Extruder Temp reads 122C

K8200 3D Printer K8200 - Wiring and electronics
1

Hello everyone,

Since I have not found any concrete answer on similar posts about wrong read out of the extruder temperature and most shockingly, no one from Vellman has not left a single comment below similar threads.

About the problem, I have made the last print and turned off the printer. next time I turned it on, it was showing that the extruder temperature is 122C. I thought that the hotend might be still hot since the last print. I touched it, and it was cool.
Then, I have unplugged the thermistor for the hotend, but still it’s showing 122C. I made a shot screen this morning:

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Printer ON, USB cable connected, all board connectors are plugged off.

I have switched the hotend thermistor and plugged into the bed and it works, shows almost the same temperature as the bed thermistor was connected

My guess is something is wrong with the board, could anyone from Vellman leave a comment or solution please.

Regards,
Nezam

PS: link to the attached image: https://ibb.co/eS1LTG

2

From your description this does sound like a defective board.

3

So, what should/can I do now?

4

You can check the thermistor.
Disconnect Therm1 Top of the control board
See if the temp has dropped to 0C if it has check the resistance across the connector (wires) of Therm1 at room temp it should read around 100Kohms.
if it is still at 122C then it is in the board.
If the printer is still under warranty you can open a ticket here.
http://support.velleman.eu/
If not you will need to order a new control board.
Part number VK8200/SP