Author Topic: Which 'Scope was this??  (Read 3230 times)

0 Members and 1 Guest are viewing this topic.

Offline Sparc

  • Contributor
  • Posts: 16
Which 'Scope was this??
« on: November 24, 2013, 10:14:21 pm »
Hi.  I was thinking about an oscilloscope I briefly used many years ago.  It was long ago and I didn't pay attention to the make or model at the time.  The recollection of this scope still sticks in my mind.  I was wondering if anyone could help me identify who made it and the model? 

It was a vacuum tube based scope, but was fairly compact, so I guess it was probably built at the end of the tube era.  It had a feature that I still think is very unique.  The horizontal timebase was selected with 2 decade knobs and a multiplier.  For example, 37 microseconds/div could be selected by setting the first knob to (3), the second knob to (7), and the multiplier to (1) microsecond.  The other aspect I remember was the phosphors.  The scope had the most beautiful, brilliant, royal-blue colored phosphors.  Really striking compared to the blue-green phosphor that are common.

Thanks for any replies, maybe someone can jog my memory or knows what this scope was. 
 

Online tautech

  • Super Contributor
  • ***
  • Posts: 15350
  • Country: nz
  • Taupaki Technologies Ltd. NZ Siglent Distributor
    • Taupaki Technologies Ltd.
Re: Which 'Scope was this??
« Reply #1 on: November 25, 2013, 03:41:44 am »
How many years ago?
UK Telequipment (acquired by Tek) had a crisp blue trace.

"The horizontal timebase was selected with 2 decade knobs and a multiplier.  For example, 37 microseconds/div could be selected by setting the first knob to (3), the second knob to (7), and the multiplier to (1) microsecond."

Was this just a dual delayed timebase?
Avid Rabid Hobbyist
 

Offline Sparc

  • Contributor
  • Posts: 16
Re: Which 'Scope was this??
« Reply #2 on: November 25, 2013, 10:17:11 am »
How many years ago?
UK Telequipment (acquired by Tek) had a crisp blue trace.

"The horizontal timebase was selected with 2 decade knobs and a multiplier.  For example, 37 microseconds/div could be selected by setting the first knob to (3), the second knob to (7), and the multiplier to (1) microsecond."

Was this just a dual delayed timebase?

This was in the late 90's that I used the scope.  (I'm not too old, LOL).  The scope must have been pretty old then.  The scope used tubes for its internal amplifiers and circuitry.

I don't think it was a dual delayed timebase.  As best I remember, the primary timebase was selected with these 2 decade knobs and multiplier. 

Thinking about it, that does sound really unusual.  Perhaps you are right and it was a delayed timebase.  But, I don't remember a "simple" primary timebase with the usual 1-2-5-10... sequence.  I remember being impressed with the flexibility of such fine adjustments to the horizontal, but at the same time being annoyed having to rotate so many knobs just to get 2.0 ms/div for example.  (and then not being sure if it was 2ms or 200us/div because of how the multiplier was arranged!).

I searched Google images for UK telequipment, but didn't see anything that looked similar.

« Last Edit: November 25, 2013, 10:32:21 am by Sparc »
 

Online tautech

  • Super Contributor
  • ***
  • Posts: 15350
  • Country: nz
  • Taupaki Technologies Ltd. NZ Siglent Distributor
    • Taupaki Technologies Ltd.
Re: Which 'Scope was this??
« Reply #3 on: November 25, 2013, 11:44:29 am »
Vacuum tube amps wow. That will be going back a bit. Ones i have had went back to late 60's but no tubes, all discretes with linear supplies. I have come across museums online in the past searching for manuals and parts for old scopes. Didn't save any links though. |O I'm sure some other old bugger like me will have some info.
Avid Rabid Hobbyist
 

Offline vk6zgo

  • Super Contributor
  • ***
  • Posts: 4736
  • Country: au
Re: Which 'Scope was this??
« Reply #4 on: November 25, 2013, 12:16:03 pm »
Sounds a bit like a Tek 524AD.
They had a strange combination of dials to set the time/div.

Was it very large?
 

Online PA0PBZ

  • Super Contributor
  • ***
  • Posts: 3986
  • Country: nl
Re: Which 'Scope was this??
« Reply #5 on: November 25, 2013, 12:24:01 pm »
That's indeed a fascinating way of setting the timebase.



It's just that as far as I can see they have a green tube, not blue.
Keyboard error: Press F1 to continue.
 

Offline ElectroIrradiator

  • Frequent Contributor
  • **
  • Posts: 614
  • Country: dk
  • More analog than digital.
Re: Which 'Scope was this??
« Reply #6 on: November 25, 2013, 03:04:58 pm »
Tek offered a CRT with blue phosphor as an option for some models (one of the 7000 series mainframes that I am certain of). This was due to the different persistence between colors. Finding these are hard though, they were never common to begin with.
 

Offline vk6zgo

  • Super Contributor
  • ***
  • Posts: 4736
  • Country: au
Re: Which 'Scope was this??
« Reply #7 on: November 25, 2013, 04:04:42 pm »
After some thinking about it,my memory seems at odds with the pictures on the 'Net.

The 524AD had a very dense green filter,which when fitted,made the trace appear as the traditional green.
Someone had removed this filter to obtain a brighter  trace for use with a CRT camera.
The trace was a "greenish -blue",(not nearly as intense blue as later models,though).
 

Offline PaulAm

  • Frequent Contributor
  • **
  • Posts: 652
  • Country: us
Re: Which 'Scope was this??
« Reply #8 on: November 25, 2013, 04:19:15 pm »
Different phosphors were sometimes available as options.  P7 is blue, but not common.  P31 is sometimes seen, but I think P2 was the standard blue/green phosphor.  P1 was also popular.

I think P7 was popular when you used a scope camera.
 

Offline Sparc

  • Contributor
  • Posts: 16
Re: Which 'Scope was this??
« Reply #9 on: November 26, 2013, 04:32:00 am »
Sounds a bit like a Tek 524AD.
They had a strange combination of dials to set the time/div.

Was it very large?

You might have identified it.  The 524AD looks bigger than I remember, but this is probably it.  Downloading a manual from the net, the Tek 524AD has continuous timebase control from 0.01 sec to 0.1 us .   It looks like the left decade was a ten position switch and the right decade was a continuously variable potentiometer.  It probably had the P11 blue phosphor.  I've occasionally remembered this old scope and I'm glad to find which one it is.  Thanks!

 

Offline N2IXK

  • Frequent Contributor
  • **
  • Posts: 694
  • Country: us
Re: Which 'Scope was this??
« Reply #10 on: November 26, 2013, 09:17:43 pm »
The blue phosphor was P11. Usually used with a Polaroid scope camera for permanent waveform recording in the days before digital storage scopes.

The original oscilloscope phosphor was P1 green. This was the standard for a long time, but was eventually replaced by the blue/green P31, which was more resistant to phosphor burn at the higher accelerating voltages that came into use as bandwidth and writing rates increased.

P7 is an interesting "dual layer" screen, developed originally for radar.  It has a very short blue/white fluorescence while being hit by the electrons, and a very long (several seconds) persistence yellow/orange phosphorescence afterward.  Usually used with an orange filter to suppress the original blue flash.

A fairly comprehensive list of CRT phosphors is available here:

www.bunkerofdoom.com/tubes/crt/crt_phosphor_research.pdf

Tektronix made their own CRTs, and could supply most types with any phosphor you wanted for a fee.


« Last Edit: November 30, 2013, 06:10:25 pm by N2IXK »
"My favorite programming language is...SOLDER!"--Robert A. Pease
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf