Anycubic error 10123 (Hotbed NTC Abnormal) appears on the Kobra 2, Kobra 2 Pro, Kobra 2 Plus, Kobra 2 Max, Kobra Plus, Kobra Max, and Kobra S1 when the heated bed thermistor cannot return a valid temperature reading. The touchscreen may display an implausible temperature value — such as 0 °C, 300 °C, or ”---” — and the printer will not allow heating to proceed.

What the Error Means

The NTC (negative-temperature-coefficient) thermistor is a small two-wire sensor that changes its electrical resistance as temperature changes. The mainboard reads this resistance through the T1 port and converts it to a temperature value. Error 10123 fires when the reading falls outside the plausible range, which typically means the NTC cable connector has come loose from the mainboard, one or both thermistor wires are broken, the ambient temperature is below 10 °C (causing an out-of-range low reading), or the mainboard NTC input circuit has failed.

Step-by-Step Fix

1. Power off the printer. Locate the hotbed NTC cable — it runs from the heated bed edge to the mainboard’s T1 port. Firmly unplug and reseat the connector at the mainboard, confirming it is fully inserted and the locking tab (if present) is engaged.
2. If your workshop or print space is below 10 °C, move the printer to a warmer room and allow it to reach at least 15 °C before powering on again. Cold ambient air can cause the thermistor to read below the firmware’s valid range.
3. With the printer powered off and the NTC connector unplugged at the mainboard, set a multimeter to resistance mode and measure across the two NTC cable pins. At 25 °C the resistance should be approximately 100 kOhm, within ±15 kOhm. A reading of 0 Ohm (short) or infinite (open circuit) indicates a broken thermistor wire or a failed sensor.
4. With the printer powered on and the NTC connected, use the multimeter set to DC voltage mode and probe the mainboard T1 port pins (pin 1 positive, pin 2 negative). The voltage should measure 1.8 V ±0.3 V at room temperature. A reading far outside this band suggests a mainboard input fault.
5. Inspect the NTC cable along its full length from the bed to the mainboard for any sharp kinks, pinching against the bed frame, or areas where the insulation has been abraded by bed movement. Reroute or replace the cable if damaged.
6. If the resistance reading is out of range and the cable appears intact, the thermistor element itself has failed. Replace the hotbed NTC thermistor or the heated bed assembly if the thermistor is integrated.

Parts Required

• Replacement hotbed NTC thermistor (100 kOhm at 25 °C, model-specific)
• Replacement heated bed assembly (if thermistor is not separately replaceable)
• Multimeter (for resistance and voltage measurement)

If error 10123 returns after replacing the thermistor and reseating the cable, contact Anycubic support for mainboard diagnosis.

Frequently asked questions

What does Anycubic 10123 mean?

Anycubic error 10123 (Hotbed NTC Abnormal) appears on the Kobra 2, Kobra 2 Pro, Kobra 2 Plus, Kobra 2 Max, Kobra Plus, Kobra Max, and Kobra S1 when the heated bed thermistor cannot return a valid temperature reading. The touchscreen may display an implausible temperature value — such as 0 °C, 300 °C, or "---" — and the printer will not allow heating to proceed.

How do I fix Anycubic 10123?

Anycubic error 10123 means the hotbed thermistor is returning an invalid reading. Diagnose and fix NTC sensor cable faults on Kobra 2, Kobra 2 Pro, Kobra 2 Max, and Kobra S1.