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Tek 1A5 and 132 on eBay for 85 bucks

John Williams
 

Here is a 1A5 in a 132 for $85. Looks pretty nice but no pictures of it working. Still a good price.

https://www.ebay.com/itm/Tektronix-1A5-Differential-Amplifier-in-a-Tek-132-Power-Unit-Vintage/324480953564?hash=item4b8c926cdc:g:GvEAAOSws2dgIuH3


Re: 549 transformer question

ykochcal
 

Yes I totally agree,
just did not want to exclude any possibility if a core was found that was
close.

There are real cores around but not everyone has the same access to them.

Not all the uses of the core have the same physical limits. So a Different
shape core might work in a 547 but not fit in a 647.

John

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Ed Breya
via groups.io
Sent: Tuesday, February 09, 2021 12:11 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 549 transformer question

That's true John, it would be less affected by the roughness. It depends on
one's skill at working the saw and the piece, to get a somewhat decent
finish and square/plumb fit. Ed


Re: Tm500 Extender on eBay

John Williams
 

Received the extender yesterday. I haven’t used it yet but looks really good so far. Excellent packaging too. Stay tuned for a user report.


Re: 2445B 2467B - non Tek probes

 

Raymond,

I had a P6121 that appeared to be picking up excess noise, but it was an eBay refugee, and I assume that it was damaged somehow. Whatever the problem was it appeared to be in the tip of the probe. I think I swapped the BNC off of that one to another probe that had a damaged BNC connector, and put the remains in my "to be investigated later" box (or maybe I swapped the compensation box to the cable and tip from a P6122 to make a good P6121; all I seem to have in the "to be investigated later" box are P6122s).

-- Jeff Dutky


Re: 549 transformer question

Ed Breya
 

That's true John, it would be less affected by the roughness. It depends on one's skill at working the saw and the piece, to get a somewhat decent finish and square/plumb fit. Ed


Re: 549 transformer question

ykochcal
 

"but not anything involving the core leg faces"

Due to the gapping I don't think that would be true in all cases.

As long as the total gap comes out about right, and a spacers could be used
to keep the distance in a rougher cut.

some cores have a figure "8" winding on the outer legs to balance them.

The 305 gapped all three legs of the "E"

John

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Ed Breya
via groups.io
Sent: Tuesday, February 09, 2021 11:09 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 549 transformer question

If you do manage to find cores that are similar enough in size, it is
possible to sculpt a larger core down to smaller size, or to make a wider
window. Any material feature that can be attacked on a diamond wet tile saw
can be ground smaller, but not anything involving the core leg faces - you'd
need precision grinding and lapping capability to restore the finish and
fit.

Ed


Re: 2445B 2467B - non Tek probes

 

On Tue, Feb 9, 2021 at 08:08 PM, Ondrej Pavelka wrote:


The main difference I noticed was the amount of noise/interference picked
up. I was surprised because the probe cable length as well as the ground
wire length is the same
That's very strange. I am not aware of these Tek probes picking up any significant noise/interference, let alone significantly more than competitive probes. Of course, all kinds - frequencies and signal levels - of external sources may influence the signal as it comes out of the probe but again, it shouldn't be significantly worse than other probes. A 500 MHz high-impedance 10x probe's output may - and will - show more HF noise entering it than a 100 MHz 10x, of course.

Raymond


Re: TDS5054 infos...

mill_glen_chevy
 

Nope. Miguel sent a link that was suppoed to go to some posts on EEVblog, but they didn't work properly and I couldn't figure out how the software works.

--
Brian St Pierre


Re: 549 transformer question

Joel B Walker
 

As Chuck says, there probably isn't that many people in need of a new transformer. IIRC, folks were asked to send in their old transformer in order to receive a rewound one. Also, there should be plenty of duds around to get cores from. I have a couple that I know of without even looking around. As for my 549, I have ordered an original beeswax impregnated 120-0275-00 from a 564 non B off eBay to try the method described a few posts ago.


