Date   

Re: 453 CRT removed from screen: photos

 

On the 7834 where I have separated the shield from the CRT a couple of
times, they are completely separate pieces. There it is possible to
install the CRT without the shield although all of the magnetic
interference from the rest of the oscilloscope renders the CRT useless
until the shield is installed; the display becomes a smear.

On Thu, 20 Jun 2013 16:01:06 -0000, "John S" <John@sykesj.co.uk>
wrote:

Purely from curiosity, I removed this CRT from its Mumetal screen: not an easy task, as it was "glued" in at the front corners with what looked like foam.

To my surprise, the front face detached in the process, so I've taken some photos looking back down the tube. I was also surprised to see a "window" through which the electron beam fires: the last object prior to hitting the screen. You can just see where beam has "written" on this window.

The Y-plates are segmented, but all wired in parallel: I did wonder if this was a part common to the 454, and for this latter variant they added inductors to create the delay line?

Photos at

http://www.flickr.com/photos/jaybs/sets/72157630205984812/

John


Re: Waaayyyy OT for Portland folks

 

On Thu, Jun 20, 2013 at 8:24 PM, <larrys@teamlarry.com> wrote:
Dave C <davec2468@yahoo.com> wrote:
The story back then was that programming for the fancy lighting
effects
What "fancy lighting effects" are those?
Been a long time. ISTR some really flexible chase lights, strobes,
screens rolling down from the ceiling (for earthquake loops),
synchronized with loud audio. Back around 1980, it was one of those
places where "If you have a trip to Beaverton you have to go there."
In today's world, it would probably be called quaint :-/
-ls-
Quaint is the new exciting, though.


Re: OT: Capacitors in general

keantoken
 

Look at this page for a bridge comparison of different capacitors, with some pictures of the residuals.

Also see his article on a capacitance bridge:

http://www.conradhoffman.com/cap_bridge.pdf


Re: Waaayyyy OT for Portland folks

teamlarryohio
 

Dave C <davec2468@yahoo.com> wrote:
The story back then was that programming for the fancy lighting
effects
What "fancy lighting effects" are those?
Been a long time. ISTR some really flexible chase lights, strobes,
screens rolling down from the ceiling (for earthquake loops),
synchronized with loud audio. Back around 1980, it was one of those
places where "If you have a trip to Beaverton you have to go there."
In today's world, it would probably be called quaint :-/
-ls-


Re: Waaayyyy OT for Portland folks

Dave C <davec2468@...>
 

The story back then was that programming for the fancy lighting
effects 

What "fancy lighting effects" are those?

Dave


Re: Waaayyyy OT for Portland folks

teamlarryohio
 

"Ed Breya" <edbreya@yahoo.com> wrote:
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.
The story back then was that programming for the fancy lighting
effects was done by one of Howard's sons. It supposedly ran on a PDP-8.
-ls-


Re: Did anyone see this 2465?

Michael A. Terrell
 

Michael A. Terrell wrote:

http://www.ebay.com/itm/350805825418

"Tektronix-2465-4-Channel-300-MHz-Portable-OscilloscopeDisplay-Flashes-Parts-"

BIN $174.99 & free shipping

It arrived today, and is in good condition, other than one push button. I plan on cleaning the case and recapping it before I see what else it may need. The seller packed it with rigid polyurethane foam, about 1.5" on all sides.


453 CRT removed from screen: photos

John
 

Purely from curiosity, I removed this CRT from its Mumetal screen: not an easy task, as it was "glued" in at the front corners with what looked like foam.

To my surprise, the front face detached in the process, so I've taken some photos looking back down the tube. I was also surprised to see a "window" through which the electron beam fires: the last object prior to hitting the screen. You can just see where beam has "written" on this window.

The Y-plates are segmented, but all wired in parallel: I did wonder if this was a part common to the 454, and for this latter variant they added inductors to create the delay line?

Photos at

http://www.flickr.com/photos/jaybs/sets/72157630205984812/

John


Re: CRT magnetic screens: Mumetal?

Ed Breya
 

It's not about degaussing, it's a problem with losing the grain orientation that was imparted during annealing.

Annealing it is very difficult since the temperature is quite high - like approaching its melting point, and the hydrogen atmosphere is very risky. It occured to me once to maybe try an oxy-hydrogen torch with an over-rich flame, but then the problem is what do you do about the opposite side, and the transition region from flame to not, and hot to cold. It really needs to be in a uniform environment.

If you buy raw sheet stock, it may be un-annealed, so won't work as well as that in a finished piece that definitely would have been. If the stock is labeled so or known to be annealed, then it's good stuff to keep around.

Ed

--- In TekScopes@yahoogroups.com, Peter Hildebrandt <petertech99h@...> wrote:

Hi Steve,

Can you save a dropped shield with a AC degauss coil?  How high a temperature
was needed to anneal the Mu metal?
A local guy over here is sitting on a little stock of Mu, maybe I'll get it for future
use! you never know!

see ya

Peter
 
 




________________________________
From: Steve <ditter2@...>
To: TekScopes@yahoogroups.com
Sent: Wednesday, June 19, 2013 5:05:53 PM
Subject: [TekScopes] Re: CRT magnetic screens: Mumetal?



