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I did a bad thing


czucker

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Posted · I did a bad thing

My hot end (UBIS ceramic) stopped working today and I was trying to jiggle the wires a bit to see if I could get it working (more on that in another post).

Then I heard a pop, powered down the UM, and powered it back on.

Now, it's reading 130º without the hot end even attached.

I'm guessing I blew something on the board, but I don't know where to look.

Any thoughts?

Thanks,

Chris

 

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    Posted · I did a bad thing

    Sorry, I was unclear. I was fiddling with the wires at the print head. And, it's an Ultimaker original.

    It did cycle power by itself at one point. I'm wondering if maybe the firmware went back to factory. Is that possible? It does read 0 degrees if I pull the 4.7k resistor on the um board.

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    Posted · I did a bad thing

    You should ask the UBIS experts. I don't know what's in a UBIS hot end. Does it have the same thermocouple as on the UMO? The one on the UMO goes through a board on the print head that converts the temp into a voltage from 0V to 5V representing temps from 0C to 500C linearly.

     

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    Posted · I did a bad thing

    It's the Printrbot hot end. No board prior to the UM board. I'm kind to refresh an see what happens.

    By the way, we met briefly at Maker Faire, no?

    I was eating a navy ball cap. Spoke about the new build platform. . .

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    Posted · I did a bad thing

    So from what I can deduce from the information. The Ubis uses a thermistor for temperature readout since you are using a 4k7 pullup resistor. If the temperature wires make a short the temperature readout will be very high or error. If the wires are open then the readout would be 0 or error. In your case you claim they read 130. That is very odd... Did you make a short between the thermistor wires and the hotend? Now it depens on how the hotend is connected to your UM board, I can't say anything about that. A short between the 19V and the thermistor input could damage your microcontroller input circuit. The only advise I can give is start measuring the voltages on the inputs of the UMO board. Given the 130 degrees and the reset behavior you described I think something happened between the UMO inputs for the temperature input and your hotend output. If your are 100% sure the thermistor is ok and connected correctly and still have wrong values you could try the second temperature sensor readout and build a Marlin to experiment with that if your AD converter in the microcontroller is permanently damaged.

     

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    Posted · I did a bad thing

    What Zoev89 says makes good sense. Probably broke the ADC pin on the arduino.

    A 100K thermistor should be about 100k at room temperature (actually officially it would be at 25C). A 10k thermistor should be about 10K at room temperature. You could test the thermistor.

    Then you can put the 4.7k resistor back in and see if the voltage there makes sense (read about resistor dividers on wikipedia). Then if that voltage is correct and Marlin still thinks it is at the wrong temp then it's the arduino that is broken. Fortunately they are VERY inexpensive. Maybe $20 including shipping.

     

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    Posted · I did a bad thing

    By the way, we met briefly at Maker Faire, no?

     

    What? You were eating a hat? I don't remember anyone eating a hat - sorry. But you probably saw me there. I was at the booth about 50% of the time. Bald guy with moustache.

    Oh gosh - do you have the ultimaker heated bed upgrade? If you do and installed the firmware for that then your thermistor UBIS would probalby stop working.

    I guess you really need to determine what kind of temp sensor you have in the UBIS - is it the UM original sensor (thermocouple) or is it a thermistor?

     

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    Posted · I did a bad thing

    Wearing. . . .Wearing. Stupid predictive text correction.

    It is indeed a thermistor on the hot end. And I have a home built heated bed upgrade. Buit everything was working just fine until last night.

    However, I get a reading of 130º with absolutely nothing plugged in to the board beyond the ulticontroller.

    I'm also finding that Cura times out when trying to upload firmware. . . . . I'm kind of at a loss. . . .

     

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    Posted · I did a bad thing

    So, just an update here. Whatever it is that I did yo my UM board, it seems to be damaging the Mega 2560.

    I can no longer connect to the one that came with my UM via Cura or the Arduino IDE.

    I was able to flash firmware to a spare Arduino, but as soon as I hooked it up and turned the printer on, it also lost it's ability to communicate via USB. . . .

     

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    Posted · I did a bad thing

    Weird i am having a similar problem with not being able to start the heated be as it only reads zero, but i had to replace my arduino as i lost the ability to connnect to it via usb. I thought it was just a bad arduino but now i think otherwise.

     

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