Kincaid Radio Controlled Clock Instruction Manual [updated] Link

A: Remove the batteries. Press and hold the "SET" button (or manual set wheel button) for 15 seconds. Release. Wait 1 hour. Reinsert fresh batteries. This clears the internal capacitor and resets the microchip.

If you absolutely must set the time before the atomic signal arrives (perhaps you are timing a soft-boiled egg): kincaid radio controlled clock instruction manual