Date   

Re: Fw: You have been removed from TekScopes@groups.io

Richard Knoppow
 

There is definitely hacking going on. Periodically I get notices that my ISP is discontinuing me unless I send a mail with all sorts of stuff on it. Its a stupid message because it says first that my e-mail address is invalid despite its being the address they use and my billing address is invalid. Just stupid. I just delete them. I suspect this is something of the same sort, If you answer you will get an authentic looking site that will ask you to give away everything you own. Just delete the message. It didn't come from the list or Groups IO but others may have gotten them.

On 10/31/2020 1:07 PM, Thomas Dodge wrote:
Thanks Richard, I appreciate the email. I did look in my spam folder and
didn't see anything from TekScopes in there. I think this forum is valuable
because its good to know how to work on the scopes. I actually have
three scopes at home. I have an old Tektronix 533 which I need to fix. I
have the manual for it. It does show a beam in the beamfinder but that's
about it. I also have a 7000 series scope and I think it works but not
sure. I also have a TDS684 that is in very good shape that I picked up from
a place with old equipment, and I had my eye on this scope for months and
finally got it. When I first turned it on, it didn't do anything, but after
a while, it all lit up, and was ok. when I turned it on later, it did the
same thing as before, so not sure how to fix it. It would be cool if I
could work on it with someone in my area, who has a lot of experience with
these, because I am very aware of the high voltage section. How would I get
in touch with someone in my area? I am in Glendora, Calif. Thanks.

Thomas Dodge

On Sat, Oct 31, 2020 at 12:53 PM Richard Knoppow <dickburk@...>
wrote:

This message came through the list so you seem to still be
on it. I wonder if this is hacking of some sort. You can check if
you are subscribed on the web site. I would not return anything
until you are sure. I suspect there is a hidden URL in the Resume
Subscription link. Most e-mail clients will tell you if there is.
The whole message doesn't quite make sense so I suspect it is
phishing of some sort and you will be asked for all sorts of
personal info.

On 10/31/2020 12:48 PM, Thomas Dodge wrote:
Hi,
I don't know why I was removed. I saw the email message, but it was not
from me. Can you please resubscribe me? Thanks. Also, the link to
subscribe was not there. It was just the word, but no link.

Thomas Dodge

On Sat, Oct 31, 2020 at 10:38 AM Ken Wright via groups.io <kenwright309=
yahoo.co.uk@groups.io> wrote:

This is the message I receivedKen M0KHW ----- Forwarded message
-----
From: TekScopes@groups.io <tekscopes+owner@groups.io>To: "
kenwright309@..." <kenwright309@...>Sent: Friday, 30
October 2020, 10:09:01 GMTSubject: You have been removed from
TekScopes@groups.io
Hello,
You have been automatically removed from TekScopes@groups.io because
your
Email Service Provider reported to us that message Re: source for blue
filters for 2465 family scopes ??from TekScopes@groups.io has been
marked
as spam.

We suggest that you check your spam folder as soon as possible to see if
your Email Service Provider has diverted other legitimate messages into
it.
You will receive no more emails from that group. If this was a mistake,
you can resume your subscription within the next 7 days by clicking the
following link:

Resume Subscription

Groups.io groups offer several options for controlling how much and what
types of emails to receive. See this Help Center article for more
information.

If this happens repeatedly please check with your Email Service Provider
to learn about how they decide to send feedback reports to list services
(such as Groups.io groups).

The Groups.io Team







--
Richard Knoppow
dickburk@...
WB6KBL







--
Richard Knoppow
dickburk@...
WB6KBL


Re: Filament Isolation Transformer

Robert Simpson
 

Ed,
Thank you for the reply. Actually based on all this new information to me, I am looking into several possibilities. Although I hadn't planned on monitoring the generator, your suggestion would make that safe and easy. I hove boxes of wall warts and likely have an AC only version.
I am also looking into using this technique for other types of testing. Belonging to this group often opens new worlds to explore which helps to keep my aging brain active.
Bob


Re: Fw: You have been removed from TekScopes@groups.io

Thomas Dodge
 

Thanks Richard, I appreciate the email. I did look in my spam folder and
didn't see anything from TekScopes in there. I think this forum is valuable
because its good to know how to work on the scopes. I actually have
three scopes at home. I have an old Tektronix 533 which I need to fix. I
have the manual for it. It does show a beam in the beamfinder but that's
about it. I also have a 7000 series scope and I think it works but not
sure. I also have a TDS684 that is in very good shape that I picked up from
a place with old equipment, and I had my eye on this scope for months and
finally got it. When I first turned it on, it didn't do anything, but after
a while, it all lit up, and was ok. when I turned it on later, it did the
same thing as before, so not sure how to fix it. It would be cool if I
could work on it with someone in my area, who has a lot of experience with
these, because I am very aware of the high voltage section. How would I get
in touch with someone in my area? I am in Glendora, Calif. Thanks.

