Date   

Re: CRT magnetic screens: Mumetal?

d.seiter@...
 

While I've never played with Mu-metal, I have kept all my shields too, knowing about the properties of the material.  My question- I know bending and heating affect the metal, but I didn't know that cutting it had an effect.  What is the best way to cut it?  I'd assume no deflection, so a small cutting disc on well supported stock with coolant would seem to be the best approach?

-Dave



From: "Ed Breya"
To: TekScopes@...
Sent: Wednesday, June 19, 2013 4:36:41 PM
Subject: [TekScopes] Re: CRT magnetic screens: Mumetal?

 

I think in the earlier days, or in some manuals, there were warnings about avoiding stresses on the material. It's not practical to re-anneal to original performance if seriously banged up, but the overall shielding is still pretty good even so, and certainly better than nothing. For our purposes, I wouldn't worry too much about a few dings here and there - just don't put any magnets near the defects, which could become slightly magnetized and possibly cause distortion in the CRT.

I've saved the shields from every CRT item I've ever junked out, and have worked and re-used the material for a number of applications. It loses some of its effectiveness near any cuts or sharp bends, but large planar areas that aren't stressed too much tend to be OK.

Ed

--- In TekScopes@..., "John S" wrote:
>
>
> Thanks for the confirmation guys: must have been an expensive component. There's no "warning" lable on either the shield or the manual to tell you not to knock etc.
>
> John
>


Re: Tektronix Plug-in Extension Cable "012-0030-00" ?

 

Hi mda,

On Thu, Jun 20, 2013 at 3:31 AM, mda231 <mda231@yahoo.com> wrote:


Have just done a search and found this:

http://tech.groups.yahoo.com/group/TekScopes/message/92338

- Seems the part numbers are correct.
from what I've seen all amphenol connectors are the same, they just
differ on the number of pins.

If you want to make one on the cheap, grab a Centronics cable and a Dremel.

D.


Re: Waaayyyy OT for Portland folks

Ed Breya
 

Ethel's was long gone even twenty five years ago - I think a car parts store was in its place the last time I was there about fifteen years ago.

For some reason, I was reminiscing the distant past after someone mentioned Howard's 100th BD. I especially remember Building 50, and visiting people at Tek Labs for various future product technology possibilities, and the environmental lab, for current tests and problem resolution. Does anyone remember Crazy Marv, who did most of the EMC and environmental tests back then? Also Jim Smiley, the chemistry expert - I would credit him with harassing everyone enough to ensure that this old gear still mostly works today, after decades of environmental exposure. I doubt this group would even exist if not for him.

One of my last memories of B50 was when I taught my future wife standard transmission hill-holding on the sloped ramp down to the loading dock in my '68 MGB - the "Rust Bucket." It was after work, but there were still plenty of people around to notice, but hopefully not laugh too loudly. It was pretty hard to be inconspicuous, since the back "seat" was full of boxes of empty beer bottles destined for recycling the next day - just a coincidence. Improper clutch action really rattles those things around, but it gives great feedback.

Ed

--- In TekScopes@yahoogroups.com, larrys@... wrote:

Just thinking back to a couple Beaverton trips 30+ years ago.
Is Earthquake Ethel's still around?
-ls-


Re: Spot the 'scope

Jerry Barr
 

too busy watchin the brunette
 
Jerry KJ6NTL

From: mda231
To: TekScopes@...
Sent: Wednesday, June 19, 2013 3:24 PM
Subject: [TekScopes] Re: Spot the 'scope
 


Hello Julian,

I know I'm a "bit" late on this one, but the scope is definitely a 545A.

If you go to the Youtube link of the video, pause it at about 1:03 - 1:04 and go into full-screen mode, you will see the scope's name in the usual place. It's the scene where the scientist seems to be adjusting the scope's "VARIABLE" control.

It's a really nice track, by the way: I am quite a fan of Benny Benassi's stuff and have been since I heard "Satisfaction".

http://www.youtube.com/watch?v=8k01lcSB0-g

Did anyone spot what looks like an MPC-3000 at about 1:10?

MDA.

