Date   

Re: Vacuum forming 7K interface "covers"

Dave Casey
 

As thick as they are, I always assumed they were injection molded. I
believe someone has already drawn these up and 3-D printed them; I seem to
recall some list traffic about that a couple years ago. If I were in a
pinch for one, I'd be looking for that existing model to print some.

Dave Casey

On Tue, Apr 21, 2020 at 1:28 PM Ed Breya via groups.io <edbreya=
yahoo.com@groups.io> wrote:

The original parts probably were vacuum-formed, or possibly extruded. I
think nowadays, people would be more inclined to 3D-print them, which could
also allow for structural improvements in the design.

Ed




Re: Tektronix 577 crawling dots and CRT noise

Eric
 

I wonder if something is oscillating or out of alignment. At 0V collector there should be little to no deflection in any mode I know from talking to some people here that adjusting the storage / tube sections of the D1 is quite an undertaking and very fiddly adjustment.


Re: Vacuum forming 7K interface "covers"

Ed Breya
 

The original parts probably were vacuum-formed, or possibly extruded. I think nowadays, people would be more inclined to 3D-print them, which could also allow for structural improvements in the design.

Ed


Vacuum forming 7K interface "covers"

Eric
 

An Idea to save more 7K frames. The plastic covers for the “fingers” on the main interface boards of the 7K series are starting to show their age especially in units that have not been stored well. When I started working on 7000 frames about 2 years ago I was made aware at how rare these are getting. I have 2 spare covers that I have picked up along the way but I hate the idea that the only way to get these now it to canalize them from other units. I was thinking has any one tried vacuuming forming new ones?

From looking at the shape these seem like they could be duplicated in a vacuum forming operation with the correct mold possibly even 20 to 30 at a time out of one sheet. Has this been tried before?


Re: Tek 2465 and 2465A

 

You are a weak fallible human that makes mistakes?
Shame on you, and on all our human race!


Re: Tektronix 577 crawling dots and CRT noise

DW
 

Earplugs, there I fixed it!


Re: Artek Manuals

Colin Herbert
 

Eric,
I think there are a couple of inconsistencies/mistakes here.

The title of your post is "RE: [Tekscopes] Artek Manuals", but it has nothing to do with Artek Manuals.
You start off mentioning a 577, but then go on to mention a 177 twice. As far as I am aware, there is no Tek 177.

I also think that Tam is advising the OP NOT to scrap the 577, so your request is possibly out-of-place.

Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Eric
Sent: 21 April 2020 18:13
To: TekScopes@groups.io
Subject: Re: [TekScopes] Artek Manuals

If you are scrapping out a 577 I am in need of a high voltage cap from the 177 or would be interested in the whole 177 if it is available.



On Wed, Apr 15, 2020, 10:02 AM Tam Hanna <tamhan@tamoggemon.com <mailto:tamhan@tamoggemon.com> > wrote:

Hello,

on the risk of a beating: if you want to scrap the 577 because of a dead
CRT, do NOT do it.


A fix is forthcoming. Send an e-mail OFF LIST, saying STINKELY.


Tam

--
With best regards
Tam HANNA

Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at https://www.instagram.com/tam.hanna/


SC-502 Intensity Stuck at Maximum

Giovanni Carboni
 

Hello guys,

I am new here and this is my first question.

In my SC-502 scope the intensity is stuck to the maximum value and the knob cannot adjust it. I could reduce the intensity by reducing the beam current but I would like to fix the adjustable control. I measured voltages on the various transistors and checked waveforms but no results. Has anybody ecountered the same problem?

Giovanni


Re: Possible source for 1502 20mA tunnel diodes

Paul Amaranth
 

I haven't quite met the number of requests to make this viable
yet and added to that the current state of international shipping,
(heck, half of my domestic parcels are going missing) I'm putting
this on hold for a bit.

I have the emails of those who expressed interest (and if anyone
else is interested, please let me know) and I'll let you know if
this goes forward.

We'll see in a month or so. It may get better as things open up
a bit.

Paul

On Fri, Apr 17, 2020 at 04:03 PM, Paul Amaranth wrote:

I've located a possible source for the Russian replacement for
the 20mA tunnel diode used in the 1502. This is the 1i308E
which I've been looking for, on and off, for a few years.
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix & Windows


Re: CRT 'whine' - What causes it?

greenboxmaven
 

I have noticed this on occasion as well. I think it is the result of electrostatic attraction between the plates, much like electrostaic headphones or loudspeakers. Considering the plates are in a vacuum, the sound is heard via the mechanical structure, and makes one wonder how much movement is actually happening.

