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Tektronix 5000 and SC503 bi-stable storage CRT can worn-out ?


Ke-Fong Lin
 

Hi everyone,

Title says it all, I have a noob question : Does bi-stable storage CRTs can worn-out?
That is, be less able to store, or store trace but very blurry?

I have one such 5000 series scope along with a 5CT1N curve tracer.
Idea being to do A/B comparison of transistors, typically for matching purpose.
But the stored traces are very blurry my scope.

So is it just a matter of calibration/adjustment or even repair, or the CRT has to be eventually replaced.

Also, there's currently an SC503 on ebay that I would be interested.
I also have a 7000 scope and would prefer to just keep the 7000 instead of having both a 5000 and a 7000.
The SC503 being very compact and light, I would be quite interested.

So knowing if the CRTs can worn out, is an important information regarding whether to buy or not.

Thank you

Best regards,


snapdiode
 

Yes, for sure. Much more than a non-storage CRT.


Harvey White
 

The problem with the SC503 is that it's not going to work with your curve tracer.   The 5CT1N will not work with your 7000 series scope.  The main board is the same, the front panel is the same, but there's an interface board you're missing.

If you had a 7Ct1N, that would work in the 7000 series, otherwise, you need a 5000 series

You could take a scope camera (or make one), attach it to a generic 5000 series scope, and then store traces and overlay them

not the worlds most elegant solution.

AFAIK, *any* crt can be worn out.  See especially the 500 series curve tracer standalone units (let alone HV transformer problems).

Harvey

On 12/14/2020 6:05 PM, Ke-Fong Lin wrote:
Hi everyone,

Title says it all, I have a noob question : Does bi-stable storage CRTs can worn-out?
That is, be less able to store, or store trace but very blurry?

I have one such 5000 series scope along with a 5CT1N curve tracer.
Idea being to do A/B comparison of transistors, typically for matching purpose.
But the stored traces are very blurry my scope.

So is it just a matter of calibration/adjustment or even repair, or the CRT has to be eventually replaced.

Also, there's currently an SC503 on ebay that I would be interested.
I also have a 7000 scope and would prefer to just keep the 7000 instead of having both a 5000 and a 7000.
The SC503 being very compact and light, I would be quite interested.

So knowing if the CRTs can worn out, is an important information regarding whether to buy or not.

Thank you

Best regards,





Ke-Fong Lin
 

The problem with the SC503 is that it's not going to work with your
curve tracer.   The 5CT1N will not work with your 7000 series scope. 
Hi Harvey,

I plan to get rid of the 5CT1N in the process.
From a practical point of view, I don't think it's much easier to use, or even more precise than a modern equivalent:

https://www.peakelec.co.uk/acatalog/dca75-dca-pro-semiconductor-analyser.html

The standalone 577 or 576 have the capability to test high current device, with not much equivalent now.

Back to the CRTs, my 5000 is very "sharp" when displaying traces, no problem with that.
It's just that when trying to use the storage feature, the stored traces are really blurry.
If the CRTs worn out, there's no point to buy used bi-stable scopes.

Best regards,


Michael W. Lynch
 

On Tue, Dec 15, 2020 at 03:25 AM, Ke-Fong Lin wrote:


Back to the CRTs, my 5000 is very "sharp" when displaying traces, no problem
with that.
It's just that when trying to use the storage feature, the stored traces are
really blurry.
If the CRTs worn out, there's no point to buy used bi-stable scopes.
Understanding and working within the limitations of "storage" CRT technology is essential. Even a perfectly functional and properly operated storage CRT does not always "store" a really sharp trace. I have several Storage scopes as well as a 577 D1 Curve tracer, when the controls are set properly and once I learned how to use the technology, these instruments will store a very decent trace. When adjusted or used incorrectly the stored image is pretty much useless. It takes effort and precision to get a "good" stored image. As far as being "worn out", I have one Storage Scope that has less than perfect storage across the CRT screen and some "burning", but it is not evidenced by a "blurry" trace. This might be something in the adjustment of the instrument. As Clint Eastwood said in "Dirty Harry" "A man has got to know his limitations", this applies to storage scopes as well. I am certain that Dennis can speak volumes on this subject. Good luck with your quest.

