Date   

Email contact oddity - Spam Blacklisted?

Colin Herbert
 

I have belatedly thought of another route to examining this oddity. Apart
from Siggi and Carsten contacting me directly, maybe others might like to
give it a try? My email address can be extracted from that which appears on
Tekscopes, but it is:



Colingherbert(at)blueyonder(dot)co(dot) uk



I will reply directly to any messages that get through to me, so as not to
take bandwidth from Tekscopes.

TIA, Colin.


Tek 224 repair

Fred S.
 

I got a Tek 224 a few weeks back, that seemed to be completely dead.
I found a defective high voltage ceramic cap and the high voltage transformer had an internal short.
Replaced the transformer with one out of a Tek 222A and the cap. Finally I got the scope back to work, so I thought.
But the trace(s) (ch1 or ch2) are only half length, they start in the correct position on the left edge of the grid, but end in the middle of the screen. The readout is in the correct position on both halves. If I turn on the horizontal X10, the traces are full length.
Did anybody see that issue before?

--
Best regards,

Fred S.


Re: Dennis Tillman

Colin Herbert
 

Hi,
If this problem with my email server is irritating anyone else, I apologise profusely. I receive emails from many people with no problem, but this is puzzling me completely. Apart from contact from Tekscopes, I also get plenty of other email, so I cannot understand why Dennis (and others) cannot get through to me.

May I thank those of you who have emailed me at my personal address - Siggi and Carsten got through fine. I have also had messages from Susan at Sphere, so what is going wrong?

My knowledge of email systems is rudimentary at best, so I am at a loss as to what might be the cause. Please bear with me.
TIA, Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Michael W. Lynch via groups.io
Sent: 07 November 2020 23:24
To: TekScopes@groups.io
Subject: Re: [TekScopes] Dennis Tillman

I think Dennis mentioned that he was working on a project. So he may be deep in thought.

Michael Lynch

From My I-Phone

mlynch003@yahoo.com

479-477-1115


Re: Dennis Tillman

Jean-Paul
 

Dear Dennis! Fine to see your note, I have exactly the same issue with certain (non-TEK/iogroup) contacts.

A few notes of my experience:

Worst email domains are Yahoo and Free.fr,: The correspondent can send to me but ever reply is rejected with multiple notices sent periodically as you mention.
The correspondent never has any clew what to do and even if you try to whitelist its never effective.
I believe that the offending email servers have a hardware antispam filter with blacklists updated dynamically.
The issue can be either your IP address or that of your email server is on the BL, OR that your email server domain is on the BL.

For years I tried to fix this both in France and USA, to no avail!

Bon soiree,

Jon


Re: Clean and Lubricate Pots in Tek 475

 

It looks like I was mistaken about what came with my father's 2213: I just found the printed copy of the 2213 Oscilloscope Operators Instruction Manual in a box with what looks like the other contents of the scope pouch (including the manual for the probes, assorted cables, wires, and components, all neatly bagged and labeled). In the front of the operators manual is the edge tag from what was clearly a perforated card. Handwritten on the tag is the note "Sent for Service Manual 8/24" which I must assume means August 24, 1981, because the front page of the manual reads only "First Printing JUN 1981" while the pdf version I downloaded from BAMA reads "First Printing JUN 1981, Revised AUG 1982". I guess this means I've got at least the 2213 service manual in some box in the attic or basement.

That probably means the chance of finding the 475 service manual, probably in the same box, has dramatically increased.


Re: Troubleshooting an old Tek 475

 

on Sat, Nov 7, 2020 at 10:56 PM, Paul Amaranth wrote:

On the 400 series of scopes if I have to replace one of those can
electrolytics, I'll replace all of them. Their tendency to dry out
and fail open is a common, known, failure mechanism.
Oh, the cap I replaced wasn't one of the big cans, it was probably the smallest axial lead electrolytic in the whole machine. I was worried that the big caps in the power supply might be bad too (and I've bought some adapters to allow easy replacement with new components) but after checking the voltages and ripple on the power supply test points I'm much less immediately concerned about them.

