Topics

485 Cordwrap Feet


Jeff Davis
 

I had a customer approach me about developing a replacement cord wrap foot for the Tektronix 485. He sent me one of his that was mostly intact - but it led to some questions that I'm now posing to the group.

The 485 service manual shows that the cord wrap looks a lot like the cord wraps on a 2465, i.e. two assemblies, one right side and one left side, that extend from the bottom to the top, and the cord wraps around the two of them.

On the other hand, what my customer sent to me looked more like a foot from a 465, i.e. 4 pieces, one on each corner, with flanges to hold the cord. The cord wraps around the four pieces located at each corner.

Did early and later versions of the 485 have different cord wraps? If so, are they interchangeable? I can only find one version of the service manual, and it shows the 2465-like cord wraps.

Would greatly appreciate anyone who could shed light on this mystery.

Thanks,
Jeff / N0DY
www.n0dy.com


Michael W. Lynch
 

Jeff,

My 485 does not have cordwrap feet as such. I suppose it just has something like the 2465 series? I posted a picture in the photo section.

Here:

https://groups.io/g/TekScopes/album?id=250894

Hope this helps.

--
Michael Lynch
Dardanelle, AR


Michael W. Lynch
 

Jeff,

Looking at 2 different manuals, one from 1977 and one from 1978; both show the same 2465 like cabinet foot P/N348-0298-00 and no indication of any other type ever being used. The manuals that I have list parts from S/N B010100 and up, so it would appear that these units all use the same part. Perhaps you could somehow incorporate the 465 cord wrap feet into the 485 style cabinet foot?

--
Michael Lynch
Dardanelle, AR


Jeff Davis
 

Hi Michael,

Thanks for the photo - that's what I pictured from the drawing in the service manual. I'm still mystified how my customer's 485 came by the feet he sent me.

Jeff

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Michael W. Lynch via groups.io <mlynch003=yahoo.com@groups.io>
Sent: Tuesday, July 21, 2020 1:46 PM
To: TekScopes@groups.io <TekScopes@groups.io>
Subject: Re: [TekScopes] 485 Cordwrap Feet

Jeff,

My 485 does not have cordwrap feet as such. I suppose it just has something like the 2465 series? I posted a picture in the photo section.

Here:

https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgroups.io%2Fg%2FTekScopes%2Falbum%3Fid%3D250894&amp;data=02%7C01%7C%7C547ce97c1b73422019b808d82db71f2d%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637309611805858729&amp;sdata=DZOMfXYDeyeHixyq0T8JvYoC%2F18Ysvd3Z47aI7iAr9g%3D&amp;reserved=0

Hope this helps.

--
Michael Lynch
Dardanelle, AR


Michael W. Lynch
 

Jeff,

I don’t see any way that a 485 could use cordwrap feet like a 465/475. The area where these mount to the scope is very narrow. Too narrow for the footprint of the 465/475 type of foot. It would take a hybrid design, sort of a melding of the 465 foot with the 485 foot.

I would ask the customer for a picture of the back and front of the scope.

I would be very interested to see what they have.

Thanks

Michael W. Lynch
11993 Wildcat Hollow Road
Dardanelle, AR
72834

From My I-Pad
479-477-1115
479-229-0126

On Jul 21, 2020, at 16:27, Jeff Davis <n0dyjeff@...> wrote:

Hi Michael,

Thanks for the photo - that's what I pictured from the drawing in the service manual. I'm still mystified how my customer's 485 came by the feet he sent me.

Jeff

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Michael W. Lynch via groups.io <mlynch003=yahoo.com@groups.io>
Sent: Tuesday, July 21, 2020 1:46 PM
To: TekScopes@groups.io <TekScopes@groups.io>
Subject: Re: [TekScopes] 485 Cordwrap Feet

Jeff,

My 485 does not have cordwrap feet as such. I suppose it just has something like the 2465 series? I posted a picture in the photo section.

Here:

https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgroups.io%2Fg%2FTekScopes%2Falbum%3Fid%3D250894&amp;data=02%7C01%7C%7C547ce97c1b73422019b808d82db71f2d%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637309611805858729&amp;sdata=DZOMfXYDeyeHixyq0T8JvYoC%2F18Ysvd3Z47aI7iAr9g%3D&amp;reserved=0

Hope this helps.