--
Michael Lynch
Dardanelle, AR


Michael W. Lynch
 

On Mon, Dec 14, 2020 at 05:19 PM, snapdiode wrote:


Yes, for sure. Much more than a non-storage CRT.
Absolutely, they can "wear out" or more likely fail from other issues. There are so many more things that can go wrong, both inside and outside the CRT.

--
Michael Lynch
Dardanelle, AR


Chuck Harris
 

Remember that storage screens store things that your eye might
not otherwise notice, and bistable storage screens can only store,
or not store... they don't do levels of grey.

So, if your signal has wispy transient signals floating on it that
are normally not visible, the bistable storage screen, if set too
bright, will store those wispy transient signals as a fuzzy trace.

Best focus comes when the intensity is set at the minimum level that
will make a displayable image.

Also, make sure the storage circuits are calibrated so that the visible
intensity (in your normal room lighting) matches up with the storage
sensitivity. You don't want a normal non storage trace to result in
an overly exposed storage trace.

-Chuck Harris

Michael W. Lynch via groups.io wrote:

On Tue, Dec 15, 2020 at 03:25 AM, Ke-Fong Lin wrote:


Back to the CRTs, my 5000 is very "sharp" when displaying traces, no problem
with that.
It's just that when trying to use the storage feature, the stored traces are
really blurry.
If the CRTs worn out, there's no point to buy used bi-stable scopes.
Understanding and working within the limitations of "storage" CRT technology is essential. Even a perfectly functional and properly operated storage CRT does not always "store" a really sharp trace. I have several Storage scopes as well as a 577 D1 Curve tracer, when the controls are set properly and once I learned how to use the technology, these instruments will store a very decent trace. When adjusted or used incorrectly the stored image is pretty much useless. It takes effort and precision to get a "good" stored image. As far as being "worn out", I have one Storage Scope that has less than perfect storage across the CRT screen and some "burning", but it is not evidenced by a "blurry" trace. This might be something in the adjustment of the instrument. As Clint Eastwood said in "Dirty Harry" "A man has got to know his limitations", this applies to storage scopes as well. I am certain that Dennis can speak volumes on this subject. Good luck with your quest.


Mlynch001
 

Thanks Chuck for explaining what my feeble mind could not . Those are some of the nuances that you and many others will articulate much better than I can.

--
Michael Lynch
Dardanelle, AR


Roy Thistle
 

On Tue, Dec 15, 2020 at 01:25 AM, Ke-Fong Lin wrote:


If the CRTs worn out, there's no point to buy used bi-stable scopes
Who "buys" a Tek analog storage scope, for working with stored waveforms? ... especially an SC 503 with that small display.
For looking at stored signals, the SC 503 could handle, a cheap DSO is much better... especially for repetitive signals.
I dunno, the SC 503's tube could be a little soft (you say the normal trace is bright. ... at low intensity too?)
Are you looking at noise on the stored trace?
Let it warm up for an hour.
Use a slow (SC 503 is only 10 MHz BW!... try much slower), very clean, maybe levelled sine wave signal... and also try using the "integrate" button... vary the storage control.... maybe try triggering on a single sweep... then see what you get.
Did you go through the adjustment in the SC 503 service manual?


Ke-Fong Lin
 

Hi everyone,

Thanks for your answers and suggestions.

So it rather seems my storage CRT is not necessarily worn-out or even broken, but that it may need adjustements.
And also, being so used to very high resolution LCD screens, my expectation regarding the quality of the stored traces are may be unrealistic.
I'll look more closely at the service manual of my 5000 scope this weekend.



Best regards,


Michael W. Lynch
 

We are all spoiled by the quality of these new LED and LCD screens.

--
Michael Lynch
Dardanelle, AR


Ke-Fong Lin
 

Who "buys" a Tek analog storage scope, for working with stored waveforms? ...
especially an SC 503 with that small display.
For looking at stored signals, the SC 503 could handle, a cheap DSO is much
better... especially for repetitive signals.
Hi Roy,

It's just that there's currently an SC503 on ebay, very clean.
Indeed, there's not much practical advantage over a cheap DSO.
But I just want to own a storage analog scope. Plus, my hobby is mainly audio related, so its low BW is fine.
My 5000 is just too big and I will get rid of it eventually, plus I have a "fully loaded" 7603.
So it's rather about how to buy the right SC503, fully working, including storage.

Best regards,