--- In mailto:TekScopes%40yahoogroups.com, "Julian" wrote:
>
> I happened upon a music video by Benny Benassi that features a nice vintage Tektronix 'scope, I think it's a 545, but am not sure?
>
> Here is the link - the 'scope appears right at the start, and throughout.
>
> http://www.lp33.tv/artists/bennybenassi/
>
> The track is called "Cinema".
>


Re: 533 and 535 on Seattle Craigslist

 

On Thu, 20 Jun 2013 02:54:30 -0000, "yankee495"
<yankee495@mailshack.com> wrote:

--- In TekScopes@yahoogroups.com, "sipespresso" <sipespresso@...> wrote:

I have no affiliation with the seller.
http://seattle.craigslist.org/est/ele/3882133784.html
-Kurt
I think those are electric heaters...hehehe.

No really...hope someone grabs them.
Definately. I lived in a drafty loft for a while and my clone 545A
made an excellent convection space heater. I avoided using it during
summer of course.


Re: 533 and 535 on Seattle Craigslist

yankee495 <yankee495@...>
 

--- In TekScopes@yahoogroups.com, "sipespresso" <sipespresso@...> wrote:

I have no affiliation with the seller.
http://seattle.craigslist.org/est/ele/3882133784.html
-Kurt

I think those are electric heaters...hehehe.

No really...hope someone grabs them.


Waaayyyy OT for Portland folks

teamlarryohio
 

Just thinking back to a couple Beaverton trips 30+ years ago.
Is Earthquake Ethel's still around?
-ls-


533 and 535 on Seattle Craigslist

sipespresso <sipespresso@...>
 

I have no affiliation with the seller.
http://seattle.craigslist.org/est/ele/3882133784.html
-Kurt


Re: Tektronix Plug-in Extension Cable "012-0030-00" ?

David Holland
 

Have you prepared for the sticker shock when pricing those parts?

You can buy a whole extender for just what the connectors alone cost new......


On Wed, Jun 19, 2013 at 9:31 PM, mda231 <mda231@...> wrote:


Have just done a search and found this:

http://tech.groups.yahoo.com/group/TekScopes/message/92338

- Seems the part numbers are correct.

MDA.

--- In TekScopes@..., "mda231" wrote:
>
>
>
> Hello Tim,
>
> I suspect I may have to make my own, as you suggest.
>
> Having done some searching based on what you and Damian have said, I think the plug is an "Amphenol 26-159-16" and the socket is an "Amphenol 26-190-16".
>
> Can you or anyone else who's made their own confirm this, please?
>
> Thanks.
>
> MDA.
>
> --- In TekScopes@..., "Tim Phillips" wrote:
> >
> > from Tim P (UK)
> > Sometimes some rigid extenders appear on the 'bay, but for flexibles, most people roll their own.
> > The connectors are reasonably easy to get, and you just need wire that can carry the currents involved,
> > and co-ax for the signal and trigger lines. (I *think* these may be 93 ohm.)
> > Tim
>




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Re: Tektronix Plug-in Extension Cable "012-0030-00" ?

mda231
 

Have just done a search and found this:

http://tech.groups.yahoo.com/group/TekScopes/message/92338

- Seems the part numbers are correct.

MDA.

--- In TekScopes@yahoogroups.com, "mda231" <mda231@...> wrote:



Hello Tim,

I suspect I may have to make my own, as you suggest.

Having done some searching based on what you and Damian have said, I think the plug is an "Amphenol 26-159-16" and the socket is an "Amphenol 26-190-16".

Can you or anyone else who's made their own confirm this, please?

Thanks.

MDA.

--- In TekScopes@yahoogroups.com, "Tim Phillips" <tim@> wrote:

from Tim P (UK)
Sometimes some rigid extenders appear on the 'bay, but for flexibles, most people roll their own.
The connectors are reasonably easy to get, and you just need wire that can carry the currents involved,
and co-ax for the signal and trigger lines. (I *think* these may be 93 ohm.)
Tim


Re: 7854 readout jitter

 

On Thu, 20 Jun 2013 00:36:29 +0100, Chris Wilson
<chris@chriswilson.tv> wrote:

Yes easy, just put a time base into a vertical slot, nothing in the
horizontal. You'll get a line up the screen, adjust to centre, job done.
Regards,
David Partridge
20/06/2013 00:33

I tried this, and get no display at all save for the readout. Maybe I
moved it more than I thought, or it's incredibly sensitive? Or maybe
I am misunderstanding and missing some point? I can try David Whess's
idea, but don't want to muddy the waters further if I am
misunderstanding your all external save twiddling the pot method. I
had a 7B85 in the leftmost slot, and no other plugins in the chassis.

