Re: vintageTEK Museum Microfiche FINANCIAL help
Is the website down at the moment? Cannot access at all.
Geoff.
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On 18/05/2018 20:04, Adrian wrote: Yup, that's how to do a general donation. Right below that toolbar is the headline:
*/Help the vintageTEK museum acquire a microfiche scanner.
/*
*/See our Microfiche Scanner Fundraiser blog <> for more information!/*
Following that link takes you to the fundraising page for the scanner on Youcaring.
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Re: vintageTEK Museum Microfiche FINANCIAL help
Count me in. I've donated $100 because the museum needs to be supported. I'd recommend setting up a fundraising page for Tekscopes too.
Rick Bale
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Re: Questions on impedance matching
This
might help you understand where the 600 ohms came from.
It's unlikely that a consumer grade piece of audio equipment would be able to drive a 600 ohm input.
In the commercial sense, connections are usually balanced XLR's using 600 ohm transmission line.? You do have long cable to deal with.
The only real object is to have x volts p-p at the end of the cable, so you drive with the lowest impeadance into something reasonable like 10K.? Tubes were an entirely different animal.
With a power amp, you have say an 8 ohm speaker and 100 W/ch, both channels driven.? If I had an 8 ohm output Z at my amplifier that would not be very good.? So, I really need the lowest output Z.? This is actually expressed as Damping factor.? A damping factor of 100, means the output Z of the amp is 8 ohms/100.
Speaker impeadance is actually measured at 1 kHz and is usually about 6 ohms for an "8 ohm speaker".
We also have losses in the wires going to the speaker.? We don't have sense leads in our audio amplifiers.
Professional audio is usually more precise.? So, the output is assumed to be driving a 600 ohm balanced load.? That's not the case in consumer audio.
==
A comment about scope impeadance.? Two standards exist of 1 M and 50 ohms.? They may have different parallel capacitances.? 1M || 22 pF is common.
Why the capacitance?? We try to create the perfect voltage divider.? So of the scope has 1 M || 22 pF and the probe has 1 M || with x-22 pF, then it's possible to create a near perfect divider at "all" frequencies.
? By doing probe compensation (vary the capacitor on the probe with a square wave input such that the waveform is square) does just that.? In return, we get a probe that sees 10 meg ohms resistive and attenuates the signal by 10x usually. ?? The scope probe cable has capacitance too.
==
You also need to remember a couple of things:
Twisting helps eliminate EMI because the EMI radiates into both conductors "equally" and the differential receiver removes the common mode signal as well as the act of twisting.
Shielding reduces EMI.? Shields should be connected at one end only and this is typically the signal source.
Thus, twisted-pair shielded cable is very common for process control and professional audio too.
Ground loops are really our enemy.
A square wave by Fourier analysis requires infinate bandwidth to re-produce.
It's made up of the sum of the odd harmonics of sine waves.
Bandwith is usually measured at the -3db frequency or when the signal is down by ~0.707.? there is a rule of thumb that relates rise time and bandwidth.? See:
Worry about stuff when it's important.
Is three resistances in series e.g. 3K equivalent to three 1K resistors in series??? I can argue no and be right.
Does a moving wire in free space on earth develop a current???? The answer is yes.? The practical answer is no.? It is a wire that's rotating in the Earth's magnetic field, so it generates a current based on physics.? Have I measured such a current - Yes.
In a college glass we had a test and I successfully argued that my answer was correct. ? His answer was, "Your not supposed to know that yet."
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On Friday, February 16, 2018, 6:00:25 PM EST, nielsentelecom@... <nielsentelecom@...> wrote:
In telephony, bridging is a common concept. The impedance could be
anything. on repeater equipment, there is a switch setting if the unit
was at the end of the trunk, or in the middle somewhere. The settings
are; 150 ohm, 600 ohm, or 1200 ohm. The 600 is the usual setting. The
1200 ohm is considered a compromise setting. You have to be careful with
the settings. Setting 1200 ohm can cause overdriving an amplifier or
repeater with the usual accompanied distortion or 'ringing'. When
sending test tones to check level, or realigning a circuit, the
transmission test set had to be set properly to either 'terminated' or
'bridged' to measure the tone correctly. Otherwise a bad reading will
result.
