On Wed, 14 Dec 2011, gene heskett wrote:
> Date: Wed, 14 Dec 2011 09:42:24 -0500
> From: gene heskett <ghesk...@wdtv.com>
> Reply-To: "Enhanced Machine Controller (EMC)"
> <emc-users@lists.sourceforge.net>
> To: emc-users@lists.sourceforge.net
> Subject: Re: [Emc-users] Scopes
>
> On Wednesday, December 14, 2011 09:02:43 AM Mark Wendt did opine:
>
>> A bit off tangent, but Jon's post in the Encoder thread brought
>> something to mind. I recently became the proud papa of a Tektronix
>> 7623A O'scope, purchased off the Bay of E. It's a mainframe storage
>> scope, capable of handling three plugins - two vertical amps and a
>> horizontal timebase. I got that machine, a few different plugins, a
>> number of probes, and some other odds and ends for less than $500. It's
>> an analog scope, but in it's time, it was one of the high-end scopes
>> that Tek made, and it's still going strong even at close to 30 years of
>> age.
>>
>> This one is identical to the one I have:
>>
>> <www.ebay.com/itm/Tektronix-7623-Oscilloscope-Modules-and-Manuals-/23055
>> 2776690>
>>
>> You can get better prices by waiting a bit. I got mine for $100 plus
>> shipping.
>>
>> A venerable high quality machine that you can use to help troubleshoot
>> problems like the ones that showed up in the Encoder thread.
>>
>> Mark
>
> Mark, be aware, very aware that tek has one HUGE Achilles heel. Its input
> attenuators are all custom, in house made parts. And they age out of
> calibration, both for DC measurements and for waveform fidelity on the
> screen, with square waves no longer being shown as square waves, and no
> amount of fiddling with the probe comp screws can fix it. This starts to
> get noticeable at about the same time tek takes advantage of the statutes
> re service parts and discontinues the parts 5 years after production
> ceases, or decides if they still have one, that it is worth 20x what it was
> worth a year before when it was still subject to the federal parts
> availability statutes. Been there, done that, threw it in the ditch when
> it was 7 years old in one case, 8 in another, because I could not believe
> what it was telling me.
>
> My now 25 year old Hitachi V-1065 (computerized, dual trace 100 mhz,
> triggered & delayed sweep, good to at least 200mhz with some rolloff & loss
> of headroom in the vertical amps) is still within a couple percent for any
> measurement its simple computer can make including frequencies by
> reciprocal of time. And the tube is as bright and sharp as it was when new
> as of last night when I measured the baud rate on a serial data line I
> thought was off. And yes, a midi port was running at about 37,000 baud.
> The keyboard obviously ignored the data. :(
>
> I have worn out at least 8 sets of 10x probes in its time. The 200mhz
> models I can get from MPJones are as accurate at $40 a copy as anything
> else I've ever bought, and mechanically sturdier than Tek's $200/copy
> versions.
>
> Sadly, the Tektronix that earned our trust as the final word back in the
> early 60's, and had lifetime warranties on any in-house built parts
> including their CRT's & power transformers, has been sold to the stock
> market 25+ years back, and is no longer worthy of our trust as a standard
> test gear item unless its still in warranty AND they will fix it. Note the
> caps, voice of experience. Whether they will honor the warranty is 100% up
> to the rep that sold it and there effectively is no warranty on anything
> you didn't buy new from him. If you buy it new from Rudy, but move to
> Jeffs territory, Rudy won't service it since its out of his area now, and
> Jeff won't service it because he didn't sell it. Obviously, its been 15
> years since I have considered the purchase of anything from Tektronix.
>
> Cheers, Gene
> --
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> My web page: <http://coyoteden.dyndns-free.com:85/gene>
> Executive ability is deciding quickly and getting somebody else to do
> the work.
> -- John G. Pollard
>
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The 7623 is a 7000 series plug-in type scope >35 years old
vertical plugins (and the attenuators, which are socketed)
are a dime a dozen...
Peter Wallace
Mesa Electronics
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------------------------------------------------------------------------------
Cloud Computing - Latest Buzzword or a Glimpse of the Future?
This paper surveys cloud computing today: What are the benefits?
Why are businesses embracing it? What are its payoffs and pitfalls?
http://www.accelacomm.com/jaw/sdnl/114/51425149/
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