Date   

Re: 7A26 transient response 5 nS all atten

Albert Otten
 

Hi Jon,
Anyone with a link or scan of the -01 Rev SEP 1985
You might ask Dave at ArtekManuals.com which Rev his 070-1484-01 pdf is.
I mentioned SEP 1985 since that's the one I have (also one of OCT 1987). Perhaps DEC 1984 or even APR 1984 already mentions your board versions.
I'm afraid a paper manual posted to you might never arrive because of all those strikes in Paris ;=)

Albert


Re: What Tektronix means to me

Jim Ford
 

Crap, Dennis, now you make me want a 7854 even more!  Fortunately I know several people who will gladly sell me one when the time comes.  Got to satisfy my frequency domain cravings first.I'm chuckling that HW jocks would fear the internal Tek SW language!  The one and only time I wrote software for a living was the summer of 1987 when I worked in a medical research lab at CWRU.  They had an Apple ][ with 8 inch floppy drives, and it was ancient even back then.  Turns out Apple stored the program lines just adjacent to the "hi-res" graphics page.  So as I added features to the data acquisition program I was writing, I got to the point where these strange lines appeared on the screen!  A different way of collapsing under its own weight!  And one sure way to curtail scope creep.Great story!JimSent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: Dennis Tillman W7PF <dennis@ridesoft.com> Date: 1/16/20 3:36 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] What Tektronix means to me The 7854 is both analog (400MHz) and digital. It combines the best of both worlds.As the very first digital lab scope they did many things that were ground breaking. Start with the fact that the 7000 series was designed before the concept of digital scopes could even have be conceived of. It would have been understandable if the already released 7000 plugins were not compatible with it but they all work just fine. The 7854 design team chose to use 10-bit samples when everyone else settled on 8-bits because it was more efficient and less complicated. 10-bit samples make for a much SMOOTHER display of stored traces. It has an astounding vector processing software language built into it that terrified hardware EEs. Tek quickly removed any reference to it from their marketing materials when they got negative feedback about this from potential customers. In 1980 nearly 100% of all hardware engineers viewed programming as black magic. This built in language for processing waveforms was revolutionary. It is unfortunate that this was developed decades before engineers were willing and able to use anything like it. It was the first scope with a GPIB interface so you could talk to it. I wrote an extensive program in 1993 in MSDOS Quick Basic that allowed me to do anything I wanted with my 7854. It took advantage of the GPIB interface to read and store waveforms on disk or to write waveforms back to the 7854 for later display. I wrote programs using the external keyboard and ran the programs on the 7854 or saved them for later use on disk. I could write 20 lines of text on the 7854 CRT. My software automatically calculated and displayed dozens of parameters about any waveform I captured and displayed them on my PC monitor alongside the waveform. As do most BASIC programs it eventually grew so complicated it collapsed under its own weight when I could no longer keep track of the interactions between different sections of it.Since I knew you would ask what did the results looks like I put six waveforms I captured with it (and all the parameters it calculated) up on TekScopes photo section. They are in: https://groups.io/g/TekScopes/album?id=238613Dennis Tillman W7PF-----Original Message-----From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Abc XyzSent: Thursday, January 16, 2020 1:29 PMTo: TekScopes@groups.ioSubject: Re: [TekScopes] What Tektronix means to meDennis, I'm curious...of all the Scopes you have been exposed to you say the 7854 is your Favorite. Why is that? JROn Thu, Jan 16, 2020, 12:57 PM Dennis Tillman W7PF <dennis@ridesoft.com>wrote:> Hi Jim,> The job offer letter from Tektronix is laminated on a plaque where it > sits on my wall along side my diplomas. No. I never went to work at > Tek. But in a way I got to become an honorary member of Tek.>> I have been embraced by everyone I meet that is a current or ExTek > employee. I have been included in their private mail reflector, I have > been a member of the vintageTEK Museum since before it opened when > Stan Griffiths first took me over to see the empty store front that > would soon be its first home.>> The biggest surprise was when Michael Dunn asked me to take over as > moderator of TekScopes. Why me?>> Usually 4 times a year I am in Beaverton visiting my Tek friends. > Somehow one of the most famous design engineers at Tek heard about me > several years ago and quite by accident I introduced myself to him at > the museum. He replied "You're Dennis Tillman!" which stunned me. He > is now one of my best friends. He is so highly regarded among ex-Tek > employees that I will often call him to arrange a lunch with someone > at Tek that was legendary. They never refuse. I have had many > fascinating lunches with the people I might have known if I had become > a Tek employee. We often met for lunch in the Tek cafeteria. Tek > closed the cafeteria last month so I'm not sure where we will have those lunches next.>> My favorite scope is the 7854. When I mentioned this to Deane Kidd at > a swap meet one day he said the 7854 project manager was in the next > room having a bite to eat and he introduced me to him. A few days > later I asked him to autograph the cover of my 7854. He was puzzled > why I would want his autograph.>> Asking for autographs was something I had started to do when I was at > Microsoft. For each Software Developer Conference I held I asked all > the speakers to autograph their section of the conference notebooks. > Bill Gates and Steve Ballmer's signatures are in them as are all the > Windows developers and many of the famous software developers of the > mid-1980s that attended the conferences.>> By now that 7854 cover is so full of autographs of ex-Tek employees > that I have had to switch to the other cover. When I'm all done with > the covers I will give them to the 7854 Project Manager who is now a > good friend of mine that I see every time I'm at a swap meet.>> Dennis Tillman W7PF>> -----Original Message-----> From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of > Jim Ford> Sent: Thursday, January 16, 2020 6:48 AM> To: TekScopes@groups.io> Subject: Re: [TekScopes] What Tektronix means to me>> Hey, don't keep us in suspense, Dennis!  