Date   
Re: Craigslist; Lynchburg, VA: 7xxx Scope

David DiGiacomo
 

Looks like a 7904 mainframe.

On Mon, Mar 23, 2020 at 8:35 PM John Clark <johnclark05@...> wrote:

Anyone in the Lynchburg, VA area interested in a 7xxx scope with plug-ins? I'm not familiar enough with them to know exactly which model it is from the single picture but looks to be free for the first one to come pick it up. Listing says it works. I've no affiliation with the owner. It just popped up in a saved search I have.

https://lynchburg.craigslist.org/zip/d/lynchburg-tektronix-oscilloscope/7097981758.html
[https://images.craigslist.org/01717_JnH9hntqVw_600x450.jpg]<https://lynchburg.craigslist.org/zip/d/lynchburg-tektronix-oscilloscope/7097981758.html>
Tektronix Oscilloscope - free stuff<https://lynchburg.craigslist.org/zip/d/lynchburg-tektronix-oscilloscope/7097981758.html>
To the best of our knowledge, this works! Will remove listing once someone picks it up. Please...
lynchburg.craigslist.org

John
Charlotte, NC


Re: Tek Blue Paint

JJ
 

Bob, I found this thread from 2009. https://groups.io/g/TekScopes/topic/7640708?p=Created,,,20,2,0,0. Reed Dickinson posted a formula. Stan also had the paint made up - minimum order quantity is 24 spray cans! Stan was selling them for $15/can. I don't need 24 cans.
The Tek blue subject was brought up back in 2004 and then again in 2009 where the reference to 2004 was made.
It's still not clear whether Reed's posted formula came from Tek or whether he had a sample analyzed by a paint firm? And, whether Stan's paint was Reed's same formula made by Sherwin Williams?

John Justin

Re: TDS3000B calibration

benj3867
 

Glad to be of service ;)

If you do go ahead with the calibration, please be kind enough to report back with more details.

Re: Mr Carlson's Patreon and test tool designs - was Re: [TekScopes] enclosures for ESR meters

 

AMEN!

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Chuck Harris
Sent: Tuesday, March 24, 2020 7:56 AM
To: TekScopes@groups.io
Subject: Re: Mr Carlson's Patreon and test tool designs - was Re: [TekScopes] enclosures for ESR meters

If you really want to see how Dennis makes this conversation stop, just keep it up.

While you have lost your posting privileges, you might find this group less fun.

-Chuck Harris

Lawrance A. Schneider wrote:
Again, I agree. I'm simply not equipped nor interested in making my own boards. I only have a small room in my house - in Maine heating a garage is ??? - wherein I do my computer work and my electronic work.
I understand Dennis would rather we somehow end this conversation on TekScopes. While I read and understand his reasoning, I think the subject will die on its own accord soon. I hope not until some resolution is come to relative to boards. I think the subject will be dropped when the present group of people do come to some sort of resolution. Clearly, I would prefer a group buy as to the making of boards.
I bought a HP E3630A power supply a while ago. I forget which -
voltage or current - reading was not working. I ask question on the Agelent-HP and was given some answers. The answers helped and I fixed the power supply. The subject was dropped when I told ALL that I had fixed it. I believe this topic - ESR and Mr. Carlson - will soon die.







--
Dennis Tillman W7PF
TekScopes Moderator

Re: Tek Blue Paint

 

Hi JJ,
Nonsense. This subject comes up so often I'm going to guess you didn't bother to look through our archives. The Tek blue paint has never been a problem for anyone who was willing to take a minute and do a search for themselves.

Many members have posted in our archives numerous ways you can buy it. For instance:
* Stan Griffiths has always sold it until 2 months ago when he passed away.
* TekScopes members have determined alternate sources.
* TekScopes members have identified the pigment combination to make it.
* Still other members have pointed out which paint stores will match the color for you if you bring in a side panel.

Aside from listing it on Amazon what more would you like us to do?

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of JJ
Sent: Tuesday, March 24, 2020 7:12 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek Blue Paint

Wow, this Tek blue paint thing has been a problem for decades. I would love to get my hands on a spray can. I'm wondering if the people at Tektronix would be willing to give us the formula? I imagine it's been a trade secret in the past - but nowadays, it can be duplicated fairly closely through technology.

From what I remember, a spectrophotometer (with more than 30 filters) is only 90% accurate at the very best - and that assumes that you can measure both reflected light from and transmitted light through the specimen - so one would need a paint chip.

There are specialty shops (not the big box stores) that will use a spectrophotometer's input together with manual mixing by a highly experienced individual to get as close as humanly possible.to a match. But, I'm sure it would be costly.

