1lc board stopped working, but still responsive to m122

Phaedrux

It sounds like another case of ESD buildup causing the fault. How well is the print head grounded?

BlueDust

@phaedrux
Sorry for the delay in my response. I was somewhat confused by what you said and with other problems I have been having with the my printers just stopped printing for awhile.

When you say grounded, are you referring to the black wire, already apart of the wiring diagram or an additional grounding of the printer and/or 1lc board?
Everything on the 1lc board looks tight, but want to confirm what I am looking for before I start chasing my tail.

Thanks!

Phaedrux

See the wiring notes here on grounding: https://docs.duet3d.com/en/Duet3D_hardware/Duet_3_family/Duet_3_Toolboard_1LC#wiring-notes

In general though it is recommended that your metal frame, stepper motors, hotend metal, etc be grounded to prevent the build up of ESD.

BlueDust

@phaedrux

Is there a picture of how this ground is wired? Unless I am mis understanding what is being grounded, I can't picture where or how the ground wire would be appropriately attached.

Thanks!

jay_s_uk

@bluedust the metal part of the hotend. So somewhere on there you should attach the ground to

BlueDust

@jay_s_uk
I guess that is part of my question.
Am I just wrapping wire around the top of the heat sink? Do I need to attach it using solder? Possibly thread a small hole into the top heat sink fin and screw a ground wire to it? Is this ground then being connected to to a screw hole on the 1lc, to the frame, and then to the black wire on the 24 volt side of the power supply or the ground/frame of the power supply? I don't quickly see a ground on the output side of my power supply (was looking for a screw on the chassis).

Sorry for my ignorance here, but it has never been super clear to me how people are grounding their printers, to the power supply, or a separate ground to the wall. Most of my printer are plastic parts, and if I was going to ground it, it would have 100 wires all around to bypass all of the plastic, and have never seen anyone actually do it before to take note of (as this would make me ask, how are full 3d printed printers grounded?).
I am really looking to understand to do it right the first time and not just hot glue a wire on to give my self a warm and fuzzy feeling.

Thanks for the help!

jay_s_uk

@bluedust from dc42 One option is to connect it to one of the ground pins on the tool board through a 100K resistor. to the hotend. so that should probably be to somewhere on the heatsink. Solder should work fine.

Generally, if you have any metal parts on the printer, such as motors, frame etc, they should all be grounded. In the UK, we have a separate ground connection so I use that for grounding the frame etc.

BlueDust

@jay_s_uk
Do you ground your printer/frame directly to the wall or do you ground it to the 24v power supply chassis (I currently don't see a way to do this)?

jay_s_uk

@bluedust i ground my frame to the incoming ground pin on the IEC C14 socket on my printer. That then goes directly to the wall.
I think the voron wiring instructions are very good. they can be found on page 236 of this https://github.com/VoronDesign/Voron-Trident/blob/main/Manual/Assembly_Manual_Trident.pdf

dc42

@bluedust to clarify: we have strong evidence that extruding plastic through a nozzle builds up static charge on the nozzle and connected metalwork. If this charge has nowhere to go then it tends to arc over to a heater, thermistor or stepper motor connection. That can damage the tool board, or just cause it to lock up until powered down.

If the tool board is mounted directly on a Hemara or similar extruder (such that the stepper motor body is in electrical contact with the hot end), then one option is to put a solder tag or wire under one of the tool board mounting screws and connect that to a ground pin on the tool board, preferably through a resistor of about 100K. The new tool board we have made to fit the Hemera XS has these resistors built in.

Many other schemes are possible. For example if the hot end is electrically isolated from the stepper motor, then you could use a spring to contact the heatsink; or wrap a piece of solid core wire around the heatsink between a pair of fins and twist the ends together to secure it.

It's possible to use a direct connection instead of a 100K resistor, however we suggest using a 100K resistor to prevent excessive current flowing in the event that the hot end gets a short to something else, for example a short between the heater cartridge element and its case.

BlueDust

@jay_s_uk & @dc42

Thanks for the help!
The detailed information to the problems and suggestions on how to wire it up is very helpful!

BlueDust

@dc42
Looking at getting a 100K resister...
(Please help correct my ignorance as I am new to the electrical engineering side)
It seems there are wattage requirements in picking the correct resister.
Looking at kits on Amazon, I was able to quickly find 1/8 to 2 watt range.
For this requirement, I am assume wattage (dissipating heat?) doesn't really matter and the smaller the physical size of the resister the better, but didn't want to assume and asking for confirmation.

Thanks!

Phaedrux

@bluedust said in 1lc board stopped working, but still responsive to m122:

For this requirement, I am assume wattage (dissipating heat?) doesn't really matter and the smaller the physical size of the resister the better, but didn't want to assume and asking for confirmation.

I think that's a safe assumption.