Duet Maestro E0 Temperature Problem



  • I've got a Duet 2 Maestro purchased direct from Duet on 9 Sept last year.

    Yesterday evening I was printing away, and I checked on the web control to see that the print had automatically paused as there was a temperature error, the extruder heater was off, and the temperature slowly cooling from over 400 degrees. The temp graph showed a sudden temperature spike a minute or so earlier. The temp eventually cooled to about 283 degrees, but the hot end was cool to the touch.

    This morning I set about testing with a meter & some resistors.

    I've got a genuine E3D Titan Aero extruder, the thermistor shows a resistance of 145K ohms (room temp about 15 degrees), and a spare genuine E3D thermistor I have shows almost exactly the same resistance.

    My heater setting in config.g is

    M305 P1 B4725 C7.060000e-8

    With either of the E3D thermistors I have connected, extruder temp is 243 degrees.

    With nothing connected to the board on the E0 temp header, the extruder temp shows a slightly fluctuating 3-4 degrees.

    No shorts visible or detected with a meter in the E0 thermistor wiring from the duet connector to the E3D connector by the hot end.

    With a 100K ohm resistor (carefully!) directly across the E0 temp header pins on the board I get an extruder temperature of 250 degrees.

    This is leading me to believe that the Duet board has broken itself (at 7 months old), is this a reasonable diagnosis, or is there something else I'm missing?


  • Moderator

    @robbuckley Can you map the temp sensor to E1 temp header pins, and see if you have the same problem there? This would narrow down where the problem might be. Check the reading with your 100k ohm resistor before connecting the thermistor, in case there is a wiring fault causing high voltage to short to the thermistor circuit. There is a VSSA fuse to protect a short in the temperature circuit killing the rest of the board, though.

    Ian



  • I put X2 at the end of my M305 line

    With nothing connected, 2000 degrees.

    With a 100k resistor, 25 degrees.

    With thermistor connected, 17 degrees and heats up believably when I hold it in my fingers.

    That seems to get me operational again, but has the E0 thermistor channel died on the board?


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