Re: 7904A checkout + calibration
Hey Chris,
??? What you need will vary greatly based on the plugins you need calibrated. I have not done a 7904A mine did not need adjustment but I have done 7603's and 7704A's to do one "right / by the book" it is a pretty involved process at a minimum you have 3 calibration documents you have to work through, The frame then vert amp then time base. Also depends on the vert plugins you needs calibrated. 1 plugin or both or more. For the most part the signals needed are pretty modest up until you do the high frequency calibration of the vertical amps. Anything over 200 Mhz the sources can get a little exotic. Tunnel diode pulses. So the limits of my bench at this point are 500Mhz I cant do a 7104. Before I did my own I got one quoted from Tek If I remember correctly they will still do a factory calibration on a 7K frame but I think the 7704A was $1,100 for the calibration. It inspired me to do my own.
Eric
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On 6/1/2020 11:14 AM, Chris Wilkson via groups.io wrote: All of this 7904(A) talk has inspired me to get my 7904A (SNB011071) checked out and calibrated.
But I don't have the equipment to do it. Does anyone here do scope calibrations for hire within say 200 miles of Detroit?
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Re: 7904a raised name badge?
As someone who feels style is important as well as function, I have wondered why Tektronix never (to my knowledge) used any sort of medallion on their equipment beyond a silk screened trademark. For what the instruments co$t, something three dimensional like an RCA or General electric "meatball" or the old Collins emblem would have been very appropriate. Fluke, DuMont, Fairchild, and in many cases, Hewlett Packard embellished their work with medallions or plaques.
Bruce Gentry, KA2IVY "Do Everything with Style" - Kurt Hummel on the TV show "Glee".
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On 6/1/20 10:56 AM, Chris Wilkson via groups.io wrote: There is a 7904a mainframe, SN B010951, on ebay here:
It has a raised Tek badge that I've never seen. Is that a factory installed badge, or something aftermarket?
My 7904A (#B011071) doesn't have it and none of the other 7000 scopes that I have seen has it.
For posterity, I uploaded some photos in the "7904A raised Tektronix badge" album.
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Re: In Defense of the 7A19
On Mon, Jun 1, 2020 at 05:31 PM, Dennis Tillman W7pF wrote:
Why doesn't someone try this on an early serial number 7B70 time base using a
swept signal up to 200MHz and see how it does.
I just tried 7B70 s/n B060762 and 7B71 s/n B050779 and a 7B71 without visible s/n in a 7904 at 10 MHz 50 MHz and 1 and 2 div. deflection. In some positions, these modules tend to do double triggering, i.e. trigger on both rising and falling edges, as if no correct arming and triggering. Not much different wether in PP Auto, Auto or Normal position. I didn't systematically try other signal frequencies but trigger holds well when varying the frequency over a plus and minus 30% range and I didn't check the trigger calibration of the time bases. Certainly not as clean and solid as I'm used to with other time bases. BTW, the mechanism of arming level *and* trigger level allows a time base to determine whether it triggers on a rising or a falling edge. So, a bit more complicated than just "waiting for a level". Raymond
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Re: In Defense of the 7A19
Well, if you can get a schematic for the HP ‘scope, you might be able to figure out why the HP trigger circuit works differently than a Tektronix trigger circuit by comparing them. Perhaps Dennis can tell us the model number of the HP ‘scope that was used in the demo.
I, too, need to re-read the Tektronix books now that I am retired.
DaveD
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On Jun 1, 2020, at 11:55, Michael W. Lynch via groups.io <mlynch003@...> wrote:
Dave,
I am going to re-read this once again, if only to clarify how the TEK Trigger Circuit operated.
I was mainly concerned with how HP did it versus TEK. Obviously a "TEK Concepts" document will not go into how HP out performed the TEK Circuit.
As Dennis has suggested, It is quite possible that HP tuned their circuit to work really well in a situation where the TEK scope performed much less accurately.
There is a good chance that we may never know the answer to this.
Thanks!
--
Michael Lynch
Dardanelle, Arkansas
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Re: 2215A repair and restoration [Solved]
Sorry, I modified the title, and now it became a new thread, my bad, will try to remember not to do this again.... Pictures of the repair are here: /g/TekScopes/album?id=242324Un saludo, Leo
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Re: 2215A repair and restoration [Solved]
Hi all,
Today, finally, thanks to the slowest delivery ever!! in the history of the Spanish postal service, the CA3127E 's arrived :-)
Ordered 4th of March ( this year) delivery today June 1st, but.....