Did you ever get to work for > Tek?Jim Ford Sent from my Verizon, Samsung Galaxy smartphone> -------- Original message --------From: Dennis Tillman W7PF < > dennis@ridesoft.com> Date: 1/15/20  10:36 PM  (GMT-08:00) To:> TekScopes@groups.io Subject: Re: [TekScopes] What Tektronix means to > me Hi Harvey,Yes, there is no simple solution to things being too far > away but saying "I never expect to go there" (to the Tek Museum) is > not the best way to start out if your goal is to get there. You never > know what you ae capable of until you try. On more than one occasion I > decided to hitch hike cross country from New Jersey to LA and up to > San Francisco. Along the way I stopped at the St. Louis Gateway Arch, > Grand Canyon, Mt Palomar to see the telescope, and the meteor crater > in Arizona. On another trip down to the Keys I stopped at the new > Disney World in Orlando. I've been to Mardi Gras three times.I had an > offer to join Tek in 1968 when I was starting my junior year in > college. But they recommended that I get my degree first and assured > me that the job would still be there when I did. Life took me in a > different direction by the time I got my BS E.E. degree. For the next > 20 years I regretted that mistake. Instead I moved into a beach front > apartment on the New Jersey shore and, to my surprise, I became a > stained glass artist and beach comer and I went back to college, this > time for a BA in Fine Arts. When I first heard it was possible to > build a computer (a childhood dream of mine) I changed direction again > and began building my own S-100 microcomputer. There were very few > people doing that so I quickly found a job working on microcomputers. > Eventually I became frustrated because I didn't understand software. > That became my next challenge. Once I learned microcomputer > programming I thought it would be smart to broaden my computer > background with some mainframe experience. When I tried to do that I > found out very few head hunters even knew what a microcomputer was. > They were focused on filling the thousands of jobs available in the > mainframe world. So I spent the next 6 months trying to get a mainframe job with no success. Eventually I was hired by an IBM 370 based time sharing company which saw there was an opportunity linking microcomputers to mainframes.> That exposed me to IBM's premier operating system: Multiple Virtual > Systems> (MVS) and the many different IBM operating systems and applications > that worked under MVS. Three years later someone recommended me for a > job with Digital Research, the creator of CP/M (which I knew well), > the industry standard 8-bit OS on microcomputers. Four years later > that led to a job at Microsoft which I was desperate to get because it > would finally bring me to the Pacific Northwest (Tektronix territory) > where I would have been 20 years earlier if I had joined Tek. After 3 > years at Microsoft it became clear I had the wrong background. They > had their pick of graduating students with an MS in Computer Science > or an MBA. So I went back to college a third time for an MS in > Software Engineering. While I was getting that degree, Microsoft went > from 500 people which was small enough that I knew almost everyone too > many thousands of people. I don't like big companies and there were > other opportunities for me now that I had an MS S.E.If you are on the > other side of the earth and looking at a very small map it may appear > that Microsoft (a few miles from Seattle), and Tektronix (a few miles > from Portland) are right next to each other. It is a boring 3> 1/2 hour trip to get there. Sphere Research is more than twice as far. > On more than one occasion I decided to hitch hike cross country from > New Jersey to LA and up to San Francisco. Along the way I stopped at the St.> Louis Gateway Arch, Grand Canyon, Mt Palomar (to see the telescope), > and the meteor crater in Arizona. On another trip down to the Keys and > Key West I stopped at the new Disney World in Orlando. I've been to > Mardi Gras three times. You shouldn't say things like I never expect > to get there. It sounds like you really want to go. If you can make it > to Seattle you have a place to stay with us. Portland is a train ride > away. Beaverton is accesable by light rail from Portland. Dennis > Tillman W7PF-----Original> Message-----From: TekScopes@groups.io [mailto:TekScopes@groups.io] On > Behalf Of Harvey WhiteSent: Wednesday, January 15, 2020 5:28 PMTo:> TekScopes@groups.ioSubject: Re: [TekScopes] What Tektronix means to > meI understand what you say, parallel to an extent, not congruent > experiences.The Tek museum is 3000 miles from me, and I never expect > to go there.Might we have something on the east coast?(and yes, I'm > annoyed that Sphere's "free" days are even further fromme.)  Still > would like to find a> 214 vertical amplifier board because mine has a bad channel A > attenuator, not that I've asked before.)HarveyOn 1/15/2020 5:15 PM, > Dennis Tillman W7PF wrote:> Like everyone here I have created a > problem my wife will have to deal with when I am no longer around. She > has the phone number of the vintageTEK Museum on our refrigerator. > Problem solved.>> Now that that's out of the way I'm not concerned > with recyclers and what will come of my stuff. I plan on enjoying the > afterlife with a Tek 214 portable dual-trace storage scope in my > coffin. The Egyptians had the right idea. Take what you can with you > when you go.>> Tektronix gives me a reason to get up every day. I can > explore anything in electronics with the instruments they designed. I > am the beneficiary of the legacy of Tektronix; the standard of > excellence they strove for; and the support they provided for their products.>> IN 1967 I bought my first Tek scope, a 453, new for $2,000.> What I learned in the next two years by using that scope every night > propelled me to the top of my class. That was the best investment I > ever made. Tektronix instruments were investments in my future. 10 > years later I bought a 7704A / 7A26 / 7B80 / 7B85 and a pair of P6106 probes for $7,000.> I went into debt to do this because I knew it would pay off for me > just like my 453 had. Two years later I bought a 7D01 / DF2 / DL2 for > another> $4,000 to study microcomputers. I eagerly learned microcomputer > assembly language to control the microcomputer hardware I was > designing. The next 10 years I had a very rewarding career in > microcomputers, mainframes, operating systems, and software > marketing.>> Several totally unexpected things happened starting in > the late 1990s that were to enrich my life yet again. EBay gave me a > way to buy all of the Tektronix instruments I could never afford back > in the 1970s. In 2000 Michael Dunn started TekScopes and I joined 2 > years later. Suddenly I was not alone. I had a vast resource of > expertise to help me fix all the Tek instruments I was buying on eBay. > 10 years ago Stan Griffiths and Ed Sinclair started the vintageTEK > Museum as a showcase for all the things Tektronix had made possible.> The museum is preserving the Tek legacy for the benefit of all of us. > Last but not least we have our own specialized Wikipedia. TekWiki has > become THE professional repository of Tektronix documents thanks to > the tireless work of Kurt Rosenfeld. Working long hours alone, into > the night, feeding every Tek document he can find into scanners. He > has single-handedly assembled those papers, manuals, photographs, and > comments into a beautiful, easy to use, library at our finger tips. > TekWiki is every bit that is the rival of Wikipedia.>> I'm too busy > using my collection of Tek instruments to dwell on what will happen to > it someday. Because of Tektronix, eBay, TekScopes, the vintageTEK > museum, and TekWiki my life is never dull when a Tektronix scope is > within arm's reach.>> Dennis Tillman W7PF>>>-- Dennis Tillman > W7PFTekScopes Moderator>>>>>> --> Dennis Tillman W7PF> TekScopes Moderator>> >>-- Dennis Tillman W7PFTekScopes Moderator


