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On Fri, Dec 24, 2021 at 05:42 AM, Dave Peterson wrote:

There are many fine points to learn regarding the TDR use. I think the most
valuable thing you can do at this point is to play with it. Presumably you
have no pressing need for this and you can take your time familiarizing
yourself with not only the controls, but the documentation and physics of what
you're looking at. Go through the "First Time Operation" section of the
manual. Review the Calibration section, study the schematics, but don't worry
about knowing it all yet. Just get familiar with it. Maybe order a hardcopy
from your favorite auction site?


Build up appropriate hardware - having good/proper accessories goes a long way
toward making the equipment easier to use. Build different lengths of cable,
see what effects they have. Look at waveforms with and without termination.
Get to know what does what. I tested all my SMA and BNC connectors and
discovered I had a batch of 75ohm T's, not 50ohm. Friggin' Amazon. Caveat
emptor. But it's all qualitative at this point. Get a good feel for the
qualitative stuff first.

Have fun! Great find!
Dave

Thanks Dave.
Yes, at this point I’m just playing with it, and I will keep doing so until I become more proficient with it.

I also saw that the Type 106 calibration procedure calls for the use of a sampling scope. Maybe I’ll be able to use this for that purpose…?

Cheers

Good day,
wow, I think Harvey has covered it all pretty nicely.
May I just add that a TM500 mainframe such as a TM501/502/503?still makes a?nice platform for DIY projects. You can buy a defect TM500?plugin or a mechanically compatible plugin for the?5000 oscilloscope?series (note: electrically incompatible which also includes the rear connector) for little money. And then design & make?your custom board and front panel?as you have all sorts of supply voltages plus a nice, space saving setup…I did take advantage of that when I built a simple electronic load several moons ago. Let me know if you are interested in seeing?more details…
Have a great festival season, all!
Greetings from Bavaria, Germany.
Cheers,
Magnus

There are many fine points to learn regarding the TDR use. I think the most valuable thing you can do at this point is to play with it. Presumably you have no pressing need for this and you can take your time familiarizing yourself with not only the controls, but the documentation and physics of what you're looking at. Go through the "First Time Operation" section of the manual. Review the Calibration section, study the schematics, but don't worry about knowing it all yet. Just get familiar with it. Maybe order a hardcopy from your favorite auction site?


Build up appropriate hardware - having good/proper accessories goes a long way toward making the equipment easier to use. Build different lengths of cable, see what effects they have. Look at waveforms with and without termination. Get to know what does what. I tested all my SMA and BNC connectors and discovered I had a batch of 75ohm T's, not 50ohm. Friggin' Amazon. Caveat emptor. But it's all qualitative at this point. Get a good feel for the qualitative stuff first.

Have fun! Great find!
Dave

BTW, you’ll see in the pictures that the 2003 calibration seals are still intact. So I’m not gonna touch it unless something breaks.

Hello,

For those who have followed my thread on the purchase of the 7704A with the 7S12, you May remember that yesterday my 7623 blew tons of smoke out the back when I turned it on.
So I removed the back vents cover. Nothing is apparently burnt…
I slowly powered it on on a Variac and current limiting bulbs. Nothing bad happened…
The fan started spinning, the trace appeared. I disengaged the limiting bulbs, and now everything is working great as if nothing happened…

Someone mentioned that it was safe to power it on, and that the RIFA cap probably burnt.
But I can’t see it unless I remove the 4 feet. The problem is that on one of them the screw has a stripped head. Can’t get it out. Gonna probably have to drill it out just to replace that cap, if it is that cap…. (and I have no imperial-thread replacement for it)…

TM500 units have proven to be very handy for me, I have them on almost every workbench, and have several of the high end scope modules, plus all the other goodies.
Look for the later polycarbonate front panels rather than the anodized ones (scopes only come anodized) to get the latest designs and best lifespan.

I find a fluke or Tek DMM to be much better than one in the frame, although I do have some of the high end ones. A fluke 87 remains may favorite.
Using a TM504 you can get the best stuff all in one rack, and it is certainly easier to work with and more compact that an assortment of discrete boxes.
keep in mind, all the pushbutton units will need a bit of de-oxit through the rear of the switch to make them stay working due to the silver-plated contacts.