Drumroll.... NOS, slightly dirty pins, probably due to age, but they work!
I put the chip in a low profile 16 pin socket, that, with a piece of sellotape I attached to a long piece of shrinking tube.
With that I was able to move the chip-socket combo into the board's holes, underneath the attenuators, without the need of removing all of the input attenuators.
Long story short: the 2215A is back in business :-)
I am a happy bunny!
Will add pictures to the album.
Un saludo,
Leo
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Re: Nice Document Site with Tek manuals; New to me
I guess I missed the email about the manual site being discussed.? Would some one, please, repeat the address of the site.
David
KW4DH
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On 5/31/2020 3:25 PM, Dennis Tillman W7pF wrote: From:[email protected] [mailto:[email protected]] On Behalf Of tgerbic
Sent: Saturday, May 30, 2020 6:35 PM
To:[email protected]
Subject: Re: [TekScopes] Nice Document Site with Tek manuals; New to me
I am not sure if I am happy or disappointed about this site. I did a spot check on the HP manuals ( I have a comprehensive list of over 100 I scanned and uploaded) and found that every one I checked are scans I did for the hparchive.com. The differences are that they have the acknowledgements removed, some front/back covers removed, and in some cases a little cosmetic work. Some have the color in the text removed. A good example is the HP 1704B Service or the 130B/BR.
I guess the upside is that the scans are being used, so they have some value.
I have been scouring the web for 20 years looking for Tek, HP, Heathkit, and many other manuals and I cannot remember seeing this exact site with this navigation/color. It looks a bit like another that had similar content. It might have been there with a different web layout. Have to look back at my saved links.
Interesting comment on full-sheet scans. I will often do full sheet if it will fit on my scanner (scans up to 11.7 x 16.5), or will do overlaping 16.5 scans if over that. Most people cannot print these out and they are a bit small on most monitors so I have gotten feedback to break these up.
I provided the 410C alternative 1 and 2 manuals on the hparchive which are very clear but I did break up the schematics to make them large and legible. Are they unusable like that?
/Tony
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Re: In Defense of the 7A19
Dave,
I am going to re-read this once again, if only to clarify how the TEK Trigger Circuit operated.
I was mainly concerned with how HP did it versus TEK. Obviously a "TEK Concepts" document will not go into how HP out performed the TEK Circuit.
As Dennis has suggested, It is quite possible that HP tuned their circuit to work really well in a situation where the TEK scope performed much less accurately.
There is a good chance that we may never know the answer to this.
Thanks!
--
Michael Lynch
Dardanelle, Arkansas
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Re: TLA711 Benchtop controller schematic needed
Good Day Jim,
no intentions to discourage you, but I‘d be seriously surprised if you can get access to component level schematics for your TLA.
I had tried the same for my TLA715 unit three years ago, and my search has?not yielded to?anything.?Tektronix seems?very keen to keep the?schematic non-public. Even the smart team from xdevs failed the same with their TLA714, see? so my conclusion is that the schematics for Tektronix Logic Analyzers from that era are unobtainium.
Cheers,
Magnus?
Hi, everybody.
I'm looking for a schematic for the Benchtop Controller module that goes
in the TLA711 logic analyzer mainframe.? The Benchtop Controller says
"039-0039-03" on it, and I have the service manual for it, 070-9778-03,
but it doesn't contain schematics for the boards.? opweb.de didn't have
it, nor did BAMA.? Anybody have one of these?? I'd pay for one; <$100,
else I'll just get a TLA704 on ePray.
Thanks.
Jim Ford
Laguna Hills, California
U.S.A.
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------ Original Message ------ From: "Dennis Tillman W7pF" <dennis@...> To: [email protected]Sent: 5/30/2020 5:03:19 PM Subject: [TekScopes] Nice Document Site with Tek manuals; New to me I just discovered a new (to me) source for documentation and I am scratching
my head wondering why it took me so long to stumble across it since he says
his archive has been available since 2007 and it contains over
11,000manuals.
At first glance it appears to have as much as The Boat Anchor Archive.
I haven't had a chance to explore what it offers us but there are 637
documents / manuals / etc listed for Tektronix.
It has a very nice, clean web interface.