Thomas Dodge

On Sat, Oct 31, 2020 at 12:53 PM Richard Knoppow <dickburk@...>
wrote:

This message came through the list so you seem to still be
on it. I wonder if this is hacking of some sort. You can check if
you are subscribed on the web site. I would not return anything
until you are sure. I suspect there is a hidden URL in the Resume
Subscription link. Most e-mail clients will tell you if there is.
The whole message doesn't quite make sense so I suspect it is
phishing of some sort and you will be asked for all sorts of
personal info.

On 10/31/2020 12:48 PM, Thomas Dodge wrote:
Hi,
I don't know why I was removed. I saw the email message, but it was not
from me. Can you please resubscribe me? Thanks. Also, the link to
subscribe was not there. It was just the word, but no link.

Thomas Dodge

On Sat, Oct 31, 2020 at 10:38 AM Ken Wright via groups.io <kenwright309=
yahoo.co.uk@groups.io> wrote:

This is the message I receivedKen M0KHW ----- Forwarded message
-----
From: TekScopes@groups.io <tekscopes+owner@groups.io>To: "
kenwright309@..." <kenwright309@...>Sent: Friday, 30
October 2020, 10:09:01 GMTSubject: You have been removed from
TekScopes@groups.io
Hello,
You have been automatically removed from TekScopes@groups.io because
your
Email Service Provider reported to us that message Re: source for blue
filters for 2465 family scopes ??from TekScopes@groups.io has been
marked
as spam.

We suggest that you check your spam folder as soon as possible to see if
your Email Service Provider has diverted other legitimate messages into
it.

You will receive no more emails from that group. If this was a mistake,
you can resume your subscription within the next 7 days by clicking the
following link:

Resume Subscription

Groups.io groups offer several options for controlling how much and what
types of emails to receive. See this Help Center article for more
information.

If this happens repeatedly please check with your Email Service Provider
to learn about how they decide to send feedback reports to list services
(such as Groups.io groups).

The Groups.io Team








--
Richard Knoppow
dickburk@...
WB6KBL







Re: Filament Isolation Transformer

Ed Breya
 

If this is just to make a quick and dirty way to monitor the generator, the simplest perhaps is to get a wall-wart that puts out AC. Lots of stuff use this kind, so a good collection of old ones in a well stocked junk department should yield something about right. Just cut off the output connector and hook the wires to a binding post to BNC adapter and into the scope. Then plug the wart into one of the generator's outlets - done.

If it's now evolving (as many things do) into a more general purpose, clean line monitoring probe, then you should revisit my previous post #172658 here:

https://groups.io/g/TekScopes/message/172658

Ed


Re: Fw: You have been removed from TekScopes@groups.io

Richard Knoppow
 

This message came through the list so you seem to still be on it. I wonder if this is hacking of some sort. You can check if you are subscribed on the web site. I would not return anything until you are sure. I suspect there is a hidden URL in the Resume Subscription link. Most e-mail clients will tell you if there is. The whole message doesn't quite make sense so I suspect it is phishing of some sort and you will be asked for all sorts of personal info.

On 10/31/2020 12:48 PM, Thomas Dodge wrote:
Hi,
I don't know why I was removed. I saw the email message, but it was not
from me. Can you please resubscribe me? Thanks. Also, the link to
subscribe was not there. It was just the word, but no link.

Thomas Dodge

On Sat, Oct 31, 2020 at 10:38 AM Ken Wright via groups.io <kenwright309=
yahoo.co.uk@groups.io> wrote:

This is the message I receivedKen M0KHW ----- Forwarded message -----
From: TekScopes@groups.io <tekscopes+owner@groups.io>To: "
kenwright309@..." <kenwright309@...>Sent: Friday, 30
October 2020, 10:09:01 GMTSubject: You have been removed from
TekScopes@groups.io
Hello,
You have been automatically removed from TekScopes@groups.io because your
Email Service Provider reported to us that message Re: source for blue
filters for 2465 family scopes ??from TekScopes@groups.io has been marked
as spam.

