Weird power loss issue
I have had my Mk3s for about a month. It has been printing PLA nearly flawlessly for most of that time. I went to try printing PETG today, and the printer loses power about 20mins into the print. This has happened 3 times now. The bed is set to 90 and extruder at 240. So I went back to PLA without an issue.
Could this be a printer issue? When it loses power, the printer resets but acts like did not realize it was printing anything. So I can't recover were it stopped. Maybe thinking there might be a problem with the power draw through the surge protector.
Re: Weird power loss issue
Well I lowered the Temps to 70 and 230 and made it all the way through a 3 hr PETG print. Reset everything and tried 90 and 250 and the printer reset itself after about 20 minutes again. So does the MK3s have a problem at higher temps or do I have a faulty printer?
Re: Weird power loss issue
Somewhere down deep in the menu you can get a readout of the voltages being supplied to the Einsy board. Next time you start running a high temperature run, check those values out. Watch these values over time.
The idea here is I've heard that Prusa runs the power supplies at or near their upper limits. (This is the reason given in the Lack enclosure instructions for making sure to put the power supply outside the enclosure to keep it from overheating.) As electronics heat up, resistance goes up. As the resistance of a part goes up, the voltage drop across that part can go up throwing the circuit out of balance. So if something is slowly heating up in the power supply the voltage output may start to drop or suddenly cut out.
I can't say that the problem is the power supply (though it smells like a power supply issue), but this might help locate the issue.
See my (limited) designs on:
Printables - https://www.printables.com/@Sembazuru
Thingiverse - https://www.thingiverse.com/Sembazuru/designs
Re: Weird power loss issue
Thank you for the information Christopher. (still digging into the menu looking for that info) PETG is printing okay at 70 bed/230 extruder just fine but every time I try to run any higher the machine resets about 20mins into the print. I have now tried seven different simple designs, so its not slicer issues.
I wonder if the power supply is over heating. My printer is in a climate controlled area (60-70F , 15-21C) The printer is on its own dedicated 15amp circuit, nothing is on that line.
Should I ask for a new power supply? I would really like to print in ABS in the future but it looks like this printer will not be able to in its current state.
Re: Weird power loss issue
Were you present during the reset episodes? Wondering if there were any Trinamic over temp warnings displayed before the reset.
Printer should be able to sustain higher bed temps without shutting down.
You can load the system without starting print job by setting bed temperature to 110C without even starting a print.
Two things at top of my dx list.
1. Bad power supply - will suddenly shutdown
2. Low power supply voltage adjustment. Check the voltages reported in support menu
3. MOSFET overheating and causing over temp shutdown. New PWM system in current firmware to reduce clicking of heat bed has been reported to generate more switching loss and heating up the bed MOSFET. This is likely to first display a warning before the reset occurs, but you have to be present to observe.
#3 is why I would manually load the heat bed with a 110 C setting and observe what happens. However, If failure takes a long time, heater safety timer may kick in shutting down heating.