Motors will run smooth

Hi Guys, I really need help now, tried everything I know.
I installed a Rams 1.4 with Large LCD, Marlin software on Mendel90.
I use a ATX power supply and divided the power (yellow wires) and ground (Black wires) into 2 pairs and connected them to the 2 power inputs.
I use normal NEMA 17 stepper motors with J head. (everything standard as supplied by nophead).

The LCD works, I tested the endsops with M119 - and register min as Low.
All axis jog very slow.
I tuned the potentio's by first turning them down then slowly increase. first the motors slightly make a jerking noise the the noise increase. When jogging the motors they also jog in the same jerky manner. I then increased the power to the motors and the moise increased and the motors continue to move in the jerky manner. Until I reach maximum power to the motors, the jerky sound remains on, and the motors also only move i the jerky manner. Even if the motors stop moving the jerky sound remains.

Apart form this, everything so far worked perfect. I also downloaded a Ramps / Mendel90 Marlin file and tried that. I compared the setps per minute and other settings with the file I got from nophead - and all is the same.
I tried the power supply on a Melzi board the same on the same machine and the motors works and jog perfect. Reason why I do not use the Melzi board, I accidentally fried the Extruder motors controller when connecting the hotends (crossed wires)

What's the problem?

Quote
nambass
Hi Guys, I really need help now, tried everything I know.
I installed a Rams 1.4 with Large LCD, Marlin software on Mendel90.
I use a ATX power supply and divided the power (yellow wires) and ground (Black wires) into 2 pairs and connected them to the 2 power inputs.
I use normal NEMA 17 stepper motors with J head. (everything standard as supplied by nophead).

The LCD works, I tested the endsops with M119 - and register min as Low.
All axis jog very slow.
I tuned the potentio's by first turning them down then slowly increase. first the motors slightly make a jerking noise the the noise increase. When jogging the motors they also jog in the same jerky manner. I then increased the power to the motors and the moise increased and the motors continue to move in the jerky manner. Until I reach maximum power to the motors, the jerky sound remains on, and the motors also only move i the jerky manner. Even if the motors stop moving the jerky sound remains.

Apart form this, everything so far worked perfect. I also downloaded a Ramps / Mendel90 Marlin file and tried that. I compared the setps per minute and other settings with the file I got from nophead - and all is the same.
I tried the power supply on a Melzi board the same on the same machine and the motors works and jog perfect. Reason why I do not use the Melzi board, I accidentally fried the Extruder motors controller when connecting the hotends (crossed wires)

What's the problem?

Have you installed the Micro step jumpers under the driver boards?

Doug

Make sure you power down before doing anything with the driver boards/motor connections!!

If they make clicking noises when not moving the drivers are overheating and shutting down momentarily. Unlike the Melzi, RAMPS will need heatsinks and a fan to keep the drivers cool.

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[www.hydraraptor.blogspot.com]

Yes, All the jumpers are installed under the driver boards. I also attached the heatsinks on the driver boards. Why is it then that the motors, not even moving smooth, but always move in a jerk manner symilar to the noise they make. And I can turn the potentio meter to any side. the only time when the motors are quite, are when they are turned down completely.

Can it be something to do with my power supply?
It is a new ATX power supply. I used a normal PC power supply connected the following:
I connected a 10R (gold in the kit) dummy load resistor to one black and one red wire and connected one black and one green wire onto one side of a 4R7 resistor and a brown sense wire and one orange wires to the other side of the resistor.

I then split the 12 remaning black wires into 2 pairs and connected them to the 2 ground points of the power connection.
The 6 yellow wires, I split into 2 pairs and connected them to to the 2 positive points on the power connector.

If the drivers get too hot they switch off, then they cool and switch back on again. They can cycle on an off like this quite fast. As they enable and disable the motors twitch and clunk. If they are told to move they move in short bursts, pause and then move again. The higher the pot is set the faster they cycle. If you turn the current low enough they should stop pulsing and move smoothly.

If this describes what you mean by "a jerk manner symilar to the noise they make" then they will be so hot they will burn your finger if you touch them. If it is isn't the problem you will need to describe it in more detail or post a video.

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[www.hydraraptor.blogspot.com]

I did checked, but the heatsink is not getting that hot to burn my finger. Mmm, let me see if I can explain better..... The noize is almost like a slow buzzer. and the motors move in steps, and the movement is not smooth. The setps the motor makes is similar to the noise it makes.

The only alternative in trying to explain this is to make an video and upload to youtube, if this explanation is not clear.

I don't know what would make a low pitched buzz while they are stationary other than having the current set way too high, so they switch on and off very quickly. What sort of drivers are they?

If the power supply output was oscillating it might do that but I have never known a PSU oscillate so fast. Why are you not using the PSU from the kit?

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[www.hydraraptor.blogspot.com]

Does the frequency of the buzz change when you adjust the pot?

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[www.hydraraptor.blogspot.com]

yes, when I increase the power then the noise increase, but only go away, when the power is completely turned off and the motors not moving at all. bit as I increase the power, the noise also increase.

Not something I have experienced before. Perhaps the PSU is oscillating or the drivers are faulty.

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[www.hydraraptor.blogspot.com]

Just a thought that came reading this thread:

Could it be that your ATX PSU is missing a base load on the 5V/3.3V rails? The Wiki mentions such kind of oscillating behaviour under "Minimal Load/Balanced Load"...

Thanks guys for the feedback so far!

Well, /i have an older 300W ATX power supply and am busy to get the wiring as defined in the the reprap wiki. One thing I am unclear about is the purple wire. in the link for "Choosing a Power Supply for your RepRap", they mentioned to use the purple wire in adding a dummy load on the 5v rail is required to maintain a steady power output.

The connectivity of the purple wire is unclear to me. and this could just be the problem I am currently experiencing, seems the power supply and not steady.

The purple wire is the 5V standby power that is on all the time. It is best left unconnected.

What happened to the PSU supplied with the kit?

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[www.hydraraptor.blogspot.com]

Mu original PSU got with the mendel is fine, is just I am trying to resolve the problem, and because I do have this extra power supply, I recon why not trying it - nothing to loose.

So do you get the problem with the original PSU and the RAMPS board?

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[www.hydraraptor.blogspot.com]

That, I still need to find out. That is why I am trying another PSU.

Sorry, I don't understand. Why not just connect the RAMPS to the original PSU that is known to work?

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[www.hydraraptor.blogspot.com]

LOL Sorry for being unclear...

The original PSU is currently connected and is with that PSU I am getting this problem as explained. So now I want to in the process of elimination to try another power supply as well.
I really do hope my replacement Melzi board arrives soon as I want to get printing and these waist my time and energy. But I guess I need to push through.

Well as it worked with the Melzi I think you can rule out the PSU being the problem. It is stable with the dummy loads connected as per manual.

I think the stepper drivers must be faulty. They shouldn't buzz when stationary. Some may give a high pitch whine, but not a low pitched buzz.

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[www.hydraraptor.blogspot.com]

Well, seems the other supply works perfect. I also connected the 4.7 resistor to the orange+brown on the one side and the black + green onto the other side. I then used the high power 12v wires to connect to the ramps. now all is fine and the motor tuning is also fine. Well,must say I am relieved that it is finally working. I now need to get a fan for the ramps and connect to the PSU. and then also print a housing for the board.
Well, thanks you guys for advise and help.

Edited 1 time(s). Last edit at 04/27/2015 04:43PM by nambass.