Incorrect hotend temperature reading (~159°C at startup) – wiring issue suspected  

Incorrect hotend temperature reading (~159°C at startup) – wiring issue suspected

Hello,

I have an issue with my Prusa Core One.

Symptoms:

After powering on the printer, the hotend temperature is displayed at ~159 °C, even though the printer was not heating.

The temperature is constant and does not reflect ambient conditions.

Diagnostics performed:

I connected the entire hotend (including thermistor and heater) to another printer – temperature readings are correct there.

When the thermistor is disconnected from the Core One mainboard, the printer shows a normal ambient temperature.

Conclusion:

Hotend, thermistor, and hotend wiring are confirmed to be functional.

The issue appears only when the thermistor is connected to the Core One, which strongly suggests a short or damage in the internal wiring harness between the connector and the mainboard, not the hotend itself.

I kindly ask for guidance or replacement of the internal wiring harness / cable affected.

Best regards