Temperature value stays at 170C

K8200 3D Printer K8200 - Wiring and electronics
1

Hi All,
After having a completely working printer about two weeks ago, I took my printer out of the cabinet to find that my temperature readout was stuck at 170 degrees C even before the extruder was turned on. Now, after having spoken with a few other students in the organization that use it, apparently the NTC was wired to the extruder on accident and immediately removed before actually sending extrude commands to the printer.

After turning on the extruder, the temperature does rise (but not very fast) which suggests that something is wrong with the electronics and wiring I would think?

I measured the resistance value across the thermistor when the unit was off and find a value of .7 ohm at room temperature.

Any ideas?

2

[quote=“Globalwolf”]Hi All,
After having a completely working printer about two weeks ago, I took my printer out of the cabinet to find that my temperature readout was stuck at 170 degrees C even before the extruder was turned on. Now, after having spoken with a few other students in the organization that use it, apparently the NTC was wired to the extruder on accident and immediately removed before actually sending extrude commands to the printer.

After turning on the extruder, the temperature does rise (but not very fast) which suggests that something is wrong with the electronics and wiring I would think?

I measured the resistance value across the thermistor when the unit was off and find a value of .7 ohm at room temperature.

Any ideas?[/quote]

Did you measrure with the Therm plug unconnected?
If so, the Thermistor is dead or there is a short in the wiring.
If not, there may be a short in the wiring.

cheers,

Christian

3

Hi, 0.7 ohms is way lower than the 100k you should get at 25 deg C, as Christian says it is proberbly a short but also it’s not far from the stepper motor coil resistance of about 1.65 ohms - unlikely but worth a check.

4

Good point Barnaby!
It’s quite easy to switch the wires of that ribbon cable…

5

Thanks for your replies guys! I’ll look into it and make sure there’s no shorts and remeasure before buying a replacement.

6

Unplug Therm1 Top left.
Extruder should drop to 0C