I3 Mk3 MAXTEMP Error
I finished building a new I3 Mk3 kit a couple weekends ago. The printer had no problems at all, went through calibration easily and was making excellent prints almost immediately. I turned it on this weekend to make a print and got an alarm tone, the message Err: MAXTEMP and a displayed extruder temp of 739 degrees! The printer had not been touched since I was using it previously. I checked the wiring to the extruder thermistor and it seems fine. I measure ~100K at room temperature at the 2 pin plug (which seems right). I plugged the extruder thermistor into the heatbed thermistor port and it reads fine there (23 C). The extruder temp reads 739 degrees no matter what is plugged in (or even if nothing is plugged in). Any suggestions what might be happening?
The firmware at the time was 3.3.0, I just loaded 3.3.1 but no change.
Thanks,
Jim
Re: I3 Mk3 MAXTEMP Error
sounds like the einsy is faulty.
can you unplug everything bar power, lcd and thermistors... does the problem still exist?
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: I3 Mk3 MAXTEMP Error
Thanks Joan. Yes, it does still do the same thing. It is looking like that input on the board is bad. Not sure what could have happened, it was working fine. I just turned it off (and had the power strip off too) then turned it back on a couple weeks later and it didn't work.
There's another thermistor input on the board that's not used. Do you know if it's possible to reconfigure the printer to use that input (short of recompiling the firmware)?
Thanks,
Jim
Re: I3 Mk3 MAXTEMP Error - Solved
Problem Solved!
After Joan's suggestion of disconnecting most of the cables and testing, I decided (since it was all disconnected anyway) to go ahead and remove the Einsy board and inspect it under a stereo microscope. The question rapidly changed from "Why did it break?" to "How did it ever work?"! The board had fresh, unmelted solder paste and cold solder joints all over the place! An hour with a soldering iron then cleaning the board and it seems to be fine now. The solder paste was completely covering and under diode D5 which was shorting the thermistor input to ground.
Cheers,
Jim
Re: I3 Mk3 MAXTEMP Error
Yaaaayyyyy Result...
However, I would consider chatting with Prusa, as there is no guarantee that you got all of the questionable joints and may find yourself perpetually chasing the problem,
Hopefully Prusa will exchange your board for quality control investigation!
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: I3 Mk3 MAXTEMP Error
Seems to be working rock solid at this point and making excellent prints. It appeared to be every instance (about a dozen) of this same diode around the board (type BAT-54 on the schematic on reprap.org) It looks like they were either re-worked or installed later. All the other soldering on the board actually looks pretty good.
Cheers,
Jim
Re: I3 Mk3 MAXTEMP Error
The wiring sheath and the thermistor contact with the hot end is very stiff and grubby, Im unable to get the thermistor out of the hot end.
On start up the machine sounds an alarm and shows the temp at 739 degrees.
Should I purchase and entire extruder assembly and retire the original?
Re: I3 Mk3 MAXTEMP Error
unless you break the heat break unscrewing it from the heater block all that you have to replace is the heater block.
if you are in the USA Printed Solid.com is your best bet for genuine Prusa Parts on this side of the pond.. https://www.printedsolid.com/products/prusa-mk2-mk3-thermistor-cartridge
https://www.printedsolid.com/products/e3d-mk3-heatbreak
https://www.printedsolid.com/products/e3d-heater-block
I would also get a spare heater and heat block from them and as I said you will need a new heat break if it fractures on removal then I would drill out or do what you need to do to clean out the old heater block and have it ready as a spare if it happens again... I night just pick up a few extras as spares as the heater and thermistor cartridges are semi expendable over time and heavy use consider grabbing some e3d socks as well they are also limited life items that is why they sell 3 at a time.
https://www.printedsolid.com/products/e3d-silicone-socks-3-pack
if you are in the UK then https://e3d-online.com/v6 but if you get a replacement heatbreak here be sure you get the Prusa MK3 version it is slightly different from the standard v6 item
in Europe then direct from Prusa
elsewhere I have no idea
use this page to rebuild your hot end
https://e3d-online.dozuki.com/Guide/V6+Assembly/6?lang=en