Re: 7A26 transient response 5 nS all atten

Nenad Filipovic
 

Issues with 7A26 rise time/transient response are very likely associated
with aging trimmer caps going open circuit. This has been discussed already:
https://groups.io/g/TekScopes/topic/19243444#148001
My 7A26 had the same problem and I had to replace 2 of these trimmers.
After re-calibration it was good to go again.
Another possibility are the aging carbon composite resistors that tend to
drift in value over time (also discussed in the thread I posted above), but
I'd check the trimmers first.

Best Regards,
Nenad


Re: 7A26 transient response 5 nS all atten

Albert Otten
 

Hi Jon,

The range of effect of the adjustments can more or less be guessed from RC times. For instance, C1339 (7-45 pF) in series with R1337(270 ohm) has effect in the first 3.5 ns to up to first 25 ns (taking 2*RC).
BTW: I think none of your 4 pictures shows a nice step response. Could that partly be due to the attenuators you use? Which scope type did you use? I never heard of a 7804.

Albert


Re: Tek 604: Sad story, and CRT wanted

Tom Bowers
 

Hi Toby,

I am curious about your TEK 604 application. Here's a little background
about mine.

Nearly 50 years ago I was part of a group of a few hundred people. We were
developing hardware and software for a large main frame computer. It was a
24 bit machine, used magnetic core memory and 3 foot diameter fixed head
hard disk drives. It had a lot of I/O. It was over 60 feet long and 7 feet
high. We took 10 bits of the program address and ran them through a digital
to analog converter. We took another 10 bits of the program address and ran
them through another 10 bit DAC. We ignored the least significant bits. We
fed the output of these two DACs to the X and Y axis on a TEK 604. At a
glance, you could see where the machine was executing instructions. And
when it crashed, you could easily see the dreaded "spot". We had multiple
systems and one of my jobs was to replace the CRTs when they got burned.
Some years later when that project was completed, I still had one last new
CRT. It's been in storage for over 40 years now, and I would be glad to
send it on to a good home.

Tom Bowers

On Wed, Jan 15, 2020 at 10:31 PM <toby@telegraphics.com.au> wrote:

Hi group,

I bought a 604 XY from ebay late last year.

Have been checking the unit out, and while generally in good condition,
it's suffered some indignities, which appear to have destroyed the CRT.

Evidence of this was one corner of the tube faceplate chipped (without
destroying vacuum), ( https://imgur.com/a/aJQytLP ) the front CRT shroud
broken, and the blow was also enough to shatter the rear plastic
retaining clip, leaving the metal two-piece bracket and long screw loose
in the case.

However, the unit did power up to a ... spot. Actually two spots. The
upper spot is the real, controllable spot, while the brighter lower one
is apparently due to internal CRT damage:
https://imgur.com/a/SNQydLJ

So, I'm in the market for a replacement CRT. Potentially these:

154-0633-00 (p1)
154-0633-05 (p1)

But if 602 CRT's are compatible (??) then also:

154-0562-00 (p31)
154-0562-01 (p7) ****
154-0572-00 (p31)
154-0572-01 (p7) ****
154-0727-00 (p31)

154-0634-01 (p31) -- 603

I also have 602's and 603's so they'd be of interest anyway.

Thanks for any assistance

--Toby





Re: Risetime calculator (in tekwiki)

n4buq
 

Sounds like the system had lost its calibration data; however, 2 x 3 does equal 8 for large values of 3.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Dennis Tillman W7PF" <dennis@ridesoft.com>
To: TekScopes@groups.io
Sent: Friday, January 17, 2020 10:02:17 AM
Subject: Re: [TekScopes] Risetime calculator (in tekwiki)

Hi Tim,
When I was in high school my friend and I built an analog computer with 2
pots and a meter. It multiplied two numbers together and displayed the
result on the meter.
When we showed it to my friend's sister she asked us to multiply 2x3.
The result we got was around 8 on the meter. It could have been 9 or 7. It
was hard to tell.
She was not impressed.

We looked around for something better to do with our budding career in
electronics.
There wasn't much. The only "instrument" I owned was a VTVM. That limits your
options.