I've always thought the term came from the schematic drawing of a
bridged circuit, 2 parallel lines and 2 perpendicular lines crossing the
parallel lines. It looks like a bridge at the crossing points.
I use the term 'bridged' to describe any paralleled devices. Such as
duplex wall outlets.
NielsenTelecom
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Re: vintageTEK Museum Microfiche FINANCIAL help
Donated.? It's useless to have such a resource that is untappable.? I would not mind donating to Tekscopes either.? What was addressed before, too bad there isn't an index or even tags for posts.
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On Sunday, May 20, 2018, 8:27:38 PM EDT, David Berlind <david@...> wrote: Got it. I donated $25. Thanks for the pointers and of course, once again, for everyone's help on this forum for the last year. I'm a newcomer to the space and am somewhat overwhelmed by the generosity of this forum's members. On Sun, May 20, 2018 at 6:28 PM, Dave Brown <davebr@...> wrote: The home page, blog, and YouCaring site all say that monies donated above
the goal will help to improve the infrastructure for the scanner.? This
would be improved networking, new computer, and new printer.? Almost all of
the infrastructure at the museum are donated computers which are old.? Any
donations above this will be used to support the museum.? We don't charge
for admission or tours and have modest eBay sales so we rely almost
entirely on donations.? A small number of people donate through their work,
some send us a check, but the vast majority of our donations are by on-site
visitors in our "fishbowl".? We run a pretty slim operation relying
entirely on volunteers so all donations are appreciated.
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Re: Wanted 067-0681-01 Tunnel Diode Pulser by new member
Here's the link to post from Sergey Kubushyn<>: It's probably also somewhere on groups.io if you search for it...I was too lazy to go look it up. Jeff ________________________________ From: [email protected] < [email protected]> on behalf of John Griessen <john@...> Sent: Sunday, May 20, 2018 7:43 PM To: [email protected]Subject: Re: [TekScopes] Wanted 067-0681-01 Tunnel Diode Pulser by new member On 05/20/2018 09:41 PM, Jeff Davis wrote: Hi Craig,
You can easily build one in just a few hours. The only challenge is obtaining the right tunnel diode (eBay), mounting it (use conductive epoxy), and confirming the rise time is within spec (I borrowed a high speed scope from my work for this). The other parts are garden varieties obtainable from Digikey.
I built two of them but sold the second on eBay.
There was a great posting by one of our members, Sergey, on this. I don¡¯t have the details handy where I¡¯m at but Please put the link here also.
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Re: Wanted 067-0681-01 Tunnel Diode Pulser by new member
On Sun, May 20, 2018 at 07:27 pm, Craig Cramb wrote:
Looking for a working condition Tektronix 067-0681-01 Tunnel Diode Pulser for
doing the Cal 6 on a 2400 series scope. I have all other tools but am missing
this tool to complete the full calibration sequence. Please reply to
electronixtoolbox@...
if you can help.
My background is 42 years working in the HVAC industry. But I have had the
hobby for about 25 years learning about and repairing Tektronix scopes. Not an
expert just have some experience of a lot of trial and error getting them
working. I started with the 475 model and with a manual and advise from Reed
D. Learned how to navigate thru the Tek manuals and have been somewhat
successful at repairs. Since then I went to the T900, 455, 465, 2430/A,
THS700, 222 and onto the 2400 series. Which now I mainly deal with the 465 and
2465b,2467B scopes. Over time I¡¯ve acquired TG501,PG506,SG504,SG503. Several
that are non working and still don¡¯t work today and some that are fully
working. I seem to not have the knack of fixing plug-ins.
I have many scopes that I need to repair in my shop. I just hate to see them
parted out or thrown away when the majority can be fixed with a fair amount of
time and effort. I¡¯m not retired yet but hope to be soon so I then can spend
more time with the units in my shop.
If you have made it this far in this note. Thanks for reading and ask any
questions you have.
Craig Cramb
Wichita,Ks
Not easy to come by, as you have seen. Someone here may chime in on this guys pulser I personally know nothing about it but it seems some people here use it.