I don't know exactly why this scope still seems to have good caps. Its first eight years were pretty rough, but it spent the next 40 years in a cool, dry basement with only occasional use. I guess that, along with quality components chosen by Tek, is the explanation, but it's still surprising. The last time I tried to get back into this hobby was around 2005, and I bought an inexpensive BKP signal generator, which then spent the next 15 years sitting right next to the 475. The filter caps on the BK were dry as a bone when I tried to power it a couple months back, but the 475 is going like a champ.


Re: Troubleshooting an old Tek 475

 

On Sat, Nov 7, 2020 at 10:56 PM, Paul Amaranth wrote:

ESR meters are pretty handy and they really don't need to be
all that complicated. I built an analog one with a couple
of op amps and an old meter for around $10.
I really like the idea of building my own, not because I'm cheap, but because I'm just getting back into this hobby after ignoring it for many years, and I need small projects that I can complete in a short period of time. For example, I just got my feet wet a few weeks ago with digital logic, and I have not yet had a chance to build anything with discrete transistors or op amps. I bailed on an EE degree in junior year to do computer science, so I know some very basic stuff -- I can read a schematic, and do basic measurements with a multimeter and oscilloscope -- but there's all kinds of things are still essentially mysterious to me, and I need concrete tasks to get exposure to even fairly basic concepts.


Re: Troubleshooting an old Tek 475

Paul Amaranth
 

ESR meters are pretty handy and they really don't need to be
all that complicated. I built an analog one with a couple
of op amps and an old meter for around $10.

One of the nice features of an esr meter is the test voltage is
usually around 100mV so it won't turn on any semiconductor
junctions in the area and can be used in circuit. You really
don't want to be unsoldering everything to test it.

There's a couple of really nice designs on the eevblog. There's
a 5 transistor esr meter here:

https://www.eevblog.com/forum/projects/5-transistor-esr-meter-design/

Also on that thread is an adapter you can make for your dmm that uses
a handful of op amps and reads out 0-20 ohms.

https://www.eevblog.com/forum/projects/5-transistor-esr-meter-design/msg327393/?topicseen#msg327393

PCBs are nice but you can breadboard those things; there's nothing
critical about them.

Two or three decimals in resolution are overkill anyway. If a 100uF
cap is > 1 ohm you're in the bad range anyway regardless if it's 1.01
or 1.10 ohms.

On the 400 series of scopes if I have to replace one of those can
electrolytics, I'll replace all of them. Their tendency to dry out
and fail open is a common, known, failure mechanism.

I ignore tantalums unless they go bad. Finding a shorted tant in a
scope with dozens or hundreds can be a challenge, but there are ways
to make that relatively easy.

Paul

On Sat, Nov 07, 2020 at 05:49:30PM -0800, Jeff Dutky wrote:
Glenn Little wrote:
If you found one capacitor like this, you will probably find others.
Sounds like it is time to replace the electrolytic capacitors.
They are probably well beyond their design life.
You have a gift for understatement.

I have been wanting to get an ESR meter, but I just haven't gotten around to it. I'm just picking up the electronics hobby again in order to fill my extra hours during the pandemic, and to address, in some useful way, a stash of antique electronics acquired over three generations. It's taking a little while to assemble all the proper tools and instruments.

I do have an EICO model 950B resistance-capacitance bridge that belonged to my grandfather, but a) it's in dire need of restoration itself, and b) it's not a quantitative device (though I can't wait till I get that magic eye working).

I've seen good reviews for a meter that appears to only been available in kit form, possibly only in Australia, but it doesn't seem to be available any longer. Do you have any recommendations for a good ESR meter to get?







!DSPAM:5fa74eb1216121029220781!
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows


Re: Clean and Lubricate Pots in Tek 475

Eric
 

Hey Jeff isopropyl alcohol is probably one of the most used cleaners in
electronics. And yes stay away from acetone on tek gear it tends to eat the
plastics.

Eric

On Sat, Nov 7, 2020, 8:31 PM Jeff Dutky <jeff.dutky@gmail.com> wrote:

Bruce Gentry wrote:
WD-40 is acceptable as a part of a mechanical cleaning process. Flush
it out with a correct solvent after it had done it's work.