Dennis Tillman W7PF


Re: What Tektronix means to me

Jim Ford
 

Honorary Tek employee; how cool is that?!Closest I ever came to that was an interview at HP in Palo Alto in 1988, just before I graduated from Case Western Reserve University with a BSEE.  I took the red-eye flight back to Cleveland just in time to give my senior project presentation!  They hired another guy who had had a summer job there.  I ended up working at the Lockheed Skunk Works in Burbank after graduation and stayed there for 5 years until I got laid off.Yep, the 7854 is on my wishlist!  I'd like one for trace averaging, among other things.  I understand it's possible to reduce the effective jitter to 0 ps under certain conditions.  Plus I already have a 7B87 and am itching to connect a 10 MHz sampling clock from my Leo Bodnar GPSDO.  Why?  Because I can, of course!OTOH, my experience with my 7904, 7S12, 7S11, S-4 sampling heads, and S-51 or S-53 trigger heads is not that great.  Those things are a real PITA to get working, as you know well.  The prospect of getting a 11800 series scope with the killer SD-24 sampling/TDR head for $1k or less is looking better and better.  I had such a setup at the 2nd Lockheed company I worked for, and I don't recall anywhere near as much difficulty with it.We shall see how things play out.  There's always the SWMBO (She Who Must Be Obeyed) factor.  The wife doesn't share my appreciation for vintage and modern test equipment ("your machines" she calls them, at least to my face!).Great chatting with you, Dennis, albeit electronically and over a fairly long distance and timescale. JimSent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: Dennis Tillman W7PF <dennis@ridesoft.com> Date: 1/16/20 12:57 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] What Tektronix means to me Hi Jim,The job offer letter from Tektronix is laminated on a plaque where it sits on my wall along side my diplomas. No. I never went to work at Tek. But in a way I got to become an honorary member of Tek. I have been embraced by everyone I meet that is a current or ExTek employee. I have been included in their private mail reflector, I have been a member of the vintageTEK Museum since before it opened when Stan Griffiths first took me over to see the empty store front that would soon be its first home. The biggest surprise was when Michael Dunn asked me to take over as moderator of TekScopes. Why me?Usually 4 times a year I am in Beaverton visiting my Tek friends. Somehow one of the most famous design engineers at Tek heard about me several years ago and quite by accident I introduced myself to him at the museum. He replied "You're Dennis Tillman!" which stunned me. He is now one of my best friends. He is so highly regarded among ex-Tek employees that I will often call him to arrange a lunch with someone at Tek that was legendary. They never refuse. I have had many fascinating lunches with the people I might have known if I had become a Tek employee. We often met for lunch in the Tek cafeteria. Tek closed the cafeteria last month so I'm not sure where we will have those lunches next.My favorite scope is the 7854. When I mentioned this to Deane Kidd at a swap meet one day he said the 7854 project manager was in the next room having a bite to eat and he introduced me to him. A few days later I asked him to autograph the cover of my 7854. He was puzzled why I would want his autograph.Asking for autographs was something I had started to do when I was at Microsoft. For each Software Developer Conference I held I asked all the speakers to autograph their section of the conference notebooks. Bill Gates and Steve Ballmer's signatures are in them as are all the Windows developers and many of the famous software developers of the mid-1980s that attended the conferences.By now that 7854 cover is so full of autographs of ex-Tek employees that I have had to switch to the other cover. When I'm all done with the covers I will give them to the 7854 Project Manager who is now a good friend of mine that I see every time I'm at a swap meet.Dennis Tillman W7PF-----Original Message-----From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jim FordSent: Thursday, January 16, 2020 6:48 AMTo: TekScopes@groups.ioSubject: Re: [TekScopes] What Tektronix means to meHey, don't keep us in suspense, Dennis!  Did you ever get to work for Tek?Jim Ford Sent from my Verizon, Samsung Galaxy smartphone-------- Original message --------From: Dennis Tillman W7PF <dennis@ridesoft.com> Date: 1/15/20  10:36 PM  (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] What Tektronix means to me Hi Harvey,Yes, there is no simple solution to things being too far away but saying "I never expect to go there" (to the Tek Museum) is not the best way to start out if your goal is to get there. You never know what you ae capable of until you try. On more than one occasion I decided to hitch hike cross country from New Jersey to LA and up to San Francisco. Along the way I stopped at the St. Louis Gateway Arch, Grand Canyon, Mt Palomar to see the telescope, and the meteor crater in Arizona. On another trip down to the Keys I stopped at the new Disney World in Orlando. I've been to Mardi Gras three times.I had an offer to join Tek in 1968 when I was starting my junior year in college. But they recommended that I get my degree first and assured me that the job would still be there when I did. Life took me in a different direction by the time I got my BS E.E. degree. For the next 20 years I regretted that mistake. Instead I moved into a beach front apartment on the New Jersey shore and, to my surprise, I became a stained glass artist and beach comer and I went back to college, this time for a BA in Fine Arts. When I first heard it was possible to build a computer (a childhood dream of mine) I changed direction again and began building my own S-100 microcomputer. There were very few people doing that so I quickly found a job working on microcomputers. Eventually I became frustrated because I didn't understand software. That became my next challenge. Once I learned microcomputer programming I thought it would be smart to broaden my computer background with some mainframe experience. When I tried to do that I found out very few head hunters even knew what a microcomputer was. They were focused on filling the thousands of jobs available in the mainframe world. So I spent the next 6 months trying to get a mainframe job with no success. Eventually I was hired by an IBM 370 based time sharing company which saw there was an opportunity linking microcomputers to mainframes. That exposed me to IBM's premier operating system: Multiple Virtual Systems (MVS) and the many different IBM operating systems and applications that worked under MVS. Three years later someone recommended me for a job with Digital Research, the creator of CP/M (which I knew well), the industry standard 8-bit OS on microcomputers. Four years later that led to a job at Microsoft which I was desperate to get because it would finally bring me to the Pacific Northwest (Tektronix territory) where I would have been 20 years earlier if I had joined Tek. After 3 years at Microsoft it became clear I had the wrong background. They had their pick of graduating students with an MS in Computer Science or an MBA. So I went back to college a third time for an MS in Software Engineering. While I was getting that degree, Microsoft went from 500 people which was small enough that I knew almost everyone too many thousands of people. I don't like big companies and there were other opportunities for me now that I had an MS S.E.If you are on the other side of the earth and looking at a very small map it may appear that Microsoft (a few miles from Seattle), and Tektronix (a few miles from Portland) are right next to each other. It is a boring 3 1/2 hour trip to get there. Sphere Research is more than twice as far. On more than one occasion I decided to hitch hike cross country from New Jersey to LA and up to San Francisco. Along the way I stopped at the St. Louis Gateway Arch, Grand Canyon, Mt Palomar (to see the telescope), and the meteor crater in Arizona. On another trip down to the Keys and Key West I stopped at the new Disney World in Orlando. I've been to Mardi Gras three times. You shouldn't say things like I never expect to get there. It sounds like you really want to go. If you can make it to Seattle you have a place to stay with us. Portland is a train ride away. Beaverton is accesable by light rail from Portland. Dennis Tillman W7PF-----Original Message-----From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Harvey WhiteSent: Wednesday, January 15, 2020 5:28 PMTo: TekScopes@groups.ioSubject: Re: [TekScopes] What Tektronix means to meI understand what you say, parallel to an extent, not congruent experiences.The Tek museum is 3000 miles from me, and I never expect to go there.Might we have something on the east coast?(and yes, I'm annoyed that Sphere's "free" days are even further fromme.)  Still would like to find a 214 vertical amplifier board because mine has a bad channel A attenuator, not that I've asked before.)HarveyOn 1/15/2020 5:15 PM, Dennis Tillman W7PF wrote:> Like everyone here I have created a problem my wife will have to deal with when I am no longer around. She has the phone number of the vintageTEK Museum on our refrigerator. Problem solved.>> Now that that's out of the way I'm not concerned with recyclers and what will come of my stuff. I plan on enjoying the afterlife with a Tek 214 portable dual-trace storage scope in my coffin. The Egyptians had the right idea. Take what you can with you when you go.>> Tektronix gives me a reason to get up every day. I can explore anything in electronics with the instruments they designed. I am the beneficiary of the legacy of Tektronix; the standard of excellence they strove for; and the support they provided for their products.>> IN 1967 I bought my first Tek scope, a 453, new for $2,000. What I learned in the next two years by using that scope every night propelled me to the top of my class. That was the best investment I ever made. Tektronix instruments were investments in my future. 10 years later I bought a 7704A / 7A26 / 7B80 / 7B85 and a pair of P6106 probes for $7,000. I went into debt to do this because I knew it would pay off for me just like my 453 had. Two years later I bought a 7D01 / DF2 / DL2 for another $4,000 to study microcomputers. I eagerly learned microcomputer assembly language to control the microcomputer hardware I was designing. The next 10 years I had a very rewarding career in microcomputers, mainframes, operating systems, and software marketing.>> Several totally unexpected things happened starting in the late 1990s that were to enrich my life yet again. EBay gave me a way to buy all of the Tektronix instruments I could never afford back in the 1970s. In 2000 Michael Dunn started TekScopes and I joined 2 years later. Suddenly I was not alone. I had a vast resource of expertise to help me fix all the Tek instruments I was buying on eBay. 10 years ago Stan Griffiths and Ed Sinclair started the vintageTEK Museum as a showcase for all the things Tektronix had made possible.  The museum is preserving the Tek legacy for the benefit of all of us. Last but not least we have our own specialized Wikipedia. TekWiki has become THE professional repository of Tektronix documents thanks to the tireless work of Kurt Rosenfeld. Working long hours alone, into the night, feeding every Tek document he can find into scanners. He has single-handedly assembled those papers, manuals, photographs, and comments into a beautiful, easy to use, library at our finger tips. TekWiki is every bit that is the rival of Wikipedia.>> I'm too busy using my collection of Tek instruments to dwell on what will happen to it someday. Because of Tektronix, eBay, TekScopes, the vintageTEK museum, and TekWiki my life is never dull when a Tektronix scope is within arm's reach.>> Dennis Tillman W7PF>>>-- Dennis Tillman W7PFTekScopes Moderator-- Dennis Tillman W7PFTekScopes Moderator


