1 (edited by 3d-oodler 2013-08-23 05:11:32)

Topic: Y Stepper Crawling

Hooked up the new E3D and completed my first print.

After shutting everything off, I went to print something else a bit later and the Y stepper is crawling (Y belt turns, but very slowly).

So I connected the Y motor to the Z stepper on the board, and the Y motor is working fine.  (similarly the Z axis was crawling in this configuration)

It seems it's the stepper driver.

I re-uploaded the firmware and checked the voltage, but no go.

Anything I should try/adjust?

2

Re: Y Stepper Crawling

Thinking it was the stepper driver, I went ahead and ordered a SureStepr SD8825 today, thinking I'd swap the existing extruder A4988 with the bad Y stepper and use the new driver for the extruder.

Then tonight I tested the theory and swapped the bad Y stepper and extruder only to learn that it's not the driver :-/

While I had my eyes close to the board I noticed one of the ATMega1284 pins (I installed that last week) was bent and seemingly not making contact (how in the heck did I manage to print anything with it like that?)

I straightened the pin and have the microprocessor seated properly now, but that did not fix the problem.

Which makes me think it's either the 100k resistor (AXIAL-0.3) or the thermistor high pass RC filter (CPOL-RADIAL-100UF-35V) beneath the driver that's the problem.

I'm a noob at all this.

Anyone have a guess as to which I should try replacing first?

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Re: Y Stepper Crawling

Which pin was bent on the 1284? would like to know, should be able to guess if this would cause the stepper issues.... or just a coincidence.

4

Re: Y Stepper Crawling

PIN 10 (VCC)

5

Re: Y Stepper Crawling

Hmmmm. Yeah I see what you mean by surprised you could print at all smile I was thinking you would have bent #28 and a faulty connection *might* behave this way but from what you say it is even in it's actions... so....probably not..... btw, how did you bend an inner pin ??? I always seem to bend the pins on corners wink

Oh, one other thing... you have checked the trim pot voltage on the stepper driver right? 

Other things it may be is metal debris on the back side of the main board... it wouldn't be the first time an errant piece of tiny wire trim was causing problems on the back of a SD printer board....

6

Re: Y Stepper Crawling

Voltage was the first thing I checked, it's fine.

I didn't remove the reset jumper when I first installed the chip and I'm guessing it got caught up on that.

Back of the board was clear.

Tomorrow I'll hit Radioshack for these:
http://www.radioshack.com/product/index … Id=2062350
http://www.radioshack.com/product/index … Id=2102510

And see if I can get things working again before the new stepper arrives.

7

Re: Y Stepper Crawling

you could probably check them in circuit with moderate results.... if you check the resistor and it's open or a lot higher ohms than it's supposed to be of course it's bad same with the cap if it shows a short it's probably bad... I kinda doubt it's this though... I have an extra sang board laying around here somewhere... if I get a chance I'll look at it and try to do a reverse simulation of what might cause this... too late now, got to hit the hay... wakeup time comes early tomorrow sad

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Re: Y Stepper Crawling

ronsii wrote:

Other things it may be is metal debris on the back side of the main board... it wouldn't be the first time an errant piece of tiny wire trim was causing problems on the back of a SD printer board....

That happened to me once, piece of tiny wire on my stepper driver... I guess everyone's workshop is the same.

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"1kg should last for an while" is a lie!

9

Re: Y Stepper Crawling

ronsii wrote:

you could probably check them in circuit with moderate results.... if you check the resistor and it's open or a lot higher ohms than it's supposed to be of course it's bad same with the cap if it shows a short it's probably bad... I kinda doubt it's this though...

I checked both the resistor and cap relative to each of the steppers and am getting consistent measurements across them.  They also look fine physically.  So they seem OK, and now I'm at a loss for what to check/try next :-/

10

Re: Y Stepper Crawling

Your connections to the motor maybe intermittent and/or it is only driving one coil. It wouldn't hurt to take a small flat blade screw driver and try to "recrimp" the wires in the connector for that motor.

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

11

Re: Y Stepper Crawling

2n2r5 wrote:

Your connections to the motor maybe intermittent and/or it is only driving one coil. It wouldn't hurt to take a small flat blade screw driver and try to "recrimp" the wires in the connector for that motor.

It's not the motor as I swapped the Z and Y leads and the Y motor worked fine.

It's also not the driver as I swapped those.

It's something on the board.

12

Re: Y Stepper Crawling

To rule out the ATMega, I swapped the pin assignments for X and Y in PINS.H and confirmed the changes took (Y moved for X and visa versus).

So I've now ruled out:
- The stepper motor, wire, and connector
- The driver
- The microprocessor

Here's what I think is left:
- The resistor
- The capacitor
- The PCB (perhaps dry solder)

Anything I'm missing in this list?

13

Re: Y Stepper Crawling

have you tried a little pushing/prying on the board/plugs/whatnot when you are commanding it to move...

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Re: Y Stepper Crawling

I've replaced the resistor and capacitor with no change in behavior.

I also did as you suggested ronsii and pushed/pried on the board & plugs while the monitor was turning.

I also checked the voltage during this operation and it fluctuates +/- .005v, which I don't imagine makes a difference here, but this is something different than the other stepper drivers which only vary .001v generally.

So at this point I'm contemplating upgrading to a Ramps 1.4 / Mega 2560 combo.

15

Re: Y Stepper Crawling

Hmmm....


very strange... I thought for sure you would find something while wiggling plugs around.... been too busy aat work to have much time to actually do anything with my spare board... maybe this weekend smile

16

Re: Y Stepper Crawling

I wonder what would happen if you swap your good drivers into the y driver slot? Reminds me of the time I replaced my timing chain on my Pontiac gto, and then could not get it started. The fuel pump went out at the same time I was fixing the timing chain. What are the odds.

17

Re: Y Stepper Crawling

Did you end up checking for dry solder conditions on the back of the board?  This happened to me on another piece of equipment...sometimes very difficult to see.

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Thanks for All of Your Help!

18

Re: Y Stepper Crawling

IronMan wrote:

Did you end up checking for dry solder conditions on the back of the board?  This happened to me on another piece of equipment...sometimes very difficult to see.

Yeah, I have seen this many a time on older televisions, usually in the hi frequency circuit.

19

Re: Y Stepper Crawling

Briggs wrote:

I wonder what would happen if you swap your good drivers into the y driver slot?

I swapped drivers (the driver is fine).
I swapped stepper wires (the wires/motors are fine).
I swapped PINS on the ATMega (PINS are fine)
I swapped the resistor, and capacitor (those are fine).

IronMan wrote:

Did you end up checking for dry solder conditions on the back of the board?  This happened to me on another piece of equipment...sometimes very difficult to see.

The only questionable solders I saw were my own on the replaced resistor and capacitor and I redid those better...no difference.

Thanks all for the suggestions.

I ordered a Ramps 1.4 / Mega 2560 combo today, though it would have been nice to isolate the problem with the Sanguino, I feel I made a good effort to fix what I had before spending the money on an upgraded board.

20

Re: Y Stepper Crawling

Just closing the loop on this thread.

I've had the RAMPS/MEGA combo up and running for a couple weeks now.

Clearly the problem was the Sanguino as things just worked once I had the everything put back together with the new board.