[time-nuts] Rare HP clock
brooke at pacific.net
Mon Oct 3 15:54:21 EDT 2016
Let me second Chuck's comment on the noise. You can NOT have this inside any living space.
I saw this based on running an HP 117 for some time in the garage but also have one of the 115BR units.
PS there are internal momentary switches on the117 multipliers that need to be tweaked to start them so if it totally
stops it takes some effort to get it going again.
The lesser of evils is still evil.
-------- Original Message --------
> I have one of those, only in light gray.
> It works quite nicely, though it is obscenely loud!
> It has a divider network that takes 100KHz from a
> companion reference unit, and divides it down to 1KHz,
> that it uses to drive a stepper motor used as a synchronous
> motor. The motor drives the mechanical counter mechanism.
> Because the motor is being driven with a single phase
> 1KHz signal, you have to give its shaft a spin to start
> There is a little crank driven synchro generator that
> is used to insert a phase difference into the 100KHz
> reference signal that serves to shift the edge of the
> 1PPS output.
> It is built into a cast aluminum chassis, that is sealed
> with O-rings, and even has a humidity monitor to show
> the condition of the air in the unit.
> The biggest issues I can see with it are the strong
> 1KHz audio note, the condition of the ball bearings
> that support the motor shaft, the little herd of
> wet tantalum capacitors in its circuitry, and the
> internal nicad pack that keeps it live during short
> power failures..
> The mechanical counter probably needs some cleaning
> and lubrication at this point.
> -Chuck Harris
> Dave M wrote:
>> It's Ebay item 351861979923
>> Dave M
>> KA2WEU--- via time-nuts wrote:
>>> I can not find the item on EBAY , Ulrich
>>> In a message dated 10/3/2016 11:51:24 A.M. Eastern Daylight Time,
>>> jn6wfo at gmail.com writes:
>>> According to my -hp- catalogs it was available only in rack-mount
>>> form, not in a cabinet. That suggests it was being marketed to a
>>> specific small group so it may indeed have been manufactured in
>>> small quantities.
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