Yes, pretty sure the cheap Chinese A4988's don't have ROSC shorted, and if I look very carefully (through several magnifying glasses) I can just make out a 10K resistor that seems to be labeled R4. I've measured 12.1v from the PSU when I hear the loud whine from motor on idle, and tried vRefs all the way from 0.2 up to 0.65v (0.5amps - 1.625amps), the frequency goes UP as I increase vref (not dowby plankton - Controllers
@NoobMan, these drivers already have ROSC shorted to ground, see the schematic here @nophead, it's a 12v PC supply (a Corsair CX430M, to be specific) I have 4 of these drivers, all behave the same, however the supplier has sold hundreds of these without problems, which would imply something unique in my setup or environment. I made this video last night of an A4982 on the Y axis of my old printby plankton - Controllers
Yes, both boards use 0R05 ohm sense resistors, and in that video they both have Vref set to about 0.58v, which equates to 1.45 amps (the motor is a 17HS19-1684S, rated for 1.68 amps). I've also had the current right down to about 0.5 amps with no appreciable reduction in noise when stationary. (Good to hear that this isn't a generic A4982 problem though)by plankton - Controllers
Just trying out some A4982 drivers (these ones) on my new M90 (RAMPS and Arduino mega). The idea was that I could run these without a fan to cool them, but I hadn't anticipated that they would be so noisy, is this normal? In particular they have an annoying whine after the motor stops moving (while it is still energised), but they are also louder than my cheap Chinese A4988's during motion, so mby plankton - Controllers
With RPi most people use a USB Wifi dongle, those are dirt cheap, but not sure how easy it would be to implement support for that (drivers, USB A port)?by plankton - Controllers
Quotedc42 Screw terminals are nice for anyone who designs and builds a printer from scratch and doesn't want to pay £20 or so for for a crimp tool. Yes, for a scratch builder the cost of a crimp tool, plus the crimp housings and the pins, can be in excess of £30 (not insignificant for someone building on a budget). However that's a somewhat hidden cost that many people won't consider when comparby plankton - Controllers
I think we can probably all agree that some form of network connectivity is a desirable feature, however if it will add significantly to the projected cost then that will defeat the intended purpose of this board (and Oco-Print is certainly a good solution for anyone that needs a Web interface). @AndrewBCN You make a good point that the software toolchain could be redesigned to remove more of thby plankton - Controllers
Quotenophead Mine are only warm to the touch when not in a heated chamber. I.e. at room temp of 20C the get to about 40C, which is only just above body temperature. I measured mine yesterday at 5C over ambient of 21C, after a 2 hour print.by plankton - Reprappers
Quotenophead the motors and extruder run at chamber temp plus about 20C I hear this all the time (that other peoples motors run hot), mine never even get warm to the touch. I suppose it is due to a combination of motor model, print speed, and stepper current (mine are listed below), maybe I'm just printing very slow. Motors Wantai 42BYGHW609 Stepper current up to 1.6A #define DEFAULT_MAX_FEEDRby plankton - Reprappers
Three very different opinions so far. Anyone actually using PLA printer parts inside a heated chamber (or tried, and failed)?by plankton - Reprappers
RAMPS has 2 polyfuses which will "trip" if they overheat (but that is usually when the heatbed is drawing too much current), and the stepper drivers have thermal overload protection. Adjusting the stepper current is a balancing act between too little current (insufficient torque), and too much (overheating). Some people find the A4988's (particularly the cheap Chinese ones) need a small fan to kby plankton - Reprappers
Try searching the forum for "skipping steps". main causes are: mechanical binding on the axis that is skipping (usually x or y), check smooth operation of bearings, belts tight enough, etc too much current to stepper motors (the drivers overheat, and cut out) too little current to steppers (insufficient torque from the motors) speed or acceleration settings too high in firmwareby plankton - Reprappers
I want to try building a box around my printer to improve ABS printing (hopefully relying on "passive" heating from the heatbed and extruder, with maybe a thermistor controlled extractor fan to regulate temperature), but most of the printer plastic parts (apart from the extruder) are PLA so I'm concerned I don't overheat these (I'd like to avoid having to rebuild my printer in ABS if possible).by plankton - Reprappers
