Bed heating
June 09, 2017 08:27PM
Hi,
Just recenly had a quick power outage whilst printing, printing resumed all over the place as expected, but now the bed is not heating.
Can anyone tell me what may have gone.
Have checked the fuses they have continuity across them.
Not sure where else to look, maybe it needs a new ramps.
Re: Bed heating
June 09, 2017 09:58PM
Have you tried turning it off and on again?
Re: Bed heating
June 11, 2017 01:26AM
Yes , that's the first thing I tried.
Could the heat sensor cause a problem, my thinking says no, but stranger things have happened.
Re: Bed heating
June 11, 2017 02:21AM
If the bed thermistor is read room temperature, it probably not that

what could have gone..
The high current fuse.
The mosfet itself could have died.
The IO line controlling the mosfet could have died... (dead mega IO pin)
Dead heated bed.


Wire the heated bed -ve and +ve directly to the power supply, does it heat up? No dead bed
Move the +ve back to the ramps D8 +, this now goes threw the 11 amp fuse, Does it still heat up? No, dead polyfuse

Remove the mega. load up the blink test firmware, set it to blink D8, and check D8 is going to 5v with multimeter, if it does its good.

leaving dead mosfet, which is the most common thing to fail.
Re: Bed heating
June 11, 2017 05:47PM
Thanks Dust, for the diagnostics, I will give them a try.
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