Is this Windows? Might be the infamous FTDI clone chips problem(. Check the console from the Arduino IDE (Menu -> Tools -> Serial Monitor). See if you get any message there like "counterfeit chip" or something. I use linux and had to use a windows machine to reprogram my controller (GT2560) to use 115200 baud as linux doesn't seem to like 250000 baud which is the default on a lot of conby hoxsiew - Reprappers
What firmware are you using? For Marlin, the GT2560 uses BOARD_ULTIMAKER.by hoxsiew - Prusa i3 and variants
I contacted them through ebay directly. Whomever it was that I got was not a native English speaker so it was tough to communicate, but he was pleasant and keenly interested in resolving my problems.by hoxsiew - Reprappers
0.2Ω is way to little. Something is wrong with the bed. I'm surprised that didn't blow the fuse. That's more like a short circuit. I wouldn't activate it until you get this figured out. Hotbed thermistor is apparently the same as mine. I tried to build a custom table for it, but ended up just replacing it with a 3950 and using table 1 (#define TEMP_SENSOR_BED 1). The Z axis (or any axis) oby hoxsiew - Reprappers
I bought the same printer from the same ebay store, and had almost identical problems. First, the bed heat. Mine was a fried fuse holder. The 15A surface mount fuse is too much for the holder. The holder, best I can tell from digikey datasheets, is rated for about 7 amps. If yours is still intact (and you're good with soldering in tight places), unsolder the holder and solder the fuse directby hoxsiew - Reprappers
I think the biggest problem with the "threaded rod" type systems is that the rods are actually quite a bit smaller than 8mm so that they don't line up very concentric to the motor shaft. Also, mine weren't very straight either. Unfortunately, I don't have an answer for your question. I reworked mine by straightening the screws as best I could and to use shop-built rigid couplers made on a lathby hoxsiew - Reprappers
Doesn't the firmware prevent activation of the extruder motor unless the hotend is at temperature?by hoxsiew - Prusa i3 and variants
Good deal. I hope it still runs stutter free.by hoxsiew - Prusa i3 and variants
None of my 4988s had heat sinks so I thought I'd ask. I never checked the temperature before so I don't have a reference. It is definitely hotter than the other steppers, but it is doing a lot more work and is very near the hotend. Mine runs cool enough that I can hold my hand against it at any time which means it is probably below 50C. The sink on my 8825 is also not too hot to hold my fingby hoxsiew - Prusa i3 and variants
Interesting. I've never seen that in the firmware. Now I'll have to look for it.by hoxsiew - General
I had issues with inconsistent z-stop zero with the stock firmware on my Chinese prusa i3. I ended up installing 1.1.0_rc3 because of a thermistor replacement, and I was surprised when I hit my first "home all" to see the double movement (I assume that's what you mean by "babystepping"). I had previously put an indicator of sorts on my Z couplers (just a tack taped on) and after homing, I wouldby hoxsiew - General
Do you have a multimeter? Can you check the voltage when directly connected? Can you check the resistance of the bed?by hoxsiew - Printing
I've got a Prusa I3 with a Mk8-ish (Chinese) extruder. It has a 0.4 mm nozzle, and lately I've noticed that when it extrudes in open air, the extrusion kind of curls up toward a particular direction. It's like maybe something (debris, erosion, out-of-round, ???) is causing some drag on one side of the nozzle bore and thus causing the extrusion to curl in the direction of the anomaly. I was goiby hoxsiew - General
The arduino maps their own pin numbers. I think this has to do with the variety of CPUs that the various arduinos can use. They are not just for RAMPS controllers. As far as CAD, I use FreeCAD which is not the easiest to learn, but has a ton of features once you get to know it. As far as squaring off circles, I think that's more a parameter of the meshing function. FreeCAD lets you mess withby hoxsiew - Reprappers