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Re: Wanted 067-0681-01 Tunnel Diode Pulser by new member
On 05/20/2018 09:41 PM, Jeff Davis wrote: Hi Craig,
You can easily build one in just a few hours. The only challenge is obtaining the right tunnel diode (eBay), mounting it (use conductive epoxy), and confirming the rise time is within spec (I borrowed a high speed scope from my work for this). The other parts are garden varieties obtainable from Digikey.
I built two of them but sold the second on eBay.
There was a great posting by one of our members, Sergey, on this. I don¡¯t have the details handy where I¡¯m at but Please put the link here also.
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Re: Wanted 067-0681-01 Tunnel Diode Pulser by new member
Hi Craig,
You can easily build one in just a few hours. The only challenge is obtaining the right tunnel diode (eBay), mounting it (use conductive epoxy), and confirming the rise time is within spec (I borrowed a high speed scope from my work for this). The other parts are garden varieties obtainable from Digikey.
I built two of them but sold the second on eBay.
There was a great posting by one of our members, Sergey, on this. I don¡¯t have the details handy where I¡¯m at but if you are interested in going this route I¡¯ll look them up and send them to you.
Jeff / N0DY
Sent from my iPhone
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On May 20, 2018, at 7:27 PM, Craig Cramb <electronixtoolbox@...> wrote:
Looking for a working condition Tektronix 067-0681-01 Tunnel Diode Pulser for doing the Cal 6 on a 2400 series scope. I have all other tools but am missing this tool to complete the full calibration sequence. Please reply to electronixtoolbox@...
if you can help.
My background is 42 years working in the HVAC industry. But I have had the hobby for about 25 years learning about and repairing Tektronix scopes. Not an expert just have some experience of a lot of trial and error getting them working. I started with the 475 model and with a manual and advise from Reed D. Learned how to navigate thru the Tek manuals and have been somewhat successful at repairs. Since then I went to the T900, 455, 465, 2430/A, THS700, 222 and onto the 2400 series. Which now I mainly deal with the 465 and 2465b,2467B scopes. Over time I¡¯ve acquired TG501,PG506,SG504,SG503. Several that are non working and still don¡¯t work today and some that are fully working. I seem to not have the knack of fixing plug-ins.
I have many scopes that I need to repair in my shop. I just hate to see them parted out or thrown away when the majority can be fixed with a fair amount of time and effort. I¡¯m not retired yet but hope to be soon so I then can spend more time with the units in my shop.
If you have made it this far in this note. Thanks for reading and ask any questions you have.
Craig Cramb
Wichita,Ks
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Wanted 067-0681-01 Tunnel Diode Pulser by new member
Looking for a working condition Tektronix 067-0681-01 Tunnel Diode Pulser for doing the Cal 6 on a 2400 series scope. I have all other tools but am missing this tool to complete the full calibration sequence. Please reply to electronixtoolbox@...
if you can help.
My background is 42 years working in the HVAC industry. But I have had the hobby for about 25 years learning about and repairing Tektronix scopes. Not an expert just have some experience of a lot of trial and error getting them working. I started with the 475 model and with a manual and advise from Reed D. Learned how to navigate thru the Tek manuals and have been somewhat successful at repairs. Since then I went to the T900, 455, 465, 2430/A, THS700, 222 and onto the 2400 series. Which now I mainly deal with the 465 and 2465b,2467B scopes. Over time I¡¯ve acquired TG501,PG506,SG504,SG503. Several that are non working and still don¡¯t work today and some that are fully working. I seem to not have the knack of fixing plug-ins.
I have many scopes that I need to repair in my shop. I just hate to see them parted out or thrown away when the majority can be fixed with a fair amount of time and effort. I¡¯m not retired yet but hope to be soon so I then can spend more time with the units in my shop.
If you have made it this far in this note. Thanks for reading and ask any questions you have.
Craig Cramb
Wichita,Ks
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Re: vintageTEK Museum Microfiche FINANCIAL help
Got it. I donated $25. Thanks for the pointers and of course, once again, for everyone's help on this forum for the last year. I'm a newcomer to the space and am somewhat overwhelmed by the generosity of this forum's members. On Sun, May 20, 2018 at 6:28 PM, Dave Brown <davebr@...> wrote: The home page, blog, and YouCaring site all say that monies donated above
the goal will help to improve the infrastructure for the scanner. This
would be improved networking, new computer, and new printer. Almost all of
the infrastructure at the museum are donated computers which are old. Any
donations above this will be used to support the museum. We don't charge
for admission or tours and have modest eBay sales so we rely almost
entirely on donations. A small number of people donate through their work,
some send us a check, but the vast majority of our donations are by on-site
visitors in our "fishbowl". We run a pretty slim operation relying
entirely on volunteers so all donations are appreciated.