John Justin





--
Dennis Tillman W7PF
TekScopes Moderator

Where you can find more ESR, Tesla Coil, etc Info

 

Thank you to Roy Thistle who reminded me that a
"good resource... with good people too... which has been recommended is The
EEVblog Forum. There are pages and pages of posts about ESR meters there."

I can second his recommendation. It is a very active site.

Dennis Tillman W7pF

Re: Mr Carlson's Patreon and test tool designs - was Re: [TekScopes] enclosures for ESR meters

Chuck Harris
 

If you really want to see how Dennis makes
this conversation stop, just keep it up.

While you have lost your posting privileges,
you might find this group less fun.

-Chuck Harris

Lawrance A. Schneider wrote:

Again, I agree. I'm simply not equipped nor interested in making my own boards. I only have a small room in my house - in Maine heating a garage is ??? - wherein I do my computer work and my electronic work.
I understand Dennis would rather we somehow end this conversation on TekScopes. While I read and understand his reasoning, I think the subject will die on its own accord soon. I hope not until some resolution is come to relative to boards. I think the subject will be dropped when the present group of people do come to some sort of resolution. Clearly, I would prefer a group buy as to the making of boards.
I bought a HP E3630A power supply a while ago. I forget which - voltage or current - reading was not working. I ask question on the Agelent-HP and was given some answers. The answers helped and I fixed the power supply. The subject was dropped when I told ALL
that I had fixed it. I believe this topic - ESR and Mr. Carlson - will soon die.



Re: Tek Blue Paint

stevenhorii
 

I don't have anything to do a side-by-side, but Tek blue looks like
"Federal Blue". Has anyone compared them?

On Tue, Mar 24, 2020, 10:12 JJ <jajustin@...> wrote:

Wow, this Tek blue paint thing has been a problem for decades. I would love
to get my hands on a spray can. I'm wondering if the people at Tektronix
would be willing to give us the formula? I imagine it's been a trade secret
in the past - but nowadays, it can be duplicated fairly closely through
technology.

From what I remember, a spectrophotometer (with more than 30 filters) is
only 90% accurate at the very best - and that assumes that you can measure
both reflected light from and transmitted light through the specimen - so
one would need a paint chip.

There are specialty shops (not the big box stores) that will use a
spectrophotometer's input together with manual mixing by a highly
experienced individual to get as close as humanly possible.to a match.
But,
I'm sure it would be costly.

John Justin



Re: Tek Blue Paint

Bob Koller
 

Here is the Sherwin Williams info:
Call:
Portland (Oregon) Commercial at (503) 249-0222
They supply Tek Blue (Portland Commercial 4383)
The Omi-Pak cans of spray lacquer are marked:
OPEX L61 Lacquer
L61XXL42-4383

Re: Tek Blue Paint

JJ
 

Wow, this Tek blue paint thing has been a problem for decades. I would love
to get my hands on a spray can. I'm wondering if the people at Tektronix
would be willing to give us the formula? I imagine it's been a trade secret
in the past - but nowadays, it can be duplicated fairly closely through
technology.

From what I remember, a spectrophotometer (with more than 30 filters) is
only 90% accurate at the very best - and that assumes that you can measure
both reflected light from and transmitted light through the specimen - so
one would need a paint chip.

There are specialty shops (not the big box stores) that will use a
spectrophotometer's input together with manual mixing by a highly
experienced individual to get as close as humanly possible.to a match. But,
I'm sure it would be costly.

John Justin

Re: Mr Carlson's Patreon and test tool designs - was Re: [TekScopes] enclosures for ESR meters

Lawrance A. Schneider
 

Again, I agree. I'm simply not equipped nor interested in making my own boards. I only have a small room in my house - in Maine heating a garage is ??? - wherein I do my computer work and my electronic work.
I understand Dennis would rather we somehow end this conversation on TekScopes. While I read and understand his reasoning, I think the subject will die on its own accord soon. I hope not until some resolution is come to relative to boards. I think the subject will be dropped when the present group of people do come to some sort of resolution. Clearly, I would prefer a group buy as to the making of boards.
I bought a HP E3630A power supply a while ago. I forget which - voltage or current - reading was not working. I ask question on the Agelent-HP and was given some answers. The answers helped and I fixed the power supply. The subject was dropped when I told ALL
that I had fixed it. I believe this topic - ESR and Mr. Carlson - will soon die.

Re: TEKTRONIX 491 measuring wifi signals

Chuck Harris
 

What works as shielding at 30MHz, looks like a sieve at 2.4GHz.

The principle leak is around the door... traditionally.

