“the heatbed temperature is abnormal; the sensor may have an open circuit”
I received a new A1 yesterday afternoon. Set up, run the calibration and run a couple of prints - one that lasted about 5 hours and a couple of small ones. Everything seemingly going well.
This morning I ran a small print which went fine but an hour or so later I go to run another print and I get an error about the heatbed. Since then I have been getting consistent heatbed errors. The bed itself does get hot but it seems like after it reaches a certain temperature or something it goes wrong and raises the error and the temperature readings are no longer correct.
I’ve tried:
Factory reset
3 different firmware versions (oldest, somewhere in the middle, and latest)
I’ve tried measuring the resistance of the power (47 ohms) and the signal (125 kohms - a bit high compared to the 100 kohms expected but not crazy)
I’ve tried reseating all of the cables
I have a ticket open with Bambu but I thought I’d reach out and see if anyone knows anything else I can try in the meantime because I’m sure it will be at least a couple of days before I hear back and I only have the weekends to do 3D printing so trying to see if there’s still a chance I can print a larger object this weekend. I am assuming this is a “wait for Bambu to respond” thing though
The resistance measurement looks like it is telling you something. A 25% error is pretty big.
I’d bet it’s exactly like the message says - an “open” which may not always be open. Temperature causes expansion and contraction so there is physical movement as the heater heats the build plate besides the actual build plate motion tugging on wiring. I’d trace the heater wires from the build plate to the circuit board they plug into and make sure all connections are tight and the wiring isn’t damaged, pinched, or cut anywhere along its length.
As an aside, the extra 25k ohms you’re seeing could be a weak connection somewhere or a wire cut, etc.
I think I have done as much tracing as I can do without disassembling the heatbed itself but Bambu doesn’t have any docs on this so I will just have to wait and see what they say!
I have the exact same error message on my new A1. Only had it 24hrs and managed to do 2 big prints totaling 13 hrs. After every build plate has done I get this message. I will have to do a wire trace and make sure everything is good but apart from that I’m not comfortable doing electrical testing using a meter.
Not what I expected from Bambu, I already have an A1Mini and that’s been brilliant so I decided to step up a size. I’ve tried opening a ticket but got this annoying robot answering my question, need to open a ticket now, not wait until I’ve checked through only to find it’s faulty and in need of changing out.
Hey @user_1425967748 I reached out to Bambu and they sent me a new heatbed unit.
I had a play with the old heatbed and replaced the thermistor and with a new thermistor it did work fine but the bed is really hard to put back together properly so ultimately I binned it and used the new unit when it arrived from Bambu.
The heatbed is connected directly to mains voltage so I would just get a new one from them and perform the replacement if you are comfortable.
I’ve had my A1 for about 6 months and a firmware update just came out. Since then I have had heat bed errors. Whenever I start a print the heat bed goes to maximum temp, I think 69F then drops to 0. If I don’t manually adjust it on the printer itself it gives me the error. It’s not a setting that I’ve changed on any of my profiles it’s just since the firmware update. Make sure your heat bed isn’t maxing out. I set mine to 55F.
Can you please give me a link or the specs of the thermistor you changed?
It appears to be a 100k NTC but the ones I found have a glas enclosure on the tip of the sensor and I would like to know if those work
ive just got the same issue with my brand new h2d , two small prints now heatbed temerature abnormal, now it just heats up and gets and stays extremley hot and fires the error, Rubbish start to 3d printing waiting for help now
