Arduino Mega voltage regulator overheats with RAMPS board
This is my problem:
I'm assembling a 3D printer with the RAMPS 1.4 board and Arduino Mega. I have assembled the structure and the electronics (set drivers, placed the jumpers, connected stepper motors...) and have uploaded Marlin firmware (configuring: thermistor, endstops...) on the Arduino Mega.
I've tried to connect, via USB, to the computer and using the Repetier software I have commanded the printer which did do some movement. The printer worked perfectly. After a few tests, however, I've noticed that the Arduino was restarting several times and at one point I saw a component on the Arduino board burning. Searching the internet I saw that the burned component was the voltage regulator.
I heard also about unplugging the screen because it consumes a lot of current, that passes through the voltage regulator, thereby heating it up. I then proceeded to buy another Arduino Mega. I also checked the voltage of my 12V 360W power supply and it is correct. I always powered the Arduino with USB and RAMPS 1.4 was connected to the power supply from the two terminals.
When the new Arduino arrived, I connected the whole (without connecting the screen) and tried. The printer worked very well until it started giving the same problem as the first Arduino board. Someone can tell me if I have done something wrong, or is it the RAMPS board that does not work properly?
I read that the endstops can cause this problem. I have these endstops: 1 PZ di Alta Qualità Finecorsa Meccanico Per rampe Reprap 1.4 stampante 3D Con imballaggio indipendente kit fai da te and I connected the black wire to GND, red wire to 5V and the green wire to SIGNAL.
It seem unlikely that the endstops particularly cause this problem. Yes, unplugging the screen will help (but not fix the problem). This seems like a hard problem to diagnose without some experience. With the screen disconnected, your electronics really shouldn't be taking too much power. Maybe it is the stepper motors, these are able to take a lot of power, particularly if there is a mechanical problem.
@SeanHoulihane Your last suggestion makes no sense, as the stepper motors are not powered using the 5V regulator.
I wouldn't be so quick to rule out the endstops. Perhaps the connector is backwards, or the black and green wires exchanged, who knows? Maybe try measuring the resistance between 5V and GND (on the RAMPS shield) with the endstops inserted (and triggered/not triggered).
@TomvanderZanden, I wasn't sure, thats why I didn't try to post an answer.
Thanks for the replies! I measured the endstops resistance between 5V and GND and when the endstop is not triggered there is no resistance but when i press the button there is resistance. I tested also the boards without endstops but the voltage regulator heat up the same (but now i think that arduino doesn't work very good because the computer doesn't recognize the board). @SeanHoulihane
@Francesco The resistance between 5V and GND being zero is a very bad sign. You hooked up the endstops wrong.
@Francesco - Did you manage to solve your problem? If so, would you like to post an answer, as it may prove to be very useful for someone else who is experiencing the same problem. Was the issue, as Tom suggests, related to the endstops? Indeed, if there *is* zero resistance (0 Ohms) between 5 V and GND, when the endstops are closed (not triggered), then that would indicate that there is a short circuit, and that is, most probably, what is damaging your Arduino board(s).
@Greenonline Yes i've solved. The problem was that the voltage regulator on the Arduino wasn't the original, so it wasn't able to absord too much current. To resolve the problem i unsoldered the diode(D1) on RAMPS board so the Arduino is only powered by the USB and everything works good.
@Francesco - that's great that you managed to fix the issue. It sounds as if other people would find this very useful information too. Could you expand upon your comment, maybe with a photo or two, and post it as an *answer* (not as a comment) and then *mark it as the accepted answer*, using the tick icon? That way, it will remove your question from the "Unanswered question" list. Thanks. :-)