Thermal Runaway, Instant heating up

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hun46y3
Posts: 3
Joined: Thu Apr 22, 2021 10:10 pm

Thermal Runaway, Instant heating up

Post by hun46y3 » Thu Jan 20, 2022 12:59 am

Hey there!

After a nozzle change (nothing else changed on my printer) this started:
As soon as I turn the printer on, the hotend starts to heat up, and it just goes higher and higher until I turn the printer off.
The temperature reading on the display also increases, so it's not a thermistor issue.

Maybe a mosfet burend out, or something, and it just constantly supplies voltage to the heating cartridge?
Do you guys have any idea what to check, what to do?

Thanks in advance!

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vert
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Re: Thermal Runaway, Instant heating up

Post by vert » Thu Jan 27, 2022 1:04 am

if the thermistor and heater wires touch the heater block and short to each other it fries the board and will require replacement.

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