Ultimaker Original - temperature drops of 30°C!

[stewe 0]

Hello everybody. I have problems with my Ultimaker Original. It started 3 months ago. Temperature readings were inaccurate as it was too cold or too hot. PLA strated making bubbles. Ok, I though I need new temp sensor. Oredered 2 of them to prevent off times in future.

So I replaced temperature sensor and started test print. Heated up to 220/220°C, but as soon as it started homing, the temperature drop to 190°C and printer continued with heating to 220°C. It reached 220°C again, but real temperature was in that moment about 250°C.

I thought it was a bad temperature amplifier. So I changed the amplifier board. Same story. Reached print temperature of the test print, but as soon as it was homing (reaching 0;0;0), temp dropped to 189°C...

Is there anybody with similar issue? Or does somebody have clue what is wrong? Thanks for every hint and tip!

[zoev89 73]

I would check if there is not a half loose wire in the temperature sensor or to the connection to the board. If I am not mistaken if it can not read the amplifier it keeps the old value. Since you say when homing it changes that makes me think it is a half loose connection.

Not very scientific advise...

Wiggle a bit with the cables to see if the temperature readout remains the same.

[LePaul 321]

I recently upgraded my UMO to the Heated Bed Plate and while I had everything apart, I discovered a lot of things had come loose over the years.

Some of the electronic terminals needed a half twist to be snug again.

I also had the two back cover pieces to the rods come apart...the nut was still on the thread but it wasn't a lot of fun to put back together!

Good luck!