The ovens use what is called a choke seal around the door, which
physically is a dead ended slot around the door. Both the gap
between the door and the door frame, and the slot in the door
form a high Q, inductance to the 2450MHz signal, and stop most
of it from leaking into the room.

"Most" is still about a watt.

I just noticed that my microwave is one labeled Montgomery Wards,
a retailer that has been gone for two decades. They sent it to
my in-laws from their repair facility, where it was tagged both
unrepairable and repaired. It worked fine. They put the wrong
tag on it. Still going strong!

The Tektronix 491's mixer is pretty old fashioned, using discrete
glass diodes. But, I would still be careful when using it around
a 1500W RF source that leaks several watts.

I remember when my MIL tested a brand new microwave oven leakage
tester by putting it in the oven... God I miss her!

-Chuck Harris

Miguel Work wrote:

My Pansonic microwave oven is working since late 80s, is one of the first micro controlled, the keyboard has no signs of wear 30 years after, has survaived my four brothers family!
Using it every day and still working. It has a double shield.

It costs about 800$

Regards!




-----Mensaje original-----
De: TekScopes@groups.io [mailto:TekScopes@groups.io] En nombre de Chuck Harris
Enviado el: martes, 24 de marzo de 2020 13:44
Para: TekScopes@groups.io
Asunto: Re: [TekScopes] TEKTRONIX 491 measuring wifi signals

When the first commercial microwave ovens were made, they had simple mechanical timers, and no "heat" settings. The next generation had simple mechanical timers, and thermal timers similar to turn signal "clickers" to adjust the on vs off time. Every enhancement since has been simply refinements of the same basic formula: Turning mechanical timers into electronic timers, into microprocessor timers.
Turning mechanical bells into electronic bells. Turning linear transformers into switching power supplies...

But the basic on/off, "bang-bang" method of controlling the heat has remained intact: how many seconds on, out of 10 seconds, determines the "heat" from the oven.

Some researchers wanted to take the microwave oven into the realm of laboratory heating, and found the "bang-bang" style of heat adjustment way too brutal. For instance, if you wanted to heat a saline solution in a watch glass, it would explode around the edges where the water was so very thin, even though the "heat" was on low... even one second at full power followed by 9 seconds of being off was too brutal.

So, a colleague of mine developed a precision microwave that took the duty cycle modulation of the magnetron from seconds on out of 10 seconds, to power line cycles on out of 10 power line cycles. And, even balanced the distribution of on cycles so that if you were at 50%, it was every other cycle of the 60Hz power, (that may have been my suggestion, I don't remember anymore) ... Saline in a watch glass was his standard test.

Heading back to 491's, and wifi signals:

Modern microwave ovens have replaced the heavy, and copper laden, power transformers with switching power supplies...
which is why they are now available for less than $100.

There is a big cost, however. High voltage capacitors are still expensive, so the new supplies aren't at all well filtered, and end up modulating the 2450MHz nominal magnetron output at the switching supply rate, and the switching supply rate is not at all stabilized, so it changes with load. This wreaks havoc with wifi routers which occupy the same ISM band as do the ovens.... Only the ovens leak way more power than the routers put out.

A friend once asked me why his "smart" house, and his cordless phones, stopped working every so often... I asked him if he had a microwave oven. He said yes. I asked him to notice if his wife was using the microwave oven when his "smart"
house stopped being so "smart".

You should be able to see this wandering RF noise fest on your
491 whenever the microwave oven is running.

-Chuck Harris
on off timer that im Ford wrote:
I stand corrected (not all that unusual).  Thanks, Chuck.  My guess
would be that microwave oven manufacturers either don't know about or
don't want to deal with the subtleties of magnetron anode and filament
voltages and currents.JimSent from my Verizon, Samsung Galaxy
smartphone




Re: Tek Blue Paint

Paul Amaranth
 

I had some matched up at my local Sherwin Williams in a semigloss enamel, I think.
It's packed away now and unavailable, but this topic comes up periodically so
if you search the archives here and maybe on eevblog you should get the formula.
I'm sure I posted it at least once.

In the olden days you could get lacquer mixed up and even put into a spray can. But
you can get a cheap spraygun from HF for under $20 that does a decent job.

Auto paints, which used to be pretty cheap, are getting a bit prohibitive these days.
And some of them need full hazmat gear to be around.

OK, back in 2015 there was this thread with a discussion:

https://groups.io/g/TekScopes/topic/7656224

Recipe is about a quarter of the way down.

Paul

On Tue, Mar 24, 2020 at 07:50:31PM +0800, Li Gangyi wrote:
Can't somebody go get it specteophotometered for a close match like with
custom car colors? I know where I was previously the English color near me
had that tool.

