Hotend preheat error
Hello! We recently bought a MK3s Prusa printer and assembled it with (almost) no trouble, however we had a printing error with a huge blob of PLA around the hotend. When attempting to clean it up, we accidentally ripped out the tiny cables attached to the hotend. (Probably the hothend thermistor). We thus bought a replacement hotend, however now each time we attempt to preheat, the hotend does not heat at all and we get the message 'Preheat error'. We checked the placements of the cables and everything seems fine on that end.
Our hypothesis:
- the hotend thermistor works fine. The temperature are recognised without issue.
- we feel that the issue might come from the hotend heater cable.
We already tried to :
- check the placements of the cables on the EINSY; rescrew tightly the hotend heater cables on the plug (Everything seemed fine)
- attempted to test the thermistor cable of the new hotend while plugging in the heater cables of the previous one (Hotend did not heat, Same error message).
- attempted to test the thermistor cable of the new hotend while plugging in the heater cables of yet another hotend from our previous 3D printer (ender 3). (Hotend did not heat, Same error message).
- Attempted to heat the hotend externally with a hairdrier to test the heat sensor. (The temperature was recorded just fine.)
We noticed that there was a red light lit up inside the EINSY when we ask for a preheat, and it blinks just before we see the error message. We have no idea what it means.
We don't have any other information. If you have any idea on how to fix this issue, we would be very grateful!
Have you checked the fuses?
Cheerio,
RE: Hotend preheat error
It was indeed broken! Bless you, you are our hero. We'll change that and hope it fixes the issue.
We'll send another message if it still doesn't work. But still, thank you very much.
RE: Hotend preheat error
Hello again, with an update on the issue (yes, we're still having trouble)
We had indeed checked the fuse and found it was blown, and thus we started looking for a replacement.
We quickly found that the fuse was an ATO blade fuse of 5A.
We first bought one in the supermarket, we tried putting it in place but it wasn't working.
NOW the printer reboots when we attempt to preheat, instead of just sending us an error message.
Here's a video of what happens:
We found out they were 12V and the EINSY worked on 24V and the original fuse was apparently on 32VDC. We found a box of 32V ATO blade fuses, and installed a 5A 32V fuse in place butthe same problem remains : reboot when asked for a preheat.
Do you think the issue is with the fuse we bought? Is it somehow incompatible? Do you guys know where we could buy one that works?
Or do you think the new issue lies elsewhere?
Please, oh prusa wizards, share your wisdom with us O.O
Also, note that we now have a huge box of 50 fuses of every color of the rainbow that we have no idea what to do with. We're contemplating christmas garlands, but it's a bit out of date now. Any ideas?
RE: Hotend preheat error
Have you checked that you got the correct heater for the hot end?
if you got a 12 volt heater in error, that may cause the fuse to blow, repeatedly,
alternatively you may have a short circuit on the heater wiring.
If you have a test meter, please disconnect the heater, and test it's resistance. from the connector plug, in the einsy box towards the heater, with the cable unplugged.
in the table above, you will see that the 12volt heater has a resistance in the order of 3.6 ohms.
the 24 volt heater has a resistance in the order of 14.4 ohms.
If you use the 12 volt heater at 24 volts, it will try to draw four times the current than is expected.
If the heater resistance measures less than 3 ohms, look for a short circuit, it may simply be that the heater wires are touching where they come out of the heater block
Good luck,
regards Joan..
PS 12 volt fuses are fine... the current rating relates to what the metal parts can handle, the voltage rating relates to what the insulation can handle.
It's very unusual to get insulation that fails just above 12 volts... so that rating is probably used to indicate that the fuses are suitable for cars
the reason your other fuses are rated at 32 volts, is probably due to the construction of the fuse body, there are metal test points on the outside face of the fuse body, which you may touch when you insert the fuse. this could be dangerous at high voltages.
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Hotend preheat error
Hello again and thank you for your input!
We bought a multimeter and tested the hotend cables like this:
We obtained a reading of 3.8 Ohm which made us think you were right and this is indeed a 12V hotend. Our fuses didn't blow but the prussa rebooted each time, so perhaps they cut off the power whenever it surged?
Regardless, the issue might very well be this, and so we need to buy yet another hotend. Can we have your advice on what to buy? Considering that our prusa was just about brand new before the blob of doom incident, and that we already bought one other hotend, we would prefer not to spend 80bucks on official prusa merch if we can avoid it.
We searched amazon and found this : https://www.amazon.fr/iMetrx-extrudeuse-Hotend-Bowden-Anycubic/dp/B09F36FT2S/ref=sr_1_54?__mk_fr_FR=%C3%85M%C3%85%C5%BD%C3%95%C3%91&crid=2TT1Q939IOAYR&keywords=prusa+mk3s+hotend+24v&qid=1674160424&sprefix=prusa+mk3s+hotend+24v%2Caps%2C65&sr=8-54
Do you think it would be compatible? Do you have any other recommendations?
Eagerly awaiting your return to embark toward the next step of the prusa saga,
Epilost
RE: Hotend preheat error
We searched amazon and found this : https://www.amazon.fr/iMetrx-extrudeuse-Hotend-Bowden-Anycubic/dp/B09F36FT2S/ref=sr_1_54?__mk_fr_FR=%C3%85M%C3%85%C5%BD%C3%95%C3%91&crid=2TT1Q939IOAYR&keywords=prusa+mk3s+hotend+24v&qid=1674160424&sprefix=prusa+mk3s+hotend+24v%2Caps%2C65&sr=8-54
Do you think it would be compatible? Do you have any other recommendations?
The above, hot end is NOT compatible for a mk3. the ptfe fixture will not fit inside the extruder housing.
i would suggest that all you need is a 24 volt heater, if you look at the 'e3d online ' prusa specific items, you will find the 24 volt heater, and the 24volt prusa specific hot end.
the heater is a more cost effective option!
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Hotend preheat error
Late update from our prusa adventures! We've indeed bought a new 24V hotend and our machine now prints!
Many thanks to everyone who has helped us on this quest, we would have never managed without you 🙂