Re: 7A26 transient response 5 nS all atten

Chuck Harris <cfharris@...>
 

Hi Jon,

I am not sure what you are asking me.

The last time I calibrated my 7A26's was so long ago,
that I certainly should do it again.. I don't use them
in a way that requires close calibration.

My recollection is they simply needed a little tweak
to smarten up the leading edge, and clean up the
chomp marks from the top.

You can get some clue as to which cap does what to
the waveform by touching it with a small metal bit...
an alignment screwdriver with a metal insert is fine.

-Chuck Harris

Jean-Paul wrote:

Dear Albert and Chuck! Many thanks,

a/ Date codes of TEK ICs 413 = week 13 1984
b/ printed manuals Rev E May 1975, Rev C April 1977
c/ Bama, TekWiki, PDFs are 1972 versions.

Anyone with a link or scan of the -01 Rev SEP 1985 ?

I have 2 printed manuals (original TEK), open to an exchange if anyone has a spare of the printed late version.

to Chuck, your wisdom is appreciated re
<< calibration; page 5-7 sec 8, High Freq compensation.
...10 adjustments .order .... first 5-10 nS? >>

Bonne journée

Jon





Re: Risetime calculator (in tekwiki)

Scott Singelyn
 

Jean-Paul, very cool calculator! Is there any chance that it could be taken apart and each disk scanned? If it could, then I think we could make a paper cut-out version to play with.
Thanks for sharing.


Re: 7A26 transient response 5 nS all atten

Jean-Paul
 

Dear Albert and Chuck! Many thanks,

a/ Date codes of TEK ICs 413 = week 13 1984
b/ printed manuals Rev E May 1975, Rev C April 1977
c/ Bama, TekWiki, PDFs are 1972 versions.

Anyone with a link or scan of the -01 Rev SEP 1985 ?

I have 2 printed manuals (original TEK), open to an exchange if anyone has a spare of the printed late version.

to Chuck, your wisdom is appreciated re
<< calibration; page 5-7 sec 8, High Freq compensation.
...10 adjustments .order .... first 5-10 nS? >>

Bonne journée

Jon


Re: Risetime calculator (in tekwiki)

Chuck Harris <cfharris@...>
 

Of course it is an analog computer!

It is using the sum of three log pots to balance with a fourth
to get a result that is read on the fourth dial.

