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Paul Lackey
(@paul-lackey-2)
Active Member
Getting MAXTEMP error

On one of my printers, it's regularly giving me a MAXTEMP error at some point during every print. This stops the print and ruins the piece.  I don't think it's an intermittent connection, I have moved the head from side to side and the reported temperature stays rock solid. I also wiggled the thermistor wires themselves and there was no wavering on the reported temperature.

I did discover that the screw in the hotend that pinches the heater was loose, allowing the heater to slide a little. I was certain this was going to be my problem but after tightening it down, the next print failed with the MAXTEMP error an hour or two into it.  Any thoughts of other things to try?

Posted : 24/05/2021 9:30 pm
cwbullet
(@cwbullet)
Illustrious Member
RE: Getting MAXTEMP error

Are you sure they are plugged into the right spot on the Controller board?

--------------------
Chuck H
3D Printer Review Blog...
Posted : 24/05/2021 9:45 pm
cwbullet
(@cwbullet)
Illustrious Member
RE: Getting MAXTEMP error

Here is a prior thread:

https://forum.prusaprinters.org/forum/original-prusa-i3-mk3s-mk3-prusa-i3-kit-archive/maxtemp-error-bed-extruder-not-heating/

--------------------
Chuck H
3D Printer Review Blog...
Posted : 24/05/2021 9:48 pm
Paul Lackey
(@paul-lackey-2)
Active Member
Topic starter answered:
RE: Getting MAXTEMP error

@cwbullet

Definitely plugged in to the right place. Printer has been working for several years without issue, and the problem started abruptly without having done any work on the printer. And it will print for some period of time fine before it suddenly gives the error and ruins the print.

Posted : 25/05/2021 7:54 pm
cwbullet
(@cwbullet)
Illustrious Member
RE: Getting MAXTEMP error

What are the temperatures when it fails?

--------------------
Chuck H
3D Printer Review Blog...
Posted : 25/05/2021 7:58 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Getting MAXTEMP error

@paul-lackey-2

I think you have a problem with the thermistor wires, possibly a loose contact or broken wire. This will falsify the temperature evaluation and causes this error message. This could also fit to a somewhat older printer.

Check the wires with a multimeter. Resistance should be about 100kohms at 25 deg. roomtemp. During the measurement process, also move the relevant wires.

regards,

Karl

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 25/05/2021 8:01 pm
Paul Lackey
(@paul-lackey-2)
Active Member
Topic starter answered:
RE: Getting MAXTEMP error

It really doesn't seem to be an intermittent wire issue. I put an ohm meter on the temp sensor, and it read 80 kOhm (it's a hot day). Wiggled the wires at all points and it was rock solid, never saw any kind of intermittent.

 

When it fails and I hear the alarm, it always shows the head temperature as being several hundred degrees C (it normally is around 240) and dropping. But of course at that point the print is destroyed.

Posted : 04/06/2021 12:20 am
Paul Lackey
(@paul-lackey-2)
Active Member
Topic starter answered:
RE: Getting MAXTEMP error

Any other ideas? My printer is down at a really critical time.

Posted : 08/06/2021 5:54 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Getting MAXTEMP error

@paul-lackey-2

"When it fails and I hear the alarm, it always shows the head temperature as being several hundred degrees C (it normally is around 240) and dropping."

If the display shows a temperature of several hundred degrees, either the thermistor is not connected correctly or there is a loose contact at a connector.
Other causes can be: Defective heating cartridge or cables or a fault on the printer board.
What sometimes helps is a factory reset and flashing the latest firmware.

wbr,

Karl

 

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 08/06/2021 7:56 pm
Paul Lackey
(@paul-lackey-2)
Active Member
Topic starter answered:
RE: Getting MAXTEMP error

@karl-herbert

Thanks for the reply. I did try flashing the latest firmware. The problem is very intermittent...it will work properly for a couple of hours before suddenly faulting. And we extensively wiggled the wires while checking the thermistor resistance and there is no sign of a bad connection. Does this suggest the board is bad?

Posted : 08/06/2021 8:11 pm
JoanTabb
(@joantabb)
Moderator
RE: Getting MAXTEMP error

Mintemp error is typically a loose connection, or broken wire, or faulty thermistor, 

Maxtemp is typically a short-circuit or
running  too close to the actual maximum temperature the printer is capable of achieving, if the printer has not been PID Tuned at a high temperature, the variations in temperature may take the actual temperature too high!

thermistors are low cost items If you have an intermittent fault then changing the thermistor will probably be cheaper than losing a print whilst fault finding, and it will rule out the possibility of a defective device.

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...
Posted : 08/06/2021 8:33 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Getting MAXTEMP error

@paul-lackey-2

joan is of course right. 0.0x ohm means short circuit and thus the temperature is skewed upwards.

In your case, I would replace the thermistor. It is much cheaper than anything else.
I would always keep such cheap spare parts in stock.

wbr,

Karl

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 08/06/2021 8:59 pm
Paul Lackey
(@paul-lackey-2)
Active Member
Topic starter answered:
RE: Getting MAXTEMP error

Thanks all. I'll try swapping out the thermistor. If there's still a problem then will probably need to look into getting a replacement board.

Posted : 08/06/2021 9:09 pm
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