Date   
How I made my 577 work without a HV transformer

 

Necessity is the mother of invention. I needed to measure some transistors
but the HV transformer on my 577 was dead so there was no CRT beam and thus,
no display.



Walter Shawlee suggested I try connecting the horiz and vert output signals
from the 577 temporarily to one of the 600 monitors so I could start testing
until the replacement HV transformer arrives. The 577 horizontal and
vertical signals are differential so I needed to have differential inputs
for each axis. I have a few of these 600 series monitors but none have
differential inputs (that was an extra cost option and, apparently, not very
common).



Then it occurred to me that a 7603 with the right amplifiers might work just
as well as a 600 monitor. I needed to provide the capability for
differential inputs for each axis on the 7603 (or any 7000 scope mainframe)
for this to work. A pair of 7A13 differential comparator plugins (designed
by Bill DeVey who also did the 1A5, 7B52 and 7b92 timebases, and the 81
Plug-In Adaptor) would have the required differential inputs I needed and,
fortunately for me, I had two working ones. So I stuck one in the vertical
slot and one in the horizontal slot of a 7603. Then I made a nice cable
(from standard four wire telephone cable), to connect the two instruments
together.



It worked perfectly. Now the 7603 displays the transistor curves as if it
was the top half of my 577. Every control (except for brightness and focus)
on the 577 still works exactly as it used to. The only tiny discrepancy is
there is no blanking to dim the trace when it is just a dot in the corner,
also, the 577 has blanking at the end of each current step that is missing.
I suppose if I really wanted to I could have added a fifth wire to the cable
for the blanking signal but it really was not an issue.



Dennis Tillman W7PF

Re: 465M Power Supply Problems

n4buq
 

Well, even if a bigger, more expensive ROM were required, each byte would still cost the same as all the other bytes in it. :)

I get what you're saying, though. I'm glad I'm not generally constrained like that the way some folks had/have to be. It seems it isn't important anymore for most programming efforts these days - at least not the types of programs I write.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "edbreya@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Thursday, September 7, 2017 9:14:33 PM
Subject: Re: [TekScopes] 465M Power Supply Problems

Barry said:

"I'm a programmer. One byte costs the same as the other ones."

Not all bytes are the same cost. For example, one byte too many of code that
would cause you to need the next size up in ROM could be very expensive,
making it worthwhile to add effort to clean and reduce it to fit. There are
many instances like this in all fields of endeavor - the big decision points
are usually at the margins.

Ed



Re: 465M Power Supply Problems

Ed Breya
 

Barry said:

"I'm a programmer. One byte costs the same as the other ones."

Not all bytes are the same cost. For example, one byte too many of code that would cause you to need the next size up in ROM could be very expensive, making it worthwhile to add effort to clean and reduce it to fit. There are many instances like this in all fields of endeavor - the big decision points are usually at the margins.

Ed

Re: Smallest Tek scope

Michael A. Terrell
 

They ever caught me. Even in electronics class. :)

-----Original Message-----
From: "Barry n4buq@... [TekScopes]" <TekScopes@...>
Sent: Sep 7, 2017 2:06 PM
To: TekScopes@...
Subject: Re: [TekScopes] Smallest Tek scope

"Honest - I bought it for the articles!" (Page 21...)

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "'Michael A. Terrell' mike.terrell@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Thursday, September 7, 2017 12:30:30 PM
Subject: Re: [TekScopes] Smallest Tek scope

1970? I was a senior in high school and I took that magazine into class to
read, while my teacher bored the class with more of his meaningless stories.
It was the January Electronics Illustrated, and there is a copy is on the
site I linked to. I thought about building it but I decided that it was too
crude, so I waited a year and bought a new Leader LBO505 dual trace scope.

Here is a link to a scan:

http://www.americanradiohistory.com/Archive-Electronics-Illustrated/Electronics-Illustrated-1970-01.pdf

I think that I still have my copy of the magazine, but I can't get to where
it is stored right now.

-----Original Message-----
From: "Chuck Harris cfharris@... [TekScopes]"
<TekScopes@...>
Sent: Sep 7, 2017 8:08 AM
To: TekScopes@...
Subject: Re: [TekScopes] Smallest Tek scope

Might not have been PE magazine, I did subscribe to them
for quite a while, though, before I got disgusted with them.

