Date   

Re: I've been hacked

Jim Ford
 

I have to disagree, at least here in the sanctuary state of California, Chuck. My wife just had her computer streamlined within the last week by the Geek Squad, and they had us sign no such waiver. I asked the tech if they were contracted by the FBI, and he said no, they are not.
Possibly in Kentucky, where Best Buy and/or Geek Squad is/are headquartered, he said.

Does this mean you shouldn't be careful about Big Brother? No, not at all, but our experience with Geek Squad was very routine.

Jim Ford

------ Original Message ------
From: "Chuck Harris" <cfharris@...>
To: TekScopes@groups.io
Sent: 3/11/2020 12:09:22 PM
Subject: Re: [TekScopes] I've been hacked

Geek Squad "technicians" get paid by the FBI to take
special training courses on finding and identifying
hidden pornography, and illegal documents. They get
paid a bounty for every suspicious thing they turn
in to the FBI.

That's unconstitutional, you say?

No, it isn't. They are a private entity, and you have
to sign a waiver that gives them permission to search
for such stuff before they will work on your computer.

Anything they find, they will send right out to the FBI
for evaluation...

Best not use Geek Squad for any computer that has been
involved with anything you wouldn't want to see in the
Washington Post.

Also, a lot of the spam payloads turn your windows machine
into child pornography servers.

If Geek Squad finds that, you will get to spend a few
weeks in jail.

Me personally, if Geek Squad was my only choice, I would
remove and destroy the drive, and put a new install of
windows on a new drive, and shrug my shoulders for being
stupid enough to use Windows, and stupid enough not to
make off machine backups...

-Chuck Harris

Abc Xyz wrote:
I took my Infected Units over to Best Buy & let the Geek Squad Remove the
Virus's. They have Access to Tools we can't get. Plus, they Installed their
own Detection Software.


Re: recommended ESR meters these days

Harvey White
 

There's a tradeoff here.

When I was (very) much younger, I built things from whatever I could get from old TV sets, a source of which (non functioning) I was lucky enough to find.  I traded off time stripping the old TVs for parts I did not have the money to buy.  And yes, there was a store near me that likely had every part I needed.  I couldn't get there, and I didn't have the money.

When I had a steady job, some years after I'd gotten out of college, I had a better lab, a few more parts, some more ambitious designs, and I'd started gathering parts from the local university or the throwaways from the business where I worked.  Most of my money went into infrastructure, such as better test equipment and a unimat lathe.  (You try making holes in a plate of aluminum for mounting a C mount camera lens (used epoxy and a nut from a light assembly (1-20 thread, Imperial), and grinding cone to make the hole.)

Once I got enough money, and the like, I started buying things where the things that I wanted were easier to buy, without having to invent the infrastructure, make the case, make the PC board, design it, debug it, and THEN continue with what I wanted to do when I decided I needed one of those.

Different people have different resources at differing times of their lives.  Some are lucky, some not.  Some are lucky enough to build everything, some need more.

As far as ESR is concerned, I do have a Sprague LC75, and an HP 4262A, both of which work.  I've been lucky.

Time vs money is a tradeoff everyone makes.

Harvey

On 3/14/2020 11:35 AM, Ernesto wrote:
LOL! You people have to spend one hundred dollars in gadgets like the DE-5000 to measure ESR?

As a professional electrical engineer with large experience in the design and development of complex electronic hardware and firmware, I enjoy the use of my ONE RESISTOR ESR meter (see my previous post).

I measured (for fun) in 10 minutes the ESR of about 10 electrolytic capacitors mounted on a dual preamplifier board that is over 40 years old.

- I clipped the ground of the oscilloscope X1 probe on the negative of the electrolytic, and the probe on its positive.
- I clipped to the ONE RESISTOR of 1000 ohm a 10V positive 100Khz signal from my function generator (with the same ground as the oscilloscope), and touched with the other lead of the resistor the positive of the capacitor under test. The resistor became in fact a current source.
- I observed on the oscilloscope, set to 10 mV/div, the 100Khz signal in the equivalent scale of 1 ohm ESR per division. I found some good capacitors and many bad ones! (its amazing how well an amplifier can work even with some "bad" electrolytics...)

It could not be easier!

Ernesto



Re: Tek 576 Curve Tracer HV Replacement Transformer

Michael W. Lynch
 

Rick,
Thanks for asking.  I have reached out to the factory for an update.  They were supposed to ship this week, but I have not received tracking.  The delay was reported to be with the factory which produced the cores.  There is no US supplier for these bare cores, so we are held hostage by the foreign factory's ability to produce/deliver the goods.  This corona virus crap has everyone all stirred up around the world.  I hope to have some good news early next week. 

Very sorry for the delay. 

Sincerely,

Michael Lynch 479-226-0126 Home Phone479-477-1115 Cell Phonemlynch001@...@gmail.commlynch003@...

