1 Topic by SnakeEyes (edited by SnakeEyes 2014-03-12 20:10:56)

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Topic: Extruder Temp randomly skyrocketing

Now my sd3 has decided to give me a brand new problem.  the extruder temp is randomly going up to 270 in rh.  ran pid tuning again and its still doing it, causing everything to shut down.  could it still be a loose connection?  ive had that problem before and i could watch the temp go up and down.  Thought i had fixed it by soldering the connections.  Im nearing the end of my rope trying to figure this things problems out.  just seems like every time i fix one issue another 2 spring up.  again i always appreciate the help you guys give.  if it wasn't for this forum ......... oi!

Overkill is underrated!!!

2 Reply by ronsii

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Re: Extruder Temp randomly skyrocketing

sounds like a sketchy connection to the thermistor.

3 Reply by SnakeEyes

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Re: Extruder Temp randomly skyrocketing

so replace the blue connector, wiring, thermistor  or rip it all out and replace everything?

Overkill is underrated!!!

4 Reply by grob

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Re: Extruder Temp randomly skyrocketing

Looks like this usually happens either at the blue connector or where the thermistor is crimped (nearer the hot-end). Check and tighten up all these connections, and see what happens. Have a search, there should be a bunch of guides floating around on how to do this (if anyone has a link handy...).
Thermistor itself is likely fine (especially if it works some of the time).
It's very unlikely the wire itself is a problem, unless it's obviously damaged somewhere (pinch point? folded?).

Ideally, to maximise reliability, one would minimise the number of connections hanging around on moving parts, at the expense of convenience. If/when this problem happens to me, I intend to re-crimp the wires from the mainboard straight onto the thermistor - removing the blue connector from the equation.

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
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5 Reply by adrian (edited by adrian 2014-03-10 00:50:16)

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Re: Extruder Temp randomly skyrocketing

High temps on the thermistor means its a Short usually... 0 temps mean its a broken wire..

So your problem if the temp goes high means the thermistor shorting either to its self (leads touch) or via the Nozzle or somewhere else.

And you need to crimp it - not solder it - anywhere near the hot end as the solder will melt/degrade/dry joint/et al during normal operation - this is why the OEM plugs are crimp type and the resistor is joined with boot lace ferrules...

6 Reply by SnakeEyes

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Re: Extruder Temp randomly skyrocketing

I soldered it because the solder point is about an inch away from the hot end.  Does it really get that hot that far away?   Ive actually touched it while it was at max temp and it didnt feel hot at all.  Is there a good site to order small crimp connections and new plugs?

Overkill is underrated!!!

7 Reply by adrian (edited by adrian 2014-03-10 02:50:22)

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Re: Extruder Temp randomly skyrocketing

Yeah, and it also suffers heat cycling which introduces dry-jointing.

Solder will work fine for a while... but its kind of like living in a big city and leaving your doors unlocked - You won't experience a robbery immediately, but eventually you'll come home to discover everything gone wink

Anyway - crimp plugs - use JST, found on ebay and radioshack and listed on the soliwiki hardware compatibility page - as are the links to digikey to source the original connectors.

For the crimps - Boot Lace ferrules from any automotive or electrical store, simply trim the plastic insulation from one end. If you want the pure uninsulated butt connectors - then you will need to most likely order from the web to find it 'easily'.  An example source is Ferrules Direct

8 Reply by adrian

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Re: Extruder Temp randomly skyrocketing

I should note - I have on occasion soldered at the very top of the thermistor lead, right behind the crimp plug - but I also use high-temp insulation over that joint and then a sheath of Vidaflex insulation... the lower connections are crimped...  and then I also use high-melt-point lead-free solder (which softens at a greater temp than leaded solder). I do however happen to have all that 'at hand' so its no additional effort/cost on my behalf...

So I probably should have said - if you do it observing a couple of extra steps - its kinda ok...

9 Reply by MolecularConcept

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Re: Extruder Temp randomly skyrocketing

i dont really see why its so hard? mine are twisted together and taped and i have  zero problems.

10 Reply by adrian (edited by adrian 2014-03-10 05:25:56)

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Re: Extruder Temp randomly skyrocketing

MolecularConcept wrote:

i dont really see why its so hard? mine are twisted together and taped and i have  zero problems.

Yup - and I've used gaffa tape to hold bits together on the race bike at 160mph+ and a cheap scissor jack when working underneath a car .... doesn't make it 'right' or 'good'... smile
Also - the differentiating point is - you've at least used a mechanical joint not a solder joint..

11 Reply by SnakeEyes (edited by SnakeEyes 2014-03-10 20:08:23)

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Re: Extruder Temp randomly skyrocketing

Putting an order in now but i do have two other questions.  One - what gauge wire is this. looks smaller than 20 or 22 but im not sure.  and two - When this first started happening i noticed some burnt abs on 2 of my prints ......  if this isnt a mechanical, shorting, crappy connection issue, could it be anything else like a bad board or a software glitch?  I ask because the temp isnt just jumping that high, when i heat the extruder, it hits my heat, that just slowly keeps going up.  Its not just hitting 270 from 150 in a second like it used to be doing.

Overkill is underrated!!!

12 Reply by MolecularConcept

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Re: Extruder Temp randomly skyrocketing

i think its a glitch of some kind mine does that every once in a while if i notice it i just turn off the hotend in repetier host and turn it back on when it goes back towards normal. its only happend a few times though.

13 Reply by adrian

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Re: Extruder Temp randomly skyrocketing

have you auto tuned your pid lately incidentally ? (M303 et al...)

14 Reply by SnakeEyes (edited by SnakeEyes 2014-03-12 23:59:05)

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Re: Extruder Temp randomly skyrocketing

Solidoodle sux for 2 reasons right now.    Thermistor was shattered and it just took them a month to send me 2 pieces of Kapton.   What are the odds it doesn't take them another month to send me my new order?  I've received thing quicker from china, and i can drive to SD in an hour.  >=P   So in the end, Problem Solved............. for now.


....... and yes adrian pid was the first thing i did.

Overkill is underrated!!!