...Let's see, how long ago was 1970?... Best not think about
that!

-Chuck Harris

'Michael A. Terrell' mike.terrell@... [TekScopes] wrote:
-----Original Message-----

From: "Harvey White madyn@... [TekScopes]"
Sent: Sep 6, 2017 5:20 PM
To: TekScopes@...
Subject: Re: [TekScopes] Smallest Tek scope

On Tue, 5 Sep 2017 23:06:13 -0400, you wrote:

Back in the early 1970's, Popular Electronics magazine
did a construction article on making a scope with a 1"
diameter CRT. The construction techniques were pure
tektronix, as I remember... cam switches and everything.
Hmmm, I missed that one, but they did have a "min-o-scope" which used
a 1EP1. It needed 2 or 3 tubes 1 vertical, 1 sweep, and was as basic
as you could get. I put one together in a 5x7x2 box. I won't go with
how badly it was wired, but it did work.

The thing would easily fit in a coat pocket... about
the size of an instamatic camera. The NLS mini scope
came out somewhat later, and had a bigger CRT.
Hmmm, I don't remember that as a construction project.

Perhaps the engineer that did the scope you saw, wrote
up the design for Popular Electronics, when Tek spurned
his design?
Possible, but where to get the cam switches was another matter. The
CRT was not a cheap thing at that time, so this was one of their more
expensive projects. No transistors at all.

Maybe I'm thinking of something in the mid 60's and ignored the one in
the 70's, after I gave up on them.



Here is an archive of Popular Electronics magazines:
http://www.americanradiohistory.com/Popular-Electronics-Guide.htm

Michael A. Terrell

Michael A. Terrell

restore of 2x 2465, sharing what I found so far

satbeginner
 

Hi all,
last week I received two 2465's from eBay to restore.


Why? I just love the 2465's, I already have two 2465B's, so now I want to restore these back to perfect again.
I just like to restore these things, and then look on the web for all the missing parts, like blue screen, knobs, top-bags, angled power cables, etc.




Scope 1:
This one came from the USA, so I had to set the line voltage to 230V.
I opened the cabinet, and there were only a few small spiderwebs, so I decided to switch it on. (It was showing traces on eBay when it was for sale)
It sort of worked, the read-out was visible, but the traces were jittering a lot in horizontal direction.
After about ten minutes it ended all with magic smoke and a bang, and yes.... both RIFA's were gone :-)
From previous restores I still had a new pair of replacements, so that was a quick fix, also one of the 68 Ohm resistors needed replacement.


Now I started looking for the cause of the horizontal jitter (just the traces were moving, not the readout, so no U800 problem?!)
I cleaned contacts of U700, also swapped it with U900, but no improvement there.


I found information here in the group about the A sweep being controlled from the A5 board (A Tim Ref), and yes, I found the output of the quad OpAmp U2427B, a TL074 (pin 7) being the cause of this jitter.
The local reference voltages (1,25V and also the inputs of the opamp were solid as a rock, so it must be the opamp.
I replaced that one and: succes, traces were stables now!


I did find another problem: the ground switch of Ch-2 did not work.


I removed the input attenuator for Ch-2.
To do this I removed the front bezel, removed the right front panel, removed the little metal cover at the end of the attenuator and unsoldered the two thin connections with the A1 board.
Now I could remove two screws at the front of the attenuator and also two screws at the bottom of it. (This is the reason I had to remove the right half of the front panel.
Having the attenuator removed from the scope (beware of the very thin groups of plug-in pins at the bottom of the attenuator for the relay coils, handle with care)
I could remove the relay top half of the attenuator and clean both the gold plated contacts on the ceramic platter and the contact springs on the relay top half.
Putting things all back in reverse order showed it was all OK now.


It is clear it needs calibration, but basic testing showed that everything works now.




Scope 2:
This one is from the USA too, and was shown on eBay with a compressed screen, but both in horizontal and vertical direction. (For me a typical image with the beamfinder pressed..)
This one needed a lot more cleaning, and this time, before powering on, I did check the RIFA's, but they were already replaced, or at least another brand.


