Sorry 154-0644-05 or 154-0644-09
Thanks
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Somebody has a CRT PN 155-0644-05 or 155-0644-09 for a TEK 7904 for sale?
Thanks
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Re: Questions on impedance matching
It has been decades since we impedance matched audio lines in professional audio. When I began in professional audio nearly fifty years ago we impedance matched for 600 Ohms using input and output transformers in both tubed and transistorized equipment.
The cable used for balanced audio lines in broadcast and recording facilities has a characteristic impedance on the order of 100 Ohms. We now use voltage-sourced outputs rather than the power-sourced outputs of decades ago. Studio output impedances nowadays are on the order of 100 Ohms and inputs on the order of 10,000 Ohms.
David, your initial question concerned connecting an audio oscillator (you said signal generator but I suspect it is just an oscillator) with a 600 Ohm output. Depending upon the circuit design you may need to terminate it in 600 Ohms to optimize distortion and frequency response and simply bridge the 'scope input across that 600 Ohm termination.
I routinely impedance match RF circuits at work where cable lengths are significant fractions of a wavelength. I never do so at audio frequencies because I am not driving audio cables with wavelengths of thousands of meters. I do sometimes have to terminate audio outputs in older equipment with 600 Ohms in order to get them to behave properly in the modern studio environment.
At RF I routinely handle power output stages of up to tens of thousands of Watts, and impedance matching can be critical to maximize power transfer and minimize hating of the RF output stages. At the power levels you are working with at audio frequencies impedance matches are not critical to the power dissipation of output stages, and any output termination is normally done only to optimize the frequency and distortion performance of the stage.
Note that if you are using a true audio signal generator (such as the HP 651B that I use in the shop) the output must be properly terminated to maintain calibration, as Ted noted upstream.
Dale H. Cook, Radio Contract Engineer, Roanoke/Lynchburg, VA
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Re: vintageTEK Museum Microfiche FINANCIAL help
I am having trouble donating! I can log in to paypal o/k but when I go via the vintagetek.org link I keep getting the run-around from interminable security tests - It's driving me mad. What do I put in to the paypal "send money" page to do it?
Thanks,
Geoff.
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Re: vintageTEK Museum Microfiche FINANCIAL help
Can access it fine from the UK too.
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On 5/21/2018 1:01 PM, Artekmedia wrote: No problem reaching it here?
On 5/21/2018 7:46 AM, Geoffrey Thomas wrote:
Is the website down at the moment? Cannot access at all.
Geoff.
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Re: vintageTEK Museum Microfiche FINANCIAL help
No problem reaching it here?
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On 5/21/2018 7:46 AM, Geoffrey Thomas wrote: Is the website down at the moment? Cannot access at all.
Geoff.
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.
--
Dave
Manuals@...
www.ArtekManuals.com
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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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Dale H. Cook
Craig Cramb