Hello guys,
I had a blob during a print of PETG.
During the cleanup I broke the thermistor cable at the nozzle side and display of temperature gone to 0 - which is expected.
Removed the nozzle, removed the shroud and fan.
Removed the extruder motor assembly, then removed the heat assembly.
Replaced with new heating assembly being extra careful not to bend the cables unnecessarily.
Assembled back carefully, turned on the printer, but still no 0 at the temperature and the nozzle fan goes to full speed few seconds after the start of the printer once again.
The guide on the error says to swap a new heating assembly, but that I already did.
Topics say that there could be no communication problem to the TC board if temp is shown as 0, but that makes no logic as the problem occurred when the nozzle cable broke and it was fine before that.
Error on display is: HMS_0300-0200-0001-0002
Can you measure the NTC as described in the wiki?
It might be a little tricky to determine that in hindsight, but when you say it was “broken,” do you mean the connection was interrupted, or do you mean there was a short circuit? The difference matters quite a bit when trying to understand what could have happened.
To put it simply: when the reading shows zero, it essentially means the circuit is seeing (at least theoretically) infinite resistance - so no current is flowing at all. In practice, that usually means there’s no proper contact between the NTC and the measurement board.
A defective measurement board is possible, but typically only if there has been a short circuit. An open or interrupted connection, on the other hand, normally doesn’t harm the board.
To be absolutely sure, you’d need to check it with a multimeter. Maybe you can borrow one from a neighbor or a friend; even a simple one would be enough to confirm whether the NTC is still behaving correctly.
Hello, and thanks for the reply.
When I say broken I mean I literally broke it, by yanking it with a priers, because I did not see I caught it when pulling some plastic off, was a nasty blob that one.
So no short circuit on that one.
I have a multimeter, didnt have the super tiny ends to mesure this pin size tho.
I had a spare h2s left hot-end heating assembly that is the same part with different backing plate. People have been swapping them and using them with no issue, based of my research. That one is as well reporting 0.
I will measure for the resistance, I assume there is a change the h2s is no compatible and the brand new p2s assembly can be faulty as well. But that would be rather interesting coincidence.
So my question is more oriented to what to replace next? I have no worries of purchasing few more parts besides the wait for shipping from another country as the local dealer seams to have parts for every other printer of bambu but not P2s…
I read that the eddie sensor can cause displayed temperature 0, but that makes no sense to me.
I did a good inspection of both front and back boards of the toolhead and made sure I haven’t moved or broke any connection on the ribbons. As well I didnt’ spot any coloration or bumps in any parts.
I will measure out the resistance, but based of experience and test I would put my bet on the board possibly shorting somewhere.
So I did measure the heat assembly resistance at the showed pins.
Outer pins: measure at 6 ohms which is not that much in the 10 ohms range as it should.
Inner pins: measured at 101.2k which looks to be fine.
Other assembly I have measured at:
Outer pins: measure at 10 ohms
Inner pins: measured at 89.5k.
