开云体育

Don N3DEB <dbawatsonville@...> added the photo album Tektronix 24xx Case Plastic JB Weld Plastic Bonder Result ( /g/TekScopes/album?id=300551 ) : Tektronix 24xx Case Plastic JB Weld "Plastic Bonder" Result. Good color match with Tan version, very good adhesion. Two part polyurethane adhesive.



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The following photos have been uploaded to the Tektronix 24xx Case Plastic JB Weld Plastic Bonder Result ( /g/TekScopes/album?id=300551 ) photo album of the [email protected] group.

* Tektronix 24xx Case Plastic JB Weld Plastic Bonder Result.jpg ( /g/TekScopes/photofromactivity?id=3883302 )

*By:* Don N3DEB <dbawatsonville@...>

Note to group, my 2465B scope had cracked rear tan plastic cover. JB Weld "Plastic Bonder" tan color is a 2 part polyurethane adhesive with a great color match and adhesion. Should work other models I would think.

I uploaded photo to Photos folder.

/g/TekScopes/album?id=300551

Hey Benjamin, did you see my responses?

Thank you!

Barry

Richard Kelly <richardjkelly@...> added the photo album S-30 Inductance Standardiser ( /g/TekScopes/album?id=300542 ) : A home brew inductance standardiser for calibration of the 300?H inductor in the S-30, assuming that the associated Type 130 L-C Meter is accurately set to 140kHz on the fixed oscillator.



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Richard Kelly <richardjkelly@...> updated the photo album S-30 Inductance Standardiser ( /g/TekScopes/album?id=300542 ) : A home brew inductance standardiser for calibration of the 300?H inductor in the S-30, assuming that the associated Type 130 L-C Meter is accurately set to 140kHz on the fixed oscillator. The contained 4310pF precision cap will resonate with the 300?H in the S-30 and null the 130 on 300?H scale.

Tek has similar for 577, 576, 7CT1 tracers

Jon

Hi Ed,

Well I was aware of that and I wanted to see what Telequipment had done as my TO5 one has resistors and now I know that the TO3/66 one had ferrite beads.

I have a bunch of 43 material ferrite beads so when I get to building the fixture I'll try that first. I'll start by testing some epitaxial transistors first and see how that goes.

Thanks for chimeing in!

Sam

WOW Tony Thank you very much.

With the pictures I got from you and the TO5 one I have I think I can 3D print a facsimile of the one that you have.

I bought the curve tracer 20+ years ago at a hamfest for $10.00 and I recently got around to fixing all of its problems and calibrating it but I never had any luck finding this fixture.

The TO5 fixture has resistors where the TO3/TO66 fixture has ferrite beads and that was what I was concerned about and your work helped me answer that question.

Thanks again!

Sam
W3OHM

Ed potting shells are available, we have many but the Tektronix size may be custom.

Potting is not trivial, a certain number will fail afterwards.

Easier to just find a similar multiplyer and adapt it.

Jon

Hello everyone, UK user here. I have two 465 vintage scopes which need a new home. One, I think, needs calibration and the other does'nt work but maybe good for parts. Free to a good home. Thanks for reading and email me if interested.

Hi Dan,

Better late than never.

I am in the process of collecting all s/w. I found a local NI representative who is now down the rabbit hole at NI looking for measure for lotus 123, very early version of the data exchange plugin.

I have a DOS machine running, Tekcats, Lotus 123, kermit with 8 bit ISA PC2 GPIB card, missing critical element NI measure to complete the setup.

How are you getting on?

Regards

Gerald
VK3GM

Clark, thank you for your input, however, I’ve moved the 184 off the bench for now, and right behind it I just finished updating my 191 and moved them both to a holding shelf until needed as the ‘Work’ bench shelf space is a premium. That said, I’ll keep your comments in mind. I printed your paragraph and tucked it into the handle of the 184 for the next time it’s on the bench. I believe I understand what you’re speaking to, there is a way of successively holding traces on the screen, they build up one trace at a time. I’ll try that next time things are set up.

