Hi there,
I could not find help with my problem below. Here it is:
I have a Prusa I3 serving me good the past few months, not without problems but was quickly sorted out. I use the Arduino Mega with Ramps 1.4 and have A4988 stepstick drivers with R100 sense resistors.
At first, my printer started shifting layers and I found that one of my lead screw nuts had quite a bit of play on it and I have read I must check my A4988 to be sure the Vref is OK. It did print two short prints with no problem, but when I read further I also realized that the sense resistors may be different than that of the pololu A4988 driver. I therefore had Chinese cheapies because my sense resistors was 0.1 Ohm. I quickly set the Vref so that I get 70% of 1.7A and started a 24 Hour print. One of the best prints that I had in quite a long time. I checked the stepper temperatures every now and then and the axis steppers was between 40 and 50 degrees Celsius, and the extruder between 50 and 60. To my knowledge that is actually low temperatures for the steppers. I then did a 5 hour print thereafter but did not check the temperatures again. Also good. And then with the print thereafter I went to check the printer after a while and came across a very load noise and an Y-axis stepper that behaves very erratic. Firstly I checked the wiring and made sure all the wires are connected and checked the resistance in the coils and there seems to be no problem there with 2.5 Ohms on each coil and are correct compared to the other stepper motors.
But when I checked the wires going into the Ramps 1.4 I found a molten connector going into the Ramps 1.4. The rest of the wires looks ok and did not look like they melted also. Well then I thought it must be the stepstick that is fried and swopped it out The stepper still behaved erattically. I then put the X-axis stepper on there and it ran smoothly. WTH???
I am now at my wits end. Can anyone shed some lite please. Oh, the steppers are 42byghw609. 1.7A and I set the stepstick vref to 0.952 to get 1.19A.
