Topics

Vacuum forming 7K interface "covers"

Eric
 

An Idea to save more 7K frames. The plastic covers for the “fingers” on the main interface boards of the 7K series are starting to show their age especially in units that have not been stored well. When I started working on 7000 frames about 2 years ago I was made aware at how rare these are getting. I have 2 spare covers that I have picked up along the way but I hate the idea that the only way to get these now it to canalize them from other units. I was thinking has any one tried vacuuming forming new ones?

From looking at the shape these seem like they could be duplicated in a vacuum forming operation with the correct mold possibly even 20 to 30 at a time out of one sheet. Has this been tried before?

Ed Breya
 

The original parts probably were vacuum-formed, or possibly extruded. I think nowadays, people would be more inclined to 3D-print them, which could also allow for structural improvements in the design.

Ed

Dave Casey
 

As thick as they are, I always assumed they were injection molded. I
believe someone has already drawn these up and 3-D printed them; I seem to
recall some list traffic about that a couple years ago. If I were in a
pinch for one, I'd be looking for that existing model to print some.

Dave Casey

On Tue, Apr 21, 2020 at 1:28 PM Ed Breya via groups.io <edbreya=
yahoo.com@groups.io> wrote:

The original parts probably were vacuum-formed, or possibly extruded. I
think nowadays, people would be more inclined to 3D-print them, which could
also allow for structural improvements in the design.

Ed



Roy Thistle
 

On Tue, Apr 21, 2020 at 11:16 AM, Eric wrote:


The plastic covers for the “fingers”
Are those (on a 7603) the white (nylon?) prismatic objects above and below the gold contacts... looking down into the 7603 bay? ... or maybe just a Tek part number?
Best regards.
Roy

Chuck Harris
 

They are little plastic covers, very thin, and about 1 inch by
3 inches. Their purpose is to restrain the free ends of the gold
socket pins.

They are simply a thin sheet of plastic that is bent to a specific
shape, probably with a vacuum forming method.

They are prone to getting longitudinal cracks, and when that
happens, they fall out, or simply stop retaining the socket
pins. Often the pins will get crumpled by the plugin after this
happens. At a minimum, they won't make uniform contact on all
pins.

-Chuck Harris

Roy Thistle wrote:

On Tue, Apr 21, 2020 at 11:16 AM, Eric wrote:


The plastic covers for the “fingers”
Are those (on a 7603) the white (nylon?) prismatic objects above and below the gold contacts... looking down into the 7603 bay? ... or maybe just a Tek part number?
Best regards.
Roy



teamlarryohio
 

200-0950-XX, IIRC
-ls-

Colin Herbert
 

I thought that I knew what you were talking about until you gave the size as 1 inch by 3 inches. I am now flummoxed, because that isn't the size of the plastic parts that keep the (gold-plated) contacts in place in the backplane connector. Any chance of a photo or two?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Chuck Harris
Sent: 22 April 2020 01:33
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

They are little plastic covers, very thin, and about 1 inch by
3 inches. Their purpose is to restrain the free ends of the gold
socket pins.

They are simply a thin sheet of plastic that is bent to a specific
shape, probably with a vacuum forming method.

They are prone to getting longitudinal cracks, and when that
happens, they fall out, or simply stop retaining the socket
pins. Often the pins will get crumpled by the plugin after this
happens. At a minimum, they won't make uniform contact on all
pins.

-Chuck Harris

Roy Thistle wrote:
On Tue, Apr 21, 2020 at 11:16 AM, Eric wrote:


The plastic covers for the “fingers”
Are those (on a 7603) the white (nylon?) prismatic objects above and below the gold contacts... looking down into the 7603 bay? ... or maybe just a Tek part number?
Best regards.
Roy



 

For avoidance of doubt this is p/n 200-0950-00 shown on the mechanical parts breakdowns in all the 7000 series Service manuals.

There are two of these used on each plugin socket on the main interface board to keep pressure on the contact fingers so they press onto the contacts at the rear of the plug-ins.

I would say that 4" x 1" sounds roughly in the ball-park for size.

David

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Colin Herbert via groups.io
Sent: 22 April 2020 13:42
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

I thought that I knew what you were talking about until you gave the size as 1 inch by 3 inches. I am now flummoxed, because that isn't the size of the plastic parts that keep the (gold-plated) contacts in place in the backplane connector. Any chance of a photo or two?
Colin.