Would a "correct solvent" be isopropyl alcohol? I have access to a few
other solvents, but some of them are explicitly forbidden in the Tek
documents (e.g. Acetone) and at least one other (whether or not it's
forbidden by Tek) is known to attack some common plastics.

An esoteric collection of solvents is another unusual feature of my
father's effects which I have taken some pains to keep well sealed and
safely stored.






Re: Clean and Lubricate Pots in Tek 475

Ray
 

There is on hail mary you can try.Drill a small hole sideways into the pot if it's made of plastic. You have to be steady or put a properly cut down brass tube over the drillbit to prevent drilling to deep. Then spray in your favourite lubricant.I did this on a icom transceiver and it worked nicely.RaySent from my T-Mobile 4G LTE device------ Original message------From: Ed Breya via groups.ioDate: Sat, Nov 7, 2020 14:29To: TekScopes@groups.io;Cc: Subject:Re: [TekScopes] Clean and Lubricate Pots in Tek 475Jeff, the bad spots on pots can likely be cleaned up by lots of rotations, even if you can't open them up or get enough oil or cleaner into them. Once you get the shafts to turn easily, rotate them end to end lots of times - possibly a hundred or more. For any particular bad spot, rotate the shaft lots more right around it, instead of the whole range, and see if it seems to improve.

This is approximately what many of us recommend - lots of rotations tend to eventually scrape off old grease and debris films on the resistor element. If the films are too tough, or the element is damaged, then there's not much else you can do but remove and fix or replace.

Ed


Re: Troubleshooting an old Tek 475

Harvey White
 

Sorry, that's a sencore LC75.

On 11/7/2020 9:52 PM, Harvey White wrote:
I have a Sprague LC75, which is a capacitor/inductor tester.

I also have an HP 4262A resistor/inductor/capacitor meter.  Both will measure ESR for a capacitor.  The LC75 may be more useful for repair work since it will measure leakage at the proper voltage. There are other varieties of the LC75 which may work equally well, but I don't have one and am not familiar with them.

Harvey


On 11/7/2020 8:49 PM, Jeff Dutky wrote:
Glenn Little wrote:
If you found one capacitor like this, you will probably find others.
Sounds like it is time to replace the electrolytic capacitors.
They are probably well beyond their design life.
You have a gift for understatement.

I have been wanting to get an ESR meter, but I just haven't gotten around to it. I'm just picking up the electronics hobby again in order to fill my extra hours during the pandemic, and to address, in some useful way, a stash of antique electronics acquired over three generations. It's taking a little while to assemble all the proper tools and instruments.

I do have an EICO model 950B resistance-capacitance bridge that belonged to my grandfather, but a) it's in dire need of restoration itself, and b) it's not a quantitative device (though I can't wait till I get that magic eye working).

I've seen good reviews for a meter that appears to only been available in kit form, possibly only in Australia, but it doesn't seem to be available any longer. Do you have any recommendations for a good ESR meter to get?









Re: Troubleshooting an old Tek 475

Harvey White
 

I have a Sprague LC75, which is a capacitor/inductor tester.

I also have an HP 4262A resistor/inductor/capacitor meter.  Both will measure ESR for a capacitor.  The LC75 may be more useful for repair work since it will measure leakage at the proper voltage. There are other varieties of the LC75 which may work equally well, but I don't have one and am not familiar with them.

Harvey

On 11/7/2020 8:49 PM, Jeff Dutky wrote:
Glenn Little wrote:
If you found one capacitor like this, you will probably find others.
Sounds like it is time to replace the electrolytic capacitors.
They are probably well beyond their design life.
You have a gift for understatement.

I have been wanting to get an ESR meter, but I just haven't gotten around to it. I'm just picking up the electronics hobby again in order to fill my extra hours during the pandemic, and to address, in some useful way, a stash of antique electronics acquired over three generations. It's taking a little while to assemble all the proper tools and instruments.

