Bad Stepper Motor Driver?

[Lucas]

I've been printing with my TOM a ton as of late and everything was
working totally great.

When I came home tonight to start my nightly print (I'm printing 35 of
the same object) I had some problems. Rebooted everything and TOM came
back to life. Wanted to run some control panel tests and suddenly my X
axis was acting all strange. The feed rate was turned all the way up
for some reason but the x-axis barely move and made some horrible
noise. I'm not sure how it got turned up so high.

I turned down the feedrate and the x-axis seems to move correctly now
in both directions. So I thought it was just a weird thing.

Then I tried to print an existing file from my SD card. X axis homed
just fine and sounded great but never stopped when it hit the left
wall. It just sat their and groaned at me.

I've tried printing different files and they all do the same thing.

I've re-flashed the firmware.

I've adjusted the trim pots to make sure the stepper had enough power.

Do I have a bad stepper motor driver?

Are there any other tests I can perform?

-Lucas Saugen

[Mark Cohen]

you could switch the y stepper wires with the x ones and see if it behaves the same. also check the microswitch positions and for loose wires.

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[Ed Nisley]

X axis homed just fine and sounded great but never stopped when it hit the left wall. It just sat their and groaned at me.

You're the latest in a long series of Thing-O-Matic users with a failed stepper driver board. The A3799 driver chip stops responding to the DIP switch inputs; something internal to the chip fails. There is no "home remedy", so it's time for an RMA from MBI.

The stepper driver should operate in 1/8 step mode, but it's now in one of 1/1, 1/2, or 1/4 mode. You can compensate by adjusting the X axis stepspermm value, but the other chip input will eventually fail and the board will operate in 1/1 mode.

For a quick diagnosis, reduce the feed rate to 10 mm/min and jog the X axis by 5 mm. It will move exactly 10, 20, or 40 mm: you can figure out which input has failed.

[Lucas Saugen]

That's what I sort of expected. Just ordered a new driver.

What do you mean by RMA?

[Ed Nisley]

What do you mean by RMA?

It stands for "Return Merchandise Authorization", which is biz jargon for "We agree it's broken under warranty and we'll replace it."

Most companies won't accept a return shipment unless they know it's coming, so you must get an RMA (and perhaps write the number on the box) before returning the part.

[Lucas Saugen]

Ah. I figured something like that.

Thanks.

[Lucas Saugen]

Got my new stepper driver today and replaced the bad one. Everything
seems wonderful.

Thanks.

-Lucas

[Luis E. Rodriguez]

I had two go out but I though it was because I didn't do any of the calibration steps here: http://wiki.makerbot.com/thingomatic-doc:calibration

I received two new ones and did the calibration just the same! Crossing my fingers.

Luis E. Rodriguez

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On Thu, Apr 7, 2011 at 6:14 AM, Ed Nisley <ed.n...@gmail.com> wrote:

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