Well, I'd start by adjusting those params and re-upload your firmware. Try increasing WATCH_TEMP_PERIOD by 10% or so while also decreasing WATCH_TEMP_INCREASE by 10% or so. Just don't make them outrageously small/large as it will defeat the whole purpose and make you printer unsafe should you get a thermistor failure.by hoxsiew - Reprappers
I trust you have a heat sink on that chip. They do seem to run hotter, but I think my motor doesn't get any hotter than before.by hoxsiew - Prusa i3 and variants
The "Heating Failed" message only occurs in one place (in Temperature.cpp) in the current Marlin firmware (1.1.0_RC3). I get the same thing occasionally. Basically it is a check to make sure the the thermistor is reading a temperature increase of a certain amount within a given time frame (time frame and temp change are defined in configuration_adv.h). If the firmware doesn't see this, it assuby hoxsiew - Reprappers
tcxoman, I appreciate your input. I hadn't actually checked the schematic that closely. Good catch on the hot +12V and switched GND. As far as the pin numbers go, they are related to the Arduino pinout, not the CPU pinout. As such, PIN4 on an Arduino Mega actually routes to pin 1 on the CPU (and PIN 10 to pin 87, not 88) as per this diagram:by hoxsiew - Reprappers
The A4988 board with all three jumpers applied (as is normally the case) only provides 16 microsteps. The DRV8825 has 32 so you need to double the esteps/mm in the firmware. Mine was set for 105 in the original firmware (direct-drive extruder) so I upped it to 210. After doing a calibration, I backed that off to 207. I assume you're using Marlin. Find and change DEFAULT_AXIS_STEPS_PER_UNIT iby hoxsiew - Prusa i3 and variants
I had issues with mine too. I wasted a lot of time on this and in the end, I think it was the replacement of the driver board that fixed it. I went with a DRV8825 for the extruder only. I kept the full set of jumpers for 32 microstepping, and changed the firmware to reflect it. Other than that, I replaced my thermistor with a known type (no idea what it shipped with) and available table in thby hoxsiew - Prusa i3 and variants
Why does windows make you use a proprietary driver for something that is supposed to be an open standard (RS232 over US? The linux driver implements the standard and works for all USB serial chips.by hoxsiew - Prusa i3 and variants
What version of Marlin are you using? I'm using 1.1.0_rc3 and mine has BOARD_ULTIMAKER in pins.h. It then "#include" pins_ULTIMAKER.h which has: #define HEATER_BED_PIN 4 #define TEMP_BED_PIN 10by hoxsiew - Reprappers
Any source for single-start lead screws? Everything on ebay is 8mm lead (4-starts).by hoxsiew - General
It's AC in so it doesn't really matter.by hoxsiew - Prusa i3 and variants
Use code tags so we can see the proper spaces. Looks like not enough spaces between the terms. Should be: LCD_MESSAGEPGM(MACHINE_NAME " " MSG_OFF ".");by hoxsiew - Firmware - Marlin
Remind them that the Marlin firmware is GPL and they are required to provide their source.by hoxsiew - General
I don't know about mac OS, but with linux, I had to use 115200 bps, and to do that I had to first program the controller from Windows with Marlin and only setting the baud rate to 115200. Once set, I made all the other Marlin configuration changes in linux and haven't had windows within a country mile of my printer. Mine is a kit prusa i3 with geeetech GT2560 board so I don't know if any of thaby hoxsiew - General
I have one like this. It is a Makerbot 2 or 2x knockoff. There is no tension adjustment. I believe even the genuine Makerbot 2 is considered a flawed design. They have upgrade kits for them. You can get one from Makerbot. Their page is being uncooperative right now, but search for "Rep2 Extruder Upgrade Complete Kit" on their site (www.makerbot.com"). You can also get an aluminum one fromby hoxsiew - Prusa i3 and variants
Right there where the power cord connects, near the USB jack. It has the main board fuse (probably 5-6 amps) but the socket right next to it is empty. This is the one for the bed. 15 amp, but many people have had problems with it. I think the holder is only rated for 10 amps. A bed will draw 9 or 10 amps.by hoxsiew - Reprappers