Date   

Re: 475 questions

n4buq
 

Perhaps a stupid question, but since I don't know where you are and you might be in a part of the world where 220 mains are standard, have you checked to make sure the input voltage settings are correct? I doubt this is the problem as most likely other things would be complaining loudly, but just thought I'd ask.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "ciclista41 via groups.io" <ciclista41=yahoo.com@groups.io>
To: TekScopes@groups.io
Sent: Monday, June 22, 2020 12:11:38 PM
Subject: Re: [TekScopes] 475 questions

When I read your question, Ed, I was actually hopeful that it would be that
simple. Unfortunately, unless the capacitor, itself, is misidentifying its
negative lead, all six are correctly installed.

On Sun, Jun 21, 2020 at 09:06 PM, ehsjr wrote:



CR1412 installed backwards?
Ed



Re: Obfusctated email adresses in archive

Chuck Harris <cfharris@...>
 

From an email client, most of the time, the member's email address is in
plain text in the "FROM:" heading in the received email. Right click on
that address, and click on "Compose email" and you are good to go.

Some little bit of the time, notably yahoo addresses, you will have to
remove some silly stuff and fix the address yourself.

You will see something like:

<bloofie=yahoo.com@groups.io>

Remove the "<", ">", "@" and the "groups.io", and change the "=" to an "@"
and you are good to go.

And, in a grand total of one or two cases, where the member didn't have
an email address registered with yahoo.com, and still doesn't have one for
groups.io... then you are out of luck.

-Chuck Harris

ArtekManuals wrote:

David G

OK ...I'll bite ....How do I do that from a Email Client without going to web site

{SNIP}

Dave
manuals@artekmanuals.com
What is the reason for this request?  Why can't you just use the
private message/email function of the groups.io website?


Re: 2% Silver

Chuck Harris <cfharris@...>
 

A little background information:

Tektronix made its own ceramic terminal strips. Before
they made them, they made their own micarta strips with
riveted turret posts.

I'm guessing that one of the workers, possibly one of the
women on the assembly line, had some experience making
ceramic pottery, and got the idea. It is an obvious thought
progression: plastic insulates, but burns when soldered, need
something that doesn't burn... wait! Ceramic doesn't burn...

They found that they could with very little effort, mass
produce the ceramic strips more quickly, and at a much lower
cost than the riveted turret strips, so they economized.

One of the interesting characteristics of silver metal is
it will fuse with alumina ceramic at high temperature.
Tektronix molded the terminal strips, and then painted each
notch with a flaked silver metal paint. When they fired
the ceramic, the binder in the paint burned away, and the
silver metal "tinned" the ceramic, just like solder tins
copper.

Nature abhors a vacuum. When ordinary 60:40 tin/lead solder
(the standard for electronics assembly at the time) is used
to solder the strips, the molten solder dissolves a little
of the silver into solution, forming a tin/silver/lead alloy
that is very similar to the alloy of tin/silver/lead that
tektronix used in their factory.

If the tin/lead reaches the ceramic, the silver will instantly
be rejected from the ceramic, and you lose your mechanical
attachment of the parts to the terminal strip.

You can use ordinary 60:40 tin lead solder to rework a joint
on the terminal strips, but each time you heat the joint, and
apply more tin/lead solder, more of the silver will alloy with
the solder, and quicker than you would like, it will no longer
stick to the ceramic, as tin/lead/silver can not "tin" alumina
ceramic.

The whole idea behind using tin/silver/lead alloy solder is that
it already has quite a lot of silver in it, and will not leach
away the silver on the ceramic terminals as quickly as it would
if it had no silver already in the alloy.

But mark my words, even if you do use the correct silver solder,
if you dawdle with a hot iron on the joint, you can still
destroy the bond of the silver to the ceramic.

So, use a high wattage (50-70W), temperature regulated to 600-700F
iron with a flat sided chisel tip, and get in, get done, and get
out of the joint.