The Tek documents start at
The home page is at
The owner is:
Oliver Poggensee
Zeppelinplatz 1
25335 Elmshorn
Germany
This is what Oliver says on the site's home page:
I am happy to welcome you on my site. This download archive has been
available since 2007. Starting with a few hundred manuals, there are now
well over 11,000, and new ones are added every month. I have designed these
pages to help all people who own and use old electronic devices. So that
they can be maintained, serviced and repaired more easily, quickly and
professionally. No matter if it is a radio, a television or a measuring
device. The main focus of these pages is on older devices, but you can also
find some technical documentation for newer devices here. With my own search
for good download possibilities I often found fake pages, where you can't
download the manual you are looking for, or dubious dealers selling the
manuals that are actually freely available, I want to counter this with my
site. I hope that you will use this offer actively and that it is useful for
you. All manuals here are completely free and can be downloaded directly
without any restrictions.
Do you have any manuals or images of your device, please upload it here and
share it with others .
I have taken the effort to collect all information available about the
respective manuals. There is for example a preview of the first page, the
page number, date of publication and many other information.
I don't want to compete with professional schematic services, most manuals
are of medium to low quality, not comparable to the high resolution scans of
professional service providers. All manuals have been provided by users from
various sources. I have attempted not to publish material from professional
service providers here, but if there is material from a professional service
here, I will delete it as soon as possible. For this purpose a short message
is sufficient.
Dennis Tillman W7pF
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Re: In Defense of the 7A19
I do not know how HP was able to make a better trigger circuit. It may have been that Tek was lazy and didn't think they had to make a better trigger circuit.
It may have something to do with triggering at the higher frequencies which is always harder because stray coupling, tiny capacitances start to look like shorts, semiconductors start to run out of bandwidth, lead inductance, etc .
I think the trigger circuit they used was the creation of an HP engineer who was highly regarded by Tek as an exceptional circuit designer.
Maybe it was because the Tek trigger circuit had to use the combined slope/trigger level knob that could turn through 360 degrees that Howard Vollum wanted.
Maybe HP tweaked their trigger circuit so it could always trigger with the demonstration they came up with of the swept oscillator.
The bottom line was Tek's triggering did poorly on the same test at the show.
Why doesn't someone try this on an early serial number 7B70 time base using a swept signal up to 200MHz and see how it does.
Dennis Tillman W7pF
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Michael W. Lynch via groups.io Sent: Monday, June 01, 2020 8:06 AM To: [email protected]Subject: Re: [TekScopes] In Defense of the 7A19 Ernesto wrote: Hi Dennis,
What was in HP scope's triggering that made it far superior to TEKTRONIX? Dennis, I would like to learn more about this subject, if Dennis (or anyone else) cares to expand and such an explanation would not require a thesis length document. I have a basic understanding what triggering is and how I use it, but that is the extent of it. I am like Ernesto, I assumed this was a simple process, set the level and the slope and it just happened. From what I understand through Dennis' comment, there is a lot more to the process than meets the eye. Are ALL HP scopes superior in their trigger performance? Is it possible to somehow refine or tune the existing TEK Trigger circuits for significant performance gains. Thanks! -- Michael Lynch Dardanelle, Arkansas -- Dennis Tillman W7pF TekScopes Moderator
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Re: In Defense of the 7A19
Thanks,
Barry - N4BUQ
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----- Original Message ----- From: "Dave Daniel" <kc0wjn@...>
To: [email protected]
Sent: Monday, June 1, 2020 10:20:56 AM
Subject: Re: [TekScopes] In Defense of the 7A19
One of the Tektronix “Concepts” books is “Oscilloscope Trigger Circuits” by
Harold Magee. If you want to learn more about triggering, that book would be
a good resource.
DaveD
On Jun 1, 2020, at 11:06, Michael W. Lynch via groups.io
<mlynch003@...> wrote:
Ernesto wrote: Hi Dennis,
What was in HP scope's triggering that made it far superior to TEKTRONIX? Dennis,
I would like to learn more about this subject, if Dennis (or anyone else)
cares to expand and such an explanation would not require a thesis length
document. I have a basic understanding what triggering is and how I use
it, but that is the extent of it. I am like Ernesto, I assumed this was a
simple process, set the level and the slope and it just happened. From
what I understand through Dennis' comment, there is a lot more to the
process than meets the eye. Are ALL HP scopes superior in their trigger
performance? Is it possible to somehow refine or tune the existing TEK
Trigger circuits for significant performance gains.
Thanks!
--
Michael Lynch
Dardanelle, Arkansas
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Re: In Defense of the 7A19
One of the Tektronix “Concepts” books is “Oscilloscope Trigger Circuits” by Harold Magee. If you want to learn more about triggering, that book would be a good resource.