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

Ed Breya
 

That's a good question - I have only used tin snips, which necessarily bend the two sides of the cut. A saw or wheel would be better in that respect. I think a very fine carbide-tipped saw would give the cleanest cut. The material may be soft enough to gum up an abrasive wheel, but I don't know. If you try these methods, please let us know how they work.

I usually assume that any reworked piece will have less than half of its original effectiveness just from handling, and maybe one-tenth near any stressed zones. Even if you beat the hell out of it, it's still at least as good as the original un-annealed material, which I would think is at least as good as steel.

Ed

--- In TekScopes@yahoogroups.com, d.seiter@... wrote:

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

----- Original Message -----
From: "Ed Breya" <edbreya@...>
To: TekScopes@yahoogroups.com
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@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


Tek 335

vdonisa
 

Hello gents, quick question - what would be the entertainment factor in trying to restore a Tek 335? Would this be some pleasurable exercise or a nightmare where you need 3-4 hands in order to dis(assemble) the thing, and some unobtainium parts too for adding spice?


Re: CRT magnetic screens: Mumetal?

Richard Solomon <dickw1ksz@...>
 

MuMetal ... that brings back memories. I thought that stuff
went out of vogue after WW II. The new kid on the block
was Conetic Metal (or something like that, it's been 40 years
since I played with that stuff).

73, Dick, W1KSZ


On Thu, Jun 20, 2013 at 1:05 AM, <d.seiter@...> wrote:
 

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" <edbreya@...>
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: OT: Capacitors in general

vdonisa
 

I'll definitely do, for now David came with some good suggestions on how to watch them on the CRT so I'll spend the evening finding well matching replacements for the .22uF and 3.3uF tantalums in the HVPS and A1 board. From the LCR measurements my guts feeling says film caps would be the closest. Will report to the group with the findings.

Thanks,
Valentin

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

Valentin,

On Thu, Jun 20, 2013 at 3:48 PM, vdonisa <vdonisa@...> wrote:
Gee seems I stirred up a wasp hornet.... Sorry guys.

Let's forget the audio thing and let me rephrase the question:

Can you folks suggest a setup involving a HP function generator and a Tek scope in the 22xx or 24xx series, where I could put in evidence the differences in behavior at different frequencies between two caps of same capacitance?
why don't you read the following articles by Cyril Bateman on testing
capacitors: www.proaudiodesignforum.com/forum/php/viewtopic.php?f=6&t=153&start=1


Re: OT: Capacitors in general

 

Valentin,

On Thu, Jun 20, 2013 at 3:48 PM, vdonisa <vdonisa@yahoo.com> wrote:
Gee seems I stirred up a wasp hornet.... Sorry guys.

Let's forget the audio thing and let me rephrase the question:

Can you folks suggest a setup involving a HP function generator and a Tek scope in the 22xx or 24xx series, where I could put in evidence the differences in behavior at different frequencies between two caps of same capacitance?
why don't you read the following articles by Cyril Bateman on testing
capacitors: www.proaudiodesignforum.com/forum/php/viewtopic.php?f=6&t=153&start=1


Re: OT: Capacitors in general

vdonisa
 

Sounds like a plan... Thanks a lot! The gen is HP 3325A, it can do log sweeps too.

I'll try both methods and see what gives. The other cap that bugged me is the 3.3uF tantalum on the A1 board in the 24xx series (3 pcs). This one will be interesting as I already have in stock 3 different versions of axial tantalum (at different voltage ratings / capsule sizes) plus some film ones. I already know they behave differently when measured with LCR meter, a sweep would be even more interesting. I'm planning to re-cap A1 this summer, it would help a lot to know what I'm doing (before the expensive smoke comes out that is lol).

Thanks,
Valentin

--- In TekScopes@yahoogroups.com, David <davidwhess@...> wrote:

Use the sweep output (sawtooth) from the oscilloscope to frequency
modulate the function generator and you have an instant scalar network
analyzer. With one sawtooth out and two vertical inputs, you can even
display the results from two capacitors or display the difference
using add and invert mode.

Or if you have a swept function generator, use the oscilloscope in XY
mode. That will work better if the function generator supports
logarithmic sweeps.

On Thu, 20 Jun 2013 13:48:16 -0000, "vdonisa" <vdonisa@...>
wrote:

Gee seems I stirred up a wasp hornet.... Sorry guys.

Let's forget the audio thing and let me rephrase the question:

Can you folks suggest a setup involving a HP function generator and a Tek scope in the 22xx or 24xx series, where I could put in evidence the differences in behavior at different frequencies between two caps of same capacitance?

