Marlin 2.0.x MINTEMP BED on startup - not printing

Hello all, I think this is my first post here.

I'm getting a "MINTEMP BED" error as soon as my printer starts up. I'm using a BigTreeTech SKR v1.1 controller board, with the hardware from an Anet A8 printer (stepper motors & bed but a new hotend setup). I've flashed Marlin 2.0.x since this is a 32 bit board, and when I run the original SmoothieWare bin on the board the bed temp is registered just fine.

I can flash Marlin with the dummy sensor, 998, and everything works as it should. As soon as I re-flash with what I thought was the correct sensor, the system halts.

I have tried sensor 5, which is what is in the default Anet A8 configuration.h file and sensor 1 since that appears to be the same as the smoothieware sensor in the config.txt file.

This 'halt' happens whether or not the temp sensor is plugged in to the board. I would think that if there was no reading it would be 999/undef/something.

Short of just trying the different temp sensors for the bed, what else can be done?

Thanks

Did you use the offical marlin [github.com] or the custom one from the manufacturer? [github.com]

How recent is your version of Marlin? There were some very recent fixes to the temperature handling code for 32-bit platforms (specifically applies to the LPC1768 on the SKR) that fix some issues with temperature errors on startup. Try a fresh bugfix-2.0.x checkout and see if you have better luck with those fixes included.

I used the official Marlin GitHub download

I downloaded the latest version of 2.0.x.

But I think I found the problem. The connector that was on my Anet for the temp sensors do not securely fit on this board. Sometimes they would connect sometimes not. Found if I 'wiggled' the connections everything would work for a while then stop.

I swapped the connectors out to the correct ones, and now no more problems.

I don't know if Marlin works this way by default or not, but if there is nothing connected to the temp sensor it will read 0 or a random number, then error out with the "min" temp error and require a reset.