--
Michael Lynch
Dardanelle, AR





--
Michael Lynch
Dardanelle, AR


Daveolla
 

If the fellow read the "6" in 465 as an "8" he would get 485.

Dave

At 11:34 PM 7/21/2020, you wrote:
Jeff,

I don’t see any way that a 485 could use cordwrap feet like a 465/475. The area where these mount to the scope is very narrow. Too narrow for the footprint of the 465/475 type of foot. It would take a hybrid design, sort of a melding of the 465 foot with the 485 foot.

I would ask the customer for a picture of the back and front of the scope.

I would be very interested to see what they have.

Thanks

Michael W. Lynch
11993 Wildcat Hollow Road
Dardanelle, AR
72834

From My I-Pad
479-477-1115
479-229-0126

On Jul 21, 2020, at 16:27, Jeff Davis <n0dyjeff@...> wrote:

Hi Michael,

Thanks for the photo - that's what I pictured
from the drawing in the service manual. I'm still mystified how my customer's 485 came by the feet he sent me.

Jeff

________________________________
From: TekScopes@groups.io
<TekScopes@groups.io> on behalf of Michael W. Lynch via groups.io <mlynch003=yahoo.com@groups.io>
Sent: Tuesday, July 21, 2020 1:46 PM
To: TekScopes@groups.io <TekScopes@groups.io>
Subject: Re: [TekScopes] 485 Cordwrap Feet

Jeff,

My 485 does not have cordwrap feet as
such. I suppose it just has something like the 2465 series? I posted a picture in the photo section.

Here:

https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgroups.io%2Fg%2FTekScopes%2Falbum%3Fid%3D250894&amp;data=02%7C01%7C%7C547ce97c1b73422019b808d82db71f2d%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637309611805858729&amp;sdata=DZOMfXYDeyeHixyq0T8JvYoC%2F18Ysvd3Z47aI7iAr9g%3D&amp;reserved=0

Hope this helps.

--
Michael Lynch
Dardanelle, AR







--
Michael Lynch
Dardanelle, AR


Michael W. Lynch
 

On Tue, Jul 21, 2020 at 11:47 PM, Daveolla wrote:


If the fellow read the "6" in 465 as an "8" he would get 485.
That is the only explanation that I can imagine.

--
Michael Lynch
Dardanelle, AR


Jeff Davis
 

Hi Michael and Dave,

Thanks for your responses. Looking at Michael’s photo, I totally see his point about a 465 style foot not fitting. So the question is really, what kind of scope did the foot come from, as Michael suggests.

I’ve asked for photos and will advise when I hear more.

Jeff

On Jul 22, 2020, at 5:56 AM, Michael W. Lynch via groups.io <mlynch003=yahoo.com@groups.io> wrote:

On Tue, Jul 21, 2020 at 11:47 PM, Daveolla wrote:


If the fellow read the "6" in 465 as an "8" he would get 485.
That is the only explanation that I can imagine.

--
Michael Lynch
Dardanelle, AR



Chuck Harris
 

Jeff,

I think if you explore this further with your customer,
you will find he doesn't have a 485 at all, but rather
has one of the similar looking scopes, the 453, or 454.

-Chuck Harris

Michael W. Lynch via groups.io wrote:

Jeff,

I don’t see any way that a 485 could use cordwrap feet like a 465/475. The area where these mount to the scope is very narrow. Too narrow for the footprint of the 465/475 type of foot. It would take a hybrid design, sort of a melding of the 465 foot with the 485 foot.

I would ask the customer for a picture of the back and front of the scope.

I would be very interested to see what they have.

Thanks

Michael W. Lynch
11993 Wildcat Hollow Road
Dardanelle, AR
72834


Jeff Davis
 

Hi Chuck,

I like your reasoning - the scopes do look very similar to a 485. But the foot the customer sent me was not a 453 or 454 foot. It looks like it's an earlier vintage than that. I've uploaded some photos of the foot the customer sent me, hoping that someone on the list will recognize it. https://groups.io/g/TekScopes/album?id=250966

I've also asked him for some photos of the scope, front and back, but have not heard back.

