Dave M wrote: > Poul-Henning Kamp wrote: >> -------- >> In message <1580810140.741428.1494966823210@mail.yahoo.com>, Ulf >> Kylenfall via time-nut s writes: >> >>> That the 1820-0313 is unobtanium I can understand.Has anyone created >>> an equvalent based on discretesor is there a suitable SMD "single" >>> flip-flop like single gatesthat could be suitable? >> >> I did a divider board for the LED clock: >> >> http://phk.freebsd.dk/hacks/HP5065A/20160112_working_clock/index.html > > The 1820-0313 is a Fairchild 931HC or Motorola MC931G DTL clocked > flipflop. I think if you toy with a TTL or CMOS JK-flipflop; it > should work with no issues. The only caveat would be the 4.2V Vcc. > The DTL logic was spec'ed to run at 5V, same as TTL, but don't know > how TTL logic would work at 4.2V. . > You might find a 3.3V flipflop and zener the 4.2V Vcc down to 3.3V > and build it all onto a small piece of perfboard. > > I've attached a copy of the pertinent pages from my old Motorola > databook (1966 Motorola Semiconductor Handbook) directly to Poul. > > Dave M Oops... I meant to say that I sent a copy of the datasheet to the OP Dave M