MakerGear Forum

Hello all,

I use my printer almost solely to make inserts and other pieces for my board games. Lately I've been working on printing some coins to replace cardboard chits. Twice now my printer has just stoped in mid print, the nozzle is even still touching the part it stopped on. If I look in the machine control panel instructions are still flying by so Simplify 3D appears to still think the print is happening but the machine isn't moving and I don't think the nozzle is hot.

I know this isn't a lot of information but any idea why this is happening? Oh and if it matters both times I've been printing 39 pieces.

Does it stop at exactly the same spot, or is it random. If it's random, I suspect a loose/busted wire someplace. If it stops at the same spot, that suggests there's something in the gcode that isn't right.

Addiction wrote: ↑

Fri Oct 01, 2021 7:38 am

I don't think the nozzle is hot

Replace the hot end thermistor.

The other possibility is an almost-broken wire in the cable from the thermistor to the RAMBo board, due to all the flexing, but replacing the thermistor is where you start.

Somewhere in the torrent of printer messages, you'll likely find a MAXTEMP error message; it's not clear why S3D continues to blunder onward afterwards.

Search the forums for MAXTEMP: you're not alone.

Gwhite wrote: ↑

Fri Oct 01, 2021 1:17 pm

Does it stop at exactly the same spot, or is it random. If it's random, I suspect a loose/busted wire someplace. If it stops at the same spot, that suggests there's something in the gcode that isn't right.

I'm not sure it's the same spot as it's only happened twice and they were about a week apart.

ednisley wrote: ↑

Fri Oct 01, 2021 1:48 pm

Addiction wrote: ↑

Fri Oct 01, 2021 7:38 am

I don't think the nozzle is hot

Replace the hot end thermistor.

The other possibility is an almost-broken wire in the cable from the thermistor to the RAMBo board, due to all the flexing, but replacing the thermistor is where you start.

Somewhere in the torrent of printer messages, you'll likely find a MAXTEMP error message; it's not clear why S3D continues to blunder onward afterwards.

Search the forums for MAXTEMP: you're not alone.

I'll run down how to replace the thermistor and try that, but this V4 hot end is very new and maybe has 100-110 print hours on it. I'd hope that isn't the issue.

Also where does one get instructions on how to replace the thermistor?

I looked, and there aren't any instructions I could find that are specific to this. The thermistor & the heater are held into the hotend block by small set screws.

Here are instructions from removing the hot end, (although it sounds like you already know how to do that):

https://makergear.zendesk.com/hc/en-us/ ... tallation-

You may be able to swap out the thermistor without actually dismounting the hotend. Slide off the black cover, which will expose the two small set screws. I believe the upper one is what holds the thermistor. The instructions linked to above show you which cable is which, and you should be able to figure it out from that. I think the smaller diameter device is the thermistor.

Before you go to the trouble, you can try shutting everything down, unplug the thermistor, and measure its resistance. If it's a short or an open circuit, that's the problem. I think they should measure around 100K at room temperature.

Gwhite wrote: ↑

Sun Oct 03, 2021 2:03 am

If it's a short or an open circuit, that's the problem

A failing thermistor starts out intermittent, so the resistance will seem perfectly normal almost all the time. That's why it can start printing, then fail at some random point along the way. Finding the error message confirms the diagnosis.

The thermistor cylinder slides into the hot end block, so you can just pull it out. Otherwise, loosen the cap screw holding the hot end into the aluminum plate, rotate the hot end to get enough clearance, then pull it out.

Some pix, although I do not recommend rebuilding the thermistor:

https://softsolder.com/2018/02/07/m2-th ... r-rebuild/

Thanks for your help all got this issue fixed. Sorry, I thought I'd replied to everyone when I fixed it.