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rookardjr
(@rookardjr)
Active Member
MAXTEMP error

Every time I try print, I get MAXTEMP error with siren. I'm using PLA, and I have not tried any other material.

The troubleshooting guide tells you to check zip ties and not much else. 

I have sent Prusa email, but I never get a response. I try to chat, and no one is ever there.

Any ideas on what to do to overcome MAXTEMP error?

Posted : 20/10/2022 2:47 am
Diem
 Diem
(@diem)
Illustrious Member

Several possibilities.

One of your thermisters is not correctly fitted or is damaged.

  Check the connection.  If you have a multimeter check the resistance changes with temperature.

One of your heaters is running away - usually a faulty thermistor but could be a wrongly fitted heater.  Check connections.

Or it might be a wiring loom fault.

For support: Log into your Eshop account, navigate to Help and live chat is at bottom right in most browsers. If not you may need to disable your ad-blocker temporarily.

Cheerio,

 

Posted : 20/10/2022 5:07 am
rookardjr
(@rookardjr)
Active Member
Topic starter answered:
RE: MAXTEMP error

When log into live chat, I get the following message, "Hello, we are sorry, queues are around 2 minutes at the moment. We will join you as soon as possible." After 8 hours (yes, hours), I still get no response.

Visually, I see no obvious damage to hot end components, but I'm new to 3D printing and my inexperienced eye does not know what to look for. I do not have a multimeter.

The only thing I can think of doing is to start swapping parts until the problem is fixed. It seems the hot end thermistor is the part to start with. However, I am confused in regard to which piece that is. Is it the small cylinder with thin red/black wires, or the thick cylinder with thick bright red wires?

Posted : 20/10/2022 11:25 am
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: MAXTEMP error

thermistor is thin capsule with thin delicate wires. a short circuit could cause Maxtemp. 

did this issue occur after cleaning the hot end. 

Using a wire brush on the hot end whilst the printer is turned on, can damage the controller board. 

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 : 20/10/2022 6:06 pm
rookardjr
(@rookardjr)
Active Member
Topic starter answered:
RE: MAXTEMP error

Thanks for the clarification.

If a short circuit could cause MAXTEMP, then would changing the thermistor have good probability to fix the short? or is a short more likely to be the controller board?

The MAXTEMP error did not occur after cleaning the hot end. My machine is new (factory assembled). I have not attempted cleaning the hot end because the printer was working just fine until the MAXTEMP error began happening with every attempted printing thereafter. So far, none of the troubleshooting instructions or community forums have suggested cleaning the hot end as a method of resolving MAXTEMP error.

Additionally, I have not used a wire brush on any part of the printer, and I have not used any other metal tool to clean any part of the printer. I use a plastic scraper to scrape PLA off the metal heatbed sheet after the machine has cooled down to room temperature.

Posted : 20/10/2022 6:32 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: MAXTEMP error

a short circuit thermistor can cause a Maxtemp error
An Open circuit thermistor can cause a mintemp error.

your thermistor should read 10000 ohms at 25degrees centigrade if you have a test meter, you can test the resistance. 

does the maxtemp error occur after you start a print? 
or does the printer heat up to maxtemp when you turn the printer power on?

for information, the Heater always has 24 volts on it whenever the printer is turned on, and the printer pulls the other side of the heater down towards zero volts, with a Mosfet transistor, when it wants to cause the heater to get hot. 
many people use a wire brush to clean burned filament off the print head, whilst the power is turned on, 
If the brush causes a short circuit between the heater circuit at 24 volts, and the thermistor circuit which is low voltage, the controller board can be damaged. 

Mosfets sometimes fail, and if this occurs, they usually go short circuit, in this case, the printer would begin to heat up as soon as it was turned on. and you would quickly get a maxtemp error...

Good luck with your fault finding,

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 : 20/10/2022 7:21 pm
John
 John
(@john-6)
Reputable Member
RE: MAXTEMP error

The printer has two sensors for temp control. The hot end and the bed.

each has a wire pair and is plugged into the ensy board. If you unplug both and move the hot end one to the bed one. Turn on the printer and see if the max temp now occurs on screen as the bed temp. If it does then the likely culprit is the hot end thermistor. I don’t have a picture of the board handy to show where the wires go to so you could search the main web knowledge base for how to replace thermistor, which you will need anyway. This procedure was recommended by Prusa live chat agent. 

i3 Mk3 [aug 2018] upgrade>>> i3MK3/S+[Dec 2023]

Posted : 20/10/2022 7:49 pm
rookardjr
(@rookardjr)
Active Member
Topic starter answered:
RE: MAXTEMP error

Thanks for the information.

In my case, the MAXTEMP error only occurs while printing (usually during first layer). The error does not occur while loading or unloading PLA. It also does not occur while doing PID or other calibrations.

I plan to purchase a multimeter today. I just hope my small-town hardware store has one in stock; otherwise, I'll be waiting for the delivery of an online purchase.

