[BUG] Err: MAXTEMP: E1 on MKS TinyBee mother board. Does not occur in Marlin 2.1.2.6

[danvie4]

Did you test the latest bugfix-2.1.x code?

Yes, and the problem still exists.

Bug Description

The as soon as the printer boots, its throws a max temp error and the buzzer sounds. This does not happen as far as I can tell in Marlin 2.1.2.6. I tried installing a new thermistor, but that didn't fix it. Motherboard is a MKS TinyBee on a Anet Et4 printer.

Bug Timeline

New Bug - After version 2.1.2.6

Expected behavior

Temperature should display normally.

Actual behavior

It throws an error that says "Err: MAXTEMP: E1 PRINTER HALTED Please Reset"

Steps to Reproduce

Turn the printer on, error occurs.

Version of Marlin Firmware

Marlin-bugfix-2.1.x

Printer model

Anet Et4

Electronics

MKS TinyBee motherboard

LCD/Controller

MKS Mini 12864 V3 display

Other add-ons

No response

Bed Leveling

None

Your Slicer

None

Host Software

None

Don't forget to include

• A ZIP file containing your Configuration.h and Configuration_adv.h.

Additional information & file uploads

Marlin Config.zip

[classicrocker883]

doesn't happen in simulator so don't know what to tell you. try unplugging the thermistor, or using a dummy 999/998 in configs

[danvie4]

doesn't happen in simulator so don't know what to tell you. try unplugging the thermistor, or using a dummy 999/998 in configs

I tried using a dummy thermistor, and everything appears to work fine. When I switch to a regular thermistor, then it errors out. I thought it was a hardware problem at first, until I 1. Changed the thermistor (error still occurred) and 2. Compiled the firmware (using as close to the same configuration as possible) with an older version. When the thermistor worked properly with the older version (I've tested 2.1.2.6 and 2.1.3-b3), I suspected a bug. I'm not sure what could cause it though... Unplugging the thermistor with 2.1 bugfix doesn't appear to change anything. Before it errors out, the temperature value fluctuates all over the place. On 2.1.3-b3, the temperature readings work fine. If i unplug a thermistor, it shows err on the screen where the temperature would normally be displayed, but it does not "e-stop" the machine, make a buzzing noise, and turn the screen red, thereby forcing a machine reset.