I got stuck, troubleshooting my #BTT #BigTreeTech #Octopus 1.1 mainboard, installed in newly assembled #RatRig #V-core #3Dprinter, running #RatOS aka #Klipper.

Both #nozzle (#extruder) #heater and #hotbed one do not warm up. Beyond all doubt (using external power sources and hairdryer) I confirmed that both thermistors, heaters and wiring are ok.

Under warranty, RatRig sent me replacement board, which I configured, flashed with updated firmware and got the same error.
I also tried to redirect the nozzle heater power to another pin (see in the config file at lib.tepewu.pl/f/8f1d29fe05d44c…) where I hooked up the multimeter. Nothing happened, when I set up nozzle temp to 50*C - after timeout I had the same error "extruder is not heating fast enough", thus klipper shutdown.

I cannot believe to have such a bad luck to got two boards with the same hardware fault (especially that steppers and hotbed probe work perfectly), so it is something I do not know - and I run out of ideas.

Please, somebody suggest something new. Hjalp.

Previously in 3dPrint Odyssey....

I completed installation of the #SpritePro extruder on the #CR-10v3 #Creality chassis.
Inevitable fallout made me replace faulty nozzle thermistor, made a cable bypass, move Y-axis endstop, replace inner fans with the silent ones and...

Today's challenge is the #hotbed indicator showing flat 144*C, real temperature notwithstanding.
I checked the hotbed #thermistor circuit and it gives ~104 kOhm(?) all the way down to the mainboard (#Creality 2.5.2. #ATMega).

The only reasonable conclusion is that it is the analog port problem. If it is broken, I probably have no choice but to replace the mainboard - unless...

My clever monkey brain sees a spare analog port on the board (the one marked "Thermistor 2" below).

Would it be possible to reassign it for the hotbed thermistor? I assume it may need a recompilation of the firmware, but what the heck: I can do it if I have to, opposite to buying a new mainboard for another 120 EUR I do not have...