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Fluctuating Heatbed Temp  

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CovertContours
(@covertcontours)
Active Member
Fluctuating Heatbed Temp

Noticed recently that my heatbed is not staying at a very consistent temp. The printer is in an enclosure so the average air temp while printing is around 26 and very stable. It seems the bed will stay at 60 for a short period of time and then jump between 57 on the low and 62 on the high side. The below graph is a good representation.

Any change this is an early sign of the heatbed thermistor wearing out?

 

Posted : 15/11/2023 3:36 pm
CovertContours
(@covertcontours)
Active Member
Topic starter answered:
RE: Fluctuating Heatbed Temp

Of course minutes after my original post I get the Mintemp Error Bed.

Heatbed power cable and thermistor set ordered just to be extra safe. Tis the holiday season, need the printer to be in tip top shape!

Posted : 15/11/2023 5:28 pm
pink_clown
(@pink_clown)
Trusted Member
RE:

Could be a cabe issue. I do not think it is the thermistor issue. What I learned a few weeks ago, the cable between the power switch and the main board became rather hot, I checked the power cable contact pins.

Be aware, that the temperature hysteresis ( threshold when the regulator reacts) for bed I guess is about +-2°C. 

Posted : 19/11/2023 6:27 pm
pink_clown
(@pink_clown)
Trusted Member
RE: Fluctuating Heatbed Temp

Posted : 19/11/2023 6:38 pm
CovertContours
(@covertcontours)
Active Member
Topic starter answered:
RE: Fluctuating Heatbed Temp

Disassembled the Mini and started testing cables. Turns out there is a break in the ground on the heatbed buddy power cable. It's only noticable if I wiggle the cable while testing continuity. 

My mini was one of the semi-assembled ones. Looks like the ground may have been pinched during assembly but took almost 3 years to finally break.

Posted : 19/11/2023 6:46 pm
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