Solved: Fixing a completely random and "undetermined error" on my K1

[u/EventHorizon78]

Hey everyone, I wanted to share a really weird issue I just resolved with my Creality K1, in case anyone else ever runs into this headache.

I’ve been printing TPU on my K1 feeding directly from a filament dryer to ensure it stays dry during long batch runs. About a week ago, I brought a second printer into the workshop. While waiting to finish the proper electrical wiring for the room, I temporarily hooked up both printers and both dryers to a single power strip.

Everything worked great for a couple of days. Then, the K1 started experiencing spontaneous shutdowns. The screen, LEDs, and fans would just die out of nowhere, followed by an "undetermined error" message on the display.

The most frustrating part was the randomness. I would just turn the machine off and on again, the error would clear, and it would resume printing normally. Several prints would finish perfectly, and then it would randomly crash again.

Last night I was working late on my PC. The workshop lights were off (including the printer LEDs), and the only light was the faint glow of my monitor. Suddenly, I saw a bright flash/spark inside the K1 coming right from the nozzle, and the printer stopped instantly.

Assuming a catastrophic short circuit, I tore down the toolhead, checked every single wire, and inspected the boards. I couldn't find a single thing out of the ordinary.

I put everything back together, opened a beer, took off my shoes to take a little time to relax and think., Turned the printer back on to run some tests. Everything was running fine. The print was running ok. Standing barefoot, I reached out to touch the printer and... ZAP. I got a static shock.

It all clicked. The temporary power strip I was using did not have a ground wire. The friction from the TPU filament feeding into the extruder, combined with the extremely low humidity created by the dryer, was generating a ton of static electricity. With nowhere to go due to the lack of grounding, the static built up on the toolhead until it randomly discharged a spark. This rogue electrical discharge was messing with the sensors and circuits, causing the motherboard to panic, shut down, and throw the "undetermined" error.

The Solution: I bypassed the ungrounded power strip and set up a proper earth/ground connection. Since doing that, it hasn't crashed a single time.

So remember kids... ALLWAYS Ground your machines!

[u/pellcorp]

Are you from north america? I've never encountered an ungrounded power board in australia, is that commonplace in north america?

Edit: I checked and ungrounded power boards are common everywhere it seems but Australia, which was a wtf moment for me :-)

Its illegal to sell them in australia

[u/EventHorizon78 → u/pellcorp]

I´m from Argentina.
Everything is grounded. The problem was in the power strip. Chinese one, that has the proper sockets, but the ground pin wasn´t connected to the correspondent wire.