A quick check learned that indeed the beamfinder switch was stuck/dirty, so I cleaned it and a (almost) normal trace was shown.
It became clear that (maybe a previous repair attempt?) almost all the basic settings like focus, astig, grid bias, etc. were 'tested'.
I adjusted them as described in the calibration manual, and the image became quite sharp.


But, now also showing a single row of dots at the bottom of the screen.
As far as I could find, this is related to the scope not being calibrated, so I decided to perform a quick calibration to see if the dots would disappear.
Yes, they did, but... after about 6 minutes the would reappear.


Since this scope has a "through the board, non-smd) A5 controller with an ER1400 memory, my guess now is that this memory is "dead".
I am not familiar with the long term behaviour of this kind of technology, I hope the loosing of its data is related with the age and actually being used, and not just age only...?
Anyway, I ordered a NOS chip and when it arrives I will replace it to see if the calibration will stick.


When the scopes are both back in working order again, I will order the famous CAP list at Mouser, so I can recap both power supplies and calibrate them, so these scopes will be OK for a (maybe new user?) in the future.




To be continued,


Satbeginner (Leo)

Re: Smallest Tek scope

Ed Breya
 

This talk all made me take a stroll down memory lane. The very first scope I ever saw in person was when I was in 6th grade. It was some kind of show-and-tell event, and a kid brought in a home-made or kit form scope that his dad had built - it was probably from one of those home-study electronics courses that were so prevalent then. It had about a 2" CRT, all packaged up in classic 1940s style cabinet and knobs, etc. And it worked, set up to present a Lissajous. I was very impressed, although the other kids had no clue to its significance.

Back then there were all sorts of WWII surplus to make things from, and lots of people getting into electronics. I recall also the other extreme advertised in the magazines - "Make a Giant Oscilloscope from Your Old TV," or something like that for the headline. These would have had impressive screen size, but of course very limited bandwidth due to the magnetic deflection.

If anyone wants to seriously consider dabbling around in miniscope territory, an alternative to the old small CRTs is to use "modern" ones salvaged from equipment like camcorders of the 1970s-1980s. Tiny CRTs were used for the viewfinders, and were essentially complete miniature video monitors, with screens so small they needed a magnifier in front. Converting one from TV to scope use could be done just like in the old days. Again, the BW would be quite limited, but probably in the same range attainable with the old-school small electrostatic CRTs.

I have a few of these viewfinder CRTs that I keep in the curio cabinet, only due to cuteness - I have no practical use for them. One generation type has about 1" to 1.25" diagonal rectangular screen, and maybe 4-5" long. The smallest are 5/8" D round screens, by about 3" long.

Ed

Re: Smallest Tek scope

Michael A. Terrell
 

The schematic, and the rest of the project was published in a later issue.

-----Original Message-----
From: "Brad Thompson brad.thompson@... [TekScopes]" <TekScopes@...>
Sent: Sep 7, 2017 3:33 PM
To: TekScopes@...
Subject: Re: [TekScopes] Smallest Tek scope

On 9/7/2017 1:30 PM, 'Michael A. Terrell' mike.terrell@...
[TekScopes] wrote:
1970? I was a senior in high school and I took that magazine into class
to read, while my teacher bored the class with more of his meaningless
stories. It was the January Electronics Illustrated, and there is a copy
is on the site I linked to. I thought about building it but I decided
that it was too crude, so I waited a year and bought a new Leader LBO505
dual trace scope.

Here is a link to a scan:

http://www.americanradiohistory.com/Archive-Electronics-Illustrated/Electronics-Illustrated-1970-01.pdf
Hello--

I didn't see a schematic for the project in the article. That would add
to the difficulties<g>.

Somewhere here, I have a 1DP11 CRT, which has a dime-size screen and a
nine-pin
miniature base... think "second-generation 913(*)".

Go here...

http://www.edn.com/design/test-and-measurement/4389515/One-inch-wonders

...For a description.

73--

Brad AA1IP

(*) The 913 had a metal envelope like a 6L6 tube, with a screen about
the size of a U.S. $ .25 coin.

Michael A. Terrell

Re: Smallest Tek scope

Mark Pilant
 

Brad, the schematics and other information were in pert 2 of the article.
It appeared in the May 1970 issue (starting on page 39). The archive has
that issue as well (...1970-05.pdf).