Finally an old lady with a good eye matched the thing by eye till I
couldn't tell a difference. Granted it was a flat color though.


On Tue, Mar 24, 2020, 12:42 PM Dennis Tillman W7PF <@Dennis_Tillman_W7pF>
wrote:

Hi Steve and Brendan,
Stan Griffiths used to sell Tek paint in spray cans and other ways. I got
4 of the last cans he had in October. He only had a few left at that time.

This might be what you are looking for:
Dennis Tillman W7pF


-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
snapdiode via Groups.Io
Sent: Thursday, April 19, 2018 5:12 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek blue tyouch up paint?


https://www.sherwin-williams.com/store-locator/product-finishes-facility/portland/or/4383

phone 1-503-249-0222

You want L61 opex lacquer
L61xxcl42
Tek Blue

Or just call Tektronix, they used to have a part number just for that, in
a 7oz spray can.




--
Dennis Tillman W7PF
TekScopes Moderator






!DSPAM:5e7a0bc3134601363318633!
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix & Windows

Re: Tek Blue Paint

Dave Daniel
 

Sherwin-Williams can do that.

On Mar 24, 2020, at 07:50, Li Gangyi <li.gangyi@...> wrote:

Can't somebody go get it specteophotometered for a close match like with
custom car colors? I know where I was previously the English color near me
had that tool.

Finally an old lady with a good eye matched the thing by eye till I
couldn't tell a difference. Granted it was a flat color though.


On Tue, Mar 24, 2020, 12:42 PM Dennis Tillman W7PF <@Dennis_Tillman_W7pF>
wrote:

Hi Steve and Brendan,
Stan Griffiths used to sell Tek paint in spray cans and other ways. I got
4 of the last cans he had in October. He only had a few left at that time.

This might be what you are looking for:
Dennis Tillman W7pF


-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
snapdiode via Groups.Io
Sent: Thursday, April 19, 2018 5:12 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek blue tyouch up paint?


https://www.sherwin-williams.com/store-locator/product-finishes-facility/portland/or/4383

phone 1-503-249-0222

You want L61 opex lacquer
L61xxcl42
Tek Blue

Or just call Tektronix, they used to have a part number just for that, in
a 7oz spray can.




--
Dennis Tillman W7PF
TekScopes Moderator




Re: Mr Carlson's Patreon and test tool designs - was Re: [TekScopes] enclosures for ESR meters

Lawrance A. Schneider
 

I agree!

Re: fuzzy trace, weakish trace, CURED

aldue
 

Hi Roy, 464 now has a shaper trace. Test Point 1443 was supposed to read +27 Volts. He was about 22 Volts after replacing Q1436, Q1432 and R1437. I learned that I can not trust my DVM to measure ripple also. I had replaced R1437 ,910 Ohms, with a 9.1 K and R1443 ,220 Ohms, had grown to about 12K. The drawer with about 100 ,910 Ohm resistors had 2, 9100 Ohmers. Replacing the resistors raised TP1443 to 27.48 V and resulted in a bright sharp trace with noise. Putting the case on cured the noise.
The bad news. I must have bumped a cable or ?, the sweep is free running. A mission for another day. thank you, aldue

Re: Tek Blue Paint

Li Gangyi
 

Can't somebody go get it specteophotometered for a close match like with
custom car colors? I know where I was previously the English color near me
had that tool.

Finally an old lady with a good eye matched the thing by eye till I
couldn't tell a difference. Granted it was a flat color though.


On Tue, Mar 24, 2020, 12:42 PM Dennis Tillman W7PF <@Dennis_Tillman_W7pF>
wrote:

Hi Steve and Brendan,
Stan Griffiths used to sell Tek paint in spray cans and other ways. I got
4 of the last cans he had in October. He only had a few left at that time.

This might be what you are looking for:
Dennis Tillman W7pF


-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
snapdiode via Groups.Io
Sent: Thursday, April 19, 2018 5:12 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek blue tyouch up paint?


https://www.sherwin-williams.com/store-locator/product-finishes-facility/portland/or/4383

phone 1-503-249-0222

You want L61 opex lacquer
L61xxcl42
Tek Blue

Or just call Tektronix, they used to have a part number just for that, in
a 7oz spray can.




--
Dennis Tillman W7PF
TekScopes Moderator



Re: TEKTRONIX 491 measuring wifi signals

Miguel Work
 

My Pansonic microwave oven is working since late 80s, is one of the first micro controlled, the keyboard has no signs of wear 30 years after, has survaived my four brothers family!
Using it every day and still working. It has a double shield.

It costs about 800$

Regards!