We suggest that you check your spam folder as soon as possible to see if
your Email Service Provider has diverted other legitimate messages into it.

You will receive no more emails from that group. If this was a mistake,
you can resume your subscription within the next 7 days by clicking the
following link:

Resume Subscription

Groups.io groups offer several options for controlling how much and what
types of emails to receive. See this Help Center article for more
information.

If this happens repeatedly please check with your Email Service Provider
to learn about how they decide to send feedback reports to list services
(such as Groups.io groups).

The Groups.io Team







--
Richard Knoppow
dickburk@...
WB6KBL


Re: Fw: You have been removed from TekScopes@groups.io

Thomas Dodge
 

Hi,
I don't know why I was removed. I saw the email message, but it was not
from me. Can you please resubscribe me? Thanks. Also, the link to
subscribe was not there. It was just the word, but no link.

Thomas Dodge

On Sat, Oct 31, 2020 at 10:38 AM Ken Wright via groups.io <kenwright309=
yahoo.co.uk@groups.io> wrote:

This is the message I receivedKen M0KHW ----- Forwarded message -----
From: TekScopes@groups.io <tekscopes+owner@groups.io>To: "
kenwright309@..." <kenwright309@...>Sent: Friday, 30
October 2020, 10:09:01 GMTSubject: You have been removed from
TekScopes@groups.io
Hello,
You have been automatically removed from TekScopes@groups.io because your
Email Service Provider reported to us that message Re: source for blue
filters for 2465 family scopes ??from TekScopes@groups.io has been marked
as spam.

We suggest that you check your spam folder as soon as possible to see if
your Email Service Provider has diverted other legitimate messages into it.

You will receive no more emails from that group. If this was a mistake,
you can resume your subscription within the next 7 days by clicking the
following link:

Resume Subscription

Groups.io groups offer several options for controlling how much and what
types of emails to receive. See this Help Center article for more
information.

If this happens repeatedly please check with your Email Service Provider
to learn about how they decide to send feedback reports to list services
(such as Groups.io groups).

The Groups.io Team







Filament Isolation Transformer

Robert Simpson
 

Chuck,

Since this is more of a general topic, I thought it might be better in a separate message.
This topic came out of a different subject related to safely using an oscilloscope to look at home generator output. Chuck Harris suggest using a filament transformer to isolate the scope from the generator. This technique could be used in many applications.

Previous related messages:

---------
Filament transformers are cheaper than a repair on your scope's
front end, and will reveal everything that matters on your
generator's output signal.

A second thing about instrumentation. When you are measuring
stiff power sources, you need to take stiff protection measures.
When you are measuring weak power sources, weak protection
measures will suffice.

Your generator is a fairly stiff power source. It can dump
way more than 4000W into a dead short circuit.
---------
I think I have a 120 to 12V transformer. So I might try some tests with motor loads, such as my table saw and hand electric saw.
Question, should the output leads of the transformer be open or have a light load say 10K oms?
Bob
-----------
I usually just leave the 1M scope load to set the
output impedance.

But, since it is easy, try a few different values,
and see what looks the best.

50 ohms would not be a good idea, as it would draw
almost a watt from a 6.3V transformer.

-Chuck
---------
Chuck,
How do you connect your probe leads to the transformer output. Isn't the output side now independent of a ground reference? At my workbench, I use a 7A22 with two probes in differential setup. But my 465M is what I am using outside near the generator.
I found a 120 to 34V transformer I can use.
Bob
----------
The filament transformer complete isolates the primary from
the secondary electrically. So, I put a household plug on
the 120V side, and usually use a Pomona binding post to male
BNC adapter for the low voltage secondary.

Nothing to stop you from simply soldering a piece of RG58 that
is only terminated on one end, or soldering a BNC female to the
transformer, and using a BNC-BNC cable to connect that to the
scope.

-Chuck Harris

OK, I rigged up my 120 to 34V transformer through an on off switch. The output is connect to a terminal strip with a 100K ohm resistor across the output. I am getting a lot of distortion and wonder if I just have a cheap transformer.
Should the frame of the transformer be grounded?

