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PM for a working Tek 577 with D1 storage Curve Tracer

Kevin Oconnor
 

There has been frequent postings on various repairs for broken 577 CTs. However, mine is working ok, given its age and typical senior citizen arthritis issues.
I don’t want to fix what ain’t broken, but it would be nice to have a list of:
1) must do - or it will explode
2) should do
3) when you have the time do

My 577 issues are buttons that don’t want to latch, pots that are scratchy, display zero moving around with selector setting changes. All things that I can live with.

Kevin KO3Y

Chuck Harris
 

Generally speaking, there are no must do's for the 577.

They are very reliable.

Well, perhaps a few, if you have the storage version:

1) learn how to use it without burning the storage mesh
when in non store mode.
2) learn how to adjust the storage system for optimal
performance.
3) learn that even when performing optimally, storage
tubes aren't as nice as digital storage.

-Chuck Harris

Kevin Oconnor wrote:

There has been frequent postings on various repairs for broken 577 CTs. However, mine is working ok, given its age and typical senior citizen arthritis issues.
I don’t want to fix what ain’t broken, but it would be nice to have a list of:
1) must do - or it will explode
2) should do
3) when you have the time do

My 577 issues are buttons that don’t want to latch, pots that are scratchy, display zero moving around with selector setting changes. All things that I can live with.

Kevin KO3Y



Mlynch001
 

Kevin,

My 577 had been sitting for some time in storage. It had some balky switches. I have found that cleaning those switches with non-working latches will bring them back to proper function. This is a common switch, used in almost all Contemporary TEK instruments. I buy many so called "non-working" instruments that need only thorough cleaning of these type switches to restore their function.

--
Michael Lynch
Dardanelle, AR

Kevin Oconnor
 

So Chuck, regarding #1, I almost never use storage. That being said, I was unaware
one could do damage with it off. I’ve had this CT almost 40 years. But I can always learn something new. Don’t keep me in suspense!

K - KO3Y

Mlynch001
 

Chuck,

What is the issue with "burning the mesh" in non-storage mode? I pretty much follow the manual when using in Non storage mode.

--
Michael Lynch
Dardanelle, AR

Chuck Harris
 

Simply put, the focused electron beam, when within the viewing
area of a storage CRT, always hits the storage mesh screen. This
is because the storage mesh screen is the same size as, and is
positioned just before, the phosphor viewing screen.

Because of biasing of the storage mesh, the operation of the flood
guns around the storage mesh, and the positioning of the storage
mesh, any electron that hits the phosphor viewing screen comes from
the storage mesh... regardless of the mode the storage CRT is in.

The different viewing modes are just tweaks on the basic storage
cycle.

The storage mesh is very fine and has a delicate coating of highly
insulating material on its surface, that is instrumental in its
ability to pass, or not pass, electrons on to the phosphor viewing
screen.

The mesh actually sets the pixel size for the screen, and with a
magnifier, you can see the shadow of the mesh in every lit spot on
the screen.

A high intensity focused electron beam hitting the storage mesh will
damage the mesh. Normal mode in a storage CRT may appear similar to
a standard CRT, but the similarity is only in appearance.

From a conservative operator's perspective: avoid high intensity
settings, realize that the maximum beam intensity is limited by the
mesh, not the intensity control, and realize that in storage modes,
even though you may not see the beam, it is still writing on the
storage mesh. Never leave a bright spot on the screen! That
includes the origin spot on a curve tracer.

Keeping your storage system adjusted to manufacturer's specs will go
a long way towards saving it from accidental abuse.

Understand that even at optimal settings, storage modes are low
contrast, often blurry, blotchy back-grounded, low intensity affairs.

There is a reason why all of the world's scope manufacturers sprinted
away from storage CRT's when fast digital storage became affordable.

-Chuck Harris

Mlynch001 wrote:

Chuck,

What is the issue with "burning the mesh" in non-storage mode? I pretty much follow the manual when using in Non storage mode.

Mlynch001
 

Chuck,

Thanks for another complete answer. You have confirmed what I already thought that I understood about storage CRT's. My standard practice is to keep the intensity turned off or extremely low any time I am not viewing the screen. I do this regardless of whether I am viewing a Storage CRT or a Standard CRT. No need to burn or otherwise damage the CRT. My fear was that I was inadvertently (and through ignorance) doing something that would cause problems for me going forward.

Sincerely,

--
Michael Lynch
Dardanelle, AR

Kevin Oconnor
 

Thanks Chuck

Sent from kjo iPhone