3D Printer shutting down laptop

Hi,

I am building my first 3D Printer and am having issues with my electronics. So I received a replacement RAMPS and Mega today and installed them into the printer. Unfortunately I encountered the same problems as before.

Firstly with USB only:
The LCD turned on and displayed the info screen as normal. I could connect the printer to pronterface also.

Secondly with USB and wall power:
System turned on however my laptop was shutdown hard. (USB over current?)

Thirdly with only wall power:
The LCD display no longer displayed the info screen but instead displayed all pixels switched on. All fans appeared to be working also. When attempting to reconnect the USB the laptop shutdown instantly again.

I have checked all my wiring and the input voltages are 12.3V on both lines going into the RAMPS 1.4

Thank you for any help or ideas! Im happy to answer any further questions about this issue also.

... it's mostly the potential GND (housing) of the laptop and GND of the 'wall power' PS are not equal, so you'll get some Amperes of current over the USB-cable shield.

Best search another PS with correct grounding ...

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Hi Viktor,

I just had a check and the power supply had a 0.8V difference between its 0V rail and that of my laptop. You where spot on!
However as always answering one question only leads to more questions,

Do you think that this issue had the "potential" (ignore the pun if you wish) to damage my RAMPS 1.4 and Mega2650 ?

And further more, is it possible to normalize the Potential difference between the two or should I request a new power supply from my supplier?

Thank you!

... damage 'potential' is there, sure ... but it can wreck the USB-port of your notebook too, what would be much more problematic

You can short out the potential difference by connecting the GND/housing of laptop and PS ...

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Beware of two switching power supplies. They can be out of phase with each other. Need a scope to determine that. Had people try to connect to power supplies together and blew out both.

I have connected my desktop PC via USB extensions and the grounding appears to be very much the same between the 18A dell power pack(for printer) and my 1kw ATX (for pc) and am no longer crashing a computer every time i turn the printer on. However it is crashing the USB connection to pronterface with the error: [ERROR] Can't write to printer (disconnected?) (SerialException): Write timeout.

Furthermore when the printer is powered by mains the LCD stops working and just shows all pixels illuminated and all the fans slowly increase in speed. Any Ideas?

Edited 1 time(s). Last edit at 10/24/2015 07:22PM by Jonsmith9847.

My usual advice in this situation is to run the PC and the printer and nothing else from the same mains power distribution block, and to use a USB cable with a ferrite bead on it. Also make sure that the ground side of the power connection between the printer electronics and the PSU is secure, otherwise the printer may attempt to draw ground current through the USB cable.

To avoid the problem caused by the USB ground loop completely, don't use USB to control your printer; use Ethernet, Wifi or Bluetooth instead.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Question is, why is my LCD display not working when power from the PSU is supplied even when the USB is disconnected?


When power from only USB is applied the display works and all the information readouts work. Is this due to the PSU'S 0V/GND being 0.8Vs off?

Quote
Jonsmith9847
Question is, why is my LCD display not working when power from the PSU is supplied even when the USB is disconnected?

When power from only USB is applied the display works and all the information readouts work. Is this due to the PSU'S 0V/GND being 0.8Vs off?

It's because you are using the cheapest available electronics (i.e. Arduino/RAMPS clone), and it is well known that the 5V regulator on the Arduino isn't capable of providing any significant current on the 5V rail to anything else. The LCD backlight current is causing the regulator to overheat. This is a very common problem with Arduino/RAMPS. Somebody really ought to list this as a known issue on the RAMPS wiki page.

Your options include:

- Provide external 5V power. Easy if you are using an ATX power supply, otherwise you will need a 5V regulator board, which you can buy on eBay.
- Replace the Arduino by a Taurino, which has a beefier voltage regulator.
- Disconnect the LCD backlight anode from the 5V rail and drive it instead through a resistor from the 12V rail.
- Ditch the ancient Arduino/RAMPS combination and get a modern all-in-one 3D printer controller board that is properly designed for the job. For example Duet or Smoothieboard or one of their clones.

Edited 1 time(s). Last edit at 10/25/2015 03:11PM by dc42.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].