That makes it a computer.

Read some history. Early computers didn't necessarily have any
active components. Think slide rule.

-Chuck Harris

amirb wrote:

there are no opamps or any active device in this thing as far as I can tell. so no analog computer... See the picture...
only a bunch of resistors in some kind of bridge which must be balanced but why it will produce RMS beats me
On Fri, Jan 17, 2020 at 10:54 AM, Dennis Tillman W7PF wrote:


Hi Tim,
It is an ANALOG computer. These were very commonly used for many things but
that was probably before you were born.
I got my first real job in 1967 working in a huge lab at Allied Aerospace that
designed airplane autopilots and flight control systems. Until a year later
these were always analog computers. To design the airplane's analog flight


Re: MEMBERS PLEASE READ: Our annual Group.io payment is due in 2 weeks.

 

Hi Larry,
We won't be needing contributions for next year.
This time I learned what happens when I try to do something like this.
The next time I do anything like this I will be sure to eliminate the confusion in advance.
Thank you for your willingness to contribute but at this point it is not necessary.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Lawrance A. Schneider
Sent: Friday, January 17, 2020 7:04 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] MEMBERS PLEASE READ: Our annual Group.io payment is due in 2 weeks.

Next year is AN OTHER YEAR.
We will come to the same place as far as needing contributions.
Some succeeded and some did not (me).

So, what do we do next year. I very much enjoy this group! I would be happy to contribute!

HOW????

larry




--
Dennis Tillman W7PF
TekScopes Moderator


Re: Risetime calculator (in tekwiki)

Bruce Atwood
 

Just as an op-amp (with negative feedback) nulls the voltage between the
inverting and non-inverting inputs here the nulling is done with wetware
and the center zero meter.

On 1/17/2020 10:57 AM, amirb wrote:
there are no opamps or any active device in this thing as far as I can tell. so no analog computer... See the picture...
only a bunch of resistors in some kind of bridge which must be balanced but why it will produce RMS beats me
On Fri, Jan 17, 2020 at 10:54 AM, Dennis Tillman W7PF wrote:

Hi Tim,
It is an ANALOG computer. These were very commonly used for many things but
that was probably before you were born.
I got my first real job in 1967 working in a huge lab at Allied Aerospace that
designed airplane autopilots and flight control systems. Until a year later
these were always analog computers. To design the airplane's analog flight
control computer to have the right characteristics a team had to measure the
airplane's response to various (controlled) inputs such as how it responded
when commanded to make a sharp turn.

The job of the airplane's analog computer was to take that raw response which
was converted into an equation and create another equation that had the
response the customer (an airline) wanted. Presumably that would be to turn
the sharp bumpy turn into something gentle and smooth. This was all done on a
precision analog computer that had a plug board that was at least 6ft by 10ft
long. Various modules (OpAmps, inductances, capacitances, resistances, etc.)
could be easily connected together and modified until the engineers were
satisfied with the results.

The final configuration was converted back into an equation and then a
different group of engineers took those equations and using OpAmp modules,
from companies like Philbrick Research, put it all together in a small box
that ultimately became the autopilot for that plane. By the time I arrived
Allied Aerospace was using newly developed OpAmp ICs such as the uA709. I
remember when I was only on the job for a few weeks and I blew one of those
uA709s out. I was really scared that I would be chewed out. Those things cost
$50 each because they were so new. The OpAmp ICs revolutionized everything we
did. Suddenly the autopilot could be smaller and do more things.

2 years later digital ICs were beginning to be reliable enough that they could
be used in parts of the autopilot. I worked on the Concorde Autopilot that was
done with this new family of DIGITAL logic called DTL. It had a lot of details
you had to be careful about like needing pull up resistors in certain cases.
Those caused trouble for a while. The problems were solved eventually.
For a few years after that the autopilots were a mixture of analog and digital
ICs. Most of the autopilot was analog, and parts like VOTER circuits, which
decided which of the three autopilot results (everything is triple redundant
in an autopilot) is correct, were digital. This was done with analog
comparators and digital logic. If something should go bad with one of the
three autopilots the voter circuit disconnects it and relies on the other two
autopilot results.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Tim
Phillips
Sent: Thursday, January 16, 2020 11:32 PM
To: TekScopes@groups.io
Subject: [TekScopes] Risetime calculator (in tekwiki)

from Tim P (UK)
What is this, please? It seems to be a simple analog computer, maybe with Log
pots.
In case the link doesn't work, the device is in tekwiki Other Instruments.

https://urldefense.com/v3/__http://w140.com/tekwiki/wiki/Risetime_Calculator__;!!KGKeukY!jGwTq9kVenN9hphTkjChf-o92VKRzY8LCY0yndo2kwjW0iBcvbYRWHB5DdUxKH41$

Appears to give f = sqrt(a^2 + b^2 + c^2)

thanks
Tim P





--
Dennis Tillman W7PF
TekScopes Moderator

.
--
Bruce Atwood PhD
Department of Astronomy
The Ohio State University
100 West 18th Ave., Room 4055
Columbus, OH 43210

Phone 614.314.0189
FAX 614.292.2928


Re: Risetime calculator (in tekwiki)

 

Hi Tim,
When I was in high school my friend and I built an analog computer with 2 pots and a meter. It multiplied two numbers together and displayed the result on the meter.
When we showed it to my friend's sister she asked us to multiply 2x3.
The result we got was around 8 on the meter. It could have been 9 or 7. It was hard to tell.
She was not impressed.

We looked around for something better to do with our budding career in electronics.
There wasn't much. The only "instrument" I owned was a VTVM. That limits your options.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Albert Otten
Sent: Friday, January 17, 2020 1:15 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Risetime calculator (in tekwiki)

Ideally you would use pots (as variable resistors) for which the resistance increases quadratically from ccw to cw. Then compare the sum of the first 3 resistances with the 4th resistance in a bridge circuit and tune the 4th pot to zero reading. I don't think that the quadratic behavior can be approached good enough with log pots and some trimpots and extra resistors.

