There are very few journals devoted to the harpsichord. These are the ones we have; only the first and last on the list are current:

Harpsichord & fortepiano  electronic 

Harpsichord and Fortepiano Magazine  print, 1987-1989

English Harpsichord Magazine  print, 1974-1986

Harpsichord Magazine  print, 1973

Harpsichord (from the International Society of Harpsichord Builders)   print, 1968-1976

Diapason; an International Monthly Devoted to the Organ, the Harpsichord and Church Music  print, 1909-current