I have just recently started collecting old Hewlett Packard test equipment, though I have been actively collecting and restoring Tektronix equipment for over a year. I started my HP collection with several of Nixie display counter-timers (5245L, 5246L, and a 5326B), a function generator (8116A) and a bunch of bench power supplies (6211A, 6212A, 6216A, 6217A and 6218A) and have been really happy with everything. My most recent acquisition is an 8660C synthesized signal generator, and while searching for a service manual I ran into a confusing situation that I have seen before with HP equipment: the model number appears to have been reused for at least one other instrument (in the case of the 8660C it is also the model of a phase modulation test set).
Unlike other model number collisions I have seen, these two instruments are not separated by decades: the 8660C test set is from 1975, while the 8660C signal generator is from 1981. Is there some explanation for why HP would reuse instrument model numbers like this?
-- Jeff Dutky
