1 Topic by chenderson

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Topic: Press - Extrusion thermistor shorted wire, fried main board?

After a day of mostly successful printing (I received my Press on Wednesday) my Press stopped working. Both bed and extruder temps show really high, 300+C for extruder and 150+C for the bed. When I attempt to just move an axis it errors with a M999.  Long story short I found the insulation on the extruder thermistor had worn off and shorted out to the metal. I have left the thermistor out of its hole and confirmed no longer shorted by measuring the resistance at the board. Soliprint still shows really high temps and wont do anything. I believe the short took out the main board? I submitted a support email yesterday but still no response. Can anyone help?

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2 Reply by wardjr

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Re: Press - Extrusion thermistor shorted wire, fried main board?

It is unlikely that it took out the main board.  The thermistor could be shot but these short out all the time and this would be the first time (that I am aware) it took out a board.

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3 Reply by chenderson (edited by chenderson 2015-01-23 18:34:59)

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Re: Press - Extrusion thermistor shorted wire, fried main board?

Measured resistance at the board connector is 116k for the extrusion thermistor and 118k for the bed at room temperature. Do these sound correct? Do I need to send any reset commands now that the short has been removed?

4 Reply by wardjr

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Re: Press - Extrusion thermistor shorted wire, fried main board?

Not if you have disconnected and reconnected.
Those numbers seem fine.

Printit Industries Model 8.10 fully enclosed CoreXY, Chamber heat
3-SD3's & a Workbench all fully enclosed, RH-Slic3r Win7pro, E3D V6, Volcano & Cyclops Hot End
SSR/500W AC Heated Glass Bed, Linear bearings on SS rods. Direct Drive Y-axis, BulldogXL
Thanks to all for your contributions

wardjr's Website

5 Reply by chenderson

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Re: Press - Extrusion thermistor shorted wire, fried main board?

So I am assuming my board really is bad? Anyone know what the wait time is for support to respond to emails?

6 Reply by chenderson

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Re: Press - Extrusion thermistor shorted wire, fried main board?

Is anyone willing to measure the resistance across resistor R51? It is the small surface mount one next to the extruder thermistor connector. I think this is what may have fried when my extruder thermistor shorted. It is labeled as a 4.7k and I am measuring 2.9k with the thermistor disconnected. R9 which I believe is the similar pullup resistor on the bed thermistor connector is showing a true 4.7k with its thermistor disconnected. Any help would be appreciated. Been waiting a week now for a response from support.

7 Reply by rrssll

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Re: Press - Extrusion thermistor shorted wire, fried main board?

When you measure across that resistor you're measuring the resistance of whatever circuit it's a part of, looking in from the two terminals you're touching. So you won't see 4.7kΩ unless you cut the resistor off from the rest of the circuit (don't do that :-) ).

I'm seeing a similar issue with my thermistor. It measures 118kΩ when it's not in the aluminum block. When I put it in and tighten down the grub screw I get 35Ω. So I assume I must've cut through the insulation with the grub screw while reassembling it. Seems like a very easy failure to cause.

From another thread on this forum, it sounds like the thermistor may be a Semitec 104GT-2.