Heatbreak power cables possible short circuit
Hi! I'm having a possible short circuit in the spot where the thick red and black power cables are attached to the heat block (see photos).
What I see:
- the printer's self-diagnostic runs OK;
- heat bed and the heat block successfully reach their normal PLA temperatures (210/60 degrees);
- during the first layer calibration (printing of the meander path), I see bright light spot appearing at where the thick pair of red and black cables attach to the heat block;
- no such sparks during when only warming up the heat block;
What happened prior to that:
- During my last printing session with my usual PLA material, the plastic has completely covered the heat block instead of sticking to the bed. I have noticed it when it was about 1h30 into the printing, all plastic curled up and hardened there (see photo). Just 10 minutes prior to that I had a rather perfect print, and this one was just next on the line. I stopped the print by pressing X and left the thing for the night.
- Next day, I have heated the heat block to 210 degrees and slowly pulled away the clog and the remaining lumps of plastic. Then, attempted to do the calibration and got the sparks I described above. During that short period until I stopped the printer, the plastic was getting extruded in a wiggly form (possibly due to temperature instability).
Some additional info: I have disconnected these two wires from the control box and measured the resistance between them, it has shown 13 Ohms.
I would like to ask for your opinion, on what could be my next step:
- should I attempt to clean the spot where power cables attach to the heat block (and how do I do it properly)?
- should I consider replacing the heat break entirely?
Thanks for any help and suggestions,
Best Answer by Artur5:
13 ohms is correct for the heater cartridge. Therefore it isn’t broken ..yet, because those sparks are a clear sign that the insulation of the cables was damaged when you had to remove the plastic covering the hotend. Now there’s intermittent electrical contact between both cables or between one cable and the hotblock metallic body. so the heating is irregular. To avoid worse problems ( something blown inside the Einsy board ) I wouldn’t power the printer again until the heater cartridge is replaced, because it can’t be repaired once the wires or the insulation are damaged.
To be clear, you need to replace only the heater cartridge, not the entire hotend. If you purchased a MK3/S/+ kit, you’ll know more or less how it’s done. If you got the printer already assembled see Prusa’s guide on how to proceed. Not a difficult task but it’s quite tiresome,
https://www.prusa3d.com/product/hotend-heater-cartridge-24v-40w-mk3-s/
RE: Heatbreak power cables possible short circuit
13 ohms is correct for the heater cartridge. Therefore it isn’t broken ..yet, because those sparks are a clear sign that the insulation of the cables was damaged when you had to remove the plastic covering the hotend. Now there’s intermittent electrical contact between both cables or between one cable and the hotblock metallic body. so the heating is irregular. To avoid worse problems ( something blown inside the Einsy board ) I wouldn’t power the printer again until the heater cartridge is replaced, because it can’t be repaired once the wires or the insulation are damaged.
To be clear, you need to replace only the heater cartridge, not the entire hotend. If you purchased a MK3/S/+ kit, you’ll know more or less how it’s done. If you got the printer already assembled see Prusa’s guide on how to proceed. Not a difficult task but it’s quite tiresome,
https://www.prusa3d.com/product/hotend-heater-cartridge-24v-40w-mk3-s/
RE: Heatbreak power cables possible short circuit
Inspecting closely your pictures, although I'm not totally sure, it seems that the fan shroud has suffered some damage, It's very easy to remove it and check if it's OK or it needs to be replaced too. If the air duct is partially blocked, you'll get poor cooling.
RE: Heatbreak power cables possible short circuit
Hey, sounds good, thank you, I'll replace the cartridge then. Will report here once done.
RE: Heatbreak power cables possible short circuit
To conclude the topic, I've replace the heat block and the heatbreak, to have a cleaner assembly. No sparks, of course, after that. I believe, the initial problem was some plastic leakage between heatbreak and heatblock.
Thanks, cheers!