Re: Waking a slumbering 475

Mlynch001
 

On Tue, Feb 9, 2021 at 01:01 PM, Jeff Davis wrote:


. I haven't found anything better than good old trial and error to do that and
have gone through literally dozens of reels of filament in developing the
parts that I do offer
Jeff,

I do quite a bit of 3D printing myself (non-commercial and for personal use) and you have hit the nail on the head. Most of the process is very straight forward. That is until the printing starts. I find that I must do several (sometimes dozens) prints before I am able to work through the “unforeseen” issues, orientation, surface finish and the “sizing” issues. The things that most people do not see with 3D printing are those behind the scenes details that appear when the STL file goes into the slicer. There are literally hundreds (at least) of parameters available within the slicer, with an unbelievable number of possible combinations and almost all affect the outcome. I have tried to print knobs for 24xx series scopes, not much success with FDM, as you say, the details are too fine. Some things lend themselves quite well to FDM, but small and finely detailed items are particularly difficult. I would also be glad to discuss any specific questions that people might have if they want to contact me privately.

--
Michael Lynch
Dardanelle, AR


Re: 2445B 2467B - non Tek probes

Ondrej Pavelka
 

Sorry the 600 was a typo it's the 500MHz probes it came with.

On Tue, 9 Feb 2021, 01:17 Raymond Domp Frank, <hewpatek@gmail.com> wrote:

On Tue, Feb 9, 2021 at 12:54 AM, Ondrej Pavelka wrote:


I can clearly see the Testek probes are superior
to P6136 but the lack of the coding ring is driving me mad.
I couldn't find 600 MHz Testec (Testek?) passive probes, 500 MHz being the
max. What did you find that makes the Testek probes superior to P6136's?
Are you talking about the (1.2 GHz) active ones?

In most cases, it doesn't make much sense to use any passive probe at
these high frequencies, because of their large input capacitance of around
10 pF min. I don't know any passive 1:10 probes spec'ed higher than 500 MHz.

Tek P6137's aren't very expensive and recommended for the 2465B/67B. I
guess that makes more sense than trying to add a readout feature.

Raymond






Re: 549 transformer question

Ed Breya
 

If you do manage to find cores that are similar enough in size, it is possible to sculpt a larger core down to smaller size, or to make a wider window. Any material feature that can be attacked on a diamond wet tile saw can be ground smaller, but not anything involving the core leg faces - you'd need precision grinding and lapping capability to restore the finish and fit.

Ed


Re: 2445B 2467B - non Tek probes

Ondrej Pavelka
 

The main difference I noticed was the amount of noise/interference picked
up. I was surprised because the probe cable length as well as the ground
wire length is the same

On Tue, 9 Feb 2021, 01:17 Raymond Domp Frank, <hewpatek@gmail.com> wrote:

On Tue, Feb 9, 2021 at 12:54 AM, Ondrej Pavelka wrote:


I can clearly see the Testek probes are superior
to P6136 but the lack of the coding ring is driving me mad.
I couldn't find 600 MHz Testec (Testek?) passive probes, 500 MHz being the
max. What did you find that makes the Testek probes superior to P6136's?
Are you talking about the (1.2 GHz) active ones?

In most cases, it doesn't make much sense to use any passive probe at
these high frequencies, because of their large input capacitance of around
10 pF min. I don't know any passive 1:10 probes spec'ed higher than 500 MHz.

Tek P6137's aren't very expensive and recommended for the 2465B/67B. I
guess that makes more sense than trying to add a readout feature.

Raymond






Re: Waking a slumbering 475

Jeff Davis
 

Hi Jeff (Dutky),

I'm generally open to creating new offerings if they're something that can reasonably be done with 3D printing. I've found that knobs, in general, have too much fine detail and tolerances too tight to be good candidates for 3D printing (at least at my skill level and with my equipment complement).

The other items you mention might be possibilities. If you continue to strike out with MakerSpaces, feel free to contact me off-list and we can discuss further. I'd probably need to see photos, and if 3D fabrication appears feasible from them, eventually have a physical sample to take measurements from.

What I've found to be the challenge in creating these parts is not so much in creating the 3D model in a CAD tool. The true challenge seems to be developing and controlling the process to replicate the CAD model in ABS or whatever the material of choice is. Each part is different. I haven't found anything better than good old trial and error to do that and have gone through literally dozens of reels of filament in developing the parts that I do offer.

Good luck to you! Also feel free to contact me off-list if there's any 3D printing advice i can provide from my admittedly limited knowledge.

