Heatbed - takes long to heat, temp drops, thermal runaway
I just finished building my i3 MK2s and have printed a few objects in PLA and ABS over the past few days but tonight, I noticed something strange.
I'm trying to print something small (endcaps for a fidget spinner) in ABS. I noticed the heatbed takes a lot longer to come to temperature (over 10 min -- room ambient temp is 20 deg), and while it prints, the temperature drops steadily to about 88 degrees and I get a BED THERMAL RUNAWAY error.
I've printed these objects before and did not have this problem.
I've turned off the printer to let the power supply cool off and tried again with the same problem.
The thermistor under the bed is still attached, there's nothing visually wrong with the RAMBO or any wires/plugs attached.
Voltage measured at the heatbed heater terminal is 11.66V.
Any ideas why this is happening? (I've searched...)
Re: Heatbed - takes long to heat, temp drops, thermal runaway
Try this search: http://shop.prusa3d.com/forum/search.php?keywords=increase+voltage
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Heatbed - takes long to heat, temp drops, thermal runaway
Thanks. I'll try increasing the PSU supply voltage and see what happens.
Re: Heatbed - takes long to heat, temp drops, thermal runaway
Take a look at my post in the link below, If you see how heatbed's red led turning off when it should be on indicating it's heating up then this could also be your problem.
Re: Heatbed - takes long to heat, temp drops, thermal runaway
I turned up the supply voltage so that the heatbed measured 12.4V and now everything is fine! The heatbed didn't drop below 94 degrees and stayed at 95 for most of the print. No more heatbed thermal runaway error either!
For those wondering, you need to undo a few screws to remove the power supply from its black base to access the voltage adjustment pot.