Jeff

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Chuck Harris <cfharris@...>
Sent: Wednesday, July 22, 2020 8:26 AM
To: TekScopes@groups.io <TekScopes@groups.io>
Subject: Re: [TekScopes] 485 Cordwrap Feet

Jeff,

I think if you explore this further with your customer,
you will find he doesn't have a 485 at all, but rather
has one of the similar looking scopes, the 453, or 454.

-Chuck Harris

Michael W. Lynch via groups.io wrote:
Jeff,

I don’t see any way that a 485 could use cordwrap feet like a 465/475. The area where these mount to the scope is very narrow. Too narrow for the footprint of the 465/475 type of foot. It would take a hybrid design, sort of a melding of the 465 foot with the 485 foot.

I would ask the customer for a picture of the back and front of the scope.

I would be very interested to see what they have.

Thanks

Michael W. Lynch
11993 Wildcat Hollow Road
Dardanelle, AR
72834


 

Hi Jeff,
It was not unusual for the design engineers at Tek to pay attention to
product details (known as Human Factors Engineering in those days) just like
this one. This was one of the things that distinguished Tek from many other
companies. The 485 was a portable scope which meant things like a power cord
had to have a secure place to be while it was being moved from one place to
another. The logical way to carry the scope was by the handle with the scope
in an upright position so there would need to be feet on the rear of the
scope. Why not kill two birds with one stone and design a foot that would
also secure the power cord?

There are some things that the mechanical engineers at Tek never seem to be
satisfied with and cord wraps are one of them. The cord wrap evolved
constantly. It was almost as if the mechanical engineers saw each new
portable scope as an opportunity to improve on the design of the previous
instrument. My 453 (the 454 and 453 were the original portables Tek designed
to meet the needs of the IBM Field Engineers) had fairly simple rear feet
which the power cord could be wrapped around. I think there was a chance the
power cord could become undone from around the rear feet while travelling
with the 453 scope. By the time the 485 appeared the cord wrap foot was just
about optimal: It holds the power cord securely, and it communicates to the
user, by its unusual shape, what its intended purpose is, without the need
for any further explanation.

In other words its unusual shape tells you what it does. Donald Norman in
his book "The Psychology of Everyday Things" coined the term "affordances"
for the properties of objects which show users the actions they can take.
Users should be able to perceive affordances without having to consider how
to use the items. A simple example we all encounter every day is the handle
on a door leading into or out of a store. The shape of the handle should
communicate to you whether you should push or pull it to open the door.
Instead most of them are so poorly designed that it is necessary to include
a sign saying "Push" or "Pull".

With the advent of the IEC power connector standard in 1970 many instruments
gradually started using power cords that could be unplugged from the
instrument which created a totally different problem of what to do with the
proliferation of these power cords now that they are everywhere. Somehow we
all end up with more of them than we can possibly use.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jeff
Davis
Sent: Tuesday, July 21, 2020 12:30 PM
To: TekScopes@groups.io
Subject: [TekScopes] 485 Cordwrap Feet

I had a customer approach me about developing a replacement cord wrap foot
for the Tektronix 485. He sent me one of his that was mostly intact - but it
led to some questions that I'm now posing to the group.

The 485 service manual shows that the cord wrap looks a lot like the cord
wraps on a 2465, i.e. two assemblies, one right side and one left side, that
extend from the bottom to the top, and the cord wraps around the two of
them.

On the other hand, what my customer sent to me looked more like a foot from
a 465, i.e. 4 pieces, one on each corner, with flanges to hold the cord. The
cord wraps around the four pieces located at each corner.

Did early and later versions of the 485 have different cord wraps? If so,
are they interchangeable? I can only find one version of the service manual,
and it shows the 2465-like cord wraps.

Would greatly appreciate anyone who could shed light on this mystery.

