A 30 year tech told me my multimeter leads were the problem, not the board
I was chasing a no heat call in a Kenmore dryer for 2 hours and he asked to see my leads, then showed me they read 1.2 ohms shorted together. Swapped to a $22 set of Silicone leads and now I check them first on every call, so what is the one small tool thing you check before you even open the panel?