[volt-nuts] Tek gear
Marvin E. Gozum
marvin.gozum at jefferson.edu
Fri Nov 19 12:25:08 UTC 2010
Thanks Dick, those historical tidbits are priceless.
Ceramics vs glass: That's funny, but they must have been very good at
it given the qualities of these material.
Tuning Tek vs clone analog scopes: shows why much high end gear,
even in today's digital world, are like musical instruments. Its
easy to make any instrument look like a piano, but the tuning or
subtleness in material and workmanship, makes all the difference.
I am awaiting a Chinese clone of the 25 year old design of the HP
3458a, does anyone know?
There is a very active group in reverse engineering, say China. But
in many high end things, their folks reach a brick wall, but until
that happens, it seems like their growth rate is enough to run
through us. Solution? Pour into US/EU engineering schools to get the answer.
At 05:37 PM 11/18/2010, Dick Moore wrote:
>On Nov 18, 2010, at 4:00 AM, volt-nuts-request at febo.com wrote:
> > Message: 2
> > Date: Wed, 17 Nov 2010 15:07:35 -0500
> > From: "Marv Gozum @ JHN" <marvin.gozum at jefferson.edu>
> > Subject: Re: [volt-nuts] Keithley - and Tek gear
> > Thanks Dick, that's priceless insight.
> > Can you explain the benefit of the ceramic jug over just plain glass?
>Marv, there was no advantage to the ceramic jugs at all, quite the
>contrary -- it's just that Tek had a very sizable and expensive
>building devoted to making ceramics, and it wasn't going to be used
>any more -- what to do with it? "I know, we'll make ceramic CRTs!!!"
> > ------------------------------
> > Message: 3
> > Date: Wed, 17 Nov 2010 15:59:59 -0500
> > From: Chuck Harris <cfharris at erols.com>
> > Subject: Re: [volt-nuts] Keithley - and Tek gear
> > To: Discussion of precise voltage measurement <volt-nuts at febo.com>
> > Message-ID: <4CE4424F.40006 at erols.com>
> > Content-Type: text/plain; charset=UTF-8; format=flowed
> > Dick Moore wrote:
> >> It was a little more complicated -- When I started at Tek in
> 1961, I was told that in the 50's, during the Korean
> >> conflict, Tek had military contracts that stipulated that Tek
> had to allow other firms to build the mil-spec gear as
> >> a matter of national security. Lavoie Labs and Dumont built Tek
> scopes under these contracts, and then continued to
> >> build Tek scope clones for years afterward, on into the 60's,
> most notably, clones of the 530 and 540 series, which
> >> had mil contract provisions on them. Tek of course had the
> ceramic terminal strips and the others didn't -- Tek made
> >> those ceramic strips themselves.
> > To quote Stan Griffiths:
> > " Counterfeit Instruments
> > ------------------------
> > During the late 50's, and early 60's, at least three different
> > companies produced copies of popular Tektronix oscilloscopes.
> > These instruments were sold to the U.S. Military under large
> > contracts and show up occasionally in the surplus market today.
> > If you are not aware of this situation, you could easily buy
> > one of these bogus instruments thinking it was manufactured by
> > Tektronix because their appearance is so similar to the real
> > thing. These copies provoked a 20-year-long lawsuit for patent
> > infringement against the Federal Government that Tektronix
> > eventually won."
> > - Oscilloscopes Selecting and Restoring a Classic,
> > by Stan Griffiths - ISBN: 0-9633071-5-0, p37.
> > (Apparently self published)
> > He goes on to say the companies are Hickok, Jetronics, and Lavoie.
> > As an additional point, my dad, a life time DOD engineer, once told me
> > that Tektronix refused to make milspec scopes, in the 50's and 60's,
> > because they didn't want to get tied into the government contracting
> > requirements, second sources being among them. All tek scopes, during
> > that time frame, were bought off the shelf.
> > The Hickok, Jetronics, and Lavoie scopes were entirely made at the
> > government's request to fulfill their need for control. They basically
> > told the companies not to worry about the patents, the US would take
> > care of it.
> > -Chuck Harris
>Thanks Chuck for the note. It's true that Tek didn't build to
>mil-spec, and that their government sales were off-the-shelf
>product, although, the 647 was supposedly a "ruggedized" scope which
>was, so I was told, aimed at military sales, though not as a mil-spec unit.
>I only actually touched one clone, which was, as I remember, a 535
>(or maybe a 531) from Lavoie. It was a pretty good copy, but the
>word was that they had reliability problems. I was also told that
>the clone makers all had problems making and tuning the distributed
>delay lines, which resulted in crappy risetime,
>overshoot/undershoot, and generally poor pulse fidelity. Tuning
>those lines was a real art, and only a few guys in Final Test could
>do it well.
>I heard that Hickok made some clones, but I only heard that as a
>rumor, same way I heard that Dumont was making them. I never heard
>about Jetronics at all. But I was a grunt in those days -- very low
>level employee, just starting my working life.
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