Thanks,
Jeff / N0DY
www.n0dy.com





--
Dennis Tillman W7pF
TekScopes Moderator


Roy Thistle
 

On Wed, Jul 22, 2020 at 11:39 AM, Dennis Tillman W7pF wrote:


Somehow we
all end up with more of them than we can possibly use.
Yes!
Around here, they do toss good usable Tek equipment into the dumpster... but, they always keep the power cord. I'm not sure of the thinking (One could need a 1 dollar power cord; but, not an expensive oscilloscope?) I get it for the probes; but, not the cords. Anyway, yes! ... barrels of the things.


Roy Thistle
 

On Tue, Jul 21, 2020 at 12:30 PM, Jeff Davis wrote:


Would greatly appreciate anyone who could shed light on this mystery
If you look at the back of a horizontal 475, lying on a table top... (not standing on its feet)... it looks, by your pics... that the intact foot in those picture... is one of the two feet, on a 475... that would be closest to the table top.
By the crafty design, of that/those particular foot/feet (no doubt the work of a devil)... it has a rectangular shape to the "bottom" of the foot (as in your pics)... rather than the 1/4 pie shape of the two other feet. By the bottom of the foot, I just mean the part that touches the surface the scope would be standing on.
Perhaps, as Dennis pointed out... the rectangular shape, versus the 1/4 circular shape, helps to hold/store the cord.


Harvey White
 

They're WIRES.

WIRES can be removed, put in a big bin, and sold to copper salvage companies.  Scopes?  They'll sell for just as much without the power cables.  Probes (attached or otherwise) Gee, they're WIRES.

Harvey

On 7/22/2020 3:55 PM, Roy Thistle wrote:
On Wed, Jul 22, 2020 at 11:39 AM, Dennis Tillman W7pF wrote:

Somehow we
all end up with more of them than we can possibly use.
Yes!
Around here, they do toss good usable Tek equipment into the dumpster... but, they always keep the power cord. I'm not sure of the thinking (One could need a 1 dollar power cord; but, not an expensive oscilloscope?) I get it for the probes; but, not the cords. Anyway, yes! ... barrels of the things.



Jim Ford
 

Funny you should mention those IEC power connectors, Dennis, as I just received a new wired router (opting for security, reliability, and speed for my 3 computers that stay in one place) today, and what do you know, it did not have an IEC connector on it. Instead, the power cable had a "3 merged circles" (kind of like 3/5 of the Olympics symbol) connector.
Not sure why.

Now, my Tek 5103N/D10 and 7603 scopes have attached power cables, and every other piece of gear (most of it Tek or HP) I own except for the HP 400E AC voltmeter (pre-1970, no doubt) has a detachable cord with an IEC connector on it. No, wait, that's not true. I noticed some time ago that the 3 power supplies I own, an HP 6111A, an Elenco Precision XP-581, and a Trygon TL8-3, all have attached cords. I wonder why that is...

Another oddball is my Tek TLA711 mainframe. While it has an IEC male connector on the back of it, there is an extra rib below the GND pin, so a normal IEC female will not mate with it. Until you chop a groove into it with a utility knife, that is. I don't know why Tek did that. Maybe if you fill up the chassis with a thousand channels worth of logic analysis it draws so much current you need an extra beefy power cable (with a special notched IEC connector) hooked up to a 100 A circuit?

Speaking of extra beefy power cords, I have one I got from Mercury Transformers at the L.A. Guitar Amp Show some years ago. They were giving away these slick, fat, red cables. I'm not going to hook that up to just anything; no, that one is being saved for something special!
Seems like I have dozens of normal ones, though. The ones with the right angle IEC connectors come in handy when using a deep piece of equipment like a 7904 up close to the wall. But they always seem to point the wrong way, as do GPIB connectors. ;)

Rambling again - sorry.

Jim Ford

------ Original Message ------
From: "Dennis Tillman W7pF" <@Dennis_Tillman_W7pF>
To: TekScopes@groups.io
Sent: 7/22/2020 11:39:48 AM
Subject: Re: [TekScopes] 485 Cordwrap Feet

Hi Jeff,
It was not unusual for the design engineers at Tek to pay attention to
product details (known as Human Factors Engineering in those days) just like
this one. This was one of the things that distinguished Tek from many other
companies. The 485 was a portable scope which meant things like a power cord
had to have a secure place to be while it was being moved from one place to
another. The logical way to carry the scope was by the handle with the scope
in an upright position so there would need to be feet on the rear of the
scope. Why not kill two birds with one stone and design a foot that would
also secure the power cord?

