Re: using scope channel 1 and channel 2 invert and add functions vs floating DUT
Harvey, thanks for your example. I do somewhat the same with a voltmeter in respect to measuring voltage drop/gain rather than doing the math, I can get higher resolution too since the decimal moves over.
Your high voltage idea in respect to exceeding limits; would it be possible to use the 2 channels to measure a floating high voltage that exceeds the single channel to scope chassis limit of say, 500V peak? Given a 1M channel impedance, do I end up with a 2M impedance? Could this be a method to cut scope loading on the DUT in half?
And yes, this is an academic question, the examples help me to understand the testing possibilities with my scope.
NielsenTelecom
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Re: vintageTEK Museum Microfiche FINANCIAL help
Thanks... I just finally had a chance to go to the VintageTek home page and
it says the goal has already been reached. So, I'm trying to ascertain
whether a donation is still necessary?
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On Fri, May 18, 2018 at 2:16 PM, Adrian <Adrian@...> wrote: I just donated - The easy way is go to Vintagetek home page and follow the
link to the YouCaring donations page. Takes any credit/debit card but not
PayPal as far as I could see..
On 5/18/2018 7:02 PM, David Berlind wrote:
I would like to donate $25. How do I do that?
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SOLD OUT Tektronix Stuff for Sale
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Re: using scope channel 1 and channel 2 invert and add functions vs floating DUT
Jeff, thanks for the example. A question, I believe I've seen with this type amp, push-pull IIRC, where there is a common 'center' rail, where that voltage is 0, and there is a negative voltage for the lower waveform, and positive for the upper waveform, could you attach both probe's ground to that center rail and get the same waveform when displaying both channels? Assuming there is no potential between that rail and scope chassis.
Also, I'm not really thinking in terms of elevated voltages, perhaps I should be so not to limit the discussion either.
NielsenTelecom
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Re: WTB - Front Cover For 485 Portable Scope
I have a cover for my recently purchased 2213A- I tried not to reveal my delight to the seller :-)
Anyone know what other scopes it would fit? Measures about 13x5.25 inches.
Not sure I'd want to part with it, but I'd rather have a working scope! (I have two scopes that need repair- 465 and 464.)
Now if I could just get someone to visit Southern Indiana and fix my scopes...
Keith Ostertag
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Re: Test devices to check out new scopes??
Thanks to all who responded to my question.
Yes, I had in mind the waveform generator and not the LOGO generator.
Reasonable cost is in my mind is less than $100.
They are now hard to find the originals.
I used to attend the Tek sales demos where each person had a scope to play with and
they gave you a board that you could have to take home with you.
This was many years ago :-)
Again thanks to all who responded.
Marvin
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Re: 7a26 C130 (input compensation)
I'm using a pg506 and adjusting the trimmer right next to C134 the schematic has a pretty clear picture.
Albert Otten
3:53 am #148118
In theory with a 10X probe the sensitivity of the front corner amplification is nearly doubled compared to using a normalizer. So don't expect to see more effect with a normalizer.
Are you sure you use a not too slow (rise, fall) square wave generator?
Are you sure you adjust the correct trimmer? It's a thin tube trimmer with a long shiny center screw.
I am "trying" to calibrate my 7a26. Per table 5-2 on page 5-6 the instructions
tells me to adjust C130 for a square corner. Turning C130 on both channel one
or channel 2 have zero effect on the front corner, or any effect I can see at
all. I'm assuming this is a PEBSAC issue (problem exists between scope and
chair). I have no normalizer. I have ordered a 22pf and a 20pf but they wont
be here until Tuesday-Wednesday so I am using a 10X probe. Any tips on what
I'm doing wrong?
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Re: 7a26 C130 (input compensation)
In theory with a 10X probe the sensitivity of the front corner amplification is nearly doubled compared to using a normalizer. So don't expect to see more effect with a normalizer.
Are you sure you use a not too slow (rise, fall) square wave generator?
Are you sure you adjust the correct trimmer? It's a thin tube trimmer with a long shiny center screw.