Posted : 20/10/2022 7:52 pm
John
 John
(@john-6)
Reputable Member
RE: MAXTEMP error

This link shows the hot end thermistor position on the board. See Step 10. https://help.prusa3d.com/guide/how-to-replace-a-hotend-thermistor-mk3s-mk3s_131675
. As per previous post move it the position two spaces to the left which is the hearbed sensor. You need a small screw driver to depress a tiny tab to release the plug. 
if you are unsure where to move the plug see the instructions for heatbed https://help.prusa3d.com/guide/how-to-replace-a-heatbed-thermistor-mk3s-mk3s-mk2-5s-mk2s_1927 step 15

i3 Mk3 [aug 2018] upgrade>>> i3MK3/S+[Dec 2023]

Posted : 20/10/2022 8:00 pm
TMS
 TMS
(@tms)
Eminent Member
RE: MAXTEMP error

I'm a noob at this but was wondering, does the MAXTEMP appear immediately after starting the print or do you see the temperature climb?  Do the fans work?

Posted : 20/10/2022 8:51 pm
John
 John
(@john-6)
Reputable Member
RE: MAXTEMP error

In my case  after a blob of death the hotend thermistor wires had lost their insulation and shorted. Im my instance the temperature "reading" immediately skyrocketed to 900ºC or thereabouts. I didn't actually test if the hotted was heating. I was nervous that the thermistor might be hard to remove so I wanted to heat it up. Rather than use a heat gun I was able was able to carefully separate the thermistor wires to heat the block and make sure all the plastic was removed from the grub screw socket. It is very tiny and didn't want to strip the hex recess inside trying to remove while some plastic was holding it back. I had been using polycarbonate filament so my melt temp was at the limit of the printer. After making sure the screw had no polymer inside ( with a pointed implement) it came our fairly easily. 

I dont think the thermistor directly controls the fan operation ( only via the G code).

So just to be clear the MAX temp for me showed immediately. As per previous post swapping the connections on the board will inform if it is the thermistor or the board is faulty.

i3 Mk3 [aug 2018] upgrade>>> i3MK3/S+[Dec 2023]

Posted : 20/10/2022 10:02 pm
rookardjr
(@rookardjr)
Active Member
Topic starter answered:
RE: MAXTEMP error

The fans work. The print starts normally at first. Then there are temperature fluctuations that over time, increase in the deviation high and low from the desired temperature. Eventually, the MAXTEMP error occurs. This usually happens before completion of the first layer.

Posted : 21/10/2022 2:22 am
John
 John
(@john-6)
Reputable Member
RE:

you should keep trying the live chat - may consider the time in Europe 

Also your issues could be due to room temperature if it is a bit extreme or maybe under an air conditioner

Posted by: @rookardjr

The fans work. The print starts normally at first. Then there are temperature fluctuations that over time, increase in the deviation high and low from the desired temperature. Eventually, the MAXTEMP error occurs. This usually happens before completion of the first layer.

 

i3 Mk3 [aug 2018] upgrade>>> i3MK3/S+[Dec 2023]

Posted : 21/10/2022 2:24 am
Diem
 Diem
(@diem)
Illustrious Member

In my case, the MAXTEMP error only occurs while printing (usually during first layer).

Intermittent errors that only occur when the extruder is in motion but not when stationary are usually due to damaged wiring or in rare cases a loose plug at the Einsy end.

Cheerio,

Posted : 21/10/2022 2:11 pm
Paul Cobbaut
(@paul-cobbaut)
Eminent Member
RE: MAXTEMP error

 

Posted by: @diem

In my case, the MAXTEMP error only occurs while printing (usually during first layer).

Intermittent errors that only occur when the extruder is in motion but not when stationary are usually due to damaged wiring or in rare cases a loose plug at the Einsy end.

Cheerio,

I have the exact same problem now. I have had over 100 successful prints, most with PLA and PETG and recently started with ASA. The first five ASA prints were perfect, but now the printer fails with MAXTEMP error on the first or second layer.

It is indeed as you say, stable at 260 when nothing is moving, occasionally showing 259 or 261. But when printing starts, after about five seconds, it start jumping to 191, then 262, then 224, then 273, all within one second.

So the question is now, which wire? I am not an electronics person, nor native English speaking. Is this 'thermistor' the wire that needs replacing?

 

-- Sent from Debian

Posted : 27/11/2022 9:55 pm
Diem
 Diem
(@diem)
Illustrious Member

First check that all the plugs in the Einsy electronics board are firmly in place.  One may have vibrated loose.

Look at the layout plan on:  https://help.prusa3d.com/article/einsy-rambo-electronics-wiring-mk3-mk3s-mk3s_2107

Cheerio,

Posted : 28/11/2022 12:21 am
karl-herbert
(@karl-herbert)
Illustrious Member
RE: MAXTEMP error

A damaged thermistor cable can also trigger a maxtemp error. I would check the wires and the internal resistance of the thermistor with a multimeter (internal resistance approx. 100kOhm at room temperature).

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 : 28/11/2022 7:05 pm
Paul Cobbaut
(@paul-cobbaut)
Eminent Member
RE: MAXTEMP error

Well, I looked briefly at the Einsy board, and I am not going to touch that (for now). I did change the nozzle, and have had four successful PLA prints. Will try with ASA again tomorrow or later. Will update later this week!

-- Sent from Debian

Posted : 28/11/2022 8:00 pm
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