DaveD
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On Jun 1, 2020, at 11:06, Michael W. Lynch via groups.io <mlynch003@...> wrote: Ernesto wrote: Hi Dennis,
What was in HP scope's triggering that made it far superior to TEKTRONIX? Dennis,
I would like to learn more about this subject, if Dennis (or anyone else) cares to expand and such an explanation would not require a thesis length document. I have a basic understanding what triggering is and how I use it, but that is the extent of it. I am like Ernesto, I assumed this was a simple process, set the level and the slope and it just happened. From what I understand through Dennis' comment, there is a lot more to the process than meets the eye. Are ALL HP scopes superior in their trigger performance? Is it possible to somehow refine or tune the existing TEK Trigger circuits for significant performance gains.
Thanks!
--
Michael Lynch
Dardanelle, Arkansas
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Re: Digital Oscilloscopes: When Things Go Wrong
On Mon, Jun 1, 2020 at 05:35 AM, Carl Moon wrote:
But, that sampling process brings a few issues
Hi Carl: From the conclusion of the article: "Remember that the rewards of using a digital oscilloscope greatly outweigh these annoyances..." Best regards and wishes Roy
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Re: 7904a raised name badge?
Thanks for adding the link, Raymond!
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7904A checkout + calibration
All of this 7904(A) talk has inspired me to get my 7904A (SNB011071) checked out and calibrated.
But I don't have the equipment to do it. Does anyone here do scope calibrations for hire within say 200 miles of Detroit?
|
Re: 7904a raised name badge?
On Mon, Jun 1, 2020 at 04:56 PM, Chris Wilkson wrote:
For posterity, I uploaded some photos in the "7904A raised Tektronix badge"
album.
Link: /g/TekScopes/album?id=247921Raymond
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Re: In Defense of the 7A19
Ernesto wrote: Hi Dennis,
What was in HP scope's triggering that made it far superior to TEKTRONIX? Dennis, I would like to learn more about this subject, if Dennis (or anyone else) cares to expand and such an explanation would not require a thesis length document. I have a basic understanding what triggering is and how I use it, but that is the extent of it. I am like Ernesto, I assumed this was a simple process, set the level and the slope and it just happened. From what I understand through Dennis' comment, there is a lot more to the process than meets the eye. Are ALL HP scopes superior in their trigger performance? Is it possible to somehow refine or tune the existing TEK Trigger circuits for significant performance gains. Thanks! -- Michael Lynch Dardanelle, Arkansas
|
There is a 7904a mainframe, SN B010951, on ebay here:
It has a raised Tek badge that I've never seen. Is that a factory installed badge, or something aftermarket?
My 7904A (#B011071) doesn't have it and none of the other 7000 scopes that I have seen has it.
For posterity, I uploaded some photos in the "7904A raised Tektronix badge" album.
|
Re: 184 Time-Mark Generator lamp
Hi Sean, I had the same Problem, but it is easy to fix. You can take the plugable power lamp apart and you will find a small bulb inside. Just remove it and solder in a replacement bulb. I had one in my parts bin (I think it was 7volts at About 20 mA, but not sure) which fit nicely. If you cannot find a replcement bulb, just use an LED instead (with limiting resistor, of Course) which fits nicely within the lamp plug housing. Gesendet von Mail<> für Windows 10 Von: [email protected]<mailto: [email protected]> Gesendet: Freitag, 29. Mai 2020 00:19 An: [email protected]<mailto: [email protected]> Betreff: [TekScopes] 184 Time-Mark Generator lamp Hi all, I recently acquired a rather nice shape 184 for the princely sum of $70. After some good burn in and exercising the controls following by a few adjustments, it ticks along perfectly except for the HF oscillator (but that's beyond the scope of this topic) and the green power lamp (above the oven lamp, which is working), which is burned out. I was surprised to find the bulb is one assembly that plugs into the socket. I assume these are probably unobtainium, but would be interested in being contacted off list if someone has one they are willing to part with. Thanks! Sean
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Digital Oscilloscopes: When Things Go Wrong
DSOs (digital oscilloscopes) offer a great many advantages over their analog equivalents but as they say, “There’s no such thing as a free lunch.” Digital scopes sample, digitize, and store waveforms and let you for measure, analyze, and archive signals. But, that sampling process brings a few issues along as “baggage.
Here is a few of them and how to handle them
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Raymond Domp Frank
satbeginner
Michael W. Lynch