- Mark N1VQW

Re: 465M Power Supply Problems

n4buq
 

I've never been in this situation, but I'd have to think that the accountants (a.k.a. "bean counters") get involved. "Yes, you want an X part, but we just bought a gazillion Y parts so see if you can use that instead."

I'm a programmer. One byte costs the same as the other ones.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "edbreya@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Thursday, September 7, 2017 2:17:31 PM
Subject: Re: [TekScopes] 465M Power Supply Problems

I agree with David on this. Especially on PS DC filtering, the Ls can work
just fine with a wide range of values, as long as they can take the required
current - it's not at all a precision application.

There's also the concept of minimizing cost by using the cheapest parts that
get the job done, AND using the smallest possible variety of parts, so there
are fewer part numbers and stock to deal with all the way through the
process. Many parts in circuits of all kinds are not necessarily the ideal
or exact value required, but are close enough, and in a proper design, will
minimize the variety needed.

There's also the concept of "rule of thumb" in choosing and placement of
common things like PS decoupling and bypassing - like so many of such and
such cap per so many logic ICs, etc, without any fancy analysis of each and
every item.

Sometimes you need the "exact" right parts in the exact right places, but for
most common circuitry, close enough is perfect.

Ed



Re: Smallest Tek scope

Brad Thompson <brad.thompson@...>
 

On 9/7/2017 1:30 PM, 'Michael A. Terrell' mike.terrell@... [TekScopes] wrote:
1970? I was a senior in high school and I took that magazine into class to read, while my teacher bored the class with more of his meaningless stories. It was the January Electronics Illustrated, and there is a copy is on the site I linked to. I thought about building it but I decided that it was too crude, so I waited a year and bought a new Leader LBO505 dual trace scope.
Here is a link to a scan:
http://www.americanradiohistory.com/Archive-Electronics-Illustrated/Electronics-Illustrated-1970-01.pdf
Hello--

I didn't see a schematic for the project in the article. That would add to the difficulties<g>.

Somewhere here, I have a 1DP11 CRT, which has a dime-size screen and a nine-pin
miniature base... think "second-generation 913(*)".

Go here...

http://www.edn.com/design/test-and-measurement/4389515/One-inch-wonders

...For a description.

73--

Brad AA1IP

(*) The 913 had a metal envelope like a 6L6 tube, with a screen about the size of a U.S. $ .25 coin.

Re: 465M Power Supply Problems

Ed Breya
 

I agree with David on this. Especially on PS DC filtering, the Ls can work just fine with a wide range of values, as long as they can take the required current - it's not at all a precision application.

There's also the concept of minimizing cost by using the cheapest parts that get the job done, AND using the smallest possible variety of parts, so there are fewer part numbers and stock to deal with all the way through the process. Many parts in circuits of all kinds are not necessarily the ideal or exact value required, but are close enough, and in a proper design, will minimize the variety needed.

There's also the concept of "rule of thumb" in choosing and placement of common things like PS decoupling and bypassing - like so many of such and such cap per so many logic ICs, etc, without any fancy analysis of each and every item.

Sometimes you need the "exact" right parts in the exact right places, but for most common circuitry, close enough is perfect.

Ed

Re: Smallest Tek scope

Michael A. Terrell
 

My mother took care of that problem. She threw out almost all of my magazines and catalogs while I was in the Army. I have about ten left, that she missed. I learned a lot from studying the the circuits in those magazines. Enough, that I tested out of the hardest electronics school in the Army, in the early '70s. A three year, depot level course for broadcast engineer.

I had hundreds of computer magazines boxed up in my garage, but termites found them.

-----Original Message-----
From: "Chuck Harris cfharris@... [TekScopes]" <TekScopes@...>
Sent: Sep 7, 2017 2:18 PM
To: TekScopes@...
Subject: Re: [TekScopes] Smallest Tek scope

I was in 9th grade, which then was jr high school, but
now is high school, but I don't recall having
a subscription to Electronics Illustrated.. I am
quite certain the scope I saw had cam switches, as
I recall thinking they were interesting. It wasn't
until years later that I saw my first 7000 series
plug-in, with its cam switches.