Just to check before you replace any more hardware, you did check that PID is correctly tuned, didn't you? If the heatbed has an LED it is easy to check, the LED shouldn't flicker before you get close to your target temperature. If it flickers that is PID switching the current on and off, when it hasn't been tuned PID can cut in way too soon, meaning you are not getting full current to the bed wby plankton - RAMPS Electronics
Quotecdru How confident are you that your 5VSB is exactly 5V and you won't draw more current than the Arduino traces can handle? I think the concern is that powering via the 5V pin bypasses the voltage regulator, providing more than 5V could damage the Arduino. Current draw is a function of voltage and resistance, a badly regulated PSU isn't going to "push" more current through the board unlessby plankton - RAMPS Electronics
That's not entirely correct I think. In the Wiki it says: QuoteWithout D1 installed, or when the 12VIN is not connected, the Arduino gets its power from USB. If you want your kit powered without USB connected you need to solder in D1 OR connect VCC to your PSU. The VCC pin can be connected to your ATX's 5Vsb to continuously power the Arduino from your ATX power supply. You will want to make surby plankton - RAMPS Electronics
Microsoft have advised they were able to reproduce the problem and diagnose the cause (they don't tell us what it was), the next Windows 10 update should have the fix.by plankton - General
Look at the video ("Tom's Update") linked from the Github pageby plankton - General
The Pololu website gives you the procedure, you measure vRef from the metal dial of the pot, and any ground on the stepper or RAMPS, using the formulae: I (current limit) = Vref x 2.5 So for example, a measured Vref of 0.52 volts = 1.3 A The A4988's can provide up to 2A (more than many of the motors we use can take), so the aim is to keep current high enough to stop the motors binding (more cby plankton - General
QuoteThe other problem is you never know what the current is actually set to Well, unless you actually measure it (which is easy enough to do)by plankton - General
Yes, that's the thread I started with MS.by plankton - General
Hmm, you may be right about the small gap (that example certainly does), I thought I had tried single perimeter, but can't find any examples in my failure bin. I'll do some more testing with single walls, and keeping an eye on the infill, when I get a chance. Yes it was a typo, I was printing at 242C of course. I don't have the means to measure temperature inside the nozzle, but I was going by wby plankton - Mendel90
Has anyone else had problems printing the linear bearing holders (Y axis, and in the X carriage), and how did you dial in your print to fix it? I started by printing the X carriage in ABS, then found the bearing holders split along layer boundaries when I inserted the bearings, similar to this Y axis bearing holder: So I spent some time printing a single Y axis bearing holder with different sby plankton - Mendel90
I don't have Marlin available to check right now, but isn't motherboard 35 an extruder and 2 fans, so I assume it expects pin 10 to be the Extruder the same as motherboard 33, with fans on 8 & 9.by plankton - General
A hotend fan could just be connected to 12v (as you want it on all the time you're printing), but if you want to control it try M42by plankton - General
Actually I found IRF2804 which I think should be a good substitute VDSS = 40V RDS(on) = 2.0mΩ (at Vgs 10v) ID = 75Aby plankton - Controllers
Thanks, that makes much more sense now. So I can see that the mosfet I suggested would be ok for low current devices, but not for switching a heatbed, and the gate series resistor explains the SevenSwitch design (I was confusing the gate threshold voltage with the max gate voltage, which is why I thought a voltage divider was needed). Now I can build the circuit, AND understand it.by plankton - Controllers
Okay, probably my fault, I should have been more specific. I need to order from this company if possible (in order to make up a minimum order value), I also like to try to understand what I build, and the components selected (rather than blindly copy someones design). I'm not an electronics engineer, so maybe overlooking some factors, but as far as I can see the requirements for a RAMPS mosfet aby plankton - Controllers
I want to buy a MOSFET in the UK to switch an additional 12v fan under control of one of the GPIO pins, and I'll get a couple of spares in case I ever need to replace the ones in my RAMPS. I shall probably use the 7switch circuit design by Traumflug, but I can't find the IRLB8743 available locally. Yes, I've seen the recommendations ( IRLB3813, IRLB8743, FDP8870, AOT240L, CSD18502KCS) but they aby plankton - Controllers
I'm talking to Microsoft support about this, so I'll update here when there's a fix.by plankton - General