And, do not ever put the chisel tip in the notch, trying to heat
the lead that way, it will crack the ceramic every time. Put
one of the flats of the chisel tip on the side of the terminal
strip, and let the adjacent flat, or the tip, touch the lead,
and heat the joint that way. Stay out of the notch!

-Chuck Harris



David Kuhn wrote:

"The tektronix solder is definitely not lead free, and you definitely
do not want to be using lead free solder on the terminal strips in
a tektronix 500 series scope. "

Hello Chuck. I thought they used "silver" solder on those? Is that not
lead free? If not, what does "Silver" solder mean?

Sorry, just curious.

Dave

On Mon, Jun 22, 2020 at 12:07 AM Chuck Harris <cfharris@erols.com> wrote:

The tektronix solder is definitely not lead free, and you definitely
do not want to be using lead free solder on the terminal strips in
a tektronix 500 series scope.

The Kester Sn62 solder makes beautiful joints, though.

-Chuck Harris

Randy.AB9GO wrote:
I purchased a 1 lb roll of Multicore 2% at of all things a farm equipment
show 4-5 years ago for $3.00! No one wanted because it was too thin.
You
just never know where stuff like this is going to show up. I will
probably
bite the bullet and buy a new roll when I need it. It makes some of the
prettiest joints you've ever seen. I use it on everything. On the other
end of the spectrum is lead free and unless I have to work on something
that is already lead free I'm just not buying it or using it. Awful
awful
stuff.

randy.ab9go@gmail.com






Re: 475 questions

ciclista41@...
 

Hi Chuck,

No, ever since the experience with the supposedly bad tantalums that were awful according to my GMI-236 "in circuit" ESR tester, but fine out of circuit (I returned that item), I have not depended on in-circuit measurements unless I've "lifted a leg" first. The measurements I included in my recent post were out of circuit.

Bruce

On Mon, Jun 22, 2020 at 03:18 AM, Chuck Harris wrote:


It sounds to me like you are using one of those transistor/capacitor/ESR/
SCR/diode/inductor/... testers on in-circuit components.

You shouldn't do that!

These cheap Chinese/Ebay testers are definitely not suitable for in-circuit
testing. Hook a storage scope onto the terminals and look at what they are
doing to the part. They are applying significant voltages, typically ramps
of +/- 5V to the part to see how it behaves, and voltages like that will
activate most of the semiconductor junctions in the scope, and certainly
will be confused by parallel combinations of parts.

The only testers that are truly suitable to use in circuit have to use less
than a diode/transistor junction voltage in their tests, and of course, they
can't test diodes and transistors that way...

ESR meters, like the Dick Smith variety, apply a couple of tens of millivolts
signal to the capacitor at 50KHz to do their testing.

-Chuck Harris

ciclista41 via groups.io wrote:
Hi folks,

Here's where I'm up to. All six large capacitors have been replaced, along
with the two tantalums that I pulled, thinking they were bad based on
in-circuit tests which turned out to be wrong--they were good. Made sure I
had correct polarity.

The large capacitors were good except for C1412 and C1414. C1414 was the
worst. It reads 0L on my Fluke 87-V for capacitance (same as shorting the
probes together). My "transistor tester" shows it as 12.59 nF with 14% vloss.
The C1412 still shows 399 μF (rated 360 μF), but the "tester" shows 347 nF,
6.5 Ω ESR, and 3.8% vloss.

Okay, so in replacing all these, I used Alex Cuoghi's PCB's. I wanted to
make sure I hadn't created any shorts due to poor soldering (my soldering
looks pretty good to me, but just being careful), so after soldering the four
pins into the PCB's, I checked for continuity among the ground pins to the via
where the negative of the cap goes, and from the positive pin to the positive
via. All good in all cases. Then I soldered the caps in place, followed by a
re-checking of appropriate continuities. Finally, I soldered the PCB pins to
the A9 board, making sure each was in its appropriate location and rechecking
for continuity and no shorting. Then I noticed that I had not replaced the
CR1412 rectifier before installing the C1412, so had to pull that again,
install the CR1412, then reinstall the C1412 cap. Again checked for
appropriate continuity and lack of shorts.