-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Chuck Harris
Sent: 22 April 2020 01:33
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

They are little plastic covers, very thin, and about 1 inch by
3 inches. Their purpose is to restrain the free ends of the gold
socket pins.

They are simply a thin sheet of plastic that is bent to a specific
shape, probably with a vacuum forming method.

They are prone to getting longitudinal cracks, and when that
happens, they fall out, or simply stop retaining the socket
pins. Often the pins will get crumpled by the plugin after this
happens. At a minimum, they won't make uniform contact on all
pins.

-Chuck Harris

Roy Thistle wrote:
On Tue, Apr 21, 2020 at 11:16 AM, Eric wrote:


The plastic covers for the “fingers”
Are those (on a 7603) the white (nylon?) prismatic objects above and below the gold contacts... looking down into the 7603 bay? ... or maybe just a Tek part number?
Best regards.
Roy



Colin Herbert
 

Thank You, David, I am now un-flummoxed. It is exactly the part that I was thinking of, but the 3 inch measurement is way too short. As you suggest 4 inch is about right. These parts are also used on the 7000-series extenders, both the rigid and flexible versions (I know because I have one rigid and two flexibles).
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David C. Partridge
Sent: 22 April 2020 14:17
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

For avoidance of doubt this is p/n 200-0950-00 shown on the mechanical parts breakdowns in all the 7000 series Service manuals.

There are two of these used on each plugin socket on the main interface board to keep pressure on the contact fingers so they press onto the contacts at the rear of the plug-ins.

I would say that 4" x 1" sounds roughly in the ball-park for size.

David

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Colin Herbert via groups.io
Sent: 22 April 2020 13:42
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

I thought that I knew what you were talking about until you gave the size as 1 inch by 3 inches. I am now flummoxed, because that isn't the size of the plastic parts that keep the (gold-plated) contacts in place in the backplane connector. Any chance of a photo or two?
Colin.



-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Chuck Harris
Sent: 22 April 2020 01:33
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

They are little plastic covers, very thin, and about 1 inch by
3 inches. Their purpose is to restrain the free ends of the gold
socket pins.

They are simply a thin sheet of plastic that is bent to a specific
shape, probably with a vacuum forming method.

They are prone to getting longitudinal cracks, and when that
happens, they fall out, or simply stop retaining the socket
pins. Often the pins will get crumpled by the plugin after this
happens. At a minimum, they won't make uniform contact on all
pins.

-Chuck Harris

Roy Thistle wrote:
On Tue, Apr 21, 2020 at 11:16 AM, Eric wrote:


The plastic covers for the “fingers”
Are those (on a 7603) the white (nylon?) prismatic objects above and below the gold contacts... looking down into the 7603 bay? ... or maybe just a Tek part number?
Best regards.
Roy



stevenhorii
 

Colin and David,

If you look at eBay item: 133386313435 it is the plug-in backplane for a
7854.

In the fourth photo, I believe it shows one of the connectors that is
missing the cover on one side of the connector - you can see the exposed
pins. In other photos, you can see connectors with both covers.

I think this is what you are discussing if I am correct.

Steve H.

On Wed, Apr 22, 2020 at 09:30 Colin Herbert via groups.io <colingherbert=
blueyonder.co.uk@groups.io> wrote:

Thank You, David, I am now un-flummoxed. It is exactly the part that I was
thinking of, but the 3 inch measurement is way too short. As you suggest 4
inch is about right. These parts are also used on the 7000-series
extenders, both the rigid and flexible versions (I know because I have one
rigid and two flexibles).
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David
C. Partridge
Sent: 22 April 2020 14:17
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

For avoidance of doubt this is p/n 200-0950-00 shown on the mechanical
parts breakdowns in all the 7000 series Service manuals.

There are two of these used on each plugin socket on the main interface
board to keep pressure on the contact fingers so they press onto the
contacts at the rear of the plug-ins.

I would say that 4" x 1" sounds roughly in the ball-park for size.

David

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Colin
Herbert via groups.io
Sent: 22 April 2020 13:42
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

I thought that I knew what you were talking about until you gave the size
as 1 inch by 3 inches. I am now flummoxed, because that isn't the size of
the plastic parts that keep the (gold-plated) contacts in place in the
backplane connector. Any chance of a photo or two?
Colin.