On Saturday, March 14, 2020, 10:43:30 AM CDT, garp66 <@green> wrote:

hi Michael,

    Re:  bulk Replacement HV Transformers  for the Trk 576 CT


Status ?

Do we know when these will be ready to be shipped out to us ?

thank you,
rick


Re: recommended ESR meters these days

 

On Sat, Mar 14, 2020 at 09:07 AM, Tony Fleming wrote:


Thanks for your information. I'm not an engineer in electronics, but I do what
I can, including buying meters that I use. I do have couple scopes, but I
usually just pull out my meter for the job at hand..... By same tocan I'm
interested in learning electronics, after 50+ years of hiatus so it is little
harder to learn than when I was young.
If you have a place where I can learn stuff like you've mentioned, I'm all
ears.
Have a great weekend.
Hi Tony,

First of all, there is no reason you cannot learn electronics after a 50+ hiatus. I keep learning electronics, some of it from this group, after 70++ years of existence. Instead being harder, as seniors we have more patience and perseverance.

I assume you have a good background in physics, electricity. To progress to "electronics" it is best to have some passion. Nothing inspires this passion better than the oscilloscope, the KING of the electronic instruments.
The oscilloscope is the only means to VISUALIZE the abstract electrical signals. This visualization stays with us all life long and makes electronics something CONCRETE and familiar.

So if you want to become expert in electronics, my advice is: BUILD AN OSCILLOSCOPE FROM SCRATCH (with some nice CRT tube, of course)

Right after college I did this for a couple of months, designing and building with an old 4 inch CRT an oscilloscope in the style of Tektronix. It was a dual-channel with all options, triggered with all options plus an X-Y display, and built 100% with transistors in 1971. With an 1800 V high-voltage supply running at 35 Khz, I designed and built the HV transformer and even the 50 Hz (in my country) transformer from their basic materials. All with little money, ha ha!

This launched my career of designer of analog electronics. At that time the progressive introduction of integrated circuits allowed me to learn the digital stuff, and I became a champion of designing WITH ECONOMY (minimum number of components). This economy stopped being an issue shortly thereafter, so I changed to optimum functionality no matter what, and the field of firmware, microprocessors and programmable LSI gave me a lust for complexity. Finally I became a software programmer, "software architect" and now... happily retired... I am finally back at tinkering with hardware and oscilloscopes.

There is a reason why some electrical engineers are attracted to a "TekScopes" grouop instead of "Power Distribution" or "High Voltage Transmission Lines" discussion groups.

Ernesto


Re: recommended ESR meters these days

Tony Fleming
 

I have the MLC500, but no manual and I do not know if it is accurate or not.
If anyone has one like mine and have a manual in English, I'm interested to download it.
Thank you very much.
Tony


Re: recommended ESR meters these days

Tony Fleming
 

On Thu, Mar 12, 2020 at 03:52 PM, Ken Eckert wrote:


LC103
This one is large, expensive even used and not very portable, but if someone like to donate me one, I'll find space for it!


Re: recommended ESR meters these days

Reginald Beardsley
 

On Sat, Mar 14, 2020 at 09:10 AM, Tony Fleming wrote:

Have you tried DE5000? If yes, can you compare it to any of your favorit
LCR meter?
Thanks and have a great weekend my friend.
Tony
I have the ESR70, BSIDE, HP 4284A and 8245A. I posted the ESR70 vs BSIDE comparison. I don't have a DE5000 and not much incentive to get one given all the other kit I have. I was not aware of the DE5000 when I bought the Peak Atlas units.

I'll measure the test frequencies of the ESR70 and BSIDE, then set the 4284A as close to those as possible and measure with it. But first I have to reorganize and defrost my freezer.

Reg


locked Tesla Coil help needed

Tony Fleming
 

I have a Tesla Coil kit but I don't have schematics that I can follow. All my parts are mentioned in my video: https://www.youtube.com/watch?v=Mt4y6j-foyY&list=PLv52A7rm-UViZEOlzZfZOB9Gl8cjS3ze5&index=2&t=0s
Or go to https://tonysfun.com/ and click on My Youtube Videos button. You can see more information here, before going to my videos.
I'm not an expert, but I take lots of precautions and use Variac Transformers and Isolation Transformers, among other steps to be safe.
I've built Jacob Ladders from Microwave Transformers and others, like in the video, that is for Neon Lights.....
I've tried for several month to contact people on youtube and other places, but many of them are older videos and I don't even know if the people are still around or using the youtube at all....
The seller mentioned in the video doesn't answer their phone and no option to leave a VM either.

If you know of anyone or any place that can help me with this project, I would appreciate it very much.