I'd rate them an 8-9/10, and still happy with mine.
all the best,
walter
sphere research corp.

Raymond and Harvey,

Yes I read about it being fragiles in that regard. I do keep a 50Ω load on it when not in use. And thanks to Raymond, now I do not forget to discharge the cables.

I put some more pictures of the little 6-inch patch cable I made, along with some some traces.
Info in the images description.

/g/TekScopes/album?id=270997

I have not enough experience to know if this is even good or not so much.
I’m counting on all you guys to let me know.

Regards, and MERRY CHRISTMAS TO ALL.

Thanks

UT-141 50 ohm Hardline, which is used to make the TEK jumper on the 7S12, has a MIL number RG-405.
If there where enough people (say 5) who wanted one, I have the professional tools to make them. They would cost $15.00 plus shipping (9.00 for priority mail) for material and labor. I have a 7S12 so would use that to make the mechanical model fit properly.??Regards,Jeff Kruth
In a message dated 12/24/2021 11:10:36 AM Eastern Standard Time, davidpinsf@... writes:?In the same boat, I made my own.

I did a little research on the physics of coax and electromagnetic propagation (speed of light) in it, and found that for RG-174 8 inches of cable takes approximately 1ns to propagate. I bought several feet of RG-174 from a local shop, and had a couple of packages of male SMA crimp connectors left over from another project. I painstakingly created the patch cable to as near 8 inches as I could.

While finding a place to store the resulting cable in my component drawers I came across my TinySA antenna and patch cables (2). Low and behold they are about 8 inches long - I had two in hand and didn't know it. I can tell mine from those because mine is something like 1/16" longer. So maybe its worth acquiring a TinySA (tinysa.org)?

My creation is not equal to the precision engineering and construction of the specified Tek equipment, but it's in hand and works well within the limits of my needs. Don't let the loss of fidelity keep you from making progress. In the process you'll learn and will develop a deeper understanding of the requirements of the equipment. Just always keep a healthy understanding of the limits of what you know, and what you're taking on faith.

Dave

The following photos have been uploaded to the 7704A with 7S12 album of the [email protected] group.

• 9E84D86B-97A0-474A-8B0A-7FFCDD051F4A.jpeg
• 7954EA1D-93D6-4DE4-BCEB-6050FAD6F04D.jpeg

By: Stephen <stephen.nabet@...>

Reminds me of one of my college programming classes that was centered around designing small logic circuits. In one lecture, the professor held up a piece of wire that was approximately that same length and asked what it was. I raised my hand and replied that electricity would travel from one end to the other in about 1 nanosecond. I think that surprised him a bit - until I admitted that I'd overheard him ask that same question in another class. :) I have enough of an electrical background to understand the principle but I doubt I'd have known the answer he was looking for at that time.

Thanks,
Barry - N4BUQ

In the same boat, I made my own.

I did a little research on the physics of coax and electromagnetic propagation (speed of light) in it, and found that for RG-174 8 inches of cable takes approximately 1ns to propagate. I bought several feet of RG-174 from a local shop, and had a couple of packages of male SMA crimp connectors left over from another project. I painstakingly created the patch cable to as near 8 inches as I could.

While finding a place to store the resulting cable in my component drawers I came across my TinySA antenna and patch cables (2). Low and behold they are about 8 inches long - I had two in hand and didn't know it. I can tell mine from those because mine is something like 1/16" longer. So maybe its worth acquiring a TinySA (tinysa.org)?

My creation is not equal to the precision engineering and construction of the specified Tek equipment, but it's in hand and works well within the limits of my needs. Don't let the loss of fidelity keep you from making progress. In the process you'll learn and will develop a deeper understanding of the requirements of the equipment. Just always keep a healthy understanding of the limits of what you know, and what you're taking on faith.

Dave

Yep, can't get there from here.? You might consider building a curve tracer in a TM500 or TM5000 frame, though.? Assuming you need one.