-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Chuck
Harris
Sent: 22 April 2020 01:33
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

They are little plastic covers, very thin, and about 1 inch by
3 inches. Their purpose is to restrain the free ends of the gold
socket pins.

They are simply a thin sheet of plastic that is bent to a specific
shape, probably with a vacuum forming method.

They are prone to getting longitudinal cracks, and when that
happens, they fall out, or simply stop retaining the socket
pins. Often the pins will get crumpled by the plugin after this
happens. At a minimum, they won't make uniform contact on all
pins.

-Chuck Harris

Roy Thistle wrote:
On Tue, Apr 21, 2020 at 11:16 AM, Eric wrote:


The plastic covers for the “fingers”
Are those (on a 7603) the white (nylon?) prismatic objects above and
below the gold contacts... looking down into the 7603 bay? ... or maybe
just a Tek part number?
Best regards.
Roy
















Colin Herbert
 

Yes, Steve, that is what I understand to be the item in question. However, I wouldn't particularly call them "pins", more "connectors" as they are thin and flat; I think of "pins" as being more substantial and round or rectangular in cross-section.
Some time ago I purchased one of these plastic side-covers on eBay from a UK seller, if I'm remembering correctly. I think the same seller has some of the "connectors" for sale currently on UK eBay and may still have some of the side-covers. It is worth noting that there are two types of the metal connectors. It may be that those used in the extenders differ from those in the back-plane connectors. One type is longer than the other but can be converted by careful use of wire-cutters.
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of stevenhorii
Sent: 22 April 2020 14:57
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

Colin and David,

If you look at eBay item: 133386313435 it is the plug-in backplane for a
7854.

In the fourth photo, I believe it shows one of the connectors that is
missing the cover on one side of the connector - you can see the exposed
pins. In other photos, you can see connectors with both covers.

I think this is what you are discussing if I am correct.

Steve H.

On Wed, Apr 22, 2020 at 09:30 Colin Herbert via groups.io <colingherbert=
blueyonder.co.uk@groups.io> wrote:

Thank You, David, I am now un-flummoxed. It is exactly the part that I was
thinking of, but the 3 inch measurement is way too short. As you suggest 4
inch is about right. These parts are also used on the 7000-series
extenders, both the rigid and flexible versions (I know because I have one
rigid and two flexibles).
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David
C. Partridge
Sent: 22 April 2020 14:17
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

For avoidance of doubt this is p/n 200-0950-00 shown on the mechanical
parts breakdowns in all the 7000 series Service manuals.

There are two of these used on each plugin socket on the main interface
board to keep pressure on the contact fingers so they press onto the
contacts at the rear of the plug-ins.

I would say that 4" x 1" sounds roughly in the ball-park for size.

David

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Colin
Herbert via groups.io
Sent: 22 April 2020 13:42
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

I thought that I knew what you were talking about until you gave the size
as 1 inch by 3 inches. I am now flummoxed, because that isn't the size of
the plastic parts that keep the (gold-plated) contacts in place in the
backplane connector. Any chance of a photo or two?
Colin.



-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Chuck
Harris
Sent: 22 April 2020 01:33
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

They are little plastic covers, very thin, and about 1 inch by
3 inches. Their purpose is to restrain the free ends of the gold
socket pins.

They are simply a thin sheet of plastic that is bent to a specific
shape, probably with a vacuum forming method.

They are prone to getting longitudinal cracks, and when that
happens, they fall out, or simply stop retaining the socket
pins. Often the pins will get crumpled by the plugin after this
happens. At a minimum, they won't make uniform contact on all
pins.

-Chuck Harris

Roy Thistle wrote:
On Tue, Apr 21, 2020 at 11:16 AM, Eric wrote:


The plastic covers for the “fingers”
Are those (on a 7603) the white (nylon?) prismatic objects above and
below the gold contacts... looking down into the 7603 bay? ... or maybe
just a Tek part number?
Best regards.
Roy
















Chuck Harris
 

My saying "*About* 1 inch by 3 inch" indicates that it was just a
guesstimate.

I was giving an approximate size to eliminate any of the other parts,
particularly any "prismatic" parts, from the mix.

Since my mind's eyeball approximation isn't good enough:

Measured with my caliper, I read: 3.855" x 0.764"

It is injection molded, evidenced by mold fill marks, and a swirl
in the plastic composition where the flows occurred. It has 8
sprues, arranged in a rectangular matrix.