Bruce Gentry, KA2IVY

On 4/21/20 2:14 AM, Tim Phillips wrote:
From Tim P (UK)
Another post mentions 'CRT whine' I have this on a 5441 'scope when I go
into Store mode. (This instrument has other problems with the Storage board)

What causes this whine ? I don't know the frequency, but the note reminds
me of the clarinet intro to 'Rhapsody In Blue'

Is it elements in the CRT resonating somehow ? It's certainly louder than
the gentle hum of electrons going about their business.
Tim



Re: Calibrating Just the ∆t Cursors 2465B w/o Doing Full Calibration

Jelcke de Boer
 

Same problem here with the "Noisy or Aperiodic Signal". Please post your findings if you manage to fix this. Someone suggested cal 09 to me. I tried replacing the pal chip and hybrid U500, full recap, replaced nvram but these did not fix the parametric measurement issues.

Greetings,
Jelcke de Boer


Re: Tek 2465 and 2465A

Chuck Harris <cfharris@...>
 

I have no undisputed authority on the 2465 or any other
technical subject.

I have no interest in being an undisputed authority on
the 2465 or any other technical subject.

I am a weak fallible human that makes mistakes, sometimes
more often than not.

I offer my assistance as I offer it. Given that it is my
time to spend, it is on my terms and no other.

What is your problem?

-Chuck Harris

Raymond Domp Frank wrote:

On Tue, Apr 21, 2020 at 05:39 AM, Chuck Harris wrote:


I would imagine you could have verified the prefix by spending the same
30 seconds with the manual I did.
At it again, Chuck? Why?

I noticed something you wrote that seemed a typo (it was) and decided to try and help people asking (like Don) by correcting. No need to tell me I'd need 30 seconds in the manuals like you did - and you were unclear and came up with two typos.
The compatibilities and differences between the CA3046 vs. CA3086 were discussed in their heydays ('70's I think).

Do you expect me to feel embarrassed and apologize for not correcting you correctly? Sorry, I won't. Just like you won't and shouldn't for answering the same questions to different people in these groups again and again that can be looked up in the manuals (in seconds?) - and making a mistake now and then.
Your reaction is not a good way to have your undisputed authority in and on this family confirmed.

Raymond




Re: Tek 2465 and 2465A

 

On Tue, Apr 21, 2020 at 05:39 AM, Chuck Harris wrote:


I would imagine you could have verified the prefix by spending the same
30 seconds with the manual I did.
At it again, Chuck? Why?

I noticed something you wrote that seemed a typo (it was) and decided to try and help people asking (like Don) by correcting. No need to tell me I'd need 30 seconds in the manuals like you did - and you were unclear and came up with two typos.
The compatibilities and differences between the CA3046 vs. CA3086 were discussed in their heydays ('70's I think).

Do you expect me to feel embarrassed and apologize for not correcting you correctly? Sorry, I won't. Just like you won't and shouldn't for answering the same questions to different people in these groups again and again that can be looked up in the manuals (in seconds?) - and making a mistake now and then.
Your reaction is not a good way to have your undisputed authority in and on this family confirmed.

Raymond


Simple way to simulate high currents for current probes

Ed Breya
 

My original title for this was going to be "Yoozin up stuff," as you will see, but a more technical one is better.

For some time, I have been contemplating making a high current test source for fooling around with high current clip-on type probes. I have a number of different kinds that I wanted to check out and fix and improve. I also have lots and lots of deguassing coils salvaged from color TVs and monitors over the years. I've saved every one that was intact, thinking someday I'd use some to make Helmholtz coils, or as sources of magnet wire, or to make giant gauge, short sections of Litz wire. I never did any of those things, so was considering finally getting rid of them by transfer to the scrap wire salvage department.

I put these issues together, and tried out a current multiplication scheme. There is absolutely nothing special or new about doing this - everybody knows the old trick of looping multiple turns of wire through a current probe to boost the sensitivity. What's different here, is the ease of getting quite a high multiplication factor, and especially, using up some stuff that I was prepared to toss.

TV degaussing coils are typically magnet wire coils bundled up with PVC tape to form loops maybe a foot or so in diameter, and then shaped and placed around the jug of the CRT. When power is first applied, a circuit (usually a simple PTC) puts some AC line current through the coils, which gradually diminishes to zero or a low value. This demagnetizes the shadow mask sufficiently to get the required purity.

