Extruder Stopped working after 2 months

[korser]

Printer Model

LDO v0.1 with 0.2 upgrade

I recently build a LDO v0.1 with an upgrade kit to v0.2 about three months ago. I've been happily printing for about 2 months. A few days ago my printer stopped in the middle of an ABS print. I checked the log after rebooting and it seems the connection to the mcu was lost. I saw a bunch of these

serialhdl.error: mcu 'mcu': Serial connection closed
mcu 'mcu': Timeout on connect
mcu 'mcu': Wait for identify_response

I tried to print again after but the extruder makes this really loud rattle noise. I thought it might be a loose screw. I've re-tightened all screws without success. I thought maybe the extruder gear my be grinding against another gear. I took it apart and checked all gears, I couldn't find anything. I started testing the extruder and noticed the gears goes back and forth not really turning when issued a retract/extrude. I thought maybe my motor was bad. I check the the resistance and continuity for pair pins from the cable going to the toolhead. 1 and 2 have 2.3 ohms while 3 and 4 have 2.4 ohms which seems normal. I don't have an oscilloscope to check if the signal coming from the mcu is correct. What else can I check or can I debug this issue?

 

[claudermilk]

A really loud rattle is probably the motor stalling because the filament isn't moving. First, remove your filament and get the motor moving to verify it's working. If that works, then it's time to see why the filament is jamming. Now I'm off to take my CW2 apart...because I just got a weird break and a small bit of filament is stuck in there. Which is causing a loud grinding/rattling noise.

 

[korser]

That's what I thought that something might be stuck but no. I removed the toolhead and took it apart. I removed the gears to make sure nothing was stuck. Everything runs freely and smoothly when I turn the gears. I even tried running the motor not attached to the toolhead and I can still hear the noise. I was thinking to try and plug the motor into a different plug to see if it still make the noise.

 

[korser]

You can see it in this gif when I tried to extrude 10mm



it's a bit hard to make a gif small enough for the upload limit. Hopefully it's clear what's happening.

 

[korser]

It's working correctly when directly plugged into the SKR Pico Board. Either the Toolhead PCB or Frame PCB is causing issues. I'm not sure how to check which one has the issue. Is this something I can get LDO to replace?

 

[claudermilk]

LDO is good, if there's a problem with either of those boards I would expect that they will replace them.

 

[ChrisA]

It's working correctly when directly plugged into the SKR Pico Board. Either the Toolhead PCB or Frame PCB is causing issues. I'm not sure how to check which one has the issue. Is this something I can get LDO to replace?

I think you have almost diagnosed the problem. The motor works when getting the correct signals in the wires. Those PCBs don't do anything except connectorize the wiring. My bet is on a loose connection, either the solder on a board is bad or a pin is improperly crimped. You should be able to find an open connection with an ohm meter.

Connectors make wiring easy but if ever there is a fault, it is usually the connectors or the cable pins.

 

[korser]

I spoke to LDO since and they think the harness cable from the Toolhead PCB to the Frame PCB needs to be replaced. They will send me a new one. Kudos to their super responsive support.
I do t try replacing the cable from the frame PCB to the pico. Hopefully that’s not the issue.
In the mean time I made an extension cable to plug the extruder motor directly into the Pico board. I’m happily printing once again