eriksw

UPDATE I have changed the path of the fan wires (through another hole in the printhead), twisted them, and made them shorter ( as short as possible). I have also shortened the wires of the thermocouple. So now the fan and probe leads are much further apart, minimal 20 mm as suggested. Unfortunately: only a slight improvement. Still these fluctuations when using fan between 0 and 100 %, although a bit less violent. But still no fix... I think there are 3 parts that might need replacing, either: 1. the cooling fan. Is it possible this has started to produce more interference due to aging ? It sounds ok to me... 2. the thermocouple. Can't find any info on the life span of these. Do they wear out ? It has been used for approx. 1500 print hours now... 4. the small amplifier circuit board. Perhaps it is not amplifiyng the signal (enough) anymore ? Or would I not be able to print fine with fan at 0 or 100% if this was the case ? Your help is greatly appreciated !

But if it was these wires, I would have the same problem when printing without using the fan, I thought... Disabling the fan solves the problem completely. I have been printing stuff without fan for 2 weeks now, no problem with those. And now I know I can also use the fan at 100% without any problems, that seems to work (thanks for that one). But as soon that PWM starts going, it starts acting up. So it must be that interference problem, I'm sure. I'll rewire the fan wires tomorrow and I'll keep you posted on the result. Thanks Erik

Yes I checked the wires already, no problems there. I have used Cura 14.01 since it came out, without any of this trouble. So that's not it either. Perhaps the positioning of the fan wiring has slightly changed while replacing the nozzle, but only SLIGHTLY if at all. Still, I get the impression this probe has been getting less sensitive for a while now, as it seems I have to print hotter than a year ago to get the same results. So any info on probe lifetime expectancy ? Thanks for your help, much appreciated.

Thanks gr5, you are right, no problems when starting fan at 100% at 2nd layer. Didn't know PWM was used for controlling the fan speed, it makes a lot of sense that this is the cause. And now I finally understand what that little circuit board is for... I'll change the wiring - seems like a good idea to use another hole in the printhead for the fan wiring, and I'll make sure to twist those fan wires. Still strange though, as it didn't have any problems with these intermediate fan speeds before, and I made no changes to it - the problem started "spontaneously". Is it possible that the output of the probe has become weaker due to aging ? Or is it just a heat-sensitive resistor ?

I have an Ultimaker 1 which has been intensively used for almost a year. Worked fine until two weeks ago. Problem: the temperature reading on the controller is now giving weird readings during printing.For instance, with temperature set to 220, the readings follow in rapid succession (a second or less) saying: 220-217-223-217-222- 216-223-220-223-216 and so on. So: weird hops that can not relate to actual temperature of the nozzle as this cannot fluctuate that quickly. The actual temperature seems to drop, as printing usually starts to fail then. The weird thing is that it works fine when I don't use the fan. No problems then, but as soon as I switch on the fan (or when it switches on automatically at 2nd layer) the readings become weird as described above. Switching off the fan cures the problem again... So no broken leads or faulty sensor I would think, otherwise I would have problems all the time, also when printing without fan. ANY SUGGESTIONS ANYONE ? And yes, I know that the temperature starts to swing a bit when the fan switches on, that is normal. But I have never seen these weird "jumps" before...