Harvey

Replies interleaved:

On 12/24/2021 12:10 AM, guy232 wrote:

Found this group and my enjoyment of Tektronix equipment a couple years ago while fixing my 2213A.
My repair bench doesn't have a power supply, signal generator, counter etc. I find myself needing a power supply and was wondering if the TM500 system would be something reasonable for me to get or if it would potentially be a nightmare as a novice (such as needing difficult to find parts/becoming a constant project due to sudden failures)
According to what i've read on here and in posts, the PS503A would likely be as much as i'd need for repairing vintage stereo receivers and other random projects, or may I be mistaken?

The TM500 series is older, and generally does not have a microprocessor in it.? The TM5000 series has a microprocessor, HPIB interface (which can be ignored if you don't need it now), and much more of a push button interface.?? The 500 frame has unregulated linear supplies, the 5000 frame has regulated (when needed) supplies and a fan.? Most (but not absolutely all) TM500 series plugins will work in a TM5000 frame.? No TM5000 plugin will work in a TM500 frame (the HPIB/IEEE-488 interface connectors have no matching connector), unless you severely mutilate the TM5000 plugin.?? Even then, results not guaranteed.

I've got most of the plugins, but certainly not all.

Power supplies:? 0-20 volts bipolar and 4-5 volts at 3 amps or so.? This is the typical op/amp 7400 series TTL supply.? While that's a good supply, for development work it lacks meters, so you'll need some.? I find that 0-30 volts at about 3 amps (not TMxxxx) is a better range for my projects.? If you ever go to 3.3 volt logic, you'll end up having to build in regulators in the project and feed the boards from 5 volts (I do).

The signal generators are decent, the low distortion sine wave generators are nice for audio testing, and the AA series audio analyzer is very good for distortion analyzing.? The combination is highly sought after by audiophiles who drive up the price. There's an equivalent in the TM5000 series.

Meters are somewhat useful, but most useful if you need multiple 3-4 digit meters.? I use a 6 digit DMMs, but only one or two of them.? Anything otherwise has less precision.

Pulse generators are good if you need them.

Function generators are just that.? They are not low distortion sinewave sources.

Frequency counters are good, there are quite a few.? Generally limited to 200 - 250 Mhz, although there is a 1 Ghz model.

Of particular note are the PG506 and TG501.? Those are specifically designed for oscilloscope calibration and have outputs in the 1-2-5 input sequence used in the older Tektronix scopes.? They're a bit harder to find, but if you have more than one oscilloscope and are interested in such, can be recommended.

There are oscilloscope plugins, which can be used to create a portable (TM515) measurement system.? Most are about 10 Mhz in bandwidth with a maximum of 80 Mhz for the SC504.

There are many many other specialized plugins, some of which are quite rare, and most of which I don't have.

There are some cases when a plugin in the TM500/TM5000 frames could be better replaced by a plugin in a 7000 series frame.

The 7CT1N is a low power transistor curve tracer, much sought out by audiphiles to match transistors, and often needed when trying to replace matched pairs of transistors in some Tek equipment. Expensive, though.? There are other alternatives.

The 7D12 is a digital plugin that has, amongst others, a gated sampling peak reading DC voltmeter.? Feed it a B gate, and as you slide the B gate around (A intensified by B mode) you get an accurate reading of that voltage.

the 7D15 is a 225 Mhz counter that uses the scope's readouts to display the count.? I generally keep one in the A horizontal slot and a 7B92A in the B horizontal slot.

I've shifted mostly to TM5000 series where possible, simply because I intend to automate some tasks.

I have a labcart3 and the TM504 appears to be the largest mainframe able to connect to the bottom bracket.
Thank you for any insight, gentlemen.

Yep, you might find using a TM504 for the cart, and perhaps a TM506 or TM5006 for the bench.

Harvey

Boy oh boy, I miss ChuckHarris!!

larry

Oh I forgot to include that all my test point voltages are spot on.

