Ramps keeps getting burned out, gettting tired of not having a full 3 digital pin selection.

Hi!

I have a Delta / Kossel type printer, I use arduino, repetier, RAMPS 1.4 for the printer. I have a problem with RAMPS 1.4, in that everytime I buy one, one of the digital pins usually fail, usually the extruder heater pin D10. I have had three now, that everytime I connect everything, then run repetier host, start heating up the extruder, it will heat up with the LED on, get to temp, and then the led will go off, the extruder will cool down, and then I am never able to heat up from that pin again. I'm just trying to get some input on how to stop frying this stupid things, usually I am able to still use D8 or D9 for the extruder and heated bed that I have, but now the third ramps that I have I bought so I could have three digital pins and have fan cooling capabilities, seems like all three have fried somehow because none of them are giving off the voltage, and the LED does not come on when I command to heat the extruder.

Would a resistor, diode, fuse or something stop me from frying these digital pins? Is it because I am buying cheap RAMPS boards and they aren't robust enough? This has happened with three different types of hot ends as well so I don't think it is a short or bad core.

Just looking for some input because I am going to try throwing in my old ramps board so I can print, but I don't want to buy a new RAMPS board, just to fry another pin and be back to square one.

this is very strange... no idea whats causing it, but suspect some sort of gnd issue between 12v and 5v gnd lines. (as motfets control gnd lines)

This shouldn’t be needed but...
You could try a optoisolator to a free io pin eg [www.sparkfun.com] just use 5v on the HV side, then drive a external mosfet board with that

Then just update your firmware so the hot end is on the new IO pin.

Are you just buying ramps boards?
The digital o/p is on the arduino so maybe you have a falty processor on the arduino.

Well I feel like a chum. I thought this ramps board was going to be like the other two, I had placed two diodes on the negative terminals for the 12v hookups to stop from having any current go through the negative, they were split in half for some reason. The D10 and D8 pins seem to work fine.

I do have this problem with multiple ramps boards though, this one hopefully will prove different.Replacing the diodes fixed this one though...

Edited 1 time(s). Last edit at 02/11/2017 03:16AM by Nate523.