Burning out StepSticks

Hello RepRappers!

Well, I'm writing this because I blew up 2 Stepsticks in a a row, and 1 more the next day... And I don't understand why that happened yet.

I made mayself the RAMPS 1.25 board (the one with the 1K R for the LED). I attached some photos of it. Note that the pictures were taken before the Diode 1N4004 was desoldered, and the MFR500 fuse was installed.

I'll tell my story. After verify that PCB didn't have any shorts, I connected it to the Mega, with Sprinter software configured for software endstops.
Then connected a StipStick and an SBS motor (a 7.5deg 13ohm by coil) to the X axis. Power up with 12V 1A, and the mega via USB.

Pronterface did it very well. The X Stepper was moving. And then I did the same for the other axis, including the extruder. All were fine. Also the MOS outputs were functional!

At this point, and looking all was goning good, I made a print simulation with Repsnapper. The X stepper moved flawlessly, changing speed and direction.

Then came the nightmare... That night, when showing the progress to a friend, the Stepper stopped moving, and the Stepstick started to get hot. Really hot. Disconnected the power. Because didn't knew what happened (a few hours before was running fine), moved the test to the breadboard.
So I recreated the X axis, connecting it to the very same pins in the Arduino mega board... and nothing the StepStick was dead.
The same happened with the second one... 2 drivers dead now.

Then removed the Sprinter firmware, and uploaded a very basic program that moves the motor 48 steps side to side, using the same pins on the Arduino as the RAMPS does (24, 26, 28). And It worked!!! I stopped all tests there. Without a clue of what happened to the other drivers..

I continued the tests the next day. Same config... Breadboard with the StepStick and the Mega. It was running for a while, until it stopped.
The same situation as before. The stepstick was dead.

My question is, do these drivers burn so easily??

I bought them from ebay --> HERE
Does anyone worked with these drivers before? A picture is attached of them also.

Now I don't know how to continue... Is my RAMPS killing my drivers? The firmware? The stepper or the power supply?

I hope you could help me. I was so close to start assembling my RepStrap...

Thanks guys!

I guess I'll ask one of the most obvious questions did you turn the trimpot all the way down first before testing/using them? When you were using them did you install heatsinks onto the chip to help dissipate the heat? The stepsticks do get hot so without cooling of some kind they'll burn up under the heat they generate.

Hi ECSuyu,

At first use the trimport were in te middle. In that position, the stepper motors got warm when idle. You could touche them with your fingers without any problem.
The Stepsticke had the dissipation installed.

Now when moving the trimpot, to which side is the Max or Min ??

Thanks for your help!!
LC

Counterclock wise is min, what I usually do is turn them all down to min and then adjust them until the point that they can start moving. I do this by sending move commands to the motors until I see them move while turning the trimpot at the same time. If done right it'll lower the noise level from your motors while they are running and it'll also make them run cooler. I find myself adding a fan to cool the stepsticks regardless if the heatsinks were added or not.A habit I got out of building custom cooling rigs for computers

-Eugene

Eugene,

The stepper moves even with the trimpot at its minimum. And during all work, the StepStick were not hot at all.
The steppers are ones that I took from an old HP Deskjet printer -->

• 7.5Deg per step
• 13ohm per coil
• 4 coils (6 wires).

I red somere that the StepStick needs filtering capacitors at input VCC and V-MOT. Those capacitors are not in RAMPS 1.2 or 1.4, but they are in Gen7. Could be this?

Thanks for your help.

Lucas.-

Edited 1 time(s). Last edit at 12/14/2011 09:06AM by epoxi.

The most likely way of damaging the driver is a loose motor connection or disconnecting the motor with the power on.

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[www.hydraraptor.blogspot.com]

I ordered the same ones. Burned out the extruder axis immediately, forgot to plug it in. I tried replacing the allegro chip but it still didn't work. Ended up getting Pololu's.

JKomp316, thanks for your reply!

Hmmm... so the A4984 are not an option?

Did someone experienced the same with these Stepsticks?

How about this one from tv7957ht (eBay)

Thanks!!!
LC

Quote

Burned out the extruder axis immediately, forgot to plug it in.

How did you burn it out if you didn't plug it in?

I presume you mean the motor connection. Even so it should only be a problem if you plug it or unplug it with the power on.

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[www.hydraraptor.blogspot.com]

Thats a good question. I initially started it up without the extruder attached. The whole machine locked and was unresponsive. Nothing would work until I removed that stepstick.

Epoxi how were yours packaged? Mine came in a flexible padded envelope. Shipped from netherlands to usa. I had assumed user error but nophead made me question that.

Jkomp316,

Exactly. They came from denmark in a plastic bag.
Look at the pictures from my first post. I think there is a picture of them, and the bag.

Well I got nothing but assumptions, but I did think the packaging was questionable from the start. Envelopes like that get machine sorted and passed through rollers and such. Maybe mine was bad from the start. It would explain why replacing the allegro didn't bring it back.

The stepstick you brought has trimpots without any stops/ends.
You need to calculate the resistance/voltage using a multimeter.

I noticed this when I came to set the trimpot to zero/home (or whatever you want to call it) it just kept turning.
I contacted snipermand who confirmed they don't have any stops.

You can read the values by attaching a multimeter to highlighted points.


I didn't check what they where set to before I adjusted the trimpot, but I wouldn't be surprised if it wasn't at the max setting for the circuit.

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My Reprap blog

jds-reprap.blogspot.com

Assuming snipermand stuck to the published values, the max current you can set on Stepstick is only 1A, so it shouldn't burn out, or even get particularly hot. Even if it does overheat it should shutdown, so even on a Pololu turning the current too high should not damage it in the short term.

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[www.hydraraptor.blogspot.com]