A 4011 is an inexpensive part, Mouser still carries them, I would NOT buy a chinese part. Generally ESD mishandling is the cause of short component life
Content by Scott Typos by Siri > On Apr 3, 2017, at 7:43 PM, Jeremy Nichols <[email protected]> wrote: > > I have a new-to-me HP-59309A HP-IB Digital Clock. The clock works on both the > internal crystal oscillator and on an external 10 MHz standard (GPSDO). > However, it counts only to 60 seconds and then repeats without updating the > minutes digit. The TIME SET (FAST and SLOW) push-buttons work but again, the > count will not update minutes and hours, only seconds. The DAY SET procedure > works correctly for days and months. All the other switches and buttons do > what they are supposed to do. Using my 10526T logic pulser I can force the > minutes and hours counters to work. The power supply is in good condition > (after replacement of a few components) and I see no other problems (yet). > > Tracing the clock signal through the logic circuitry brought me to U3 on the > A4 board. This (U3) is a 4011 quad 2-input NAND gate in a 14-pin DIP package. > It "connects" the seconds counter to the minutes counter and appears to have > failed. One of the people on the email list > <[email protected]> commented that the 4000 series CMOS > chips have a known limited lifetime. Since these parts are no longer in > production, the writer expressed the concern that any parts I might find to > buy may be DOA. > > Before I go hunting for parts, I'd appreciate hearing from anyone in the > group who has experience with the 59309A Clock and/or the 4000-series CMOS > family. In particular, are there modern equivalents to my 4011 chip? If the > 4000's really do have a limited lifetime I'd rather use a substitute. > > Jeremy, N6WFO > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