Wayne Green is listed in the "Masthead" as a contributing
editor for amateur radio.

If I kept all (any) of the magazines I subscribed to
in those years, I would be buried in paper. I let them
go many, many years ago. I don't think they are going
to become significantly valuable in my lifetime.

-Chuck Harris

'Michael A. Terrell' mike.terrell@... [TekScopes] wrote:
1970? I was a senior in high school and I took that magazine into class to read,
while my teacher bored the class with more of his meaningless stories. It was the
January Electronics Illustrated, and there is a copy is on the site I linked to. I
thought about building it but I decided that it was too crude, so I waited a year
and bought a new Leader LBO505 dual trace scope.

Here is a link to a scan:

http://www.americanradiohistory.com/Archive-Electronics-Illustrated/Electronics-Illustrated-1970-01.pdf

I think that I still have my copy of the magazine, but I can't get to where it is
stored right now.

Michael A. Terrell

Re: Smallest Tek scope

Chuck Harris
 

Hi Carlos,

Nope. I'm not that old. In 1960, I was
entering kindergarten.

The scope I remember seeing had cam switches,
and was solid state. Maybe 73 magazine?

-Chuck Harris

curbinap@... [TekScopes] wrote:

Hi Carlos,
That sure looks similar, perhaps Walt Henry did another that used the cam
switches? I distinctly remember the cam switches, rather than the wafer switches
used in the EI article.
The thing is, I saw this scope, with the cam switches before I had ever seen a
tektronix scope with cam switches, so I remember marvelling at the idea... and
then some time later, 1979 or 80, working on my first 7000 series, and seeing
the same thing.
I don't remember subscribing to EI, but I do remember a lot of the people on the
masthead. It seems it was a Wayne Green publication, so I have certainly seen a
lot of his stuff.
-Chuck Harris
Hi again, Chuck

I found a small scope in Popular Electronics magazine, but this one appeared in
the August 1960 issue:

<http://www.americanradiohistory.com/Archive-Poptronics/60s/60/Pop-1960-08.pdf>

A google search shows two other small scopes, this one from the July 1957 issue of
Electronics Design News, according to the website:

<http://www.ck722museum.com/page29.html>

and another 1-inch scope, but this is a tube design:

<http://hanssummers.com/tinyscope.html>

Still not the one you remember?

Carlos





------------------------------------ Posted by: curbinap@...
------------------------------------


------------------------------------

Yahoo Groups Links

Re: Smallest Tek scope

Chuck Harris
 

I was in 9th grade, which then was jr high school, but
now is high school, but I don't recall having
a subscription to Electronics Illustrated.. I am
quite certain the scope I saw had cam switches, as
I recall thinking they were interesting. It wasn't
until years later that I saw my first 7000 series
plug-in, with its cam switches.

Wayne Green is listed in the "Masthead" as a contributing
editor for amateur radio.

If I kept all (any) of the magazines I subscribed to
in those years, I would be buried in paper. I let them
go many, many years ago. I don't think they are going
to become significantly valuable in my lifetime.

-Chuck Harris

'Michael A. Terrell' mike.terrell@... [TekScopes] wrote:

1970? I was a senior in high school and I took that magazine into class to read,
while my teacher bored the class with more of his meaningless stories. It was the
January Electronics Illustrated, and there is a copy is on the site I linked to. I
thought about building it but I decided that it was too crude, so I waited a year
and bought a new Leader LBO505 dual trace scope.

Here is a link to a scan:

http://www.americanradiohistory.com/Archive-Electronics-Illustrated/Electronics-Illustrated-1970-01.pdf

I think that I still have my copy of the magazine, but I can't get to where it is
stored right now.

Re: Smallest Tek scope

n4buq
 

"Honest - I bought it for the articles!" (Page 21...)

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "'Michael A. Terrell' mike.terrell@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Thursday, September 7, 2017 12:30:30 PM
Subject: Re: [TekScopes] Smallest Tek scope

1970? I was a senior in high school and I took that magazine into class to
read, while my teacher bored the class with more of his meaningless stories.
It was the January Electronics Illustrated, and there is a copy is on the
site I linked to. I thought about building it but I decided that it was too
crude, so I waited a year and bought a new Leader LBO505 dual trace scope.

