RAMPS 1.4 issue - Laptop turns off when connecting RAMPS on 12V PSU

Just finished the assembly of my Prusa i3 and started dealing with the electronics.

I have Sintron clones of RAMPs 1.4 and Arduino ATmega2560 and a 30A 12V power supply.



Here is what happened in order:

1. I tried plugging the Arduino with the RAMPS shield attached into my laptop (usb only) to upload the firmware. No LEDs on the Arduino turned on and there was no sign of the Arduino in my device manager.

2. I unplugged the RAMPS shield and just plugged in the Arduino to my laptop. The led blinked and I successfully uploaded the Marlin firmware.

3. I then plugged in the RAMPS to the Arduino and powered up the RAMPS and Arduino with my stepper drivers inserted (correct orientation) using just 12V from PSU. LEDs came on on Arduino.

It smelled a bit funny to begin with but I was unsure if that was to do with the heat due to the stepper drivers. I tuned them with my multi-meter using the turn pots and they all tuned fine to ~0.4V but a couple got very hot very quickly.

4. I then proceeded to plug the USB cable into my laptop (Lenovo T430s) and my laptop shut down immediately. Disconnected the battery of my laptop and put it back in and laptop starts up fine.

5. Removed all stepper drivers from RAMPS and plugged USB cable into laptop again with 12V PSU also on. Same thing happened, Laptop turned off immediately.

6. Measured resistance across 5A and 11A input terminals on RAMPS when disconnected. Infinite resistance on 11A, sometimes finite resistance read on 5A terminals but never close to 0.

7. Now when I just connect the Arduino to my Laptop, the ON LED turns on but not the blinking LED and it does not show up in Device Manager.



What is likely to be the problem?

What is the best way to troubleshoot/fix the issue?




Many Thanks!

PLEASE HELP!


Replaced my Arduino and RAMPS board, successfully uploaded the firmware with just the Arduino connected.

However, when I connected RAMPS + Arduino to mains power and USB it immediately turned my laptop off like before.


Then tried using an external USB hub with mains power and successfully uploaded firmware to Arduino with RAMPS attached (just US.

Then connected RAMPS + Arduino to mains power via external USB hub to laptop and it did not turn my laptop off. However, the Arduino is not visible in device manager under Ports.



Now this strange thing happened: I then tried connecting RAMPS + Arduino to mains power without the external USB hub to my laptop and it did not turn my laptop off...

However, now the Arduino does not show up in my device manager when connecting using just USB...


How can I fix this?


See images attached of my setup:

I don't normally answer RAMPS support questions, but as nobody else has responded:

Was the laptop running from batteries when you connected the USB cable and it shut down, or was it plugged into the mains?

If the problem occurs when it is plugged into the mains but not when it is running from batteries, then the problem is most likely caused by the USB ground loop that you get when you connect two grounded mains powered appliances via USB. The first thing to check is the soundness of the connection between the negative output of the printer power supply and the input terminals of the RAMPS.

Edited 1 time(s). Last edit at 06/24/2016 04:11PM by dc42.

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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].

Laptop turns off if its plugged into mains and when battery powered.

That connection is fine. Could it be a faulty power supply/mains cable?

How can I check the PSU with my multimeter?

I don't want to fry another arduino board.

Quote
jcdrbm
Laptop turns off if its plugged into mains and when battery powered.

Can you confirm that when you tested that, the laptop was not connected to any other mains-powered equipment apart from the printer?

If so, then I think the 3D printer much be feeding current into the USB port somehow. It's hard to see how that could happen unless you have a short between the 12V input and the 5V output on the Arduino. I guess the 5V regulator on the Arduino might fail in that way, although I've not heard of that failure mode happening before. Those regulators do fail frequently, because although they are capable of supplying the Arduino + RAMPS, adding extra load on the 5V rail such as a servo or graphical LCD overloads them.

You could try applying 12V power without the USB port connected, and measure the voltage on the 5V output.

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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].

I can confirm that the only thing the laptop was connected to was the arduino/RAMPS setup.


I've just got a new Arduino ATMega2560 and tested it with USB and measured 5.04V on the 5V output. It was recognized under COMS in device manager.

Then tested the Arduino connected to RAMPS (nothing else connected) with USB only and again measured 5.04V. (Also recognized in Device manager)

Then Arduino connected to RAMPS to 12V from PSU only and measured 4.85V on the 5V output.


Is the 4.85V normal?


I then tested Arduino + USB and Arduino & RAMPS + USB and measured 5.04V each time, both times devices recognized in device manager.

So, I tried it and all was well until I connected the 3rd stepper driver and when I plugged in my laptop it turned off immediately, and after this, the laptop could not connect to RAMPS on pronterface.

I think I can assume that this driver could have caused at least some of my issues...


Anyway, everything is working now for the first time with no laptop issues after replacing the stepper driver and boards!

Thanks dc42 for your help.