Note
QST, Jan 1975, p. 164.
Retired in late 1978 with the introduction of the 8044. MFJ may have been the first to use the new chip (in its MFJ-8044 keyer announced the September QST,), and Curtis ran ad ad announcing the new chip in QST, Oct 1978, page 204.
** Check hard copy for QST Sep 1978, p. 204 for the references to previous QST articles re the keyer.