Basic blender went bad (motor ran but spindle wasn’t rotating). I wanted to disassemble to see if it could be repaired. Three of the four screws were Phillips head. I had to cut the casing open in order to discover why I couldn’t unscrew the fourth. It was a slotted spanner.
I’ve found my ratchet driver is surprisingly often too thick to get into those screw holes of many electronics. There are thinner ones available, maybe go for those