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On Sat, May 19, 2018 at 12:07 pm, lop pol wrote:
I am "trying" to calibrate my 7a26. Per table 5-2 on page 5-6 the instructions
tells me to adjust C130 for a square corner. Turning C130 on both channel one
or channel 2 have zero effect on the front corner, or any effect I can see at
all. I'm assuming this is a PEBSAC issue (problem exists between scope and
chair). I have no normalizer. I have ordered a 22pf and a 20pf but they wont
be here until Tuesday-Wednesday so I am using a 10X probe. Any tips on what
I'm doing wrong?
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Re: Special Tek resistor needed
Send me a picture, Morris-if you can. Just need something to roughly ID them. I have a box of old 535/545 bits and pieces I nearly tossed recently but conscience got the better of me (fortunately)- although no telling it might not next time I'm looking to get a bit more space......
DaveB, NZ
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Morris Odell Sent: Sunday, May 20, 2018 16:22 To: [email protected]Subject: [TekScopes] Special Tek resistor needed Hi all, I am in need of the two ¡°Graham Cracker¡± resistors for the vertical amplifier of a 535A. They are 1.3K with two taps. If anyone has a couple of spares or a 535A carcass that can be a donor, I¡¯d very grateful if you could find me a couple. All costs reimbursed of course. Thanks, Morris Odell in Melbourne, Australia --- This email has been checked for viruses by AVG.
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Special Tek resistor needed
Hi all,
I am in need of the two ¡°Graham Cracker¡± resistors for the vertical amplifier of a 535A. They are 1.3K with two taps. If anyone has a couple of spares or a 535A carcass that can be a donor, I¡¯d very grateful if you could find me a couple. All costs reimbursed of course.
Thanks,
Morris Odell in Melbourne, Australia
---
This email has been checked for viruses by AVG.
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Re: Test devices to check out new scopes??
On 5/19/18 11:10 AM, Siggi wrote: On Sat, 19 May 2018 at 11:42 Marvin Moss <mmoss@...> wrote:
Hey Marvin,
here's <> a QuickStart 8 board, which
was used to demo the TDS5/6/700 series initially. It has several
interesting signals to look at, including a fast rise clock (with
significant jitter, though I don't know whether that's intentional), etc.
See this link <
>
for a manual. The price seems fairly outrageous though. In 2015 someone
sold a batch of those and I got mine at $40 as I recall. I have one of those as well, but I think I paid more than $40, but much less than the outrageous price.? The QAM is interesting on an analog scope; I don't recall trying it on a digital scope.? My 2440 claims the fast rise is less than a nanosecond, but I don't have anything faster (except perhaps a counter). I also have the board that's intended for the Tek 2440 and similar digital scopes.? It has a signal that requires Peak Detect to see properly. I also have a third board from another scope company (Rigol?? It's not marked.).? Its identifying feature is an off-center weight on a motor, making a vibrator.? IIRC there's a microphone on board.? One 16-position rotarty switch selects the function.? It's a "Solutions 3 Oscilloscope Demo Board". Of the three, I think I paid the most for the third one, but each was under $100.
Here's another demo board <>, though
this one is more recent.
Siggi
-- Jeff Woolsey {{woolsey,jlw}@jlw,first.last@{gmail,jlw}}.com Nature abhors straight antennas, clean lenses, and empty storage. "Delete! Delete! OK!" -Dr. Bronner on disk space management Card-sorting, Joel. -Crow on solitaire
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Re: Test devices to check out new scopes??
