Chinese RAMPS 1.4 Kicking My Butt (Solved)

Hi All,

Just picked up a RAMPS 1.4 board, mounted to what is probably a counterfeit Arduino Mega 2560.

I loaded Marlin on to her quickly enough, and was monitoring thermistor temps pretty much instantly. (Using Repetier Host)

However, driving the stepper motors is absolutely kicking my butt. I have at best got motors to shudder angrily in seemingly random directions as I command them to move.

The motor will move sporadically and loudly, squealing and bumping; no matter how i adjust the driver knob.

I am powering the setup with a 400W PC power-supply.

I have been mindful to adjust the reference voltages on the little clone drivers; and have even tried other stepper motors in my shop.

I tried halving all the speeds and accelerations in Marlin.

I have tried moving them with load (attached to a printer), and without load (just sitting on the bench).

What the flip am I missing here? I bet it is something simple, and I am going to feel like a dummy.

Any tests or things I should try to narrow down why this board won't spin a stepper motor properly?

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Solution:

The clone pololu stepper drivers (chinese manufactured, white color) required a 0.1 volt reference voltage, vice the 0.4 volt reference voltage I would begin with on any other printer build.

Bumping up the reference voltage only caused more intense motor shuddering. Lowering the reference voltage to 0.1 volts allowed smooth motor control.

Big thanks to Nophead and Gazob!

Edited 4 time(s). Last edit at 09/11/2012 02:16PM by Idolcrasher.

Check the connections to the board. If they are not wired in the correct order it will cause them to move sporadically in random directions as you described.

Chelsea - QU-BD

You can try to upload this test firmware to check your motors.

Basically I had the similar issue with a cheap chinese stepshitstick - one of four ordered drivers was not working.
Motor just made some noise and vibration, but no smooth rotation. Also I've noticed that broken A4983 chip was extremely hot, even with heatsink.

Check that the sense resistors are the correct value. If they are zero ohms it means the reference voltage has to be practically zero to work.

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[www.hydraraptor.blogspot.com]

Definately check the motors are wired correctly. On the motor connector that plugs into the ramps board test you get resistance across pins 1 - 2 and 3 - 4 (use a multimeter), doesnt matter which end you count from, and conversely open circuit between pins 1 - 3 and 1 - 4.

To get to the correct ballpark, with just the usb connected adjust the trimmer measuring voltage from the through board via to the ground pin, marked in red on the diagram below



If they are genuine Pololus or 100% clones then you are aiming for around .4V or 400mV

If they are the white drivers from reprapdiscount what nophead said is correct, some different components means that your ballpark is .1V or 100mV.

If they are infact the white drivers from RRD try this and if you have no luck message him on the forums or through email. I had 3 faulty from my 5 initial drivers, whether I stuffed them following the pololu guide or whether they were always faulty wasnt an issue, he had 4 new drivers in the mail that night, and they arrived in Australia from Hong Kong inside 3 days

gazob Wrote:
-------------------------------------------------------
> Definately check the motors are wired correctly.
> On the motor connector that plugs into the ramps
> board test you get resistance across pins 1 - 2
> and 3 - 4 (use a multimeter), doesnt matter which
> end you count from, and conversely open circuit
> between pins 1 - 3 and 1 - 4.
>
> To get to the correct ballpark, with just the usb
> connected adjust the trimmer measuring voltage
> from the through board via to the ground pin,
> marked in red on the diagram below
>
> [img.photobucket.com]
> 0600-1.jpg
>
> If they are genuine Pololus or 100% clones then
> you are aiming for around .4V or 400mV
>
> If they are the white drivers from reprapdiscount
> what nophead said is correct, some different
> components means that your ballpark is .1V or
> 100mV.
>
> If they are infact the white drivers from RRD try
> this and if you have no luck message him on the
> forums or through email. I had 3 faulty from my 5
> initial drivers, whether I stuffed them following
> the pololu guide or whether they were always
> faulty wasnt an issue, he had 4 new drivers in the
> mail that night, and they arrived in Australia
> from Hong Kong inside 3 days

This was it!!!!!!! Thank goodness! This has been driving me nuts today! I never thought to use 0.1 volts, I went straight for 0.4

Thanks so much for your input everybody! You guys rock

Will find out soon enough if I blew up any of these clone drivers while searching for a fix.

Hopefully they all just spring to life with a 0.1 volt reference voltage.

Anyone know any sure fire ways to determine if a stepper driver is alive or dead?

Maybe apply some kind of input and watch for an intelligent output with an oscilloscope?

You can apply dummy loads in the form of resistors to the outputs and monitor them using a scope. Simply breadboard the driver with fixed direction, stepping etc, and use either a switch or a function generator to drive the step input.

Disclaimer: that advise only applies to those who understand what I just said and can run with it as is. Others will have to wait until the testing is spelled out in paint-by-numbers steps. For a more expanded, but still thankfully not a completely "ISO9000" type method, see a post I made here

(note: the post says nothing about applying dummy loads, but it should help to form a method if you have what it takes in the first place)

Edited 1 time(s). Last edit at 09/11/2012 03:16PM by xiando.

for my first batch I ended up getting all of mine adjusted to the same sort of level and tried them against known working motor slots on the ramps, any that didnt work +- 20mV I assumed were faulty, and RRP replaced, the ones that worked and all the replacements worked in the range of 95mV to 120mV.

GaZ

Quote

You can apply dummy loads in the form of resistors to the outputs and monitor them using a scope.

No you can't. Chopper drives need an inductive load to function.

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[www.hydraraptor.blogspot.com]

How can something open source be counterfeit? I think you mean poorly QC'd copy, or more likely an older version of the board they bought at auction.

Simba Wrote:
-------------------------------------------------------
> How can something open source be counterfeit?

It can most certainly be counterfeit. If it claims to be a real Arduino, for example, and uses the Arduino trademark, but is not made by or licensed by the Arduino foundation, it is considered counterfeit.

In other words, the Arduino name is trademarked and cannot be used by other companies, but the board design can be copied and modified and produced to your heart's content.

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Generic Arduino or Arduino Clone are nicer words to use IMO.

Most of the generic Arduinos don't call themselves Arduino outright. (Usually "Arduino Compatible")
If there is no Arduino logo on the PCB mask it's generic and not made in Italy, big deal.
Better to err on the side of caution and not call oshw counterfeit, due to the negative connotations that brings.

Edited 2 time(s). Last edit at 09/15/2012 03:21AM by Kt.

In the legal sense it is counterfeit and certainly in the UK if you import it and sell it you could theoretically be prosecuted and have them confiscated although I can't see that happening in practice because the authorities are far too busy going after dangerous stuff and designed labels, etc.

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[www.hydraraptor.blogspot.com]