Also, I am looking into buying a filament transformer and a I found some older filament transformers as as well as newer power transformers for sale. Is there a difference?
Bob


Re: Fw: You have been removed from TekScopes@groups.io

 

So did you click on the link to resume your subscription - if so all should be well. It was probably a transient problem with your or another ISP.

David

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Ken Wright via groups.io
Sent: 31 October 2020 17:39
To: TekScopes@groups.io
Subject: [TekScopes] Fw: You have been removed from TekScopes@groups.io

This is the message I receivedKen M0KHW ----- Forwarded message ----- From: TekScopes@groups.io <tekscopes+owner@groups.io>To: "kenwright309@..." <kenwright309@...>Sent: Friday, 30 October 2020, 10:09:01 GMTSubject: You have been removed from TekScopes@groups.io
Hello,
You have been automatically removed from TekScopes@groups.io because your Email Service Provider reported to us that message Re: source for blue filters for 2465 family scopes ??from TekScopes@groups.io has been marked as spam.


Fw: You have been removed from TekScopes@groups.io

Ken Wright <kenwright309@...>
 

This is the message I receivedKen M0KHW ----- Forwarded message ----- From: TekScopes@groups.io <tekscopes+owner@groups.io>To: "kenwright309@..." <kenwright309@...>Sent: Friday, 30 October 2020, 10:09:01 GMTSubject: You have been removed from TekScopes@groups.io
Hello,
You have been automatically removed from TekScopes@groups.io because your Email Service Provider reported to us that message Re: source for blue filters for 2465 family scopes ??from TekScopes@groups.io has been marked as spam.

We suggest that you check your spam folder as soon as possible to see if your Email Service Provider has diverted other legitimate messages into it.

You will receive no more emails from that group. If this was a mistake, you can resume your subscription within the next 7 days by clicking the following link:

Resume Subscription

Groups.io groups offer several options for controlling how much and what types of emails to receive. See this Help Center article for more information.

If this happens repeatedly please check with your Email Service Provider to learn about how they decide to send feedback reports to list services (such as Groups.io groups).

The Groups.io Team


Re: Scope grounding and generators

Chuck Harris <cfharris@...>
 

The filament transformer complete isolates the primary from
the secondary electrically. So, I put a household plug on
the 120V side, and usually use a Pomona binding post to male
BNC adapter for the low voltage secondary.

Nothing to stop you from simply soldering a piece of RG58 that
is only terminated on one end, or soldering a BNC female to the
transformer, and using a BNC-BNC cable to connect that to the
scope.

-Chuck Harris

Robert Simpson via groups.io wrote:

Chuck,
How do you connect your probe leads to the transformer output. Isn't the output side now independent of a ground reference? At my workbench, I use a 7A22 with two probes in differential setup. But my 465M is what I am using outside near the generator.
I found a 120 to 34V transformer I can use.
Bob






Re: Scope grounding and generators

Robert Simpson
 

Chuck,
How do you connect your probe leads to the transformer output. Isn't the output side now independent of a ground reference? At my workbench, I use a 7A22 with two probes in differential setup. But my 465M is what I am using outside near the generator.
I found a 120 to 34V transformer I can use.
Bob


Re: refurbishing TM500 and TM5000 hardware

Kevin Oconnor
 

Most failures on these mainframes are blown pass transistors, rather than lytic caps.



I have 4 TM500 frames of various sizes. I can’t remember how many times I’ve replaced those pass transistors I’m some of them. Sometimes they seem to blow on their own and other times it was clearly a failed plugin.



I always felt it was a weak point in the overall system design of the modular interface approach.



Never have needed to replace caps in the frame.



Kevin


Removed from group

Ken Wright <kenwright309@...>
 

To the moderator
I have been removed from this group due to a spurious posting in my name, I would like to re-join.
RegardsKen Wright M0KHW
kenwright309@...


Re: source for blue filters for 2465 family scopes ??

Chuck Harris <cfharris@...>
 

Bear in mind that the blue does nothing to improve the
contrast of the beam on P31 phosphors. It was chosen
entirely for esthetic reasons. It matched the tektronix
blue color used as a corporate color scheme.

-Chuck Harris

bob wrote:

EUREKA !!!

I found a source of film/plastic that almost completely imitates the original color film, and its CHEEEP !!

1 sheet thick seems to mimic the color of the factory quite closely, and if you like a darker blue color, put a second layer in.

https://www.amazon.com/gp/product/B008AXZ9M8/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

works GREAT !!!