After years of viewing analog traces, I’ve become much too comfortable with how it looks. Even though I’ve had digital gear available for a number of years, I’m still getting used to how things appear on their screens. When I slow down the sweep speed, I see a whole different set of peaks or pips from the 184 on the HP 54542C. It was initially very confusing, then, after speeding up the sweep the view, more or less, matched the analog view.

I’ve been at this for decades, and I’m the first to admit that I still have so much to learn. I make it a point to learn something new every evening I’m in my lab. The whole way digital oscilloscopes work is so different. When I first got the HP, I was sure it had power supply noise as the trace was fuzzy. But after a few YT videos, I now understand why that is. They show so much more than their analog cousins that it can be confusing for us gray beards. Once again, thanks for taking the time to share, I’ve accumulated a LOT of Tek gear and over the years have learned so much from this group of guys.

Here's a fun quick story; my last find was at a Hamfest in Oregon. I found a Tek piece I had been looking for for a few years. After visiting with the seller for quite a while, we struck up a deal. After hauling everything home I discovered that I had bought my find from the retired engineer who managed the team that designed the piece~!~ I was floored… he was the nicest guy to chat with and now I understand why he knew so much about the piece I bought. Hahah Too much fun ~!~

Hi Jon,

I'm really only trying to save the original plastic box/shell and the Alden lead which provide all the features for mounting and connection. Seeing the internal structure is just a bonus. I have one other spare 7904 HV multiplier of unknown condition, and it's good to have an empty box for rebuilding another one if necessary.

Ed

The "unknown" components inside curve tracer transistor test fixtures are likely lossy ferrite beads (anything from one to a bunch in series) to suppress oscillations in actively biased devices. At low frequencies you want to make the series Z from the DUT terminals to the measuring ports as low as possible, so direct wires are best.

You can build your own fixtures and jigs with simple wiring, then if any oscillations show up, add some beads as necessary to calm things down. It depends on the types of devices tested - RF transistors will need different treatment from audio, for instance.

Ed

Hi Sam :I had created the album " CT71 adaptor on TekScope. please check !
RdTony CheungFEB 4 2025

Yiu On Tony C <tonycheung_hk@...> added the photo album CT71 adaptor ( /g/TekScopes/album?id=300489 ) : Telequipment CT71 adaptor



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The following photos have been uploaded to the CT71 adaptor ( /g/TekScopes/album?id=300489 ) photo album of the [email protected] group.

* ct71_vorne_medium.jpg ( /g/TekScopes/photofromactivity?id=3882289 )
* IMG_3590.JPG ( /g/TekScopes/photofromactivity?id=3882290 )
* IMG_3591.JPG ( /g/TekScopes/photofromactivity?id=3882291 )
* IMG_3592.JPG ( /g/TekScopes/photofromactivity?id=3882292 )
* IMG_3593.JPG ( /g/TekScopes/photofromactivity?id=3882293 )
* IMG_3596.JPG ( /g/TekScopes/photofromactivity?id=3882294 )
* IMG_3597.JPG ( /g/TekScopes/photofromactivity?id=3882296 )
* IMG_3598.JPG ( /g/TekScopes/photofromactivity?id=3882297 )
* IMG_3599.JPG ( /g/TekScopes/photofromactivity?id=3882298 )
* IMG_3600.JPG ( /g/TekScopes/photofromactivity?id=3882299 )

*By:* Yiu On Tony C <tonycheung_hk@...>

Commonly HV multi are potted in very high solids epoxy, a diamond blade circular or band saw can slice, and a diamond charged grinding tip on a Dremel often can work.

But dissections are unnecessary, as the multi are well known, usually 3 or 7 stage Crockofft Walton voltage multipliers.

Fuji seminar and Mitsubishi made these in 1970s...1990s.

Often the HV output is a flying lead or connector in thé potted unit.

Indeed the cap value can be wide tolerances as the HV transient run 30...100 kHz.