Albert

On Fri, Jan 17, 2020 at 08:31 AM, Tim Phillips wrote:


from Tim P (UK)
What is this, please? It seems to be a simple analog computer, maybe
with Log pots.
In case the link doesn't work, the device is in tekwiki Other Instruments.

http://w140.com/tekwiki/wiki/Risetime_Calculator

Appears to give f = sqrt(a^2 + b^2 + c^2)

thanks
Tim P




--
Dennis Tillman W7PF
TekScopes Moderator


Re: 7A26 transient response 5 nS all atten

Chuck Harris <cfharris@...>
 

No letter, but starting with a "7" means it came from Tektronix Holland, NV,
Heerenveen, The Netherlands.

The last 5 digits of all of the serial numbers are sequential. I don't know
how they relate to the revisions of the manuals, and part changes, but I think
they are coordinated so that the revision ranges apply everywhere.

-Chuck Harris

Albert Otten wrote:

Hello Jon,
My other 7A26s have this format SN, but this has no letter, 708058. I think its a late model, but see no IC date codes.
Readout PCB is 672-0051-13 Amplifier PCB is 670-2549-21 attenuators are PN200-1442-00
The Readout board is probably marked 670-2310-09. Then both board versions were introduced at B251090. You need the -01 version manual for that, Revised SEP 1985. I think the ICs have 3-digit date codes, the first indicating the year (5xx pointing to 1985). Of course the plugin itself can be newer than the ICs in it. My 713121 is from 1986.
BTW did you mean 7904 or 7104?

Albert




Re: Risetime calculator (in tekwiki)

Tony Fleming
 

Thanks for sharing! You had a great job, despite stress and push to work
24/7 .... if the management could do that.
I wish I was working in a group like you did, the learning curve and new
"thinking" was a greatest teacher!
Have a great day!

On Fri, Jan 17, 2020 at 9:54 AM Dennis Tillman W7PF <dennis@ridesoft.com>
wrote:

Hi Tim,
It is an ANALOG computer. These were very commonly used for many things
but that was probably before you were born.
I got my first real job in 1967 working in a huge lab at Allied Aerospace
that designed airplane autopilots and flight control systems. Until a year
later these were always analog computers. To design the airplane's analog
flight control computer to have the right characteristics a team had to
measure the airplane's response to various (controlled) inputs such as how
it responded when commanded to make a sharp turn.

The job of the airplane's analog computer was to take that raw response
which was converted into an equation and create another equation that had
the response the customer (an airline) wanted. Presumably that would be to
turn the sharp bumpy turn into something gentle and smooth. This was all
done on a precision analog computer that had a plug board that was at least
6ft by 10ft long. Various modules (OpAmps, inductances, capacitances,
resistances, etc.) could be easily connected together and modified until
the engineers were satisfied with the results.

The final configuration was converted back into an equation and then a
different group of engineers took those equations and using OpAmp modules,
from companies like Philbrick Research, put it all together in a small box
that ultimately became the autopilot for that plane. By the time I arrived
Allied Aerospace was using newly developed OpAmp ICs such as the uA709. I
remember when I was only on the job for a few weeks and I blew one of those
uA709s out. I was really scared that I would be chewed out. Those things
cost $50 each because they were so new. The OpAmp ICs revolutionized
everything we did. Suddenly the autopilot could be smaller and do more
things.

2 years later digital ICs were beginning to be reliable enough that they
could be used in parts of the autopilot. I worked on the Concorde Autopilot
that was done with this new family of DIGITAL logic called DTL. It had a
lot of details you had to be careful about like needing pull up resistors
in certain cases. Those caused trouble for a while. The problems were
solved eventually.
For a few years after that the autopilots were a mixture of analog and
digital ICs. Most of the autopilot was analog, and parts like VOTER
circuits, which decided which of the three autopilot results (everything is
triple redundant in an autopilot) is correct, were digital. This was done
with analog comparators and digital logic. If something should go bad with
one of the three autopilots the voter circuit disconnects it and relies on
the other two autopilot results.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Tim
Phillips
Sent: Thursday, January 16, 2020 11:32 PM
To: TekScopes@groups.io
Subject: [TekScopes] Risetime calculator (in tekwiki)

from Tim P (UK)
What is this, please? It seems to be a simple analog computer, maybe with
Log pots.
In case the link doesn't work, the device is in tekwiki Other Instruments.

http://w140.com/tekwiki/wiki/Risetime_Calculator

Appears to give f = sqrt(a^2 + b^2 + c^2)

thanks
Tim P





--
Dennis Tillman W7PF
TekScopes Moderator




Re: Risetime calculator (in tekwiki)

amirb
 

there are no opamps or any active device in this thing as far as I can tell. so no analog computer... See the picture...
only a bunch of resistors in some kind of bridge which must be balanced but why it will produce RMS beats me

On Fri, Jan 17, 2020 at 10:54 AM, Dennis Tillman W7PF wrote:


Hi Tim,
It is an ANALOG computer. These were very commonly used for many things but
that was probably before you were born.
I got my first real job in 1967 working in a huge lab at Allied Aerospace that
designed airplane autopilots and flight control systems. Until a year later
these were always analog computers. To design the airplane's analog flight
control computer to have the right characteristics a team had to measure the
airplane's response to various (controlled) inputs such as how it responded
when commanded to make a sharp turn.

The job of the airplane's analog computer was to take that raw response which
was converted into an equation and create another equation that had the
response the customer (an airline) wanted. Presumably that would be to turn
the sharp bumpy turn into something gentle and smooth. This was all done on a
precision analog computer that had a plug board that was at least 6ft by 10ft
long. Various modules (OpAmps, inductances, capacitances, resistances, etc.)
could be easily connected together and modified until the engineers were
satisfied with the results.

