[time-nuts] HP-59309A Clock counts only seconds, HEF4011

Alex Pummer alex at pcscons.com
Mon Apr 3 22:14:23 EDT 2017

NOt pin-compatible but functional compatible and available is the 74C00 
or74 HC00, which has a long life I am using one in my gate alarm 
since1989, it is on all the time and the chip is available the HEF4011 
is also available -- at Mouser -- it is pin-compatible and function  
with CD4011 ad it is made by Philips [NXP]




On 4/3/2017 4:43 PM, Jeremy Nichols 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 <hp_agilent_equipment at yahoogroups.com> 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
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