There are some things that the mechanical engineers at Tek never seem to be
satisfied with and cord wraps are one of them. The cord wrap evolved
constantly. It was almost as if the mechanical engineers saw each new
portable scope as an opportunity to improve on the design of the previous
instrument. My 453 (the 454 and 453 were the original portables Tek designed
to meet the needs of the IBM Field Engineers) had fairly simple rear feet
which the power cord could be wrapped around. I think there was a chance the
power cord could become undone from around the rear feet while travelling
with the 453 scope. By the time the 485 appeared the cord wrap foot was just
about optimal: It holds the power cord securely, and it communicates to the
user, by its unusual shape, what its intended purpose is, without the need
for any further explanation.

In other words its unusual shape tells you what it does. Donald Norman in
his book "The Psychology of Everyday Things" coined the term "affordances"
for the properties of objects which show users the actions they can take.
Users should be able to perceive affordances without having to consider how
to use the items. A simple example we all encounter every day is the handle
on a door leading into or out of a store. The shape of the handle should
communicate to you whether you should push or pull it to open the door.
Instead most of them are so poorly designed that it is necessary to include
a sign saying "Push" or "Pull".

With the advent of the IEC power connector standard in 1970 many instruments
gradually started using power cords that could be unplugged from the
instrument which created a totally different problem of what to do with the
proliferation of these power cords now that they are everywhere. Somehow we
all end up with more of them than we can possibly use.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jeff
Davis
Sent: Tuesday, July 21, 2020 12:30 PM
To: TekScopes@groups.io
Subject: [TekScopes] 485 Cordwrap Feet

I had a customer approach me about developing a replacement cord wrap foot
for the Tektronix 485. He sent me one of his that was mostly intact - but it
led to some questions that I'm now posing to the group.

The 485 service manual shows that the cord wrap looks a lot like the cord
wraps on a 2465, i.e. two assemblies, one right side and one left side, that
extend from the bottom to the top, and the cord wraps around the two of
them.

On the other hand, what my customer sent to me looked more like a foot from
a 465, i.e. 4 pieces, one on each corner, with flanges to hold the cord. The
cord wraps around the four pieces located at each corner.

Did early and later versions of the 485 have different cord wraps? If so,
are they interchangeable? I can only find one version of the service manual,
and it shows the 2465-like cord wraps.

Would greatly appreciate anyone who could shed light on this mystery.

Thanks,
Jeff / N0DY
www.n0dy.com





--
Dennis Tillman W7pF
TekScopes Moderator



 

Hi Jim,
That is the official IEC connector recommended for switching mode power supplies. See examples of other official IEC 60320 shapes (there are at least 15 different ones) each specified for a different purpose.
https://en.wikipedia.org/wiki/IEC_60320
Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jim Ford
Sent: Wednesday, July 22, 2020 9:38 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 485 Cordwrap Feet

Funny you should mention those IEC power connectors, Dennis, as I just received a new wired router (opting for security, reliability, and speed for my 3 computers that stay in one place) today, and what do you know, it did not have an IEC connector on it. Instead, the power cable had a
"3 merged circles" (kind of like 3/5 of the Olympics symbol) connector.
Not sure why.

Now, my Tek 5103N/D10 and 7603 scopes have attached power cables, and every other piece of gear (most of it Tek or HP) I own except for the HP 400E AC voltmeter (pre-1970, no doubt) has a detachable cord with an IEC connector on it. No, wait, that's not true. I noticed some time ago that the 3 power supplies I own, an HP 6111A, an Elenco Precision XP-581, and a Trygon TL8-3, all have attached cords. I wonder why that is...

Another oddball is my Tek TLA711 mainframe. While it has an IEC male connector on the back of it, there is an extra rib below the GND pin, so a normal IEC female will not mate with it. Until you chop a groove into it with a utility knife, that is. I don't know why Tek did that. Maybe if you fill up the chassis with a thousand channels worth of logic analysis it draws so much current you need an extra beefy power cable (with a special notched IEC connector) hooked up to a 100 A circuit?