Depending on the number of turns in the coil, it can be used as a multiplier just by passing known current through it, resulting in a much larger equivalent current readout from a probe device clamped around it. Of course, you can wind up all sorts of nice coils that will accomplish this, but here's a ready-made deal that can be very easy to apply.

I set up an experiment with a pretty fat coil, about 10 mm diameter, and about a foot of loop diameter, looped back over itself to make a three-loop bundle, about 4" diameter. This effectively multiples the turns three more times. I ran AC through it from the 576, set up at the maximum available in the 15 V range. The current was about 2.6 A peak, so around 1.8 A RMS. This is about as high as I would want to run this particular one continuously, since it gets pretty warm - eventually the tape wrapping would fall apart if it gets too hot. A clip-on ammeter read about 450 A, so working back from the input current and the turns and loops, it looks like the degaussing coil itself is about 80 turns. The triple-looped assembly measured about 6.8 mH and 5 ohms unburdened.

Of course, this is not exactly equivalent to a single large conductor, since the loop bundle shape has different field arrangement and current distribution. But, using these kinds of probes is not exactly a high precision deal anyway - the position and angle of the jaws around the conductor has fairly large effects. With consistent positioning and methods, it should be possible to figure out the "exact" number of coil turns (without actually unwrapping the tape and counting), and make fairly accurate, repeatable measurements.

This is much simpler and more compact than producing hundreds of actual amps, measuring them accurately, and shoving them through big enough conductors to get the job done. With enough multiplication, you can control and measure in the 2 amp range, say, for checking high current probes. This also would work for DC probes.

So anyway, I guess now I'll have to keep these coils after all - so much for getting rid of stuff.

Ed


Re: Tektronix 577 crawling dots and CRT noise

Tam Hanna
 

Four step plan

a) send email to tamhan@tamoggemon.com with subject STINKELY

b) wait

c) Smash up CRT

--
With best regards
Tam HANNA

Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at https://www.instagram.com/tam.hanna/


CRT 'whine' - What causes it?

Tim Phillips
 

From Tim P (UK)
Another post mentions 'CRT whine' I have this on a 5441 'scope when I go
into Store mode. (This instrument has other problems with the Storage board)

What causes this whine ? I don't know the frequency, but the note reminds
me of the clarinet intro to 'Rhapsody In Blue'

Is it elements in the CRT resonating somehow ? It's certainly louder than
the gentle hum of electrons going about their business.
Tim


Re: Scope Probe to BNC Adaptor

satbeginner
 

Or maybe these from in China,they have two sizes:

#Aliexpress € 2,70 20%OFF | Oscilloscope Probe 3.8mm/5mm Adapter for HF Tektronix For Agilent BNC Adapter Probe BNC Quick Plug

https://a.aliexpress.com/_dWWLfPe


Re: Tek built Interad SA

nonIonizing EMF
 

On Mon, Apr 20, 2020 at 06:35 PM, Ed Breya wrote:


I'd recommend not to bother with it, except to inform Kurt so it can be shown
on tekwiki.
Thanks for the feedback as I saw where made and was thinking surveillance use as Jeff noted in his message.

I'll message the seller to verify it's OK to use the images and update the Tekwiki accordingly.


Re: Tek built Interad SA

Jeff Kruth
 

SA = Spectrum Analyzer

In a message dated 4/20/2020 11:58:02 PM Eastern Standard Time, grbosworth@gmail.com writes:
What is SA???



On Mon, Apr 20, 2020, 20:42 Jeff Kruth via groups.io <kmec=aol.com@groups.io>
wrote:

Hi Tom!

In my experience, no. It seems a shame, start with a (reasonably) good
concept, buy high quality parts, do all the front panel work, etc. =
rubbish.
Got a chuckle from your question.
Best Regards,Jeff

In a message dated 4/20/2020 5:56:26 PM Eastern Standard Time,
tbryan@nova.org writes:
Hi Jeff,

Did Interad build anything that worked?

Tom




Re: Tek built Interad SA

Gary Robert Bosworth
 

What is SA???



On Mon, Apr 20, 2020, 20:42 Jeff Kruth via groups.io <kmec=aol.com@groups.io>
wrote:

Hi Tom!

In my experience, no. It seems a shame, start with a (reasonably) good
concept, buy high quality parts, do all the front panel work, etc. =
rubbish.
Got a chuckle from your question.
Best Regards,Jeff

In a message dated 4/20/2020 5:56:26 PM Eastern Standard Time,
tbryan@nova.org writes:
Hi Jeff,

Did Interad build anything that worked?

Tom



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