Try searching the group files and past messages for the test circuits.? There should be at least two schematics available, because I built one of them, and almost built the other.? I think the one I built had about 8 fixed outputs that highlighted various features of the scope, from simple waveforms to a really bizarre one that I think was meant to show you how to isolate small sections of a complex signal.? Now I'm wondering where it is... (That seems to be a common trend!? I have a box of about 50 chucking reamers in my garage somewhere, but after a few weeks of searching, I still haven't found them) Of course, as Dennis points out, they were made for specific scopes, so YMMV. -Dave From: Marvin Moss <mmoss@...> To: [email protected] Sent: Saturday, May 19, 2018 8:43 AM Subject: [TekScopes] Test devices to check out new scopes?? Tek used to supply little PCB's with various circuits to test out and let you try out new scopes. They had triggering experiments and other waveform generators to give you some experiencce with new scopes. My question is:? Does anyone have any of these that they would be willing to part with for a reasonable cost so I could get one to have for my Tek scopes?? Thanks, Marvin
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7a26 C130 (input compensation)
I am "trying" to calibrate my 7a26. Per table 5-2 on page 5-6 the instructions tells me to adjust C130 for a square corner. Turning C130 on both channel one or channel 2 have zero effect on the front corner, or any effect I can see at all. I'm assuming this is a PEBSAC issue (problem exists between scope and chair). I have no normalizer. I have ordered a 22pf and a 20pf but they wont be here until Tuesday-Wednesday so I am using a 10X probe. Any tips on what I'm doing wrong?
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Re: Test devices to check out new scopes??
On Sat, 19 May 2018 at 11:42 Marvin Moss <mmoss@...> wrote: Tek used to supply little PCB's with various circuits to test out and let
you try out new scopes.
They had triggering experiments and other waveform generators to give you
some experiencce with new scopes.
My question is: Does anyone have any of these that they would be willing
to part with for a reasonable cost so
I could get one to have for my Tek scopes? Thanks, Marvin
Hey Marvin, here's <> a QuickStart 8 board, which was used to demo the TDS5/6/700 series initially. It has several interesting signals to look at, including a fast rise clock (with significant jitter, though I don't know whether that's intentional), etc. See this link < > for a manual. The price seems fairly outrageous though. In 2015 someone sold a batch of those and I got mine at $40 as I recall. Here's another demo board <>, though this one is more recent. Siggi
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OT need to ID plastic used in some wafer switches
I sent this message to the hpagilent group, but figured to post here too, since traffic is likely declining rapidly at the old yahoo groups.
I have a number of wafer switches from old HP and other gear, that include what I think are polysulfone material. These were used in high impedance sections, so special and different from the usual phenolic types.
The particular wafers and their rotors are clear plastic, molded (rather than punched like with phenolic), about twice the thickness of the usual types.
I know that polysulfones were used for high-Z circuit boards, and insulators in microwave/RF stuff, for low leakage and dielectric loss, etc. I believe these switch parts are the same stuff, for the same reasons. Also, being a fairly high temperature performance plastic, it makes sense for soldering the contact lugs.
Does anyone know for sure what these are made from?
Secondly, does anyone know how well polysulfone may work in terms of insulation resistance? Teflon is usually the go-to for super high resistance insulation, but not that strong for say, a switch wafer. I'd like to try some of these simple switch parts in electrometer work in place of the usual, more complicated teflon-based assemblies. Also, any idea of material compatibility, say, with an applied silicone coating to increase surface resistivity?
Ed
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Re: Test devices to check out new scopes??
Renee,
That is not one of these test boards Marvin is looking for.
That is something new that the head of the museum designed. I believe it uses an Arduino to generate the Tek logo.
Dennis Tillman W7PF
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-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of ¸é±ð²Ô¨¦±ð
Sent: Saturday, May 19, 2018 9:14 AM
To: [email protected]
Subject: Re: [TekScopes] Test devices to check out new scopes??
Hi Marvin-
evil bay has one for about $30, says Tektronix
not sure but the tek museum may have possibilities hiding in microfiche
¸é±ð²Ô¨¦±ð, K6FSB
On 2018-05-19 08:56 AM, Dennis Tillman W7PF wrote:
Hi Marvin,
Over the years Tek made several of these marketing demonstration boards. I have seen at least 4 or 5. There are probably many more. Each was
specifically designed to demonstrate some feature or features of the
"newest" line of scopes at the time, or to show how much better the Tek
scope was compared to the competition.
So the first thing you need to do is identify what scope, or scope
product line, you have. Then you need to hope Tek made one of these demo
boards for your scope. You need to find someone who has one of these that
they are willing to part with. One more thing you need to specify is what
your idea of "reasonable cost" is. That may be the stickiest problem in
locating one of these.