Speaking of extra beefy power cords, I have one I got from Mercury Transformers at the L.A. Guitar Amp Show some years ago. They were giving away these slick, fat, red cables. I'm not going to hook that up to just anything; no, that one is being saved for something special!
Seems like I have dozens of normal ones, though. The ones with the right angle IEC connectors come in handy when using a deep piece of equipment like a 7904 up close to the wall. But they always seem to point the wrong way, as do GPIB connectors. ;)

Rambling again - sorry.

Jim Ford

------ Original Message ------
From: "Dennis Tillman W7pF" <@Dennis_Tillman_W7pF>
To: TekScopes@groups.io
Sent: 7/22/2020 11:39:48 AM
Subject: Re: [TekScopes] 485 Cordwrap Feet

Hi Jeff,
It was not unusual for the design engineers at Tek to pay attention to
product details (known as Human Factors Engineering in those days) just
like this one. This was one of the things that distinguished Tek from
many other companies. The 485 was a portable scope which meant things
like a power cord had to have a secure place to be while it was being
moved from one place to another. The logical way to carry the scope was
by the handle with the scope in an upright position so there would need
to be feet on the rear of the scope. Why not kill two birds with one
stone and design a foot that would also secure the power cord?

There are some things that the mechanical engineers at Tek never seem
to be satisfied with and cord wraps are one of them. The cord wrap
evolved constantly. It was almost as if the mechanical engineers saw
each new portable scope as an opportunity to improve on the design of
the previous instrument. My 453 (the 454 and 453 were the original
portables Tek designed to meet the needs of the IBM Field Engineers)
had fairly simple rear feet which the power cord could be wrapped
around. I think there was a chance the power cord could become undone
from around the rear feet while travelling with the 453 scope. By the
time the 485 appeared the cord wrap foot was just about optimal: It
holds the power cord securely, and it communicates to the user, by its
unusual shape, what its intended purpose is, without the need for any further explanation.

In other words its unusual shape tells you what it does. Donald Norman
in his book "The Psychology of Everyday Things" coined the term "affordances"
for the properties of objects which show users the actions they can take.
Users should be able to perceive affordances without having to consider
how to use the items. A simple example we all encounter every day is
the handle on a door leading into or out of a store. The shape of the
handle should communicate to you whether you should push or pull it to open the door.
Instead most of them are so poorly designed that it is necessary to
include a sign saying "Push" or "Pull".

With the advent of the IEC power connector standard in 1970 many
instruments gradually started using power cords that could be unplugged
from the instrument which created a totally different problem of what
to do with the proliferation of these power cords now that they are
everywhere. Somehow we all end up with more of them than we can possibly use.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
Jeff Davis
Sent: Tuesday, July 21, 2020 12:30 PM
To: TekScopes@groups.io
Subject: [TekScopes] 485 Cordwrap Feet

I had a customer approach me about developing a replacement cord wrap
foot for the Tektronix 485. He sent me one of his that was mostly
intact - but it led to some questions that I'm now posing to the group.

The 485 service manual shows that the cord wrap looks a lot like the
cord wraps on a 2465, i.e. two assemblies, one right side and one left
side, that extend from the bottom to the top, and the cord wraps around
the two of them.

On the other hand, what my customer sent to me looked more like a foot
from a 465, i.e. 4 pieces, one on each corner, with flanges to hold the
cord. The cord wraps around the four pieces located at each corner.

Did early and later versions of the 485 have different cord wraps? If
so, are they interchangeable? I can only find one version of the
service manual, and it shows the 2465-like cord wraps.

Would greatly appreciate anyone who could shed light on this mystery.

