Notifications
Clear all

Help: Self-Test Error - Heater/Thermistor Not Connected  

  RSS
zawave
(@zawave)
New Member
Help: Self-Test Error - Heater/Thermistor Not Connected
Hi,
 
I am getting an error that reads "Please check: Heater/Thermistor not connected" during the heatbed portion of the self-test during the setup wizard.
 
I've inspected both the power cables and thermistor and don't see any physical signs of damage. I've also double checked they are in the correct location as shown in the assembly handbook.
 
When turned on and connected, the thermistor is getting an ambient temperature reading. However, when trying to pre-heat the bed and extruder I am not getting any current readings from the heatbed power cables. I've even tested the EINSY board power connections for the heatbed with my multimeter while trying to manually preheat the bed and those failed to show a current reading.
 
This leads me to believe it is the thermistor cable is the source of the issue but am unsure how to test/ proceed. Photos below for reference
 
 
Thanks for the help!
Posted : 25/05/2020 5:28 pm
Area51
(@area51)
Member
RE: Help: Self-Test Error - Heater/Thermistor Not Connected

The thermistor should measure a resistance about 100k at room temperature using a multi-meter. It can be difficult to find the exact spot on the wire where the break is, but bending  it and constantly measuring with multi-meter is the easiest way.

It can be soldered again, but no guaranty that it won't break again. You can get a replacement from Prusa Shop.

Have a look at my models on Printables.com 😉

Posted : 26/05/2020 12:40 am
zawave
(@zawave)
New Member
Topic starter answered:
RE: Help: Self-Test Error - Heater/Thermistor Not Connected

I think I'll order the replacement for peace of mind... thanks for the help!

Posted : 26/05/2020 9:43 pm
ColmMcG
(@colmmcg)
Member
RE: Help: Self-Test Error - Heater/Thermistor Not Connected

Thanks for raising this issue, before me. I started with a PREHEAT ERROR and ruled out the thermistor with a hair dryer, as the LCD responded. I then swapped out the entire HOT END assemble with some new parts, as it was not possible to removed the button headed screw holding the heating element in place. After re-assemble with the new parts, I did a firmware upgrade as this may afford better diagnostics,  from 3.11 to 3.13.2 and when running the calibration wizard this results in the error

Self-Test Error - Heater/Thermistor Not Connected

when running a preheat for PLA the heater does reach consistently 111 deg cel before the  PREHEAT ERROR returns

I did note that if the heating block is twisted about 35 deg off its correct angle that the Preheat error consistently appears a little earlier at 108 deg cel

the heat bed has no problem reaching the 60deg needed.

This is not a newly built PRUSA , and was working fine prior to this, 

I was recently moved to a lab, where the night  temperature does dip to 10 degs maybe cooler at  night.
I expect PRUSA is safer when turned off in when in a space cooler than 15 degs cel

The only item I can think would cause this error would be if the heating element was not receiving full power

did I read some where that this can be 15 amps at 12 volts, I need to read up to see if this is something I can test with a multimeter

as  all I normally do with a multimeter is test resistance,........

 

 

Posted : 04/12/2023 5:10 pm
hyppyayo
(@hyppyayo)
New Member
RE: Help: Self-Test Error - Heater/Thermistor Not Connected

same issue,

i upgraded at last firmware and prusaslicer and my Mk3s start to have problem, thermal error, and calibration error.

roll back on 3.10 firmware and no more error

Posted : 07/12/2023 11:32 am
Share: