X axis problem--heavy vibration, no movement

[eryker 1]

I have a UM5 running the latest stable firmware.

 

The printer has an occasional issue with movement on the X axis, and possibly also with the Y axis (hard to tell). It seems to occur about every other print I do.

 

When the printhead performs the homing routine, the printer makes a loud grinding noise and the head struggles to move under a high amount of vibration.

 

I've never encountered this during a print, only during homing or when I have to change filament.

 

Once this occurs, when I reboot the unit, it hangs on boot. I have to power it completely off and leave the power cable unplugged for a few seconds.

 

Here are the observations I have made:

 

-Mechanically the printer seems sound. Belts look fine and are tensioned appropriately. Linear shafts are all still in their bearings. With the steppers unpowered, both X and Y move fairly easily without binding for their length of travel.

 

-Limit switches all test good, tested with both multimeter and the onboard diagnostic. 

 

-Stepper cables look fine without any obvious signs of damage and are plugged in completely.

 

My inclination is that either a stepper driver is failing or a stepper cable is bad. It seems consistent with a missing phase on a stepper.

 

It seems like it would be helpful to know why booting fails. I downloaded the logs and looked though dmesg, but the last log seems like it was from the second successful boot.

 

Is there a way to ssh in while it's booting? Is there a serial connection I can use instead of the network stack?

 

Thanks for any assistance.

[gr5 2,235]

Can you take a video of the homing issue?  90% of the time it's a limit switch.  Put the head near the center left side and do homing and then put the head near the top center and do homing.  This will help you see which axis is the problem as it only does the Y axis issue when the head is near the rear and only the X axis bounc when the head is on the left side.

 

I could be wrong - it could be stepper driver or cabling which is why I want to see the video.

 

I know you tested the switches with a multimeter but...  this sounds exactly like a limit switch issue.  So the video would be helpful to be sure.

 

As far as boot, yes you can get a "olimex serial cable F".  Although I don't think this works with S5's built in the last year or so but if it's reasonably old then yes you can watch the boot sequence through the serial cable.  I detail how to set it up here: http://gr5.org/unbricking/

 

If you have an S5R1 (release 1 - side panels have robot;  release 2 - side panels have big "U") then there are deadly voltages exposed under the printer so be very careful not to kill yourself.  Please.

 

You can use my guide to find where to connect the olimex serial cable F and if the pins are there then the cable will work.  If UM doesn't have the pins anymore on your board then you are mostly out of luck.  Although I guess you might be able to solder in 3 header pins?  Not sure what the latest boards look like now.  Probably don't even have an olimex computer anymore.

 

It's possible that one of the limit switch cables isn't reaching the circuit board underneath the printer.  Maybe the cable fell out.  Maybe the cable got pinched and broke.  This is pretty rare.  Most likely the limit switch is (sometimes) just barely beyond reach on X or Y axis.

 

[gr5 2,235]

I just noticed on my S5 go to "maintenance" "diagnostics" and there is "test limit switches".  You can then push the head around and when the head hits a limit switch it changes color on the display.  I have older firmware - hopefully this feature is still there.

[Dustin 160]

the test is still in the firmware...

without a video the error sounds like the limit switch is bent out of position. 

[eryker 1]

3 hours ago, gr5 said:

I just noticed on my S5 go to "maintenance" "diagnostics" and there is "test limit switches".  You can then push the head around and when the head hits a limit switch it changes color on the display.  I have older firmware - hopefully this feature is still there.

Yep, was one of my first steps. I also replaced both limit switches, and the problem persists. I wasn't able to get it on video last time it happened as it occurred when the printer paused itself due to a nozzle clog. The serial cable should help me pin down the boot issue at least.

 

[Dustin 160]

A video of the issue very much will tell alot of what is going on as well. 
 

But I would also recommend contacting UltiMaker Support directly 
here: https://support.makerbot.com/s/contactsupport

UltiMaker does not provide direct support via the community. 

[gr5 2,235]

I'd uncover the bottom of the printer to make sure you have the correct connectors before ordering.  Also read the instructions on the olimex website where it has the description of the cable.  It talks about baud rate and how to hook it up.  It's not what I thought at first - I think you connect serial in on the cable to serial out on the printer.  Sort of backwards from intuitive.