Numitron-based tube clocks

Member Joe N submits this fascinating piece of equipment from the age of discrete logic.


He writes:

At a garage sale over the summer, where the seller had old military aviation and radio equipment, I purchased a Sequioa Pacific TAC 605e Numitron clock because it looked out of the ordinary and very official. I had never seen anything quite like it before.

I could not find any specific information online pertaining to this unit, or even the Sequoia Pacific company, but it's a neat nonetheless.

It uses six flat style Numitron (Minitron?) seven segment displays to show hours/minutes/second in the 24 hour format. Time is synced via a 60Hz AC connection or an IRIG-E timecode. Unfortunately, when using this on AC it runs slow, and I do not have a timecode generator to test the IRIG-E functionality. There are some FAA service tags on the clock indicating it was serviced in 1991, and then tested as good in 1995. I was unable to locate any dates indicating year of manufacture.

Look at al that 4000 series goodness...


Googling for the 605E doesn't turn up much information. If you have any further insights into this unit, please leave comments below.

Here is a cool 4 digit numitron clock based off of what appears to be an ardunio.  Based on the GitHub description:

  • Retro glowing numitron display featuring Soviet-era IV-9 numitron tubes
  • A DS1307 real time clock with backup battery for accurate timekeeping and alarm memory preservation during loss of power
  • Blue LED underlighting for each digit, with customizable fading light patterns
  • Programmable alarm
  • 12- or 24-hour operating mode with AM/PM indicator light
  • Easy display blanking for nighttime use and tube life preservation
  • 100% open source hardware and software
  • Arduino programming compatibility using standard TTL serial

Links: posted this video of their single digit numitron clock, the YS-950, powering an end-view numitron. Check it out:



$24.98 / $31.98 (kit / assembled)

{vimeo width="700" height="390"}17314318{/vimeo} / the Vintage Technology Association has a great new gadget for sale - it is (what I believe to be the only) single tube numitron clock for sale.  And best of all, you can't beat the price: $24.98 for a kit or $31.98 for a fully assembled and working version.  All you have to do is supply 5VDC and you're in business.  (For the record, USB ports put out 5VDC.)

The display has two parts to it - the numitron tube and 4 LEDs.  The LEDs indicate what position is being shown (HHMM).  The actual timebase is provided by a quartz crystal.  One of the unique and cool features of this clock is that you can actually correct the time base to accommodate for changes in temperature, aging, etc.  There is a coarse adjustment that adjusts in 2 second increments and a fine adjustment accomplished by adjusting a capacitor with a flat head screwdriver. The entire gadget is powered by 16F628 PIC microcontroller.

If you're looking for a stocking stuffer for Christmas or need a nice little gift, this is the one to get.


Single Tube Numitron Clock VTA Decadecounter


There are two things I like about this design: it is small and it has a black PCB.  It is hard to emphases just how small this actually is - it is only about twice the length of the PIC microcontroller!  This device is small and easy to mount.  Just supply a modified USB cable for power and you can put this guy just about anywhere.  I know it seems trivial, but compared to my NixiChron, this little thing is portable.  Of course, the exposed black PCB will make all of your nerd friends jealous.





Single Digit Numitron Clock VTA

Many more photos after the Read More link


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