Been happily printing for months on a Rostock delta. Today, an hour after a successful print, decided to print something else. Preheated HE and BED as usual when I notice that neither wasn't heating up. Check the board and notice the LEDs that usually turn on when there's power going through is no longer on. PEEK fan is ok (as well as its LED). Stepper motors etc is ok (as I can home). No burnt smell. Printer has been stationary. Checked all the connections and the board has power. I can still access the SD cardBoard otherwise appears functional with the normal status LEDs on and flicking as usual.
Help? I don't even know where to begin to where there's a problem.