[time-nuts] Re: HP 10811A vs 10811-60111

Tom Van Baak tvb at leapsecond.com
Mon Apr 25 15:23:09 EDT 2005

> Are you saying that some HP-xxxx counters/timers/whatever would ship 
> with an 10811A, whereas another instrument with the same model number 
> and options ordered would ship with a different oscillator?

It's hard to say. I've seen mil-spec versions of
the 5238A shipped with a EGG 10811 clone. It is
not impossible that HP would ship whatever met
spec or better in a counter.

But more importantly the other reason it's hard to
know is that the 10544 and 10811 are 20 to 30
years old now. So when you get an instrument
with an OCXO there's no telling what is original
and what has been board swapped over the years.

In any sort of commerical or university lab, you
have to expect that OCXO or any other removable
parts are swapped around as needed.

Also if an eBay seller has spare parts and needs
to sell a functional counter, he will install whatever

Buying gear for 10% to 1% of original cost on eBay
is wonderful; but one of the few tradeoffs is certainty.

You can't know, and often the seller can't know, just
how easy or how hard a life a piece of electronics
has had in the decades before. Nor can you know
if all the parts inside a piece of gear are original. So
we sort of take what we can get and measure it to
see what we got.


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