The plastic is white, translucent, and slippery, probably one of the
polyethylene types of plastic. The plastic is slightly unstable, as
it started to warp within minutes after my removing it from the
connector.

I don't want to burn it for further classification of the plastic,
as the part is still serviceable.

The cross sectional shape is complex in that it has special "hooks"
that retain the part. It is loosely in a class called a "C" channel.

It is not something that will be easy to make with a 3D printer of
the hobby class, as it is only 29.5 thousandths of an inch thick,
with some features that are less than 5 thousandths.

It is in the shape of an extruded solid, so extrusion would be a good,
though expensive, way of making this part, if you use the right
plastic.

The manufacturer (presumably Tektronix) obviously thought injection
molding was much cheaper and easier, and probably used manufacturing
equipment they already had on hand... Plus, it eliminates a special
machining operation to cut the pieces to length.

-Chuck Harris

Colin Herbert via groups.io wrote:

I thought that I knew what you were talking about until you gave the size as 1 inch by 3 inches. I am now flummoxed, because that isn't the size of the plastic parts that keep the (gold-plated) contacts in place in the backplane connector. Any chance of a photo or two?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Chuck Harris
Sent: 22 April 2020 01:33
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

They are little plastic covers, very thin, and about 1 inch by
3 inches. Their purpose is to restrain the free ends of the gold
socket pins.

They are simply a thin sheet of plastic that is bent to a specific
shape, probably with a vacuum forming method.

They are prone to getting longitudinal cracks, and when that
happens, they fall out, or simply stop retaining the socket
pins. Often the pins will get crumpled by the plugin after this
happens. At a minimum, they won't make uniform contact on all
pins.

-Chuck Harris

Roy Thistle wrote:
On Tue, Apr 21, 2020 at 11:16 AM, Eric wrote:


The plastic covers for the “fingers”
Are those (on a 7603) the white (nylon?) prismatic objects above and below the gold contacts... looking down into the 7603 bay? ... or maybe just a Tek part number?
Best regards.
Roy









 

I looked inside my 7704A and verified that all the 200-0950-00 COVER, ELEC CONN:PLASTIC are there.
I don't see them so fragile, and they are solidly attached (inserted?) to the connector body. But... plastic is plastic.
They also seem to have an indentation for each contact tongue to fit inside, but I'm not completely sure.
I like the good design of the connector, where the contact tongues protrude just a little beyond the edge of the cover, sufficient to make good contact with the inserted PC board, and stay at a safe distance from the opposing contact when not in use.

Ernesto

 

On Wed, Apr 22, 2020 at 02:33 AM, Chuck Harris wrote:


They are prone to getting longitudinal cracks, and when that
happens, they fall out, or simply stop retaining the socket
pins.
see www.hakanh.com/dl/docs/hardtofind/200-0950-00.pdf

/Håkan

Ed Breya
 

Thanks for the detailed info, Chuck.

Your comment

"It is not something that will be easy to make with a 3D printer of
the hobby class, as it is only 29.5 thousandths of an inch thick,
with some features that are less than 5 thousandths.'

is true - if you want to make an exact copy. I believe that with modern 3D printing, someone (not me) could design and print not an exact copy, but a better version that will provide the original function, last long, and be easy to print.

Certain characteristics and dimensions have to be maintained, but, for example, there's probably no need to be exactly 0.0295" thick - what if it's .050" or something else, as long as it can properly snap on and hold as intended, and not cause clearance problems in the plug-in's connector shroud. It would take some study of the whole mechanical situation, but a decent printable alternative may be fairly easy to make - and easily modified if found to have problems later.

Ed

Eric
 

stepping a little out of my depth here as I have not done much 3d printing. but would there be an issue with the lack of flex in the print? These specific parts the flex of the material is a key component as they need to flex when a plugin is inserted. Though I could be mistaken on this.

On 4/22/2020 1:32 PM, Ed Breya via groups.io wrote:
Thanks for the detailed info, Chuck.

Your comment

"It is not something that will be easy to make with a 3D printer of
the hobby class, as it is only 29.5 thousandths of an inch thick,
with some features that are less than 5 thousandths.'

is true - if you want to make an exact copy. I believe that with modern 3D printing, someone (not me) could design and print not an exact copy, but a better version that will provide the original function, last long, and be easy to print.

