Extruder heating nonstop when printer is connected to power supply

poiuztawea

Hello,

I'm running a modified Repetier-Firmware Version 0.91.48 (2014-11-24) on a Renkforce RF1000 printer. My issue seems to be rather strange, as I couldn't find any similar problems online, but it might be a firmware problem as there haven't been any hardware changes when the temperature control stopped working. Right now the heater is heating uncontrollably as soon as the printer is powered on regardless of whether the printer is connected to a computer or not.

The problem first occured when I was testing a change of the filament feeder. As the manufacturer doesn't support a Firmware newer than the stated above, I couldn't allow Cold Extrusion with the M302 command and heated the Hot End to 155°C in order to start the extruder motor. Because the printer didn't respond to some commands sent via Repetier Host I quickly disconnected and connected the printer again while leaving the heater turned on. Afterwards the printer didn't stop heating anymore.

So far I've tried disabling and enabling and disabling the heater again via both the controls in Repetier-Host manual control and by sending the M104 S0 T0 command manually via the latest Repetier-Host software, the modified Repetier-Host software of the manufacturer and via the software HTerm. 

Furthermore I've tried reflashing the firmware and resetting the EEPROM by sending M502 and M500 without success.

Any help is appreciated. If you need more information I'll provide it gladly.

Repetier

RF1000 is a heavily modified version, so I'm not familar with what is original and what modified.

First I'd check what output shows in host. This is what the output pin should be set to. If that shows zero I'd recheck the wires as it would maybe indicate that somehow the mosfet gets triggered from somewhere or maybe even is defect. You might check if you can access the 5V pin enabling the mosfet and check if it is 5V while it should be 0V.