I have an Ender-3 that I've been using daily for almost 2 years.

Yesterday, I updated the firmware to Marlin 1.1.9.1, using the configuration files provided for the Ender-3.

I printed out a few small pieces, everything went well.

And today, after 2 small printings of less than 15 mn, during the first layer of a printing, the printer head met one of the clamps of the bed, and the printing quickly stopped with an E1 error.

I turned off the printer, did various things (dinner, watching tv), and when I turned it back on, bed and nozzle cold, it refuses to tell me anything else than 156 °C for the nozzle, and 209 °C for the bed (the two temp_sensors of the nozzle and the bed TEMP_SENSOR_0 / TEMP_SENSOR_BED are at 1).

I did a reset of the EEPROM via the menus, turned the printer off and on, unplugged it from the mains, reuploaded the same Marlin: nothing to do.

I doubt both sensors died at the same time. Or that the card was fried, in which case it would have been rather worrying because it would have been very directly related to the Marlin upgrade, made without frills or crazy customization (I just adjusted the display fonts, enabled thermal runaway protection, disabled power failure recovery, and lowered the maximum shutdown temperatures for the bed and nozzle by 5-10 °C).

Would you be able to help me with that?

P.S.: I have reloaded my original firmware that I had saved, and when the printer has finished booting, I have the temperatures 157 °C (for the nozzle) and 211 °C for the bed displayed and the message Err: max temp bed" at the bottom of the screen.

It's very annoying.

So I ask myself: what's wrong? And above all: why did it come to this?

• Sounds like you board or thermistors might be fried. Start by measuring the resistance of the thermistors - should be around 100 kOhm at room temperature. Sidenote: Marlin 1.1.9 has been utterly obsolete for quite some time now, though that doesn't affect your issue. – towe Jun 17 '20 at 8:50
• @towe: at the same time ? Why would this happen ? As the printer runs flawlessly since 2 years with stock firmware. Because if they have died, and I buy new ones, I don't see anything I did wrong and this will happen again and again, especially as I won't be able to use the stock firmware anymore. – Oliver Jun 17 '20 at 10:28