The beautifully-renovated Mauch Chunk Opera House in Jim Thorpe came alive this afternoon with "The Sound of Music" and other exhilarating melodies. Marking the formal dedication of the interior walls in the 107-year-old entertainment and cultural center at 14 West Broadway, the occasion was a memorable one. It represented completion of the latest restoration project in a long series of such improvements, and the sponsoring Mauch Chunk Historical Society did itself proud. More than 125 members and friends of the organization ushered in the spring season.