Certain characteristics and dimensions have to be maintained, but, for example, there's probably no need to be exactly 0.0295" thick - what if it's .050" or something else, as long as it can properly snap on and hold as intended, and not cause clearance problems in the plug-in's connector shroud. It would take some study of the whole mechanical situation, but a decent printable alternative may be fairly easy to make - and easily modified if found to have problems later.

Ed

Colin Herbert
 

I don't think that the plastic side-covers that we are talking about need to flex when a plug-in is inserted. The flexing is done by the thin metal connectors. I have taken apart a rigid extender to replace broken/bent/missing connectors and the side-covers just snap into place to hold the metal connectors in place. It's a bit fiddly to do and easy for one or more of the connectors to jump out of where it should be, but it is do-able (because I've done it!).
Colin

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Eric
Sent: 22 April 2020 18:42
To: TekScopes@groups.io
Subject: Re: [TekScopes] Vacuum forming 7K interface "covers"

stepping a little out of my depth here as I have not done much 3d
printing. but would there be an issue with the lack of flex in the
print? These specific parts the flex of the material is a key component
as they need to flex when a plugin is inserted. Though I could be
mistaken on this.

On 4/22/2020 1:32 PM, Ed Breya via groups.io wrote:
Thanks for the detailed info, Chuck.

Your comment

"It is not something that will be easy to make with a 3D printer of
the hobby class, as it is only 29.5 thousandths of an inch thick,
with some features that are less than 5 thousandths.'

is true - if you want to make an exact copy. I believe that with modern 3D printing, someone (not me) could design and print not an exact copy, but a better version that will provide the original function, last long, and be easy to print.

Certain characteristics and dimensions have to be maintained, but, for example, there's probably no need to be exactly 0.0295" thick - what if it's .050" or something else, as long as it can properly snap on and hold as intended, and not cause clearance problems in the plug-in's connector shroud. It would take some study of the whole mechanical situation, but a decent printable alternative may be fairly easy to make - and easily modified if found to have problems later.

Ed


 

Since we are on the topic of the Tek 7000 main interface connectors,
I noticed on top of the 38 side connectors there is an horizontal small row of places for four connector pins, coax. maybe.
All plugins have these spaces on their connectors, none that I see uses it. The holes are empty on the mainframe side too.

Does anyone know if Tektronix had had plans to expand the connectivity of the plugins but never got to do so?

Ernesto

Chuck Harris
 

They do not flex when the plugin is inserted into the connector.
They do need to be the right shape to make sure they support the
the ends of the socket pins.

I think they could be somewhat thicker. But there are bound to
be clearance issues in the plugin's mating plastic flange.

However, I cannot see how you could print them without an
inherent weakness at the very point where the old style broke
anyway: along the outer edge.

-Chuck Harris

Colin Herbert via groups.io wrote:

I don't think that the plastic side-covers that we are talking about need to flex when a plug-in is inserted. The flexing is done by the thin metal connectors. I have taken apart a rigid extender to replace broken/bent/missing connectors and the side-covers just snap into place to hold the metal connectors in place. It's a bit fiddly to do and easy for one or more of the connectors to jump out of where it should be, but it is do-able (because I've done it!).
Colin

Chuck Harris
 

When the 7000 series was being developed, the designers
were planning on making the readout system be a fiber optic
nightmare, way worse than the 576 curve tracer.

The lights and switching was to be inside of the plugins, and
the readout images was to pass through fiber optic connectors
in the holes that you see on every plugin and main frame
connector.

They were so sure of this design that they bought the plastic
bits in bulk, preparing for what they knew was going to be a
very popular new scope series.

Unfortunately for them, the fiber optic lighting and selection
was just too bulky, twidgety, and complicated to ever be mass
produced.

Barrie Gilbert designed the now well known vector drawing
readout system as an emergency save for the botched fiber optic
design.

The rest is more history.

-Chuck Harris

Ernesto wrote:

Since we are on the topic of the Tek 7000 main interface connectors,
I noticed on top of the 38 side connectors there is an horizontal small row of places for four connector pins, coax. maybe.
All plugins have these spaces on their connectors, none that I see uses it. The holes are empty on the mainframe side too.

Does anyone know if Tektronix had had plans to expand the connectivity of the plugins but never got to do so?

Ernesto