Calibration of i3 MK1 after firmware update  

Re: Calibration of i3 MK1 after firmware update

Hi John,

Try here

https://manual.prusa3d.com/c/Prusa_i3_Plus_1.75_kit_assembly

the Mk1 wasn't originally called the Mk1

regards Joan

Re: Calibration of i3 MK1 after firmware update

Thanks for that. I have got to find my hard copy that was sent with my printer kit. The current printing manual is full of stuff about features that were not on the Mk1 printer so I'm trying to work out what exactly applies, and trying to clear the calibration request on power up. I've gone through all the steps which I though applied but the error is still not cleared on the new firmware. I don't have auto bed levelling so it shouldn't be that.

The information I need is in here somewhere.

Re: Calibration of i3 MK1 after firmware update

And having installed the latest firmware the printer is now a bit unusable because it is moaning about thermal runaway of the bed 4 hours into a print.

Re: Calibration of i3 MK1 after firmware update

I guess there ain't too many people still using the Prusa i3 Mk1, I should maybe look at the upgrade path and join the cool kids with the Mk2 and Mk3, but to be honest up until this latest firmware I've not felt the need. The latest firmware has changed the operation of the heated bed of the printer. Where as previously the heated bed used to turn on and off at a very slow rate during printing the latest firmware has increased the rate to a lot of times per second.

So previously if the bed temperature was set to a target of 50 degrees the printer used to get to 50 and then turn off. The temp would gradually decrease and perhaps at about 49 the printer controller would decide to turn on the heated bed again. That meant that the on and off pulses were rather infrequent. The updated firmware is pulsing the heated bed a couple of times a second so the temp of the bed is a solid 50 degrees and it's not going to move.

That sounds like a great improvement in operation. Unless you consider transient voltage spikes due to stray inductance and load inductance and the high frequency on and off pulses. The voltage spikes resulting in this are going to put pressure on the system. In my case the printer melted the headed bed connector, which is why I ended up with thermal runaway. Because the connector melted the heated bed failed open circuit but it could have been a lot worse. If the melted connector had shorted and failed closed then a fire would have been the result.

I'll have to download the firmware source and edit that as I'm not happy with that rate of change. Last thing I need is to have my Prusa i3 Mk1 going up in smoke.

In addtion to all that I've still not been able to clear the calibration warning screen from the printer.

Re: Calibration of i3 MK1 after firmware update

My Mk1 had issues with thermal runaway... and I raised the power supply voltage a little using the potentiometer under the plastic cover, and the runaway stopped occurring,,, originally it was just below 12volts now it's just below 13 volts...

it's been upgraded to Mk2, and then Mk2MMU v1... and the PSU is still set at around 12.8 volts...

this might be something that you want to try!

regards Joan

Re: Calibration of i3 MK1 after firmware update

I'll have to look into the upgrade path. I've managed to get the printer back working again after the connector burn out but the calibration screen on powerup just won't go away at all. Been though the menus but nothing clears it. Just have to skip it on power up