Need help: printer connects but doesn't do anything

My school has this generic printer that uses Repetier to manage the printing process and I can't get it to work. The printer connects to Repetir Server and Host but nothing works (motors, heated bed, extruder, etc). After I send the printing job the Host returns the expected printing time and that's it. The printer LCD displays a "Bed heating" message but it doesn't start. I don't know how to troubleshoot this thing. Does anybody have any clue where to start?


  • Ok sounds like communication is good at least. "Bed heating" is a blocking command as it is normally send as M190 S<temperature>. So firmware does nothing until the target temperature is reached. Only then it will check for new commands to execute. So have a close look to temperature graph for bed. Does it rise? Does it reach the target temperature? Depending on the temperature you have set your printer might not be able to reach that temperature and you can wait forever or for an error message from printer. In that case reduce the bed target temperature to what your printer can reach.

    Also bed uses highest current and has normally an own fuse. If it does not rise temperature at all also higher value is set and output is 100% you have a damage in your electronics or firmware is configured wrong (in case you wrote firmware configuration). Check for broken cables and burned bed fuse. Can also be the mosfet from board, but that is not easy to replace - just by soldering in a new one.
  • So, the bed is no heating. I sent the printing job and waited for ovr 30 minutes and it never moved over room temperature. The target temperature is not very high, I set it to 60 ºC so it really looks like a hardware issue. This thing has been inactive for several months colecting dust in a corner, I'll have to take acloser look into it.

    I didn't configure the firmware, it came preconfigured from the factory. During installation I asked the software to autodetect firmware configuration and it is now set to use Marlin, could that be the problem?

    If it is something more complicated than broken cables or a fuse I wont be able to fix it.

    Thanks for the help!
  • Marlin is quite likely. If you check console in server and there are not lots of errors that is ok to run.

    First you can just remove all M190/M109 commands from a gcode, then you should be able to print just without hot bed. If you print PLA it might work, especially if you use a specially coated bed or have something like 3d-lac on it. Hot PLA sticks normally quite well on unheated beds, just other materials like ABS require it.

    > If it is something more complicated than broken cables or a fuse I wont be able to fix it.
    Depends on your electronic skills I'd say. With a multimeter it is quite easy to measure where you stop getting power and that part must be fixed. If in doubt, do you have physics teacher on your school?
  • I checked the console and there are no error messages,

    I'll try you advice on M190/109 commands.

    we have and electronics department in our school but I can at least check with a multimiter for broken circuits/components.

    Tank you for the help! I"ll let you know if anything worked.
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