Berghaus began to build a solid reputation as a knowledgeable builder with talented craftsmen. He would often acquire maintenance contracts for newly installed Casavant organs because of his affiliation with Shawhan and partnered with them on several local installations.
The company constructed its first mechanical action instrument for O’Fallon United Church of Christ, in O'Fallon, Illinois in 1973. This instrument continues to play as it did the day was installed.
After the success of the O’Fallon UCC instrument, Len continued building smaller, two-manual mechanical action instruments. Eventually, the design of his instruments started to incorporate electric sliders to facilitate combination actions and electric pull-downs.
Late in 1973, Berghaus moved production from his garage and basement to a 4,000 square foot facility located at 537 W 25th Street in Bellwood, Illinois.. With only 13′ high ceilings, Berghaus Organ Company (as it was known then) was still able to design and construct instruments that stood significantly taller; however, to facilitate a more efficient design and fabrication process, a new two-story erecting room and design offices were added to the facility in 1984.