Re: recommended ESR meters these days

 

Hi ArtecManuals,

For the price of the BSIDE ESR tester you can buy a nice modern DDS function generator, frequency meter....
and apply my ONE RESISTOR ESR test method, at the frequency you want, with the waveform you want, sine, triangular, square, ha ha
One does not need to measure ESR every day.... maybe not even every month...,
and a signal generator + oscilloscope is all it takes.
The signal applied to the capacitor does not even need to have a DC offset.
Electrolytic capacitors, although polarized, are NOT schottky diodes. They can take a few millivolts of reverse voltage without losing their capacitance.

Enjoy,
Ernesto


Re: recommended ESR meters these days

Tony Fleming
 

Thanks for your information. I'm not an engineer in electronics, but I do what I can, including buying meters that I use. I do have couple scopes, but I usually just pull out my meter for the job at hand..... By same tocan I'm interested in learning electronics, after 50+ years of hiatus so it is little harder to learn than when I was young.
If you have a place where I can learn stuff like you've mentioned, I'm all ears.
Have a great weekend.


Re: Tek 576 Curve Tracer HV Replacement Transformer

garp66
 

hi Michael,

Re: bulk Replacement HV Transformers for the Trk 576 CT


Status ?

Do we know when these will be ready to be shipped out to us ?

thank you,
rick


Re: recommended ESR meters these days

Abc Xyz
 

One Member here said he built the one Mr. Carlson from YouTube Designed and
likes it.

On Fri, Mar 13, 2020, 5:04 PM Carsten Bormann <cabocabo@...> wrote:

On 2020-03-12, at 22:57, ArtekManuals <manuals@...> wrote:

Anyone bought one _*RECENTLY *_that they can recommend or warn me away
from?

For something completely different, try a tweezer form factor.
(With a couple of good alligator clip leads, this is useful for many
larger components, too.)

I like the MS8911 from Mastech, about €40 shipped.
Can do 100 Hz to 10 kHz (no 100 kHz, though).
Particularly useful in 0.1 Vrms mode: this allows some in-circuit
measurements other instruments can’t do.

Don’t confuse this with the cheaper MS8910, which is decidedly meh.
(If you want something simple at the MS8910 price point, try the $18
HoldPeak HP990C a.k.a. HP-4070C. Really handy for component testing,
including diodes and zeners up to 24 V, and the occasional loaded [lo-Z]
voltage measurement.
None of these $20 instruments do ESR, IIRC.)

The MS8911 is not a replacement for my DE-5000, but really handy — my goto
LCR meter.
(There are other tweezers at $200+, no idea what I would use those for.)

[1] looks at the MS8911. He also likes the full-size MS5308; I don’t have
experience with that.

The $5 (+ battery) transistor tester thingies (e.g., LCR-T4) are
surprisingly useful, too, by the way. The $18 LCR-TC1 with its nice case,
rechargeable battery (and an IR remote control tester thrown in for good
measure) is another one of my goto “instruments”, mostly for
semiconductors, but it can do a capacitor as well.

Add a HP 4329A (or Keithley 616) for leakage testing, and you have some
pretty good diagnostic capability.

Now if anyone knows a meter that can characterize SRAM backup super
capacitors (say, 0.22 F, 50 kΩ ESR (!)), I’m all ears...

Grüße, Carsten

[1]: https://www.youtube.com/watch?v=96XTelPZnfA





Re: recommended ESR meters these days

 

LOL! You people have to spend one hundred dollars in gadgets like the DE-5000 to measure ESR?

As a professional electrical engineer with large experience in the design and development of complex electronic hardware and firmware, I enjoy the use of my ONE RESISTOR ESR meter (see my previous post).

I measured (for fun) in 10 minutes the ESR of about 10 electrolytic capacitors mounted on a dual preamplifier board that is over 40 years old.

- I clipped the ground of the oscilloscope X1 probe on the negative of the electrolytic, and the probe on its positive.
- I clipped to the ONE RESISTOR of 1000 ohm a 10V positive 100Khz signal from my function generator (with the same ground as the oscilloscope), and touched with the other lead of the resistor the positive of the capacitor under test. The resistor became in fact a current source.
- I observed on the oscilloscope, set to 10 mV/div, the 100Khz signal in the equivalent scale of 1 ohm ESR per division. I found some good capacitors and many bad ones! (its amazing how well an amplifier can work even with some "bad" electrolytics...)

It could not be easier!

Ernesto


Re: recommended ESR meters these days

ArtekManuals
 

Reg
Interesting instrument...

I assume you have one of these?

It was not obvious from looking at the specs or the user manual that the frequency of ESR measurements is programmable ???

 At what frequency are ESR measurements done

I did see that it only does ESR measurement on 2uf Caps and larger which is kind of a negative
Dave
NR1DX

On 3/14/2020 9:13 AM, Reginald Beardsley via Groups.Io wrote:
Yes, The BSIDE is the Arduino tester in a *very* solid case. I can't understand why someone would buy the bare PCB versions instead of a BSIDE.