-bob








Re: Modifying Type 109 for single-shot use?

Ed Breya
 

You should be able to make it into a DC-controlled, one-shot deal, but you may have to adjust the magnetic structure and coil bias such that it won't work in its normal resonant mode. Does it need to work normally too, or just one-shot? Without any magnetic mods, I think it should be able to do it if you can (over) drive the coil hard enough with the DC/step, but I don't know how much, or if the coil can take the extra power dissipation. I don't recall what form the Hg reed switch has - A, B, or C - but I think it's "A" so normally open with no field applied. If you make it so the desired fast edge happens when the reed is turned on, then the coil power needs only to be applied for a short time, I would think, and you can hit it pretty hard without much temperature rise. If the reed needs to stay closed for quite a while, then you may have coil dissipation issues.

I'd say give it a try and see how it works without magnetic mods, just with reasonable DC coil drive hooked in place of the normal signal. If you disable/disconnect the line charger supply, you can confirm switch operation with an ohmmeter, and not have to search for pulses on a scope. You may luck out and it will be fine with fairly low coil power. The reason I suspect that it may need quite a lot though, is that as I recall, the drive is supposed to be just enough to buzz the resonant armature to lightly jump the contacts into the Hg film, but not so much that the solid parts slam together. That would aggravate the wear, and slow things down. For DC drive, you won't have the benefit of resonance, and you will want to slam the contacts together enough to assure positive contact closure for the required time. On the plus side, the Hg reed should last virtually forever in this kind of application, assuming low duty factor.

Ed


Re: source for blue filters for 2465 family scopes ??

bob
 

EUREKA !!!

I found a source of film/plastic that almost completely imitates the original color film, and its CHEEEP !!

1 sheet thick seems to mimic the color of the factory quite closely, and if you like a darker blue color, put a second layer in.

https://www.amazon.com/gp/product/B008AXZ9M8/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

works GREAT !!!

-bob


Re: Scope grounding and generators

Chuck Harris <cfharris@...>
 

I usually just leave the 1M scope load to set the
output impedance.

But, since it is easy, try a few different values,
and see what looks the best.

50 ohms would not be a good idea, as it would draw
almost a watt from a 6.3V transformer.

-Chuck

Robert Simpson via groups.io wrote:

Some results:
1. My true RMS meter arrived, so I ran a few basic tests with the meter and the 465M.
After starting the generator and letting it warm up, I connected a 500W shop lamp for a resistivity load. TRMS meter showed about 130 V
Hooked the scope up one lead and took some pictures. Unfortunately although I was in tree shade, general glare resulted in marginal pictures. Using Photoshop I adjusted the brightness and color and got a just readable image
Looks like period is approximately 16ms or about 62.5 HZ.
Peaky barely sine wave

2. I think I have a 120 to 12V transformer. So I might try some tests with motor loads, such as my table saw and hand electric saw.
Question, should the output leads of the transformer be open or have a light load say 10K oms?
Bob






Re: Scope grounding and generators

Michael W. Lynch
 

If you are reading 62.5 Hz, then your engine is running slightly fast. Generators typically run at 3600 or 1800 (depends on whether they use a 2 pole or 4 pole rotor). Check your frequency at full rated load, I would guess that it will be closer to correct. Most mechanical governors have a speed adjustment that will allow slight changes to the full load RPMs to correct frequency at full load. Better generators, like HONDA and Yamaha have better governor calibration as well as better regulation.

--
Michael Lynch
Dardanelle, AR


Re: Scope grounding and generators

Robert Simpson
 

Some results:
1. My true RMS meter arrived, so I ran a few basic tests with the meter and the 465M.
After starting the generator and letting it warm up, I connected a 500W shop lamp for a resistivity load. TRMS meter showed about 130 V
Hooked the scope up one lead and took some pictures. Unfortunately although I was in tree shade, general glare resulted in marginal pictures. Using Photoshop I adjusted the brightness and color and got a just readable image
Looks like period is approximately 16ms or about 62.5 HZ.
Peaky barely sine wave

2. I think I have a 120 to 12V transformer. So I might try some tests with motor loads, such as my table saw and hand electric saw.
Question, should the output leads of the transformer be open or have a light load say 10K oms?
Bob


Re: source for blue filters for 2465 family scopes ??

Christian
 

I have a pile of misc scope filters - what's the exact PN you're looking for?

21401 - 21420 of 193987