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

[Tom Miller]

Also, you might install a high quality machined pin socket. Save the 
non-replaceable PC board.

----- Original Message ----- 
From: "David C. Partridge" <david.partridge at perdrix.co.uk>
To: "'Discussion of precise time and frequency measurement'" 
<time-nuts at febo.com>
Sent: Monday, April 03, 2017 9:33 PM
Subject: Re: [time-nuts] HP-59309A Clock counts only seconds


> You can get a brand new CD4011BE from pretty much most suppliers at about 
> 15 cents that won't exhibit the problems of the earlier ones.
>
> Dave
>
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Jeremy 
> Nichols
> Sent: 04 April 2017 00:44
> To: time-nuts at febo.com
> Subject: [time-nuts] HP-59309A Clock counts only seconds
>
> 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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