Reg

--
Dave
Manuals@...
www.ArtekManuals.com
--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


Re: capacitor testers OT

Bert Haskins
 

On 3/14/2020 7:37 AM, greenboxmaven via Groups.Io wrote:
The Sprauge "Telohmike" condenser tester is one of the best ever made for condensers  in tube circuit voltages. The general design was used by Heathkit and Eico, as well as at least one miltary version. They are very good for re-forming electrolytic condensers, you can easily monitor capacitance, leakage and ESR as the reforming proceeds. It's strange how Sprauge made an excellent instrument, but some of the worst condensers of all time. You don't need anything but your eyes to find a bad "Bumble Bee" or "Black Beauty" condenser, if it's there, it's bad. I know a few might still be good, but it's not worth risking a power transformer, scarce tube, or other components.

       Bruce Gentry, KA2IVY


On 3/13/20 11:49 PM, John Griessen wrote:
On 3/13/20 12:57 PM, Bert Haskins wrote:
I also have a 70+ year old Heath "magic eye" capacitor tester that
I use for leakage tests.

I bought this when I was fifteen for use in repairing guitar amps.

It is still quit useful today.
I have a GR cap bridge with magic eye.  I think mine needs some repair.  I gave it a quick test when I got it
and seemed broken.  What is that magic eye tube displaying on a cap tester?  How does it differ from a meter
moved by a null detector amp?



As a prime example of a really stupid design, when Heath copied the design of the Sprauge they skipped the line fuse..

When the filter cap shorted it was the end of the power transformer.

Three guesses how I found this out.

I've been searching for years for a replacement transformer for my first one.

Needless to say I put a fuse in my second one.


-- Bert



Re: recommended ESR meters these days

Tony Fleming
 

Have you tried DE5000? If yes, can you compare it to any of your favorit
LCR meter?
Thanks and have a great weekend my friend.
Tony

On Sat, Mar 14, 2020 at 8:13 AM Reginald Beardsley via Groups.Io <pulaskite=
yahoo.com@groups.io> wrote:

Yes, The BSIDE is the Arduino tester in a *very* solid case. I can't
understand why someone would buy the bare PCB versions instead of a BSIDE.

Reg




Re: recommended ESR meters these days

ebayatessnh
 

My dad took a TV/Radio repair course in the early 60's. I still have the tube based EICO "magic eye" capacitance/resistance tester, signal generator, and VTVM. Have not fired them up in a while, but they worked last time I did about 10 years ago. He never made any money out of TV repair as a side job, but the workbench he set up started my on the way to a successful career in electrical engineering. His EICO oscilloscope (that was not triggered or calibrated) started me on the path to my current love of the 7603 and 7104 models in my collection now.


Re: Quick Calibration Question.

Eric
 

Thanks for this Sir this was exactly what I was looking for. Also good to know that the tubes arnt specked for full screen width and true spec is a reduced graticule size.

On 3/13/2020 10:33 AM, Chuck Harris wrote:
I think I know what you are asking, but not completely sure.

The scopes are generally specified to be in calibration only
in the center region of the CRT. For instance, the 2465 family
says between the second, and 10th graticule line horizontally,
and the second and 6th graticule line vertically.

The reason for this is there is some serious work done to fight
the electron beams natural desire to see a spherical screen,
rather than a flat screen.

Also, there is often confusion about what part of the lit phosphor
is the part from which to measure.

The trace is an embodiment of a probability "bell curve". The
center is where most of the electrons hit the phosphor screen, and
towards the outside is where some noise deflected electrons hit.

It is best practice to consider the brightest, most central part
of the width of the beam to be the "trace"... So, when making a
peak-to-peak measurement, it will be from brightest to brightest...
not from furthest most visible fuzz to furthest most visible fuzz.

-Chuck Harris

Eric wrote:
As I have a backlog of plugins to calibrate, I have a questions I cant seem to find a good answer too. When calibrating a scope. Is the reference the center of the graticule line, the bottom edge, or the top edge. Common since tells me it should be the center of the graticule is the alignment point. But I am hoping to confirm. Or am I asking my analog scopes to be a little too accurate?




Re: capacitor testers OT

John Griessen
 

On 3/14/20 12:57 AM, Bob Albert via Groups.Io wrote:
Wow that's beautiful!  I see it uses a 6E5 tube.  It covers a wide range.  Does yours work?
It is needing some repair -- partly working.

Is the eye tube bright?
Sure, bright green.

What is the capacitance resolution on the lowest range?

Don't know until fixed. (Could be a while..)


Re: recommended ESR meters these days

Reginald Beardsley
 

Yes, The BSIDE is the Arduino tester in a *very* solid case. I can't understand why someone would buy the bare PCB versions instead of a BSIDE.

Reg