Time to plug the scope in again. I had a 200W bulb in series with the plug
as a current limiter. Switched on the scope, and immediately switched it off
again, as the bulb lit up brightly and there were sparks at the C1412 where
soldered to the board. Sounded like frying bacon, but this is not supposed to
be a MIG welder! Figured I had somehow created a short with my soldering, so
pulled the C1412 again. No sign of any burning, so sign of solder out of
place, everything still looked and measured as expected. Even pulled the cap
from the PCB with no sign of anything wrong. Shrugged my shoulders and put it
back in the board. Tried again with the same result. Pulled again (I know,
poor board, but it seems to be handling it all gracefully). Again, so sign of
my having screwed anything up. Let it sit for a day, hoping I'd think of some
reason it could be my fault that there was a short. Full disclosure, I may
have dropped a screw through the hole in the middle of the bottom of the
board, but I don't think so. Turned the scope every which way while shaking
it and there was no rattle and nothing fell out. The only other thing I could
think of was that I may have cooked the CR1412 with soldering it, but I doubt
that, and it did measure as good before I put it back in.

So, I'm guessing that there is a short somewhere in one of the boards, and
the fact that the C1414, which is in series with the C1412 that gets so upset
when I switch on the scope, was protected from that effect by the fact that
the old C1414 measures in the MΩ range, and maybe the short was what killed
that capacitor in the first place.

Any ideas?

I don't yet have a Variac, but one should arrive in the mail tomorrow or the
next day. Alternatively, I have a DC power supply that is fixed current or
fixed voltage with up to 10A and 30V. Not sure where to feed sub 5V into the
circuit to try to find the fault. Also I tried pulling all of the power
connections to other boards and turning it on, but still got a sizzle at the
C1412.

Bruce






Re: 475 questions

ciclista41@...
 

When I read your question, Ed, I was actually hopeful that it would be that simple. Unfortunately, unless the capacitor, itself, is misidentifying its negative lead, all six are correctly installed.

On Sun, Jun 21, 2020 at 09:06 PM, ehsjr wrote:



CR1412 installed backwards?
Ed


Re: Obfusctated email adresses in archive

ArtekManuals <manuals@...>
 

David G

OK ...I'll bite ....How do I do that from a Email Client without going to web site

{SNIP}

Dave
manuals@artekmanuals.com

What is the reason for this request? Why can't you just use the
private message/email function of the groups.io website?

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


Re: Obfusctated email adresses in archive

David DiGiacomo
 

On Mon, Jun 22, 2020 at 10:15 AM David C. Partridge
<david.partridge@perdrix.co.uk> wrote:

The reason I raised this is that loads of our users regularly complain that they can't use the email addresses they see in the archive because they are obfuscated by groups.io.

As it's simple to change - I asked.
I would greatly prefer to educate those people to use the groups.io PM
facility, rather than retroactively expose all posters to having their
email addresses scraped.


Re: 2445B with a problem

John Parkins G8KVP
 

Hello,

As I don't like to leave things hanging and someone might have the
same problem in the future. This fault is now cured.

Unfortunately I can't really give a definite fault. I did replace
both U650 and U950 but that didn't solve the problem. I'd convinced my
self the problem was on the A5 board. I'd replaced a few resistors
around the DAC as I wasn't able to attain the 2.5 v swing that's
required for calibration. I also replace the famous caps on the board
and gave it a good scrubbing. I did touch up on or two dim looking
joints on the right hand side of the board, but without any luck.

So today I gave the board another good clean and although I checked
the joints under a microscope and didn't really find any that looked
bad, I gave them all a bit of heat. I put the board back in the scope
and it's all 100% ! So even though they looked fine there must have
been some bad joints in there somewhere.

The Dallas chip has been replaced, the caps in the power supply are
new and so are some of the others. Hopefully that will be it for
another 30 years............



Tuesday, June 16, 2020, 2:18:59 PM, you wrote:

JPG> Hello Chuck,

JPG> I don't get the 02 Test Fail 53 at startup. If I go into the testing
JPG> it sometimes fails other times it doesn't, if I leave it looping it
JPG> never shows a failure.