The final configuration was converted back into an equation and then a
different group of engineers took those equations and using OpAmp modules,
from companies like Philbrick Research, put it all together in a small box
that ultimately became the autopilot for that plane. By the time I arrived
Allied Aerospace was using newly developed OpAmp ICs such as the uA709. I
remember when I was only on the job for a few weeks and I blew one of those
uA709s out. I was really scared that I would be chewed out. Those things cost
$50 each because they were so new. The OpAmp ICs revolutionized everything we
did. Suddenly the autopilot could be smaller and do more things.

2 years later digital ICs were beginning to be reliable enough that they could
be used in parts of the autopilot. I worked on the Concorde Autopilot that was
done with this new family of DIGITAL logic called DTL. It had a lot of details
you had to be careful about like needing pull up resistors in certain cases.
Those caused trouble for a while. The problems were solved eventually.
For a few years after that the autopilots were a mixture of analog and digital
ICs. Most of the autopilot was analog, and parts like VOTER circuits, which
decided which of the three autopilot results (everything is triple redundant
in an autopilot) is correct, were digital. This was done with analog
comparators and digital logic. If something should go bad with one of the
three autopilots the voter circuit disconnects it and relies on the other two
autopilot results.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Tim
Phillips
Sent: Thursday, January 16, 2020 11:32 PM
To: TekScopes@groups.io
Subject: [TekScopes] Risetime calculator (in tekwiki)

from Tim P (UK)
What is this, please? It seems to be a simple analog computer, maybe with Log
pots.
In case the link doesn't work, the device is in tekwiki Other Instruments.

http://w140.com/tekwiki/wiki/Risetime_Calculator

Appears to give f = sqrt(a^2 + b^2 + c^2)

thanks
Tim P





--
Dennis Tillman W7PF
TekScopes Moderator


Re: MEMBERS PLEASE READ: Our annual Group.io payment is due in 2 weeks.

 

It is groups.io obfuscating email addresses as has been explained many times already.

Dennis' email is dennis at ridesoft dot com

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Lawrance A. Schneider
Sent: 17 January 2020 14:43
To: TekScopes@groups.io
Subject: Re: [TekScopes] MEMBERS PLEASE READ: Our annual Group.io payment is due in 2 weeks.

Same happens to me.
further, what it the difference between @Dennis_Tillman_W&PF and the same thing in blue??? I saw a missive saying to use the above in blue and the same thing in black. I again tried each at PayPal and got the same thing asking for an :an error saying please enter valid email, name or mobile phone m=number.
I know I'm getting old, but what is going on???????

larry


Re: Risetime calculator (in tekwiki)

 

Hi Tim,
It is an ANALOG computer. These were very commonly used for many things but that was probably before you were born.
I got my first real job in 1967 working in a huge lab at Allied Aerospace that designed airplane autopilots and flight control systems. Until a year later these were always analog computers. To design the airplane's analog flight control computer to have the right characteristics a team had to measure the airplane's response to various (controlled) inputs such as how it responded when commanded to make a sharp turn.

The job of the airplane's analog computer was to take that raw response which was converted into an equation and create another equation that had the response the customer (an airline) wanted. Presumably that would be to turn the sharp bumpy turn into something gentle and smooth. This was all done on a precision analog computer that had a plug board that was at least 6ft by 10ft long. Various modules (OpAmps, inductances, capacitances, resistances, etc.) could be easily connected together and modified until the engineers were satisfied with the results.

The final configuration was converted back into an equation and then a different group of engineers took those equations and using OpAmp modules, from companies like Philbrick Research, put it all together in a small box that ultimately became the autopilot for that plane. By the time I arrived Allied Aerospace was using newly developed OpAmp ICs such as the uA709. I remember when I was only on the job for a few weeks and I blew one of those uA709s out. I was really scared that I would be chewed out. Those things cost $50 each because they were so new. The OpAmp ICs revolutionized everything we did. Suddenly the autopilot could be smaller and do more things.

2 years later digital ICs were beginning to be reliable enough that they could be used in parts of the autopilot. I worked on the Concorde Autopilot that was done with this new family of DIGITAL logic called DTL. It had a lot of details you had to be careful about like needing pull up resistors in certain cases. Those caused trouble for a while. The problems were solved eventually.
For a few years after that the autopilots were a mixture of analog and digital ICs. Most of the autopilot was analog, and parts like VOTER circuits, which decided which of the three autopilot results (everything is triple redundant in an autopilot) is correct, were digital. This was done with analog comparators and digital logic. If something should go bad with one of the three autopilots the voter circuit disconnects it and relies on the other two autopilot results.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Tim Phillips
Sent: Thursday, January 16, 2020 11:32 PM
To: TekScopes@groups.io
Subject: [TekScopes] Risetime calculator (in tekwiki)

from Tim P (UK)
What is this, please? It seems to be a simple analog computer, maybe with Log pots.
In case the link doesn't work, the device is in tekwiki Other Instruments.

http://w140.com/tekwiki/wiki/Risetime_Calculator

Appears to give f = sqrt(a^2 + b^2 + c^2)

thanks
Tim P





--
Dennis Tillman W7PF
TekScopes Moderator


Re: 2445 EPROMs

Chuck Harris <cfharris@...>
 

Back in those days I was always and Intel guy.

Customers forced me to learn Motorola 6800 and 68000, but
it wasn't a labor of love, so I have forgotten almost
everything I ever knew about them.

And my data books for them are ...somewhere...

Thanks Mark!

Mark Litwack wrote:

Hi Chuck and Chris,

The external clock input on the 6802 is divided internally by four to create an internal two-phase clock (one phase is output as signal "E"). So, with a 5MHz input, the cycle time is actually 800ns, which well within range of the Intel D27128 with 250ns access time I mentioned before.

There is also the NOP exerciser which can be enabled with jumper P503. This is good for getting to the bottom of possible processor and/or bus buffer issues by looking at E, address lines, and other signals as the processor is looping. Its operation is described in the service manual.

I do recall one instance of a bad processor, but granted, they are rare.

-mark



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