Jeff (Davis) / N0DY
________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Jeff Dutky <jeff.dutky@gmail.com>
Sent: Tuesday, February 9, 2021 7:59 AM
To: TekScopes@groups.io <TekScopes@groups.io>
Subject: Re: [TekScopes] Waking a slumbering 475

Jeff (Davis),

Are you open to expanding your offerings? I've been looking (unsuccessfully) for a local MakerSpace with 3D printers, so that I could print a few things (e.g. some kickstands for DMM916s, top and bottom plates for TM500 plugins, TM500 latch release parts, and maybe see what can be done to produce press-on knobs for 2200 and 2400 series scopes). Would you be up for small runs like that?

-- Jeff Dutky


Re: 549 transformer question

Ed Breya
 

There is another option for HV transformers - the "C" core, which is commonly used in TV flybacks. But, if you want to make a replacement to properly fit in an old scope, you need to stick with the original core style. So, always save any Tek or HP HV transformers you can - even burned out or broken ones - so you can salvage the cores, if ever needed. Even a cracked core can be glued back together and still work, if you have all the pieces, and there aren't too many.

Ed


Re: 549 transformer question

Jean-Paul
 

Dear Chuck excellent information!

1/ Besides E, EE, EI with square center leg, there is an EER or ER shape with round leg and both TDK and Ferroxcube/Philips/EPCOS made some special EE like shapes with round center and large windows.

2/ I have enough info now to search my old core stock, I may find anything from zero to a few to a box, that are not identical but easily useable.

3/ It also possible that a modern part exists with similar specs and size, I will also check that possibility and contact and old friend in Switzerland, expert on SMPS and magnetics.

Kind Regards,

Jon


Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603

Attilio
 

Here I am,
I restarted with another external power supply and the frequency meter connected to the IF output of the oscillator and I have these results:
with control voltage at 17.5 V dc the frequency is 2095.050 MHz, with 20 Vdc it is 2097.600 MHz.
I made four more measurements: with a control voltage of 8.3 Vdc the frequency is 2072.019 MHz, with 12 Vdc it is 2085.740 MHz, with 15 Vdc it is 2091.650 MHz, with 16.5 Vdc it is 2093.122 MHz.
The absorbed current is constant at 28 mA.

I don't know, but I think the control voltage output from the PLL is a bit at the limit.
I suppose 20 Vdc for the oscillator is a limit not to be exceeded (with 20 V it reaches 2097.6 MHz), but the PLL stops at 17.6 V at the maximum.

--Cheers
Attilio


Re: 561 scope extender wiring?

Albert Otten
 

I meant ordinary wire except for the coax lines.

In my extender I used ordinary wire, not twisted or whatever.


Re: 2465B CRT board values

Chuck Harris <cfharris@...>
 

Hi Hirofumi,

One thing to note is that Tektronix didn't expect that you
would be able to get perfect results in the outer most
major divisions of the CRT graticule. I always try for
perfection, but if you have to have a little geometric
distortion, or less than perfect focus, that is where it
should happen.

-Chuck Harris



Hirofumi Momose wrote:

Hi Chuck,

Scopes, like the 2465B, have only a single electron beam to
draw all that is on the CRT screen. They do this by time
multiplexing the beam between the readout, and the traces.
Flicker less readout with single gun displaying multiple
traces, various timebase is a magic to me.

Especially, I feel a bit difficulty to get best result from
CRT adjustment is interact of geometry and edge focus.
To minimize the vertical edge curveture(CAL 08)
causes the edges to being some degree of defocus.
Focusing on edge causes the center to defocus...
All of these are interact at some extent and to get best result
needs 'dialog' with the scope.
But now, got satisfactory level.

Best regards,
Hirofumi JJ2PNX






Re: 561 scope extender wiring?

Albert Otten
 

Hi Charles,

You will have seen that the coax to pines 3 and 4 has a crossover between left and right connector. For fault finding in the 3T77A I would do as in the time base connector, that is with braid to pin 4. Don't connect the braid to the ground wire! The other coax at pins 18/19 is straightforward.
BUT as far as I can see the 3S2 makes no use of pins 3/4, so cannot trigger the 7T11A internally. In the 3S2 diagrams you can see that the trigger signal merely goes to the Trigger Out front panel connector.
In my extender I used ordinary wire, not twisted or whatever. Remember that you normally won't use the extender during (HF) calibration. IIRC all adjustments can be reached from the left and right side of the oscilloscope.

Albert

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