Power Panic loop  

RE: Power Panic loop

Posted by: @reed-j

Hello,

I have a MK3 that I upgraded to MK3s about 10 months ago. It was operating flawlessly when I packed it up in July to move to a new house and I finally got it set back up a few days ago. I started a print and it seemed to be fine for a few hours until it entered a Power Panic loop about 80% through the print and then asked to recover the print. I tried to recover but the print separated from the sheet so I stopped it. I checked the firmware and the printer was on an older FW so I updated to 3.10.0 thinking it may have been a FW issue. I started another print last night and it got about 30 minutes into the print before it entered another Power Panic loop.

What could be causing this Power Panic? What troubleshooting steps can I try and what should I look for? This is the first time I've encountered this problem after using this printer for several years.

Thanks,

Reed

I'm starting to think the PSU may be shot. I use the 24V from the PSU to power some LEDs in my enclosure and have wires attached at the Einsy terminal strip. While I was setting the printer up at the new house (I can't remember if this was before or after the first failed print), the ends of my LED power wires briefly crossed causing a momentary spark.

This afternoon I tried preheating the hot end so I could unload the filament, however both the hot end and bed wouldn't heat at all and it gave me a Power Panic error. I turned off the PSU, opened the Einsy enclosure and re-seated many of the connectors including the power panic connector. When I put it back together and turned it on, it successfully preheated to 230/85C so I tried to run the print that failed yesterday. It hadn't even completed the bed leveling when it threw a Power Panic error and stopped heating the bed and hotend.

I tried to preheat again and it slowly heated the bed and hotend, but I heard a ticking from the PSU and the bed heating LED blinked. The voltages are about 23.8 or 23.9V while slowly heating (bed LED rapidly blinking), occasionally dropping to 23.6 when the LED went solid for a moment. I got a Bed Preheat Error and the printer wouldn't heat at all after that, even if I reset the printer. I powered the PSU off for a moment and when it turned back on, the printer slowly warmed up but gave a Bed Preheat Error again after failing to heat quickly.

RE: Power Panic loop

Are all of your connections, particularly the bed heater connections, on the bed, on the Einsy, and on the power supply good and tight?

Loose connections can cause all kinds of issues, particularly when higher currents, such as the bed heater, are involved.

23.6 volts is only about a 1.5% error, which is really not that significant.

RE: Power Panic loop

I checked the connectors on the Einsy board, screw terminals on the Einsy board, and screw terminals on the PSU. I found one screw on the PSU and one on the Einsy that was semi-snug but now they're all tight. I powered up and set to preheat to PETG and it seemed to be working great (bed and hotend heated quickly, solid bed heating light) so I set it to print the file and after the bed leveling it went into a Power Panic loop. Once it cools down I'll take the bed heater connector cover off and verify the heater connection there seems solid.

Thanks,

Reed

RE: Power Panic loop

I contacted Prusa support and they suggested the Power Panic cable may be failing. I unplugged it from the Einsy and now it's printing as it should. My guess is there's a break in the cable or something, so I'll be repairing that next I guess...

RE: Power Panic loop

That is a common reason.  I upgraded the black power supply because it has a replaceable panic cable.  

Posted by: @reed-j

I contacted Prusa support and they suggested the Power Panic cable may be failing. I unplugged it from the Einsy and now it's printing as it should. My guess is there's a break in the cable or something, so I'll be repairing that next I guess...

All above is good but there is one other possible cause:

In a new house you are not certain of your local power conditions.  Do you have a dirty power supply?  If your mains power is also supplying machinery or even if there is a domestic appliance going out of spec then your Power Panic may be acting correctly. 

Listen to an analogue radio, not digital, while the panic events are happening.  If you hear simultaneous interference it might be an external problem. 

This sort of issue is often intermittent, ocurring only when a particular large load is switched for example.

Cheerio,

RE: Power Panic loop

Posted by: @cwbullet

That is a common reason.  I upgraded the black power supply because it has a replaceable panic cable.  

Posted by: @reed-j

I contacted Prusa support and they suggested the Power Panic cable may be failing. I unplugged it from the Einsy and now it's printing as it should. My guess is there's a break in the cable or something, so I'll be repairing that next I guess...

 

Hopefully replacing the wire with some stranded will help the longevity issue.

Posted by: @diem

All above is good but there is one other possible cause:

In a new house you are not certain of your local power conditions.  Do you have a dirty power supply?  If your mains power is also supplying machinery or even if there is a domestic appliance going out of spec then your Power Panic may be acting correctly. 

Listen to an analogue radio, not digital, while the panic events are happening.  If you hear simultaneous interference it might be an external problem. 

This sort of issue is often intermittent, ocurring only when a particular large load is switched for example.

Cheerio,

 

 

I'll keep that in mind. It had been consistently not printing well with the cable connected, but once I unplugged the cable it completed a 5hr print without a single power panic. Time will tell I guess.

Thanks for the help!

RE: Power Panic loop

Posted by: @diem

All above is good but there is one other possible cause:

In a new house you are not certain of your local power conditions.  Do you have a dirty power supply?  If your mains power is also supplying machinery or even if there is a domestic appliance going out of spec then your Power Panic may be acting correctly. 

This is why I have both printers on battery backup units.  I've tested them by unplugging them mid-print and they do not miss a beat.

RE: Power Panic loop

Does the Power Panic work well with the UPS?

RE: Power Panic loop

Posted by: @reed-j

Does the Power Panic work well with the UPS?

Well, I guess you can say that it works well with the UPS in that it never triggers.  😉

Way back when I first assembled the printer, out of curiosity I tested it mid-print (I think a calibration cube) by unplugging it, and when I powered it back up it did give me the option to resume the print, but there was some visible artifact at the point of the power interruption.

RE: Power Panic loop

After completing the 5-hr PETG print with the panic cable unplugged, I replaced the power panic cable and began a 10.5-hr PETG print. 8.5-hr into the print, the printer went into another power panic loop, repeatedly rebooting and immediately displaying the Power Panic error until it finally asked if I wanted to recover the print. I disconnected the power panic cable and told it to recover the print which it seems to be working fine.

I did not notice anything that could've been causing interference, and my desktop computer has been running for days in the same room with no interruptions. I'm starting to think that this may be a PSU issue again. I've got the old silver PSU circa 2018, is it maybe on its way out? Or maybe the Power Panic circuit board is dying?

Thanks,

Reed

RE: Power Panic loop

Or you might have a short?  

RE: Power Panic loop

Thoughts on where a short would be to cause these problems?

The solution Support has offered is to just run with the cable unplugged...