Bed not heating during setup wizard, but will heat on preheat or manual temp set.
 
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Bed not heating during setup wizard, but will heat on preheat or manual temp set.  

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areyouferretti
(@areyouferretti)
New Member
Bed not heating during setup wizard, but will heat on preheat or manual temp set.

printer: mk3s+

firmware: 3.13.1 and 3.12.2

Issue:
When I run the calibration wizard, the heated bed doesn't heat, and the LED doesn't light. However, when I ask the bed to heat by preheating or by manually setting the temperature in the settings menu, it heats just fine and the bed LED turns on.

Things I've tried:
Downgrading the firmware to 3.12.2
Checking resistance on the bed thermistor (perfectly in range)
Checking resistance on the bed heater wires at the bed and the einsy board (both perfectly in range)
Checking voltage on the bed heater wires at the bed and the einsy board after manually requesting power (both perfectly in range)
Reseated every connection on my einsy board and retested

This felt like a software issue to me, which is why I reverted my firmware, but the issue persisted. At this point, I'm at a loss.
If anyone has any suggestions I'd appreciate it.

Posted : 24/09/2023 12:52 am
areyouferretti
(@areyouferretti)
New Member
Topic starter answered:
RE: Bed not heating during setup wizard, but will heat on preheat or manual temp set.

I went back for another round of testing this morning. I have changed nothing since my last tests.

The wizard was able to pass the bed and hotend checks, get through the xyz, and then failed the thermal model.

Here's the big twist:
I can't preheat anymore.

Initially, I could preheat and I could manually set the bed and tool temp from the settings menu, but the wizard would fail to even turn the bed on during testing.

Now I can pass the tests, but I can't preheat.

The only thing I can think of is wiring, but I've tested all the wiring.

Posted : 26/09/2023 12:46 pm
areyouferretti
(@areyouferretti)
New Member
Topic starter answered:
RE: Bed not heating during setup wizard, but will heat on preheat or manual temp set.

After yet another reinspection of the wiring I found a pinched power lead in the bed wiring at the strain relief on the bed. I'm curious if this happened during my wire inspection or multimeter tests and this is what caused the change in symptoms.

I'll replace the wire and test again.

Posted : 26/09/2023 8:37 pm
areyouferretti
(@areyouferretti)
New Member
Topic starter answered:
RE: Bed not heating during setup wizard, but will heat on preheat or manual temp set.

I replaced the wiring and retested everything and it was functioning completely within spec perfect resistance from the wires through the bed and spot on 24v at the bed screws. Then suddenly wasn't. 0v at the bed terminal on the einsy.
I reviewed with prusa support and they confirmed the einsy board was faulty. I've ordered a new one and I'll update when I get it installed.

I'm the only one tracking this thread, but hopefully, it will help some googling for help in the future.

I read about someone whose board died when they upgraded to 3.13.1, which is what happened to me. Possibly a coincidence, but worth noting, I guess.

Posted : 27/09/2023 7:10 am
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