HP nixie tube module information needed

From: Joe <rigdonj_at_cfl.rr.com>
Date: Tue May 20 17:38:00 2003

At 05:04 PM 5/20/03 -0500, you wrote:
>The circuit board portion is easy, but the bit inside of the black
>box is a bit more complex. While I originally thought that it might be
>an integral HV supply of some sort, I now have additional information
>which says otherwise. Interestingly enough, that info originated from
>Tony Duel. Here it is:
> HP made a decade counter/display board where the counter FFs were
> made from pairs of transistors in the conventional way (8 transistors
> on the board). These were controlled with diodes to count in 1242
> (not 1248) BCD code.

    That makes sense. Before HP-IB HP used a BCD interface. It wasn't a 1 2
4 8 code, it was a 1 2 not2 4 or something like that and it was designed so
that there were no possible states greater than 9. Data was sent 4 bits
parallel, nibble serial fashion. I don't remember exactly how but the was
also a way to handle +/- signs and decimal points.

> The outputs of these counters drove 8 neon bulbs, and by varying the
> bias applied, the state of the counter could be latched in the bulbs
> (that's why this is relevant here). These bulbs were mounted inside a
> plastic block on the PCB, and shone onto a think-flim circuit of CdS
> photoresistors. These were connected to form a binary to decimal
> decoder to drive a nixie tube.
>At 02:37 PM 5/20/2003 -0700, you wrote:
>> >From: "Tom Uban" <uban_at_ubanproductions.com>
>> >
>> >Hello,
>> >
>> >Probably my best find at the recent Hamvention in Dayton OH was a
>> >stack of nixie tube modules made by HP. In retrospect, I wish that
>> >I had purchased the whole box of them, but I hopefully have enough
>> >to at least make a clock.
>> >
>> >I have two variations on the modules, the part numbers are:
>> > HP 05212-6016 series 648
>> > HP 05212-6003 series 415
>> >They both use Borroughs B422 nixie tubes and look like they may have
>> >an integrated HV supply of some sort.
>> I don't see anything that I'd call a power supply. The
>>transistors look like they might be flops/latches or buffers to
>>drive the nixies. If you don't find some schematics, you
>>could hand draw some. I doubt that it would be too hard to
>> >
>> >Here are a couple of pics for reference:
>> >
>> >http://www.ubanproductions.com/Images/nixie1.jpg
>> >http://www.ubanproductions.com/Images/nixie2.jpg
>> >
>> >I would appreciate if anyone can tell me what HP (or other) instruments
>> >may have used these modules. I would also like to find a schematic of
>> >the module if possible.
>> >
>> >Thanks!
>> >
>> >--tom
Received on Tue May 20 2003 - 17:38:00 BST

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