My thermistors show a fixed temperature, no matter what happens

Hi everybody!
I have a reprap 3D printer Prusa i3, and recently it stopped printing because the LCD screen started to show the same temperature, no matter what happens.
I unplugged the thermistors from the ramps 1.4 board, but it still shows the same temperature for both the hotend and the bed, that is 196 degrees C.
This started after I cleaned the hotend of the printer.
Does anybody have anything to say, please?
thank you very much!

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Let nothing disturb you,
Let nothing frighten you,
All things will pass away.
God never changes!
Patience achieves averything.
Whoever has God lacks nothing!
God alone suffices! Amen.

Saint Teresa of Ávila

You have killed the ADC's on the mega2560

Most common cause is 12v from the hotend heater got to the adc pin.

Edited 1 time(s). Last edit at 06/22/2025 10:23AM by Dust.

Do I haver to change Mega 2560?
Are there any other possibilities?
All other fraturas are doing well.
Auto home, pre heat (not completely, because of the thermistor).
Do you think I must chance Mega 2560?
Thank you Very much for your attention!

Is there any test I can do to bem sure about this?
Thank you again!

Does this mean I have to change Mega 2560?
Are there any other possibilities?
All other features in the LCD are doing well.
Auto home, pre heat (not completely, because of the thermistor).
Is there any test I can do to be sure about this?
Thank you Very much for your attention!