Thanks,
Jeff / N0DY
www.n0dy.com





--
Dennis Tillman W7pF
TekScopes Moderator







--
Dennis Tillman W7pF
TekScopes Moderator


Dave Brown
 

More commonly known as the cloverleaf power connector.......
DaveB, NZ

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dennis Tillman W7pF
Sent: Thursday, July 23, 2020 16:56
To: TekScopes@groups.io
Subject: Re: [TekScopes] 485 Cordwrap Feet

Hi Jim,
That is the official IEC connector recommended for switching mode power supplies. See examples of other official IEC 60320 shapes (there are at least 15 different ones) each specified for a different purpose.
https://en.wikipedia.org/wiki/IEC_60320
Dennis Tillman W7pF


-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jim Ford
Sent: Wednesday, July 22, 2020 9:38 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 485 Cordwrap Feet

Funny you should mention those IEC power connectors, Dennis, as I just received a new wired router (opting for security, reliability, and speed for my 3 computers that stay in one place) today, and what do you know, it did not have an IEC connector on it. Instead, the power cable had a
"3 merged circles" (kind of like 3/5 of the Olympics symbol) connector.
Not sure why.

Now, my Tek 5103N/D10 and 7603 scopes have attached power cables, and every other piece of gear (most of it Tek or HP) I own except for the HP 400E AC voltmeter (pre-1970, no doubt) has a detachable cord with an IEC connector on it. No, wait, that's not true. I noticed some time ago that the 3 power supplies I own, an HP 6111A, an Elenco Precision XP-581, and a Trygon TL8-3, all have attached cords. I wonder why that is...

Another oddball is my Tek TLA711 mainframe. While it has an IEC male connector on the back of it, there is an extra rib below the GND pin, so a normal IEC female will not mate with it. Until you chop a groove into it with a utility knife, that is. I don't know why Tek did that. Maybe if you fill up the chassis with a thousand channels worth of logic analysis it draws so much current you need an extra beefy power cable (with a special notched IEC connector) hooked up to a 100 A circuit?

Speaking of extra beefy power cords, I have one I got from Mercury Transformers at the L.A. Guitar Amp Show some years ago. They were giving away these slick, fat, red cables. I'm not going to hook that up to just anything; no, that one is being saved for something special!
Seems like I have dozens of normal ones, though. The ones with the right angle IEC connectors come in handy when using a deep piece of equipment like a 7904 up close to the wall. But they always seem to point the wrong way, as do GPIB connectors. ;)

Rambling again - sorry.

Jim Ford

------ Original Message ------
From: "Dennis Tillman W7pF" <@Dennis_Tillman_W7pF>
To: TekScopes@groups.io
Sent: 7/22/2020 11:39:48 AM
Subject: Re: [TekScopes] 485 Cordwrap Feet

Hi Jeff,
It was not unusual for the design engineers at Tek to pay attention to
product details (known as Human Factors Engineering in those days) just
like this one. This was one of the things that distinguished Tek from
many other companies. The 485 was a portable scope which meant things
like a power cord had to have a secure place to be while it was being
moved from one place to another. The logical way to carry the scope was
by the handle with the scope in an upright position so there would need
to be feet on the rear of the scope. Why not kill two birds with one
stone and design a foot that would also secure the power cord?

There are some things that the mechanical engineers at Tek never seem
to be satisfied with and cord wraps are one of them. The cord wrap
evolved constantly. It was almost as if the mechanical engineers saw
each new portable scope as an opportunity to improve on the design of
the previous instrument. My 453 (the 454 and 453 were the original
portables Tek designed to meet the needs of the IBM Field Engineers)
had fairly simple rear feet which the power cord could be wrapped
around. I think there was a chance the power cord could become undone
from around the rear feet while travelling with the 453 scope. By the
time the 485 appeared the cord wrap foot was just about optimal: It
holds the power cord securely, and it communicates to the user, by its
unusual shape, what its intended purpose is, without the need for any further explanation.

In other words its unusual shape tells you what it does. Donald Norman
in his book "The Psychology of Everyday Things" coined the term "affordances"
for the properties of objects which show users the actions they can take.
Users should be able to perceive affordances without having to consider
how to use the items. A simple example we all encounter every day is
the handle on a door leading into or out of a store. The shape of the
handle should communicate to you whether you should push or pull it to open the door.
Instead most of them are so poorly designed that it is necessary to
include a sign saying "Push" or "Pull".

