmware, this seems to be caused by a thermistor failure. I had everything plugged into the same setup as before, except for a surge protector at the end. The circuit that it is connected to has a 20A circuit breaker, with probably ~3A of it constantly used.

My theory for this is that an additional device causes a slight fluctuation in the thermistor wires, causing an error to occur. However, the Rostock Max is designed so that wires are inside of aluminum tubes, which I think would provide EMF protection. The power supply is a generic 12V 30A power supply that was included in the kit, usually seen in LED strips. Both of these occurred while printing. I have ordered a UPS for the printer: would its under/over-voltage detection help? Are there any other solutions for this?

**Tags:** electronics, switching-power-supply, repetier

> **Comments:**
> **username_1**: You have a 5 m extension cord to which both your printer and the fan are connected? Or is the printer connected directly to an outlet and the device is connected to the cord? And this extension cord is largely coiled up?  
> **username_0**: Currently, I have a short but thick extension cord, connected to the long extension cord (coiled), and then to a surge protector. I don't have many outlets near my printer, so I have to do that. Is that too long (and I replace the coiled extension cord with several short ones), or does coiling cause EMF, even with twisted pairs? Furthermore, I should mention that both cords and extension cords are from reputable sources, rated for 15A each.  

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## 1 answers

### Answer by username_2 on 2017-02-02. Score: 2 | Accepted answer

I have had the same Issue with my Maker select prusa printer, the way I found that best combats this is to attach the printer to a UPS and avoid attaching any High draw devices from the same circuit. Every Time i'd switch something on, My TV, my lights, etc. The same would happen. Hope this helps!


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