Here is a link to a scan:

http://www.americanradiohistory.com/Archive-Electronics-Illustrated/Electronics-Illustrated-1970-01.pdf

I think that I still have my copy of the magazine, but I can't get to where
it is stored right now.

-----Original Message-----
From: "Chuck Harris cfharris@... [TekScopes]"
<TekScopes@...>
Sent: Sep 7, 2017 8:08 AM
To: TekScopes@...
Subject: Re: [TekScopes] Smallest Tek scope

Might not have been PE magazine, I did subscribe to them
for quite a while, though, before I got disgusted with them.

...Let's see, how long ago was 1970?... Best not think about
that!

-Chuck Harris

'Michael A. Terrell' mike.terrell@... [TekScopes] wrote:
-----Original Message-----

From: "Harvey White madyn@... [TekScopes]"
Sent: Sep 6, 2017 5:20 PM
To: TekScopes@...
Subject: Re: [TekScopes] Smallest Tek scope

On Tue, 5 Sep 2017 23:06:13 -0400, you wrote:

Back in the early 1970's, Popular Electronics magazine
did a construction article on making a scope with a 1"
diameter CRT. The construction techniques were pure
tektronix, as I remember... cam switches and everything.
Hmmm, I missed that one, but they did have a "min-o-scope" which used
a 1EP1. It needed 2 or 3 tubes 1 vertical, 1 sweep, and was as basic
as you could get. I put one together in a 5x7x2 box. I won't go with
how badly it was wired, but it did work.

The thing would easily fit in a coat pocket... about
the size of an instamatic camera. The NLS mini scope
came out somewhat later, and had a bigger CRT.
Hmmm, I don't remember that as a construction project.

Perhaps the engineer that did the scope you saw, wrote
up the design for Popular Electronics, when Tek spurned
his design?
Possible, but where to get the cam switches was another matter. The
CRT was not a cheap thing at that time, so this was one of their more
expensive projects. No transistors at all.

Maybe I'm thinking of something in the mid 60's and ignored the one in
the 70's, after I gave up on them.



Here is an archive of Popular Electronics magazines:
http://www.americanradiohistory.com/Popular-Electronics-Guide.htm

Michael A. Terrell

Re: Smallest Tek scope

Carlos
 

Hi Carlos,
>That sure looks similar, perhaps Walt Henry did another
>that used the cam switches? I distinctly remember the
>cam switches, rather than the wafer switches used in the
>EI article.

>The thing is, I saw this scope, with the cam switches
>before I had ever seen a tektronix scope with cam switches,
>so I remember marvelling at the idea... and then some time
>later, 1979 or 80, working on my first 7000 series, and
>seeing the same thing.

>I don't remember subscribing to EI, but I do remember a lot
>of the people on the masthead. It seems it was a Wayne Green
>publication, so I have certainly seen a lot of his stuff.

>-Chuck Harris

Hi again, Chuck

I found a small scope in Popular Electronics magazine, but this one appeared in the August 1960 issue:

<http://www.americanradiohistory.com/Archive-Poptronics/60s/60/Pop-1960-08.pdf>

A google search shows two other small scopes, this one from the July 1957 issue of Electronics Design News, according to the website:

<http://www.ck722museum.com/page29.html>

and another 1-inch scope, but this is a tube design:

<http://hanssummers.com/tinyscope.html>

Still not the one you remember?

Carlos

Re: Smallest Tek scope

Michael A. Terrell
 

Electronics illustrated was owned by Mechanics Illustrated. Wayne Green was just a contributing author.

-----Original Message-----
From: "Chuck Harris cfharris@... [TekScopes]" <TekScopes@...>
Sent: Sep 7, 2017 8:06 AM
To: TekScopes@...
Subject: Re: [TekScopes] Re: Smallest Tek scope

Hi Carlos,

That sure looks similar, perhaps Walt Henry did another
that used the cam switches? I distinctly remember the
cam switches, rather than the wafer switches used in the
EI article.

The thing is, I saw this scope, with the cam switches
before I had ever seen a tektronix scope with cam switches,
so I remember marvelling at the idea... and then some time
later, 1979 or 80, working on my first 7000 series, and
seeing the same thing.