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Re: 180A Time Mark Generator
Sorry for not replying sooner Tom, but yeah, they appear to be the same ones. A fellow Tekscopes member, Dave Wise, is sending me three of the mounts. Didn't figure McMaster would have them, so I didn't check there.
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On 5/18/2018 10:18 AM, tom jobe wrote: Hello,
I didn't see that you got a reply to your fan mount question yet so let me 'take a swing' at it.
The manual for the 180A does not show us a picture of the fan mounts, but they might be the ordinary ones that were used on many of the 500 series tube style scopes and curve tracers of similar vintage.
If the mounts are rubber with a simple threaded metal stud sticking out of each end, you can buy them from McMaster-Carr and other suppliers.
Maybe have a look at this page of the Mcmaster-Carr catalog, they have quite a selection of that style mount.
tom jobe...
On 5/16/2018 12:34 PM, Jerome D Leach wrote:
Recently picked one of these up in good, original condition. Seems to be an earlier one, with the serial being 5005. Pretty filthy, but literally has no dents, and does not exhibit any evidence of being tampered with.
The one issue that is obvious at this point, is that it possesses those rubber fan mounts, and they have rotted away.
Seems I have read here in the past that some folks have developed a repair for this situation. If so, I would appreciate knowing what others have done. Being a toolmaker by trade, I am sure I can come up with some sort of mounts. Still, I would like to see how other owners have addressed the problem.
.
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Re: vintageTEK Museum Microfiche FINANCIAL help
The home page, blog, and YouCaring site all say that monies donated above the goal will help to improve the infrastructure for the scanner. This would be improved networking, new computer, and new printer. Almost all of the infrastructure at the museum are donated computers which are old. Any donations above this will be used to support the museum. We don't charge for admission or tours and have modest eBay sales so we rely almost entirely on donations. A small number of people donate through their work, some send us a check, but the vast majority of our donations are by on-site visitors in our "fishbowl". We run a pretty slim operation relying entirely on volunteers so all donations are appreciated.
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Using a Tek sampling head
I have much enjoyed the recent discussion here about the 7T11/7S11/7S12 sampling plugins and have learned a lot from the contributions.
I have a long-term quest to get my Soviet Ya4S-100/Ya4S-101 sampling plugins working properly. They're roughly equivalent to the 7T11 and 7S11 but with some neat features, most notably a delta delayed timebase and slideback-type voltage measurement, both with digital display on the scope's readout. The problem is that I don't have the sampling head for them. I'm searching high and low for one (and learning quite a lot of Russian in the process) but they're like hen's teeth and always seem to have gone missing. The official sampling head is a dual channel feed through sampler with SR50-262 (almost identical to 'N' type) connectors for input and output. The good news is that the schematic is available, though seems to have been drawn by someone whose aim was to minimise the use of paper and ink rather than to create useful documentation.
The sampling plugin has a 19-way connector for the sampling head. This carries +/-15V, the signal and feedback for each channel, a single strobe, and a mysterious signal called 'threshold' which looks like a TTL logic output which alternates state on each trigger.
The good news is that my sampling plugins seem to be working well and all the signals on the connector do the right things, so the project is worth pursuing. My idea is to create an adapter cable so I can use Tek S-series sampling heads until I find the original one. I don't have any S-series heads at the moment, only SD-22 and SD-24 ones which involve too much software, so I'd have to buy one to try out.
I've looked at the manuals for the 7S11 and various sampling heads. Is there a clear specification anywhere of the interface, for example the amplitude of the strobe pulse and the signal and feedback connections? I would be quietly amused if the Soviet system turned out to be electrically compatible with the Tek one...
All advice and thoughts much appreciated,
Chris
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Re: vintageTEK Museum Microfiche FINANCIAL help
On 5/20/2018 10:28 AM, David Berlind wrote: 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?
Necessary: No Appreciated: Yes
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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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Craig Cramb
Marvin Moss