Dennis Tillman W7PF
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
Marvin Moss
Sent: Saturday, May 19, 2018 4:44 AM
To: [email protected]
Subject: [TekScopes] Test devices to check out new scopes??
Tek used to supply little PCB's with various circuits to test out and
let you try out new scopes.
They had triggering experiments and other waveform generators to give
you some experiencce with new scopes.
My question is: Does anyone have any of these that they would be
willing to part with for a reasonable cost so I could get one to have
for my Tek scopes? Thanks, Marvin
-- Dennis Tillman W7PF TekScopes Moderator
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Re: Test devices to check out new scopes??
Hi Dennis, The PCB would have to be pried from my Cold, Dead Hand. They are also a work of Art. Ironically, most of my scopes cannot show what the Demo PCB puts out ! Have seen some on EBAY. Surprisingly the unit is "easy" to make with the modern parts they use. Maybe Tek still has them, even for sale , though I got mine for free during one of their scope-sale pushes. They may make the schematic available. Did not know they made different models. Jon B..,
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Re: Strange Tek part Numbers in an AM503B. Can anyone identify them
3) Finally I have what looks to be a specialized microprocessor (wild ass
guess). This would be an IMP (International Microelectronic Products)
I10412-01. It is a 28 pin SOIC. They are no longer in business as near as I
can tell. That isn't a Tek part. It is not a company I ever heard of. There
is virtually no reference to it anywhere on the internet except it might be
called a "daculator" (that is not a misprint as far as I know) and it might
be related to a Tek 156-6224-00. All Microprocessor, TTL, special function,
etc, etc chips start with 156-xxxx-yy but my Tek IC parts catalog stops
around 156-3000-yy so I have no information on it. Hi Dennis, Those daculators are in all of the later TDS500 TDS600, and all of the TDS700 scopes. 3 per unit. Pictures: Google for the TDS520B service manual with the schematics and you'll see how they're used. It's a DAC with 16 analog outputs. Schematic is on page 275. Do a text search for the word daculator in the manual for some theory.
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Re: Test devices to check out new scopes??
Hi Marvin-
evil bay has one for about $30, says Tektronix
not sure but the tek museum may have possibilities hiding in microfiche
¸é±ð²Ô¨¦±ð, K6FSB
toggle quoted message
Show quoted text
On 2018-05-19 08:56 AM, Dennis Tillman W7PF wrote: Hi Marvin,
Over the years Tek made several of these marketing demonstration boards. I have seen at least 4 or 5. There are probably many more. Each was specifically designed to demonstrate some feature or features of the "newest" line of scopes at the time, or to show how much better the Tek scope was compared to the competition.
So the first thing you need to do is identify what scope, or scope product line, you have. Then you need to hope Tek made one of these demo boards for your scope. You need to find someone who has one of these that they are willing to part with. One more thing you need to specify is what your idea of "reasonable cost" is. That may be the stickiest problem in locating one of these.
Dennis Tillman W7PF
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Marvin
Moss
Sent: Saturday, May 19, 2018 4:44 AM
To: [email protected]
Subject: [TekScopes] Test devices to check out new scopes??
Tek used to supply little PCB's with various circuits to test out and let
you try out new scopes.
They had triggering experiments and other waveform generators to give you
some experiencce with new scopes.
My question is: Does anyone have any of these that they would be willing
to part with for a reasonable cost so I could get one to have for my Tek
scopes? Thanks, Marvin
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Re: WTB - Front Cover For 485 Portable Scope
Sadly, I've been looking for a cover for a 454A myself for a while now with
zero success. It seems clear that there are many, many more 'scopes out
there than front covers that fit them. I have, however noticed that people
selling "just" the front covers on auction sites often list them by
physical dimensions (in inches) rather than specific model number. Hope
this helps.
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On Fri, May 18, 2018 at 5:41 PM, Mike Harmon <mharmon@...> wrote: Does anyone have a front cover for a 485 portable scope that's surplus to
your needs?
Thanks!
Mike Harmon, WB0LDJ
mharmon at att dot net
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Marvin Moss
Jon Batters