I do have an EICO model 950B resistance-capacitance bridge that belonged to my grandfather, but a) it's in dire need of restoration itself, and b) it's not a quantitative device (though I can't wait till I get that magic eye working).

I've seen good reviews for a meter that appears to only been available in kit form, possibly only in Australia, but it doesn't seem to be available any longer. Do you have any recommendations for a good ESR meter to get?





Re: Troubleshooting an old Tek 475

 

Glenn Little wrote:
If you found one capacitor like this, you will probably find others.
Sounds like it is time to replace the electrolytic capacitors.
They are probably well beyond their design life.
You have a gift for understatement.

I have been wanting to get an ESR meter, but I just haven't gotten around to it. I'm just picking up the electronics hobby again in order to fill my extra hours during the pandemic, and to address, in some useful way, a stash of antique electronics acquired over three generations. It's taking a little while to assemble all the proper tools and instruments.

I do have an EICO model 950B resistance-capacitance bridge that belonged to my grandfather, but a) it's in dire need of restoration itself, and b) it's not a quantitative device (though I can't wait till I get that magic eye working).

I've seen good reviews for a meter that appears to only been available in kit form, possibly only in Australia, but it doesn't seem to be available any longer. Do you have any recommendations for a good ESR meter to get?


Re: Clean and Lubricate Pots in Tek 475

Harvey White
 

Depends on what the solvent attacks.  Formula 409 and Simple Green can attack plastics because of some of their ingredients. Some solvents, Xylene, IIRC, attack plastics directly and will craze acryllic (for instance), or partially dissolve the base plastic.  Hence the problems.

Harvey

On 11/7/2020 8:31 PM, Jeff Dutky wrote:
Bruce Gentry wrote:
WD-40 is acceptable as a part of a mechanical cleaning process. Flush it out with a correct solvent after it had done it's work.
Would a "correct solvent" be isopropyl alcohol? I have access to a few other solvents, but some of them are explicitly forbidden in the Tek documents (e.g. Acetone) and at least one other (whether or not it's forbidden by Tek) is known to attack some common plastics.

An esoteric collection of solvents is another unusual feature of my father's effects which I have taken some pains to keep well sealed and safely stored.





Re: Clean and Lubricate Pots in Tek 475

Harvey White
 

On 11/7/2020 8:26 PM, Jeff Dutky wrote:
Thanks for the pointer to Artek Manuals, I will go get a copy of that service manual straight away.

The 475 was originally a fleet instrument for my father's employer, but he got it as part of a somewhat odd severance package (the entire division was being dissolved/sold off, and he was one of the star employees). He may have gotten the service manual, or he may not have. If he did it is probably somewhere in his effects, which I have been making my slow way through during the pandemic. So far I have only found the operators instruction manual (and that only after I had bought the 475+DMM44 operators manual on eBay. The original 475 manual has a white cover; looks nothing like a Tektronix manual from the mid-70s. The 475+DMM44 manual has the nice blue cover and a little extra heft from the added section on making measurements with the DMM44).

Did Tek always ship a service manual with their scopes? I haven't found a 2213 service manual among my father's effects either, and he bought a fairly early one brand new, after he went independent, because it was so much easier to haul around than the 475. The only manuals my father had in the pouch for the 2213 were the manuals for the probes, and a copy of The XYZs of Using a Scope tailored for the 2213. If he got an operators manual or a service manual with the scope, he must have stored it somewhere else.
From what I remember from looking through the catalogs, I do remember that service manuals *could* be an extra charge.  Once Tektronix combined the two (depended, I think, on the complexity of the manual), then that option went away.

Harvey

What you did is for your intensity pot is almost my exact plan as well. I don't think I can get at all four screws, but I figure if I loosen three of them then I might be able to get a 32G needle in the gap and inject some DeoxIT that way. There was some small improvement after I did the WD-40 thing, and it was enough to demonstrate that the beam intensity didn't really get visible until about 1/3rd of the way through the rotation, so all the dirty parts are actually in a range that I don't have much use for (maybe that low end of the range would be useful if I were using the Z axis input?).





