Bend over and grab your ankles, is going to be a long ride. You are not the first to have this trouble but have not seen a solution posted yet. Seems to be a "mystery" to configure that voltage selector switch.
Just call me B-String 2
GK Club #488 Big Cabs #175 Peavey Amps #92 50+ Club #44 Grumpy Old Fart #2