Which models would be considered the first and which the second generations?
First there were the hybrid (tube+transistor) amps which debuted in the upper-echelon consoles for the 1964 model year, the TA-900 & 690-A; then the hybrid console amps of 1965, the 49-A, 59-A & 97-A and the all-in-one hybrid console receiver from 1966, the 69-T. You also have the hybrid separates from 1965 that Brian mentioned above: the 600-T receiver, the TFM-300 tuner and the TX-300 amp. (I never knew that the 600-T consisted of the TFM-300 and the TX-300 but it makes sense: 300+300=600.) There was also an early 'economy' line of hybrid separates from approximately the same time: the 440-T receiver, the TFM-200 tuner and the TX-200 integrated amp which probably debuted in late 1965 for the '66 model year.
Would that mostly hybrid group (I'm not sure if the TX-200 & TX-300 were hybrid, or not.) from 1964-1966 be considered the 1st Generation of solid state Fishers?
If so, would you consider the 2nd Generation to consist of the following (which were nearly 100% solid state):
1967:
Console Receivers: 31-R, 22-R & 11-R.
Separate Receivers: 700-T, 500-T, 220-T.
1968:
Console Receiver: 24-R.
Separate Receivers: 550-T, 200-T.
1969:
Console Receivers: 23-R, 20-R.
Separate Receivers: 500-TX (aka - 800-T), 400-T, 250-T, 175-T, 160-T.
Tuners: TFM-1000, R-200-B (hybrid).
Integrated Amps: TX-100, TX-1000.
And perhaps the TX-50 and the TX-2000, though I am not sure of their exact dates of origin. Am I missing any solid-state tuners, integrated amps or power amps from 1967 or 1968? It seems like I must be - anyone?
It's difficult to draw a definitive line between one model year and the next with Fisher since new models were introduced throughout the year and many of the models continued on for several years. Also note that many of the console receivers have nearly identical counterparts among the separates. I've been compiling an equivalency chart but it is incomplete and currently buried somewhere among my Fisher files.
1967 would seem to be a good dividing line between the 1st and 2nd generations since that seems to have been the year Fisher committed to solid state. The real trick is defining the cut-off between the very good to excellent solid state gear that was produced while Avery Fisher was still at the helm and that which came after. I don't think we're talking about a specific date after which one really ought not bother. Perhaps a good strategy for the collector would be to consider any Fisher branded gear made after 1969 as guilty until proven innocent.