With the advent of the IEC power connector standard in 1970 many
instruments gradually started using power cords that could be unplugged
from the instrument which created a totally different problem of what
to do with the proliferation of these power cords now that they are
everywhere. Somehow we all end up with more of them than we can possibly use.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
Jeff Davis
Sent: Tuesday, July 21, 2020 12:30 PM
To: TekScopes@groups.io
Subject: [TekScopes] 485 Cordwrap Feet

I had a customer approach me about developing a replacement cord wrap
foot for the Tektronix 485. He sent me one of his that was mostly
intact - but it led to some questions that I'm now posing to the group.

The 485 service manual shows that the cord wrap looks a lot like the
cord wraps on a 2465, i.e. two assemblies, one right side and one left
side, that extend from the bottom to the top, and the cord wraps around
the two of them.

On the other hand, what my customer sent to me looked more like a foot
from a 465, i.e. 4 pieces, one on each corner, with flanges to hold the
cord. The cord wraps around the four pieces located at each corner.

Did early and later versions of the 485 have different cord wraps? If
so, are they interchangeable? I can only find one version of the
service manual, and it shows the 2465-like cord wraps.

Would greatly appreciate anyone who could shed light on this mystery.

Thanks,
Jeff / N0DY
www.n0dy.com





--
Dennis Tillman W7pF
TekScopes Moderator







--
Dennis Tillman W7pF
TekScopes Moderator


Chuck Harris
 

That is an IEC connector.... just not the type
you are used to.

It is known as a Mickey Mouse connector because of
the profile.

-Chuck Harris

Jim Ford wrote:

Funny you should mention those IEC power connectors, Dennis, as I just received a new
wired router (opting for security, reliability, and speed for my 3 computers that
stay in one place) today, and what do you know, it did not have an IEC connector on
it.  Instead, the power cable had a "3 merged circles" (kind of like 3/5 of the
Olympics symbol) connector.
Not sure why.


n4buq
 

I think I've heard those referred to as "Mickey Mouse" connectors.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Jim Ford" <james.ford@...>
To: TekScopes@groups.io
Sent: Wednesday, July 22, 2020 11:38:26 PM
Subject: Re: [TekScopes] 485 Cordwrap Feet

Funny you should mention those IEC power connectors, Dennis, as I just
received a new wired router (opting for security, reliability, and speed
for my 3 computers that stay in one place) today, and what do you know,
it did not have an IEC connector on it. Instead, the power cable had a
"3 merged circles" (kind of like 3/5 of the Olympics symbol) connector.
Not sure why.


Jeff Davis
 

@Barry, @Chuck, @Dennis, @Dave, @Jim, @Roy, @Michael W. Lynch via groups.io<mailto:mlynch003=yahoo.com@groups.io>

Thanks for your responses. At the risk of returning the thread to the original topic 🙂, I thought I'd clear the mystery up, at least a little bit.

Turns out the customer DOES have a 485. But clearly, his 485 does NOT have the original cord wrap. It appears that at some time in the past, they were replaced with the feet that I shared in the photo album. If you'll look, you'll see that there's a notch cut out of one side of the foot. That apparently was done to make the foot fit onto the scope and avoid interference with the housing protrusion. I added a photo of the foot installed to the album https://groups.io/g/TekScopes/album?id=250966.

So, mystery partially solved. I have some idle curiosity about where the foot came from as it's clearly not a 454, 465, or 475 foot (I know those by sight). But I can live with it. One day I'll come across one and the light bulb may (or may not) light up.

Jeff

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of n4buq <n4buq@...>
Sent: Thursday, July 23, 2020 6:07 AM
To: TekScopes@groups.io <TekScopes@groups.io>
Subject: Re: [TekScopes] 485 Cordwrap Feet

I think I've heard those referred to as "Mickey Mouse" connectors.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Jim Ford" <james.ford@...>
To: TekScopes@groups.io
Sent: Wednesday, July 22, 2020 11:38:26 PM
Subject: Re: [TekScopes] 485 Cordwrap Feet

Funny you should mention those IEC power connectors, Dennis, as I just
received a new wired router (opting for security, reliability, and speed
for my 3 computers that stay in one place) today, and what do you know,
it did not have an IEC connector on it. Instead, the power cable had a
"3 merged circles" (kind of like 3/5 of the Olympics symbol) connector.
Not sure why.