It might be however it might not be as well. Given the cost of some of the TM equipment on the secondary market I have seen lately when I take in to account the "power frame" and the plugin with what some people are asking I am in the range of a Rigol DP832 (non A) you will need at LEAST a 4 bay power frame to take full advantage of the power supply (high power port) as well as both the frame AND plug in are getting up there in age and will most likely need at least a recap on the electrolytics. Power frames can have pass element issues these are power transistors in the frame but most plugins use them in some way. Also given there size most TM units run hot. I prefer the active cooling of the 5000 frames. You can safely put a 500 plugin in a 5000 frame, but a 5000 plugin will not work in a 500 frame. I have had to recap a 5000 frame even so even these are not immune. Here are some known issues with some of the plugins. I have also found some of the plugin like the FG501A and FG507 cramped to use. Lots of functionality in not a large space.

Frequency counters - Display issues with extremely hard to source replacements.
Function generators - a very interesting design can sometimes be a head scratcher to fix mine had some weird faults in the sine wave output there are some videos on this I can send you the links off list if you are interested. Also cramped front panel
Power supplies - Will need a basic recap most likely there are 2 large electrolytics on the outputs.

Now the good stuff.
SG505 - Ultra low distortion oscillator - even in modern gear I have not found better when it comes to distortion specs FANTASTIC plugin. Try for a Mod 1, Mod 2 is VERY rare
AA501 and AA01A - another fantastic plugin for distortion analysis I am fortunate to have one of each in the lab. I personally like the display on the AA501A a little better. The automatic notch filter and analyzer is wonderful to use give is signal get a distortion measurement. Spec wise this also beats my HP E4411B spec an for measurement. At least in the AF the E4411B goes to 1.5 Ghz however the AA501 and A both run out of gas around 100 Khz if I remember correctly.
SG502 - a really nice clean and simple sine wave generator low distortion just not (ULTRA Low) but still respectably low.

That being said MOST of the TM gear on my bench has needed repair some extensive. And all of it has needed calibration they have not had an easy life up until this point. I still need to confirm the output of my SG505s but I have confirmed them to the limits of my measurement ability at the moment.

Tim,
The velocity factor of these semi-rigid patch cables is about 0.67 . For instance the 1 ns cable (015-1023-00) measures about 20 cm (insertion length). There is no indication like RGxxx on these cables.
Wikipedia has a large table of RG characteristics.
Albert

Ok I’m going to give more details as I left a few out. When I received this it had no power and it turned out to be the infamous tantalum cap in the HV section, replaced with electrolytic. I then had power and just a dot with no vertical or horizontal sweep just a dot. I changed out the filter caps to put and ripple issues behind and all other electrolytic with the exception of the matched ones. I cleaned all switches and connectors the best I could, very time consuming, I used MG Alcohol so no residue would be left behind. I then got the vertical sweep back and part of the horizontal as that is where I am now.
I took another video showing a bit of weirdness:



My next step is going to check the Horizontal Deflection Plate leads and see if I’m getting a signal as suggested by Harvey.

Andrew

I have the original one, and I have two chinese sma semirigid cable, blue, that I have not tested yet.

If you want I can test risetime of the two wires and post the results



SMA Male plug RG402 Cable Semi Rigid Flexible Coax Coaxial Low Loss RF 50ohm Lot




-----Mensaje original-----
De: [email protected] [mailto:[email protected]] En nombre de Tim Phillips
Enviado el: viernes, 24 de diciembre de 2021 11:45
Para: [email protected]
Asunto: [TekScopes] Patch cable for 7S12 015-1017-01 (750 pS)

Recent talk of the 7S12 prompted me to exhume my one. It lacks the 015-1017 cable from the pulser to the S6 loop-thru. I am using a SMA patch cable of six inches, and the 7S12 works OK, but I would prefer the right cable.
Alas, can't see any on That Auction Site, haven't tried Walter or Qservice.
Is it an RG-type ? If so which ? Plenty of SMA cables around from eg.
Telesonic. Must it be rigid / semi-rigid ? IOW can I make one ? Is there a table of propagation delay for RGxxx ?
Sorry, lots of questions.
Tim

--
"Success is a collection of well-curated failures"

oops confused my TEK 7000 scope plug-ins 7CT1N with the adjacentes pile of TM500 stuff....


Jon