AMS 2 Pro over temp for drying

[MrPaul]

Set up: (2) AMS 2 Pro, (1) AMS HT. All set to drying mode (one of the AMS 2 Pro has its own power supply).

Both AMS 2 Pro were set to PLA, the AMS HT to ABS. One of the AMS 2 Pro went way over temp; it was set to 45 C for 12 hours, but got to 64 C before I terminated that. Here is a pic for when it was at 61 C. If you felt the top of the case, you could feel it was quite a bit warmer then the other AMS 2 Pro. If I had to guess, it was actually doing the ABS program (which is 65) as well, despite showing it doing PLA. All AMS are on latest firmware.

There doesn’t seem to be a ticket option for AMS, so hopefully someone from Bambu sees this and can make an internal ticket.

[krellboy]

Looks like this bug:

Overshooting set temperature whilst drying filament

The past few months I have noticed the AMS 2 Pro having a “thermal runaway” at least on 3 occasions. Could have been more as there are occasions where I set it on drying (PLA 45°C) for 12 hours and don’t pay attention to it for the rest of the day. But as stated before I have noticed on a few occasions that the temperature surpasses the 45°C, by a lot.. without the AMS doing anything about it. Attached you’ll see 2 separate occasions where it reached 60°C, however I have caught it once at 72°…

And it’s not “thermal runaway”, but read the thread.

[MrPaul]

Ah, thank you, that indeed sounds the same, more or less. Yah, mine was definitely not runaway, it did actually stabilize at 64 C or so, it just happily controlled the temperature to the wrong set-point as far as I could see. I’d give extremely high odds of firmware bug when multiple AMS are drying (as reported in that thread as well).