Thanks David P and David W.
I do not know the pattern but some of the 7000 series mainframes
require a plug-in to be installed in the selected horizontal slot or
they blank the z-axis. The deflection circuits are still driven so
you can see the readout jitter depending on the timebase sweep but no
trace will be seen.

I just checked and my 7854 blanks the z-axis without a horizontal
plug-in installed but I know my 7603 does not care.


Re: Tektronix Plug-in Extension Cable "012-0030-00" ?

mda231
 

Thanks again, Damian. - I think I may have now found the Amphenol part numbers.

MDA.

--- In TekScopes@yahoogroups.com, "cheater00 ." <cheater00@...> wrote:

On Wed, Jun 19, 2013 at 5:37 PM, Tim Phillips
<tim@...> wrote:
Sometimes some rigid extenders appear on the 'bay, but for flexibles, most people roll their own.
The connectors are reasonably easy to get, and you just need wire that can carry the currents involved,
and co-ax for the signal and trigger lines. (I *think* these may be 93 ohm.)
Yeah, they're just Amphenol.

BTW, the guy also has this:
http://www.ebay.de/itm/Amphenol-Kabel-24pol-Buchse-Stecker-75cm-Cable-ADMIRAL-/230989454751?pt=Mess_Pr%C3%BCftechnik&hash=item35c80b5d9f

Then there's also this:

http://www.ebay.de/itm/Tektronix-067-0590-00-Calibration-Fixture-568-R568-Oscilloscope-Plug-In-Extender-/390600552477?pt=BI_Oscilloscopes&hash=item5af19b701d

and:

http://www.ebay.de/itm/Tektronix-067-0591-00-Calibration-Fixture-560-Series-Oscilloscope-Extender-/271199605568?pt=LH_DefaultDomain_0&hash=item3f24c19340

Cheers,
D.


Re: Tektronix Plug-in Extension Cable "012-0030-00" ?

mda231
 

Hello Tim,

I suspect I may have to make my own, as you suggest.

Having done some searching based on what you and Damian have said, I think the plug is an "Amphenol 26-159-16" and the socket is an "Amphenol 26-190-16".

Can you or anyone else who's made their own confirm this, please?

Thanks.

MDA.

--- In TekScopes@yahoogroups.com, "Tim Phillips" <tim@...> wrote:

from Tim P (UK)
Sometimes some rigid extenders appear on the 'bay, but for flexibles, most people roll their own.
The connectors are reasonably easy to get, and you just need wire that can carry the currents involved,
and co-ax for the signal and trigger lines. (I *think* these may be 93 ohm.)
Tim


Re: Tektronix Plug-in Extension Cable "012-0030-00" ?

mda231
 

Thanks Damian. - That's the general type of thing, but I am looking for the flexible cable version.

MDA

--- In TekScopes@yahoogroups.com, "cheater00 ." <cheater00@...> wrote:

Hi MDA,

On Wed, Jun 19, 2013 at 4:29 PM, mda231 <mda231@...> wrote:
Thanks for the hint. - I've had a look on ebay in the UK and couldn't see any, unfortunately.

The one I'm looking for is suitable for a 500 series scope (Type 556).

It's in Austria:

http://www.ebay.de/itm/Tektronix-Plug-In-Extension-545A-545B-547-555-551-549-531A-Extender-Verlangerung-/230986824259?pt=Mess_Pr%C3%BCftechnik&hash=item35c7e33a43

Cheers,
Damian


Re: CRT magnetic screens: Mumetal?

Ed Breya
 

I think in the earlier days, or in some manuals, there were warnings about avoiding stresses on the material. It's not practical to re-anneal to original performance if seriously banged up, but the overall shielding is still pretty good even so, and certainly better than nothing. For our purposes, I wouldn't worry too much about a few dings here and there - just don't put any magnets near the defects, which could become slightly magnetized and possibly cause distortion in the CRT.

I've saved the shields from every CRT item I've ever junked out, and have worked and re-used the material for a number of applications. It loses some of its effectiveness near any cuts or sharp bends, but large planar areas that aren't stressed too much tend to be OK.

Ed

--- In TekScopes@yahoogroups.com, "John S" <John@...> wrote:


Thanks for the confirmation guys: must have been an expensive component. There's no "warning" lable on either the shield or the manual to tell you not to knock etc.

