Hot end heater stopped working on Duet 0.6 (Solved by a power cycle)

I've been running a Duet 0.6 on my delta printer for quite some time. The other day, in the middle of a print, the hot end temperature dropped and I have been unable to get it to heat anymore.

I've probed the board with a multimeter, and find that the EO_PWM line (at the GATE of TR3) is always HIGH, regardless of whether I have set a temperature or not.

If I pull that pin LOW by shorting to the SOURCE, the red LED comes on and my hot end begins heating.

I'm afraid I may need a new controller board (another new controller board, as this is the second Duet 0.6 on this printer), but was wondering if anyone had troubleshooting suggestions, either hardware or firmware-related?

Edited 1 time(s). Last edit at 11/22/2016 09:39AM by maso.

It could simply be that the pin of the microcontroller that drives that signal is not soldered down. I've seen that before. It's hard to tell by visual inspection whether a pin is properly soldered. So try pushing it down with a hot soldering iron, then make sure you haven't created a solder bridge.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks for the idea @dc42. Unfortunately it doesn't appear to be the issue. Pin 66 is 3.3V as well, and pushing down on it didn't do anything really. I'm afraid that pin might be dead.

I could perhaps try snagging one of the pins from the expansion header -- I'm not using it for anything.

Is there an easy way I could re-assign another pin to that task within firmware? Or would that involve building from source?

Yes you can configure your hot end tool to use a different heater in your M563 command. Then use a M305 command to define the thermistor parameters for that heater channel and add the X1 parameter to that command to tell it to use the thermistor for heater 1.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

PS are you certain that heater 1 is not working but in a fault state? Use M562 P1 to reset it.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42
PS are you certain that heater 1 is not working but in a fault state? Use M562 P1 to reset it.

Heh heh. Your reminder got me thinking.

I've had this thing plugged into the USB on my computer in addition to my power supply lately. So my power cycles weren't really power cycles.

I pulled all power to the printer, then re-applied it.

The heater works again!


I had just jumped straight into troubleshooting mode because I had a board fail previously. Missed the simple stuff. Thanks once again for your help, @dc42!