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How to replace aerostruder Thermister

Posted: Mon Jul 29, 2019 6:09 pm
by PeterT
Hi folks, had a major meltdown (not me, the printer) and after pulling all the melted badness away from the head, the insulation around the thermister wires is melted away. It works, but I don't want to take chances. Can't find a clear instruction on replacing it. I have the replacement part, but I want to make sure I don't trash it.

There is one hex nut towards the heater slug, and that seems to be it. My guess is loosen that, and slide the thermister out (while not dislodging the heater unit.).

Of course, there's still some residual plastic in the seam of the block, so I would probably need to heat the head, turn off unit, quickly loosen and remove thermister before things hardened back up.

Am I right? Please advise. Thanks!

Re: How to replace aerostruder Thermister

Posted: Tue Jul 30, 2019 8:21 am
by b-morgan
Since the thermistor still works, an alternate plan B might be to just insulate the existing wires. You could try some high temperature silicone (Permatex Red RTV High Temp Gasket Maker #81160) on the wires as they enter the heater block. Be careful to separate the wires as you apply the silicone. Once the silicone dries, you should be good to go.

Another possibility would be to carefully disconnect the wires where they plug into the connector (you can remove the pin from the connector) and then put some heat shrink tubing over each wire. I'd still add some silicone at the thermistor end just to be safe.

A picture or two of the existing hotend might make it easier to help.

Re: How to replace aerostruder Thermister

Posted: Tue Jul 30, 2019 10:20 am
by PeterT
Thanks for those suggestions. Good ones indeed.

As it turns out, a bit more hunting on the e3D site gave me the instructions. Turns out it s simple set screw on the bottom of the block. Trick is, of course the head of the screw is going to be filled with plastic, so I'm going to have to heat the head and get the hex driver in there before it solidifies (without burning my fingers from heat crawl up the tool :O

Re: How to replace aerostruder Thermister

Posted: Wed Aug 07, 2019 12:42 am
by JoeBowler300
1.) A soldering iron can melt the point where the plastic is on the heater block and then use some tool to transfer the melted plastic too.
2.) You can heat up the tool’s point(screw driver or hex key), then insert it through the plastic and unscrew.
3.) replace the heater block along with the thermistor. The heater block is relatively cheap.