JPG> As I said the caps on the A5 board looked fine but I stripped them off
JPG> along with the resistors and had a really good look at the board under
JPG> a microscope. Couldn't see any damage but cleaned it with IPA and gave
JPG> the area a good scrub. I'll give it another going over though.
JPG> One of the resistors was not showing the correct value, but can't now
JPG> remember which one. After they were replaced though I set the DAC as
JPG> per the manual.

JPG> Would a stuck delta t button be causing this problem though, once on the
JPG> cursors aren't coming and going on the display. Seems more like a
JPG> sequencing problem U650 or blanking U950.

JPG> Tuesday, June 16, 2020, 12:51:31 PM, you wrote:

CH>> The Delta t switch is read by the CPU. If the CPU says it is
CH>> stuck, it is stuck. Check out the path from the switch to the
CH>> CPU. There is a twisty turney path through some opamps, and
CH>> MUXes that must work for the test on Delta t to work.

CH>> Also, did you scrub the A5 board with hot water and dish detergent?

CH>> If not, now is the time. Capacitor electrolyte is highly conductive.

CH>> -Chuck Harris

CH>> John Parkins G8KVP wrote:
Hello TekScopes,

Posted about this a while ago, but while some work has been done,
nothing has improved this problem. If you'd like to see a video.....

https://youtu.be/nyFnwWyP6XU

Shows the problem. The scope was working perfectly, then I noticed
this happening. Checked out the supply which had been re-capped and
all the voltages, ripple etc are well within spec. While I was in
there I have taken the opportunity to replace the Dallas chip with a
FM1608 having saved the contents and programmed them onto the
FM1608.

The normal problem caps on the A5 board didn't look like they had
been changed, so they have been now. I also found I couldn't get the
required 2.5 v swing on the U2102 DAC so I changed out all the
resistors in that area and now I can. Couldn't see any damage on the
board though.

I can get one error Test 02 Fail 53 which tells me the delta t
switch is stuck, it isn't.

Also noticed that the display is not as sharp as it was.

So any pointers will be gratefully received.
CH>>







--
Best regards,
John mailto:john@g8kvp.com


Re: 7854/7S11 issue

Albert Otten
 

Gentlemen,

Comparison is dangerous, it depends on the measurement range (measurement voltage) of the DMM.
I tested 3 7S11s with 4 DMMs.
Measured with the same DMM all 3 resistances at the 15DC pin are equal within a few promille.
All 4 DMMs agree within a percent or better when I set the non-auto DMMs at the 20k range.
The common reading is 1k73.
But at the 2k ranges the readings were 1k37. (I checked again to be sure I hadn't interchanged digits.) I found about that same when I supplied about 1 mA current into the TP and measured the voltage. Even 1k37 is much higher than the values mentioned so far.
Meanwhile I discovered that in one unit the nearby GND pin was isolated from the chassis.

Albert

On Mon, Jun 22, 2020 at 03:08 PM, <scm@menasians.com> wrote:


Ram,

I have 2 7S11s.
For what it's worth, I get the following values using a fluke 87 VOM, taking
care to keep the polarity correct.
Unit 1 Unit 2
+15 823 857
+15 DCPL 906 857
-15 2.09k 1.98k
+50 9.01k 8.38k
-50 7.28k 5.98k

Note that the discrepancy in +15 and +15 DCPL values in unit 1
(vs none in unit 2) may be due to a problem in one of the units. I have
actually used them recently.

Stephen


Re: Obfusctated email adresses in archive

 

This isn't in emails - its only in the archive

David

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Colin Herbert via groups.io
Sent: 22 June 2020 16:12
To: TekScopes@groups.io
Subject: Re: [TekScopes] Obfusctated email adresses in archive

Oddly enough, I get to see email addresses. At the top of emails is something like:

"TekScopes@groups.io; on behalf of; Harry Houdini <harryhoudini@magicianmail.com>"

I don't understand why, but there you go. I didn't do anything special to get this, perhaps it's because I am in the UK?

Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David DiGiacomo
Sent: 22 June 2020 15:08
To: TekScopes
Subject: Re: [TekScopes] Obfusctated email adresses in archive

On Mon, Jun 22, 2020 at 6:53 AM David C. Partridge
<david.partridge@perdrix.co.uk> wrote:

Dennis,

It's possible to change the group settings to not hide email addresses in
the archive. If anyone is concerned about exposing their email address,
they probably already use a "throw-away" email address to post to the group.

Please could I request that you change the setting?
What is the reason for this request? Why can't you just use the
private message/email function of the groups.io website?


Re: Obfusctated email adresses in archive

 

The reason I raised this is that loads of our users regularly complain that they can't use the email addresses they see in the archive because they are obfuscated by groups.io.

As it's simple to change - I asked.

David

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David DiGiacomo
Sent: 22 June 2020 15:08
To: TekScopes
Subject: Re: [TekScopes] Obfusctated email adresses in archive

On Mon, Jun 22, 2020 at 6:53 AM David C. Partridge
<david.partridge@perdrix.co.uk> wrote:

Dennis,

It's possible to change the group settings to not hide email addresses in
the archive. If anyone is concerned about exposing their email address,
they probably already use a "throw-away" email address to post to the group.

Please could I request that you change the setting?
What is the reason for this request? Why can't you just use the
private message/email function of the groups.io website?


Re: Obfusctated email adresses in archive

Carsten Bormann
 

On 2020-06-22, at 17:17, n4buq <n4buq@knology.net> wrote:

I get almost the same thing except the address is mingled with groups.io. I can usually figure it out but it isn't exactly as clear in my email reader as your example.
That is a different issue — the address is not “obfuscated" by groups.io, it is /protected/ from the evils that SPF and DMARC foist on mailing lists. This is not going away.

(As was mentioned, talking about the mail interface here — the original poster was talking about the web interface.)

Grüße, Carsten


Re: Obfusctated email adresses in archive

David DiGiacomo
 

From: "Colin Herbert via groups.io"
<colingherbert=blueyonder.co.uk@groups.io>

Oddly enough, I get to see email addresses. At the top of emails is something
> like:
>
> "TekScopes@groups.io; on behalf of; Harry Houdini
> <harryhoudini@magicianmail.com>"
>
> I don't understand why, but there you go. I didn't do anything special to get
> this, perhaps it's because I am in the UK?

You didn't read the original message carefully enough. He said "in
the archive", that is, the groups.io website.


Re: Obfusctated email adresses in archive

Steve Hendrix
 

At 2020-06-22 11:12 AM, Colin Herbert via groups.io wrote:


Oddly enough, I get to see email addresses. At the top of emails is
something like:

"TekScopes@groups.io; on behalf of; Harry Houdini
<harryhoudini@magicianmail.com>"

I don't understand why, but there you go. I didn't do anything special to
get this, perhaps it's because I am in the UK?
I think it has more to do with your viewer. I still use Eudora (archaic, I know....) and it shows no return address in the "preview", which is how I normally read emails. However, if I fully open a single email so I can see the headers, it's right there in the From address.

Steve Hendrix


Re: Obfusctated email adresses in archive

n4buq
 

I get almost the same thing except the address is mingled with groups.io. I can usually figure it out but it isn't exactly as clear in my email reader as your example.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Colin Herbert via groups.io" <colingherbert=blueyonder.co.uk@groups.io>
To: TekScopes@groups.io
Sent: Monday, June 22, 2020 10:12:09 AM
Subject: Re: [TekScopes] Obfusctated email adresses in archive

Oddly enough, I get to see email addresses. At the top of emails is something
like:

"TekScopes@groups.io; on behalf of; Harry Houdini
<harryhoudini@magicianmail.com>"

I don't understand why, but there you go. I didn't do anything special to get
this, perhaps it's because I am in the UK?

Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David
DiGiacomo
Sent: 22 June 2020 15:08
To: TekScopes
Subject: Re: [TekScopes] Obfusctated email adresses in archive

On Mon, Jun 22, 2020 at 6:53 AM David C. Partridge
<david.partridge@perdrix.co.uk> wrote:

Dennis,

It's possible to change the group settings to not hide email addresses in
the archive. If anyone is concerned about exposing their email address,
they probably already use a "throw-away" email address to post to the
group.

Please could I request that you change the setting?
What is the reason for this request? Why can't you just use the
private message/email function of the groups.io website?








Re: Obfusctated email adresses in archive

Colin Herbert
 

Oddly enough, I get to see email addresses. At the top of emails is something like:

"TekScopes@groups.io; on behalf of; Harry Houdini <harryhoudini@magicianmail.com>"

I don't understand why, but there you go. I didn't do anything special to get this, perhaps it's because I am in the UK?

Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David DiGiacomo
Sent: 22 June 2020 15:08
To: TekScopes
Subject: Re: [TekScopes] Obfusctated email adresses in archive

On Mon, Jun 22, 2020 at 6:53 AM David C. Partridge
<david.partridge@perdrix.co.uk> wrote:

Dennis,

It's possible to change the group settings to not hide email addresses in
the archive. If anyone is concerned about exposing their email address,
they probably already use a "throw-away" email address to post to the group.

Please could I request that you change the setting?
What is the reason for this request? Why can't you just use the
private message/email function of the groups.io website?


Re: Spectrum Analyzer Question

David Berlind
 

Dennis, thank you for helping me to frame my inquiry better. Your guidance is always appreciated. As you probably saw by now, I responded with a summary in which I mentioned that as I further my exploration into electronics, I often don't know what I don't know. So far, with all the answers that I've received, I know so much more and have many avenues to explore that I never even considered before. A year from now, I hope to have experimented with an SDR and/or nanoVNA device, the FFT capability on my TDS 480B, and with any luck, a dedicated spectrum analyzer. Even so, I did not want to leave your questions unanswered as I'm sure I will still see some answers come in that further my education.

Q1) First and most important: Explain what you intend to use a spectrum
analyzer for. Include every single thing it will be used for.
A1: I don't know every single thing that I will use it for. When I acquired my first oscilloscope, I thought I knew the one or two use cases that I'd apply it to. But, as I learn more about electronics, I'm glad to have my oscilloscopes to do experiments that I never thought I'd do (just to further my understanding). It will be the same with spectrum analysis. But at the onset, I am interested in observing a carrier, its sidebands, and harmonics and do some experiments with audio signals. If I'm performing an alignment of an old tube radio, I'd like to make pre and post mixer observations. There are bunch of videos that I've watched on YouTube that I'd like to reproduce in my own lab. Sometimes, these videos work off of a fixed configuration of everything in an effort to fix one DUT. But when I watch these videos, I wonder what would happen if some of the variable inputs were changed. I suspect I know the answer in some cases, but I would enjoy seeing this in my own lab.

Q2) What is the most money you can afford to spend for a spectrum analyzer. Be
specific. Do not say a few hundred dollars.
A2. Right now, I'm going to say $500. I say this based on the responses I have received so far and the understanding that spectrum analyzers are just expensive. However, I do not have $500 right now. My plan is to get my feet wet with some other options and save some proceeds from gear that I have here in the lab that I have to fix and sell. I try to keep my hobbies self-funded. So, it may take me a while to get to $500. But at the same time, it looks like I have some other short term options that will help me to develop a much better understanding. But I will continue to keep my eyes peeled for a viable stand alone unit. If I've learned enything from the gear that I've acquired so far, it's that patience pays. Sooner or later, something will come along.

Q3) What brand of Spectrum Analyzers are you considering? Be specific.
A3. If you recall my first question was really about trying to understand the 7000 plug-in option vs. a stand alone unit given that I have a few 7000-series mainframes here. So, while this started as a Tek specific inquiry, the answers here have taught me to be open to other options. I'm still interested in the plug-in approach but have a better understanding of the risks. I learned about the T1401A which looks like an interesting approach if you already own an oscilloscope but am not clear on its compatibility with all scopes or just one family. I like staying with brands that I can find help for. This forum is one reason I have a lot of Tek stuff. I know that I can get help here and in many cases, if I don't ask a question that I need the answer to, someone else will. Like today, I woke up to a thread about first time startup recommendations for a 545A. I am paying very close attention because I have two 547s here and I'll need to go through the same thing at some point. The availability of the HP/Agilent forum means that that looks like a good brand to keep a watch for too.