Re: Troubleshooting an old Tek 475

 

Chuck Harris, that was a wonderfully clear explanation. Thank you.


Re: Clean and Lubricate Pots in Tek 475

 

Bruce Gentry wrote:
WD-40 is acceptable as a part of a mechanical cleaning process. Flush it out with a correct solvent after it had done it's work.
Would a "correct solvent" be isopropyl alcohol? I have access to a few other solvents, but some of them are explicitly forbidden in the Tek documents (e.g. Acetone) and at least one other (whether or not it's forbidden by Tek) is known to attack some common plastics.

An esoteric collection of solvents is another unusual feature of my father's effects which I have taken some pains to keep well sealed and safely stored.


Re: Clean and Lubricate Pots in Tek 475

 

Thanks for the pointer to Artek Manuals, I will go get a copy of that service manual straight away.

The 475 was originally a fleet instrument for my father's employer, but he got it as part of a somewhat odd severance package (the entire division was being dissolved/sold off, and he was one of the star employees). He may have gotten the service manual, or he may not have. If he did it is probably somewhere in his effects, which I have been making my slow way through during the pandemic. So far I have only found the operators instruction manual (and that only after I had bought the 475+DMM44 operators manual on eBay. The original 475 manual has a white cover; looks nothing like a Tektronix manual from the mid-70s. The 475+DMM44 manual has the nice blue cover and a little extra heft from the added section on making measurements with the DMM44).

Did Tek always ship a service manual with their scopes? I haven't found a 2213 service manual among my father's effects either, and he bought a fairly early one brand new, after he went independent, because it was so much easier to haul around than the 475. The only manuals my father had in the pouch for the 2213 were the manuals for the probes, and a copy of The XYZs of Using a Scope tailored for the 2213. If he got an operators manual or a service manual with the scope, he must have stored it somewhere else.

What you did is for your intensity pot is almost my exact plan as well. I don't think I can get at all four screws, but I figure if I loosen three of them then I might be able to get a 32G needle in the gap and inject some DeoxIT that way. There was some small improvement after I did the WD-40 thing, and it was enough to demonstrate that the beam intensity didn't really get visible until about 1/3rd of the way through the rotation, so all the dirty parts are actually in a range that I don't have much use for (maybe that low end of the range would be useful if I were using the Z axis input?).


Re: Troubleshooting an old Tek 475

Glenn Little
 

Think of it as a power supply for an audio amplifier.
With the lack of filtering you would hear a lot of hum.
If you played music through this amplifier, you would have a hard time hearing all that the music had to offer.
The scope could not perform with all that hum.

Get a capacitance meter with ESR capability.
They are not expensive.
With the loss of capacity, the ESR probably went up a lot.
If you found one capacitor like this, you will probably find others.
Sounds like it is time to replace the electrolytic capacitors.
They are probably well beyond their design life.
Select replacements that are rated for 105 degrees C or better and that will handle the most current that will fit into the space.

Capacitor technology has come a long way since that scope was built.

You will have a very fine scope that will serve you well when you get it fixed.

Glenn

On 11/7/2020 3:18 PM, Jeff Dutky wrote:
Göran Krusell wrote:are rated
the R1059 and C1059 low pass filter is filtering the +110V voltage, the values are not critical
that's what I thought, but then I don't understand why the dead capacitor killed this circuit. I mean it looks like its just buffering an otherwise DC voltage, and it doesn't seem to have shorted, the only change that my multimeter shows is that its capacitance dropped by an order of magnitude. Should a noisy 110V rail really kill the entire sweep circuit?

(I mean, the answer is obviously "yes" because that's exactly what it did, but I don't understand WHY or HOW it did that)



--
-----------------------------------------------------------------------
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Amateur Callsign: WB4UIV wb4uiv@arrl.net AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"


Re: (nearly) free scope carts in/near Boston; offers on 7834 and 7904 - not shipping anything sorry

Bill Riches
 

Hi Christian,

I am interested in your 7904. Give me a shout!

73,


Bill, WA2DVU
Cape May, NJ
609 425 8651

9641 - 9660 of 182427