Marlin firmware fork for MakerFarm i3v w/ auto bed level & Roxy's enhancements

[printbus]

FWIW, here is that earlier thread. The thermal runaway part of the thread starts at post #19.

About to try Marlin1.1.0RC4...

[uncle_bob]

Hi

Based on a disaster that happened here over the last few days:

If the fan shroud on the e3d is damaged, it will dump a bunch of air onto the heated block. The PWM will go to 100% and it will struggle to hold temperature on the hot end. It *will* hang out long enough in this state to trigger "thermal runaway" with the stock settings. The problem will be made worse if you have a bum connection in the heater circuit or if the heater cartridge is loose in the block. A loose thermistor mounting screw would do similar things.

Simple check:

Don't try to print anything. Having stuff moving around is confusing.

Fire up the heated bed and make sure the PWM goes into blink mode (LED blinks vs full on, I watch the one on my SSR)
Check the power supply is at 12V or more

Fire up the hot end (heated bed still on) and make sure the LED goes into blink mode for it.
Check the power supply is still at 12V or more

The fans cooling the e3d must be on any time it is on, so they are already running.
Turn on any other fans you have
Watch the PWM and /or temperature
Check the power supply

Somewhere along in there you should find the problem, if not:

Start giggling wires. You likely have a loose / broken connection.

Bob