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  1. #1
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    Extruder Sensor Board Failed

    I'm down to my last extruder at the moment on my CubePro Duo. I replaced one last year as I kept getting a fillament error on it without any actual errors. The second one is now doing the same. Not surprising as they are both the origonals and probably ran about the same number of hours. The new assembly I purchased is doing well though.

    It's a failure of the seneor board in each case (Part 401380). In the UK it was just much easier to replace the whole extruder than to try and source a new board but now even extruder assemblies are unobtainable here. I've got one coming from the USA but would really like to fix the 2 broken ones to keep as spares.

    I'm assuming the chips U1 and U2 are the most likely culprits. If anyone has managed to repair or source these boards I'd really like to here about it!

  2. #2
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    Welcome to the forum capnscarlet.

    This is the first I've heard of an issue with CubePro sensor failure. Indeed we are now subject to eBay NOS for repairs. Do you have a good picture of the board to show the devices you are referring too?

  3. #3
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    cc_800x400.png

    I can only assume the board has failed as I now have 2 failed extruders and when I use the board from a working extruder everything is fine. The arrows in the photo point to the opto electronic chips. It could also be the tiny surface mount capacitor but I can't really check that.

    I'll do some more testing looking at the behaviour of the working extruder. The failed ones flag up a filament error within a few seconds of running whether there is filament present or not. If I run them slower the error takes proportionally longer to appear.

  4. #4
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    This only detects filament present, right? What if you fooled the system thinking filament is always present bypassing this board altogether?

    Where exactly is this board located?

  5. #5
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    The board is on the extruder stepper motor 3d_800x400.png

    Bypassing it would be my best solution. Its a while since I went that deep into electronics so I'll have to dig out some test equipment and see just what the board does electronically. This could take a while.

    - - - - - - - - - -

    By the way. These are not my photos. I have to credit the-Digital-Dentist on the reprap.org forum. Don't want to upset anyone!

  6. #6
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    No worries on the origin. Once posted, these become public domain.

    I had no idea that filament was being sensed. This is a good thing I suppose.

    I'm looking forward to what you find on the signal.
    I suspect it is going to be a digital state but I don't know if you can simply pull a pin hi or low to satisfy the output.
    If I had to suspect a component, I might go straight to the sensor considering it is dealing with a lot of heat.
    That should also be a simpler component to test if you got some Arduino tools lying about.

  7. #7
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    It's taken a while to get myself back up to speed but I think I've got it. Tricky getting an oscilloscope in there without shorting anything out but it really is a very simple circuit. The big black bit at the top is a generic optical endstop like those found in floppy disk drives if you rember what they were! That simply senses the presence of filament. The 2 small black chips are SMT reflective sensors, probably from the Osram 92xx series. It took a while to track them down as the 6 pin config is a red herring. 2 of the pins are dummies and only 4 are active. After that there are 5 resirtors and 2 capacitors. The reflective sensors look at the turning discs on the stepper motor and the pinch roller to detect filament jams.

    It all pushes out basic TTL signals on 5 pins. Ground, positive, End Stop, left and right turning disc. You could fool the whole system by recreating the logic with an Adruino but you would need to get an input from the stepper driver as it looks at the overall speed of the discs compared to the motor speed. A simpler option would be a physical circuit made from logic chips (I used to use 7400 series chips for this but that has probably moved on).

    The overall easiest option is to just build a new board. Nothing on there is unique. It's not repairable due to the size of the components and the equipment I've got but there is plenty of room on the extruder for conventional components.

    At the moment I don't need to bother as I've got 2 working extruders but I'll plod on and map the circuit and get the component values from the datasheets for the opto chips so I can make one when required.

    At the end of the day I reckon I probably fried the boards myself. I print in wood occasionally and need to change nozzles when I do that not to mention the frequent filament breaks and jams requiring a strip down of the extruder each time. Having worked that out I'm going to dedicate the cubepro to ABS and Nylon and look at a different printer for wood and other tricky filaments.

  8. #8
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    Thank you so much for chasing and reporting that CnS. I don't like working at the nozzles in the CubePro. I hear you on the filament changes. I run ABS exclusively in CubePro to avoid PLA cracks and breaks. I have some nylon I'm itching to try though.

    That is a lot of circuit. Yes simple but highly integrated for performance. I was not even aware they were monitoring the drive gear. Now I understand the color contrast on the gear. I like the idea of an Arduino mimicking the proper operation

 

 

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