I know you know scopes inside out, so how can I achieve this? Should I go for some differential setup where I power 2 RC series circuits, connected in parallel, with 100 Ohms resistors, and probe 1 capacitor with Channel 1 and the other one with Channel 2 and watch the screen? Wouldn't the 2 circuits in parallel influence each other? Should I do them 1 at a time instead with 50 Ohm resistors?

Please assume we're now talking stuff like the mystery .22uF tantalum caps in the 24xx HVPS and I want to compare ceramic vs film vs tantalum.

Thanks,
Valentin VE3VDO

--- In TekScopes@yahoogroups.com, "Michael A. Terrell" <mike.terrell@> wrote:

Artekmedia wrote:

Yeah but make sure it is gold plated oxygen free barbed wire...


Re: OT: Audio capacitors PLEASE STOP!

 

Gentlemen,
The serious members of the forum would appreciate it greatly if you would
please stop any further discussion of audiophiles and their beliefs before
this gets out of hand yet again.

In the past every discussion of their "interesting" beliefs has gone way off
topic and raged like a fire storm for months.

Just remember this is a forum about Tektronix. The audiophiles have their
own forum and I am sure they would love to hear your opinions about barbed
wire. Perhaps the cattle rancher forum would be interested in the audio
qualities of barbed wire as well.

Thank you in advance,
Dennis


Re: OT: Capacitors in general

 

Use the sweep output (sawtooth) from the oscilloscope to frequency
modulate the function generator and you have an instant scalar network
analyzer. With one sawtooth out and two vertical inputs, you can even
display the results from two capacitors or display the difference
using add and invert mode.

Or if you have a swept function generator, use the oscilloscope in XY
mode. That will work better if the function generator supports
logarithmic sweeps.

On Thu, 20 Jun 2013 13:48:16 -0000, "vdonisa" <vdonisa@yahoo.com>
wrote:

Gee seems I stirred up a wasp hornet.... Sorry guys.

Let's forget the audio thing and let me rephrase the question:

Can you folks suggest a setup involving a HP function generator and a Tek scope in the 22xx or 24xx series, where I could put in evidence the differences in behavior at different frequencies between two caps of same capacitance?

I know you know scopes inside out, so how can I achieve this? Should I go for some differential setup where I power 2 RC series circuits, connected in parallel, with 100 Ohms resistors, and probe 1 capacitor with Channel 1 and the other one with Channel 2 and watch the screen? Wouldn't the 2 circuits in parallel influence each other? Should I do them 1 at a time instead with 50 Ohm resistors?

Please assume we're now talking stuff like the mystery .22uF tantalum caps in the 24xx HVPS and I want to compare ceramic vs film vs tantalum.

Thanks,
Valentin VE3VDO

--- In TekScopes@yahoogroups.com, "Michael A. Terrell" <mike.terrell@...> wrote:

Artekmedia wrote:

Yeah but make sure it is gold plated oxygen free barbed wire...


Re: OT: Capacitors in general

vdonisa
 

Gee seems I stirred up a wasp hornet.... Sorry guys.

Let's forget the audio thing and let me rephrase the question:

Can you folks suggest a setup involving a HP function generator and a Tek scope in the 22xx or 24xx series, where I could put in evidence the differences in behavior at different frequencies between two caps of same capacitance?

I know you know scopes inside out, so how can I achieve this? Should I go for some differential setup where I power 2 RC series circuits, connected in parallel, with 100 Ohms resistors, and probe 1 capacitor with Channel 1 and the other one with Channel 2 and watch the screen? Wouldn't the 2 circuits in parallel influence each other? Should I do them 1 at a time instead with 50 Ohm resistors?

Please assume we're now talking stuff like the mystery .22uF tantalum caps in the 24xx HVPS and I want to compare ceramic vs film vs tantalum.

Thanks,
Valentin VE3VDO

--- In TekScopes@yahoogroups.com, "Michael A. Terrell" <mike.terrell@...> wrote:

Artekmedia wrote:

Yeah but make sure it is gold plated oxygen free barbed wire...


Re: Spot the 'scope

Jerry Barr
 

he does have the right tools for the job / Jpl also used some of his sounds in their productions for curiosity  some of the same look but didn't quite match up
lol
 
Jerry KJ6NTL

From: mda231
To: TekScopes@...
Sent: Thursday, June 20, 2013 6:01 AM
Subject: [TekScopes] Re: Spot the 'scope
 


I can understand that entirely. (- And I concur with your selection wholeheartedly, Sir).

You need to look up Benny Benassi's "Satisfaction" on youtube... Come back and dare tell me it doesn't make you want to take up DIY...

MDA

--- In mailto:TekScopes%40yahoogroups.com, Jerry Barr wrote:
>
> too busy watchin the brunette
>
> Jerry KJ6NTL
>
>
> ________________________________
> From: mda231
> To: mailto:TekScopes%40yahoogroups.com
> 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: Tektronix Plug-in Extension Cable "012-0030-00" ?

mda231
 

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

Hi mda,

On Thu, Jun 20, 2013 at 3:31 AM, 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.
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.

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