-----Mensaje original-----
De: TekScopes@groups.io [mailto:TekScopes@groups.io] En nombre de Chuck Harris
Enviado el: martes, 24 de marzo de 2020 13:44
Para: TekScopes@groups.io
Asunto: Re: [TekScopes] TEKTRONIX 491 measuring wifi signals

When the first commercial microwave ovens were made, they had simple mechanical timers, and no "heat" settings. The next generation had simple mechanical timers, and thermal timers similar to turn signal "clickers" to adjust the on vs off time. Every enhancement since has been simply refinements of the same basic formula: Turning mechanical timers into electronic timers, into microprocessor timers.
Turning mechanical bells into electronic bells. Turning linear transformers into switching power supplies...

But the basic on/off, "bang-bang" method of controlling the heat has remained intact: how many seconds on, out of 10 seconds, determines the "heat" from the oven.

Some researchers wanted to take the microwave oven into the realm of laboratory heating, and found the "bang-bang" style of heat adjustment way too brutal. For instance, if you wanted to heat a saline solution in a watch glass, it would explode around the edges where the water was so very thin, even though the "heat" was on low... even one second at full power followed by 9 seconds of being off was too brutal.

So, a colleague of mine developed a precision microwave that took the duty cycle modulation of the magnetron from seconds on out of 10 seconds, to power line cycles on out of 10 power line cycles. And, even balanced the distribution of on cycles so that if you were at 50%, it was every other cycle of the 60Hz power, (that may have been my suggestion, I don't remember anymore) ... Saline in a watch glass was his standard test.

Heading back to 491's, and wifi signals:

Modern microwave ovens have replaced the heavy, and copper laden, power transformers with switching power supplies...
which is why they are now available for less than $100.

There is a big cost, however. High voltage capacitors are still expensive, so the new supplies aren't at all well filtered, and end up modulating the 2450MHz nominal magnetron output at the switching supply rate, and the switching supply rate is not at all stabilized, so it changes with load. This wreaks havoc with wifi routers which occupy the same ISM band as do the ovens.... Only the ovens leak way more power than the routers put out.

A friend once asked me why his "smart" house, and his cordless phones, stopped working every so often... I asked him if he had a microwave oven. He said yes. I asked him to notice if his wife was using the microwave oven when his "smart"
house stopped being so "smart".

You should be able to see this wandering RF noise fest on your
491 whenever the microwave oven is running.

-Chuck Harris
on off timer that im Ford wrote:

I stand corrected (not all that unusual).  Thanks, Chuck.  My guess
would be that microwave oven manufacturers either don't know about or
don't want to deal with the subtleties of magnetron anode and filament
voltages and currents.JimSent from my Verizon, Samsung Galaxy
smartphone

Re: TEKTRONIX 491 measuring wifi signals

greenboxmaven
 

Is there a limit to how fast a magnetron can get the swirling electrons "up to speed" and begin producing an output? Radar sets do use some sharp pulses, do accommodations have to be made for the magnetron's response?

Bruce Gentry, KA2IVY

On 3/24/20 8:44 AM, Chuck Harris wrote:

Heading back to 491's, and wifi signals:

Modern microwave ovens have replaced the heavy, and copper
laden, power transformers with switching power supplies...
which is why they are now available for less than $100.

There is a big cost, however. High voltage capacitors are
still expensive, so the new supplies aren't at all well
filtered, and end up modulating the 2450MHz nominal magnetron
output at the switching supply rate, and the switching
supply rate is not at all stabilized, so it changes with
load. This wreaks havoc with wifi routers which occupy the
same ISM band as do the ovens.... Only the ovens leak way
more power than the routers put out.



-Chuck Harris
on off timer that im Ford wrote:
I stand corrected (not all that unusual). Thanks, Chuck. My guess would be that microwave oven manufacturers either don't know about or don't want to deal with the subtleties of magnetron anode and filament voltages and currents.JimSent from my Verizon, Samsung Galaxy smartphone

Fixtures for 7CT1N/5CT1N

Szabolcs Szigeti
 

Hi,

Apparently posting this in the ESR meter thread was a no-no and got
caught by moderation, so I repeat the important part here if anyone is
interested in some collaboration.

"
Good that you mentioned the 7CT1N, as this has been a long time plan
for me to make some fixtures for my 5CT1N, especially seeing the price
these are being sold on eBay. I have just started to sketch up some
design and look for parts. So I would be gladly helping with coming up
with a design. I can do the PCB, but this could be a good group effort
as it would be nice to have some 3D printed enclosures for it. Of
course it can be simple small PCB with 3 plugs and some zif socket,
but why not make it really fancy if we have the knowledge and tools.
"

Szabolcs