Enjoy

Jon

Last night I did a trial run with a little cutting into the multiplier. First I need to correct the description. I was thinking it was potted with the hard red epoxy commonly used for HV modules of all sorts. I happened to recently be junking out some big old CRT-based color TVs then later a couple of SONY OEM displays, all of which used the red stuff, so I had that on my mind when I thought about the shot 7904 one after not seeing it in a while. This one actually uses a black epoxy not the red.

I clamped it in the mill vise wrapped with a sheet of paper forming a trough to catch the turnings, and tried a standard HSS end mill about 5/16" D. It cut just fine, leaving a trail of debris and some burring on the edges just like going through plastic, with about 1/8" depth penetration and maybe a few seconds per inch travel rate. I think it will be OK with slow enough cutting and cool downs or maybe some water or oil lube. When I went faster it started to smoke, and the debris actually caught fire, smoldering away until it burned through the paper trough. I had to douse it with water to be sure, then clean up the mess. This was only cutting the epoxy - we'll see what happens with hitting the parts.

I'm confident that I can cut it all out but it will be a bit tedious and messy, and I'll need to wear a mask and keep a fire extinguisher on hand.

Ed

Thanks for the feedback. Just to clarify, this is a 570, not a 575, although there are a few similarities.

I checked with an acquaintance who also has an early 570 like mine and he said that his floating unregulated voltages were high as well. He reminded me that Tektronix mentioned upgrading the caps in the floating unregulated supply from 450v to 500v in the modification summary document. They say that the caps on the floating unregulated supplies would exceed their rating at high line. I haven't tried setting the line to high line yet (125vac) - I have a feeling it will exceed the 500v rating on those caps. He mention upgrading his to 600v. It just bothers me that the manual states they should be within 5% of -300v and +400v, and I'm sitting at 16% high on the -300v supply and 12% high on the +400v supply, when testing at their specified 117vac line voltage. All of the regulated supply voltages are spot on, as are the non-floating unregulated supplies.

-150v = -150.66
+100v = +100.03
+300v = +305v (they allow +/- 6v)
+400v unregulated = +411 (they allow +/- 32v)
-300v unregulated = -310 (they allow +/- 24v)

so, it's just the two additional FLOATING unregulated supplies that are reading high.
+400v floating unregulated = +446v
-300v floating unregulated = -350v

I think at this point I will proceed with the rest of the calibration procedure, maybe I'll run into other issues that will give me some clues.

I no longer have a 575 or manual but the power supplies will be similar to other vacuum tube Tek scopes so these comments are generic but I can't quote part designations for the 575.

As others have said, don't worry too much about the unregulated voltages. They should be a bit higher than the regulated voltages as the regulators need some headroom to operate in. What you really need to do is make sure the regulated voltages are correct.

Firstly the -150 supply needs to be correct before you do anything else. The -150 uses a gas discharge reference tube type 5651 (0G3, 82A2) and that needs to working properly. You can check that by carefully measuring the voltage across it (pins 7 and 1) which should be 85 volts. There's a preset pot to set the -150 .

All the other supplies use the -150 as a reference. They will all have a voltage divider made up of unusual value precision resistors that set the various voltages and there are 0.01 uF bypass caps on the dividers that need to be free of leakage. If those resistors have drifted or the caps are leaky that will affect the regulated voltages. And of course, the tubes in the regulators need to be good too. If you need to replace any of the resistors you will have to make up the exact value by series/parallel arrangements of 1% metal film resistors. 630 volt polyester caps are fine to replace the originals.

So there are 4 possible causes, weak tubes, a faulty voltage reference, drifted resistors and leaky caps. I have seen all 4 at various times in Tek vacuum tube scopes.

Good luck!

Mark,
Would you please confirm that the article you mentioned is the one I found?
See

Anyway, what does the author mean by " Capacitors: 470pF...2,2nF /4kV"?
I have no knowledge of HV so it seems strange to me that the capacitor values can vary in such a large range (almost 5:1).
Is this correct?
Thanks