X Axis Weirdness

tomtom

Hello guys,

After not using my A5S the for half a year I wanted do try my luck again. After Installing the latest firmware from August everything looked good so far. Nice work by the way and thank you guys!!!!!

Then I wanted to print a All_in_One_Print test wich started fine but after the third bottom layer the X axis suddenly went bonkers. I switched the printer off and on again but am not able to Home and the noise just is indicacing that something is absolutely not right. 

Before the print everything worked out fine even with Repetier.

Does anyone have a idea where that could come from and what I can do now??  

Thanks Tom

tomtom

Please have a look at the Video!

I really appreciate your help because I got no Idea what to do!!!

tomtom

I already checked the connectors on the outside and inside. They seem fine. 

Are the settings right that I got (I did not change anything)
V max X 360
Acceleration 500
  - A max X 1200
Jerk 0.020

Samuel Pinches

Ok, please try flash back to the factory firmware, that should at least confirm that the hardware is not at fault, and that the cables are fine. Then we can start to debug the firmware further. Thanks for reporting the issue.

Samuel Pinches

You could try V max X 100 and see what happens.

tomtom

Thanks for the reply!! I already saw your suggestions in the fb group!!

I decided to open the printer and checked the connections on the inside to. And somehow I had the Idea to change the wires from the X and Y motor and it turns out the motor is broken!!! 

So now I have to get a new one...any suggestions?? 
And do I have to calibrate something or so?? I got no Idea so far!!

Thanks for your time!!

tomtom

Hey guys, 

Im still stuck...

On the end of the video I switched the printer off to show that there is not that much resistance on the rails. 

The Motor is comletely new, had the issue with the original also so I was sure the Motor died.

I had it running with a different Motor while waiting for the replacement from China, but didnt check properly so I had a 12v meanwhile. Surprisingly it worked fine but *surprise* got really hot. Up to 90°C. And on a bigger print it started to skip steps reguarly so I thought it will be time to get the replacement motor fitted.

But now I got the same damn issue again. Does someone know if I can measure the voltage to make sure if the motor gets enough power??

Or can there be a issue with the Mainboard? But how did it then work with a 12v motor??
Someone suggestest me to increase vref but I thought that on the A5s they are not tuneable?! 

Thanks a lot for any suggestions!!!

Greets Tom

tomtom

🤔

tomtom

Here's the video... 

Stephen Todd

Original A5 as you pointed out had screwdriver adjustable Vref on the plug-in stepper drivers - and A5s does not have the manually adjustable potentiometers

The drivers on the new boards are "current adjustable" in the firmware

Samuel Pinches

@Stephen Todd  - The A5S drivers are not tunable in firmware or hardware, as far as I know. The only option is to change the current set resistors on the motherboard, which is far from an easy job.

Stephen Todd

Having looked at the A5984 stepper driver datasheet, the output current seems to be set by ROSC resistor to ground

I suppose you could replace that resistor with a variable potentiometer, but you could easily destroy the chip if you get things wrong - so, replacing a motor with exactly the same make and model seems the logical thing to do

Anyway, here's the datasheet
https://www.digikey.com/en/datasheets/allegro-microsystems-llca5984datasheetashx

giantrobot2001

Probably just a weird coincidence, but I just arrived on the forum with an AS5 printer that originally had a problem where the head would run left but the microswitch stop seemed to not function, so it would grind the belt trying to find home -  and sound crazy.  Is that what it did? 

That issue was actually a loose wire that was very hard to see.  When you plug the gantry's three plugs in, there is another set of plugs inside the case adjoining those connectors.  The widest plug on the bottom was askew and a loose plug was apparently the issue.  Not the plug on the outside, but inside the unit on the back of the same connector. It sounds like you are beyond this in your diagnosis, but I seen that you said it made a bad noise, and I was thinking of the connection issue for that x-stop microswitch

It fixed the issue, and I was able to home the head and level the bed, but I still have the SD card slot issue.  I wonder if it's the ribbon cable on mine - like it got yanked and messed something up like the ribbon connector end or the card reader itself.  It does not surprise me these types of loose wire issues are common on this machine; In my opinion the cable routing in several places is tight and unintuitive both inside and outside the machine - and you have to be so very careful because it's so easy to pull on wires when opening it and working on it.  While looking for info on my issue I found several people who said their machine came shipped with a loose wire or two

tomtom

Thanks for the replys!!!

Seems like I have to take it apart onece more and scheck the cables again!! 😒 Although I have looked for that several times and also checked the wires for continiuty with a wire inspector.

The replacement motor is the one from JgAurora!!! I think Samuel did had a link for me so that the right one for sure!! Thanks again for that!! 

But any ideas why the 12v motor worked??

And can I be sure that the motherboard don't got a failure? 

Stephen Todd

You pushed the 12v motor beyond its design limits - it would have burned out eventually due to overheating

https://electronics.stackexchange.com/questions/316533/can-i-run-a-stepper-motor-rated-12v-with-a-24v-or-above-power-supply

Stephen Todd

Reading through the thread, your original motor died, you got an exact replacement, and the new motor is not working as it should - got to be the driver chip for that motor surely?

Is that driver chip hotter/colder than the other chips?

Possibly the 20k resistor to ground (marked 203) on pin 8 is open circuit - but it could also be one of the other components connected to the various pins - you could compare the components local to the suspect driver chip to the components of the other chips