Rotate the speed dial until the feeler contacts are visible in the gap.

Spray with a plastic safe contact cleaner and rotate back and forth.

Check the resistor values at the slow speed settings. They should range from around 9 kΩ (at 60) to 200 kΩ (at 4s) with no dead spots.

Clean the seat for the high speed cam with isopropyl alcohol. A narrow cotton bud or a floss pick work well.

Lubricate the high speed cam seat with shutter oil.