I don't remember subscribing to EI, but I do remember a lot
of the people on the masthead. It seems it was a Wayne Green
publication, so I have certainly seen a lot of his stuff.

-Chuck Harris

Carlos Urbina Pacheco curbinap@... [TekScopes] wrote:
On Tue, 5 Sep 2017 23:06:13 -0400, you wrote:

Back in the early 1970's, Popular Electronics magazine
did a construction article on making a scope with a 1"
diameter CRT. The construction techniques were pure
tektronix, as I remember... cam switches and everything.
...
Hi, Chuck!
Like Harvey, I also don' t remember a small scope construction project in
Popular Electronics magazine during the 70s.
However, I remember one published in Electronics Illustrated magazine inthe January 1970 issue, which you can find here (the image looks much better if youfirst download it to your computer and then open the file there):
<http://www.americanradiohistory.com/Archive-Electronics-Illustrated/Electronics-Illustrated-1970-01.pdf>
I wonder if you were referring to this article?
Regards,
Carlos

Michael A. Terrell

Re: Smallest Tek scope

Michael A. Terrell
 

1970? I was a senior in high school and I took that magazine into class to read, while my teacher bored the class with more of his meaningless stories. It was the January Electronics Illustrated, and there is a copy is on the site I linked to. I thought about building it but I decided that it was too crude, so I waited a year and bought a new Leader LBO505 dual trace scope.

Here is a link to a scan:

http://www.americanradiohistory.com/Archive-Electronics-Illustrated/Electronics-Illustrated-1970-01.pdf

I think that I still have my copy of the magazine, but I can't get to where it is stored right now.

-----Original Message-----
From: "Chuck Harris cfharris@... [TekScopes]" <TekScopes@...>
Sent: Sep 7, 2017 8:08 AM
To: TekScopes@...
Subject: Re: [TekScopes] Smallest Tek scope

Might not have been PE magazine, I did subscribe to them
for quite a while, though, before I got disgusted with them.

...Let's see, how long ago was 1970?... Best not think about
that!

-Chuck Harris

'Michael A. Terrell' mike.terrell@... [TekScopes] wrote:
-----Original Message-----

From: "Harvey White madyn@... [TekScopes]"
Sent: Sep 6, 2017 5:20 PM
To: TekScopes@...
Subject: Re: [TekScopes] Smallest Tek scope

On Tue, 5 Sep 2017 23:06:13 -0400, you wrote:

Back in the early 1970's, Popular Electronics magazine
did a construction article on making a scope with a 1"
diameter CRT. The construction techniques were pure
tektronix, as I remember... cam switches and everything.
Hmmm, I missed that one, but they did have a "min-o-scope" which used
a 1EP1. It needed 2 or 3 tubes 1 vertical, 1 sweep, and was as basic
as you could get. I put one together in a 5x7x2 box. I won't go with
how badly it was wired, but it did work.

The thing would easily fit in a coat pocket... about
the size of an instamatic camera. The NLS mini scope
came out somewhat later, and had a bigger CRT.
Hmmm, I don't remember that as a construction project.

Perhaps the engineer that did the scope you saw, wrote
up the design for Popular Electronics, when Tek spurned
his design?
Possible, but where to get the cam switches was another matter. The
CRT was not a cheap thing at that time, so this was one of their more
expensive projects. No transistors at all.

Maybe I'm thinking of something in the mid 60's and ignored the one in
the 70's, after I gave up on them.



Here is an archive of Popular Electronics magazines:
http://www.americanradiohistory.com/Popular-Electronics-Guide.htm

Michael A. Terrell

Re: 465M Power Supply Problems

n4buq
 

Correction: Tolerance is +/- 2V. Ripple is 1V.

Thanks,
Barry - N4BUQ

IIRC, ripple spec for that supply is <= 2V so I'm pretty sure you're correct.

Thanks,
Barry - N4BUQ


But I am sure there is a wide range of values which will deliver
completely acceptable performance.

Re: 465M Power Supply Problems

n4buq
 

IIRC, ripple spec for that supply is <= 2V so I'm pretty sure you're correct.

Thanks,
Barry - N4BUQ

But I am sure there is a wide range of values which will deliver
completely acceptable performance.