[volt-nuts] Tek gear

Dick Moore richiem at hughes.net
Thu Nov 18 22:37:21 UTC 2010

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.

Dick Moore

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