John


Re: 7854 readout jitter

Chris Wilson
 


Yes easy, just put a time base into a vertical slot, nothing in the
horizontal. You'll get a line up the screen, adjust to centre, job done.
Regards,
David Partridge



20/06/2013 00:33

I tried this, and get no display at all save for the readout. Maybe I
moved it more than I thought, or it's incredibly sensitive? Or maybe
I am misunderstanding and missing some point? I can try David Whess's
idea, but don't want to muddy the waters further if I am
misunderstanding your all external save twiddling the pot method. I
had a 7B85 in the leftmost slot, and no other plugins in the chassis.

Thanks David P and David W.

--
Best Regards,
Chris Wilson.


Re: CRT magnetic screens: Mumetal?

Bernice Loui <rupunzels_window@...>
 

Not just dropping, bending or trying to alter the shape of those magnetic shields will reduce their effectiveness.


There are two basic version of magnetic shielding Co-NETIC and NETIC. There are versions of mu metal that does not require the hydrogen annealing process post fab, but they may not be as effective as the materials that require the post fab annealing process.


http://www.magnetic-shield.com/faqs-all-about-shielding.html


Bernice





--- On Wed, 6/19/13, Steve wrote:

From: Steve
Subject: [TekScopes] Re: CRT magnetic screens: Mumetal?
To: TekScopes@...
Date: Wednesday, June 19, 2013, 10:05 PM

 

--- In TekScopes@..., "John S" wrote:
>
>
> I've always assumed that the blue screen around the CRT on Tek scopes (400 series etc) was made of Mumetal. Is this actually true?
>
> John
>

Yes.

Tek fabricated them from raw stock. After they were cut, bent and spot welded, they went into an oven to be annealed (mu metal loses its shielding properties if physically bent or modified (drilling holes etc.) after annealing. If you drop a shield on the floor and the corner bends - throw it away.) The ovens operated at high temperature in a pure hydrogen (reducing) atmosphere. Opening an oven door before it had cooled posed an explosion hazard. To minimize the danger, Tek used several small ovens, each could only contain about 4 or 6 shields.

- Steve


Re: CRT magnetic screens: Mumetal?

John
 

Thanks for the confirmation guys: must have been an expensive component. There's no "warning" lable on either the shield or the manual to tell you not to knock etc.

John


Re: Spot the 'scope

mda231
 

Hello Julian,

I know I'm a "bit" late on this one, but the scope is definitely a 545A.

If you go to the Youtube link of the video, pause it at about 1:03 - 1:04 and go into full-screen mode, you will see the scope's name in the usual place. It's the scene where the scientist seems to be adjusting the scope's "VARIABLE" control.

It's a really nice track, by the way: I am quite a fan of Benny Benassi's stuff and have been since I heard "Satisfaction".

http://www.youtube.com/watch?v=8k01lcSB0-g

Did anyone spot what looks like an MPC-3000 at about 1:10?

MDA.

--- In TekScopes@yahoogroups.com, "Julian" <Julian.Bunn@...> wrote:

I happened upon a music video by Benny Benassi that features a nice vintage Tektronix 'scope, I think it's a 545, but am not sure?

Here is the link - the 'scope appears right at the start, and throughout.

http://www.lp33.tv/artists/bennybenassi/

The track is called "Cinema".


Re: Is this P5205 worth buying and repairing?

 

On Wed, 19 Jun 2013 21:56:20 -0000, "Steve" <ditter2@yahoo.com> wrote:

--- In TekScopes@yahoogroups.com, "cheater00 ." <cheater00@...> wrote:

On Wed, Jun 19, 2013 at 5:14 PM, David <davidwhess@...> wrote:
In theory by negating the readout current you could divide by 10
instead of multiplying by 10 but I am not aware of a probe doing that.
It would require an external power connection.
...which would fit given that a probe which amplifies stuff needs a
power connection anyways :) Very smart indeed :)

D.
Nice theory, but the readout logic does not work that way. It only detects current in one direction, and will not apply gain if you tried to reverse it, which possibly may damage the chip. The intent was only to handle attenuating probes, which back in the 1960's when this was designed, only attenuated in factors of /1, /10, /100 and /1000.

The ability to handle the inner division factors (/20,/50, /200, etc. was added with 11000 series plug-ins, which used a processor to read the encoding ring. TDS400 and TDS700C added gain factors as well. communication to the readout system in 11000 series is through a serial data bus, not the time slot current sense system used in 7000 series.

- Steve
Ah well, it would have worked if not for those meddling kids.

Looking at it now, I see that a darlington emitter follower (and a
diode) used to isolate the time slot pulses from the readout
connector. For some reason I thought the current was added directly
or via a current mirror for isolation.

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