Q4) What research have you done to to familiarize yourself with the prices and
availability of spectrum analyzers?
A4: Beyond this thread and some local searches of Craigslist and the Facebook marketplace, none.

Q5) Spectrum Analyzers come in many different physical variants. Which do you
want? Please explain why you chose the ones you did.
A5: If the answers to this thread taught me anything, it's that there are a lot of variants I didn't know about. I know so much more than I did before and am a much more educated consumer as a result. I've yet to establish a preference. This is one of those areas where I don't know what I don't know. For example, when I acquired my first oscilloscope (a Tek 466), I didn't know that oscilloscopes came in 2 and 4 channel versions or why I might need 4 vs 2 channels. Nor did I know there were modular mainframes. Thanks to a member here, I acquired my first mainframe with four channels and was able to simultaneously observe the multiple 90 degree phase shifts of the A/C signal that traverses a guitar amplifier's tremolo circuit. When I first started fixing guitar amps, I didn't even know what phase shift was, much less why a four channel oscilloscope would help me to observe it better than a two channel one.

* A spectrum analyzer plugin. If so what scope does will it plug into?
If I get a plug-in, more than likely a 7603. I also have a 7633 here but it's in my service queue and will be a while before it's ready.

* A portable spectrum analyzer
Maybe. I'd like to keep an open mind.

* A PC based spectrum analyzer, if so, how fast is the PC it will be connected
to?
I own a MacBook Pro. 2.8 Ghz. 16 GB RAM

* A stand alone spectrum analyzer?
Yes, of course I'd be interested in this option.

Again Dennis, thank you for your guidance on this issue. I know some answers were not as specific as they could have been. But I am learning thanks to everyone here and as I learn more, and do more, my desires are sure to clarify themselves.

David


Re: 2% Silver

Colin Herbert
 

"On the same note, ERSIN made a solder called save-a-bit when soldering irons had a copper tip.
They added copper to the alloy to prevent the erosion of the tip from the normal lead/tin alloy.
Glenn"

I think I remember it as Ersin "Savbit". Incidentally, soldering-iron tips are _still_ made from copper, it is just that they are now given a plating of iron, which prevents the copper from being dissolved by the molten solder (allegedly). Such bits should not be filed to renew the tip, because that removes the protective iron plating. The problem is, we all do it when our bits become pitted, but perhaps such filing is limited to the very end of the bit? I suspect that most common solder used in electronics still contains a little copper.

Colin.


Re: 2% Silver

Glenn Little
 

Regular tin/lead solder will leach the silver out of the ceramic, over time.
The silver is added to the alloy to prevent this leaching.
IIRC Tektronix used an alloy with 3% silver.
The common alloy that can be found today is 2% silver.
Serves the same purpose.

On the same note, ERSIN made a solder called save-a-bit when soldering irons had a copper tip.
They added copper to the alloy to prevent the erosion of the tip from the normal lead/tin alloy.

Glenn

On 6/22/2020 8:59 AM, David Kuhn wrote:
" The "silver bearing" solder is akin to soft solder (used in making
electrical joints) and contains a relatively low proportion of silver."

Is that the type that was included inside the old 500 series scopes for
repairs? I understand that regular lead solder was not good for those
ceramic component strips in the scopes? Did it keep the plating from
unbounding to the ceramic? If that roll of solder is missing from the
scopes (and most likely is), what solder should be used for repairs? I
always thought it was some sort of silver solder? It must still contain
lead.

On Mon, Jun 22, 2020 at 7:52 AM Colin Herbert via groups.io <colingherbert=
blueyonder.co.uk@groups.io> wrote:

"Silver Solder" is a hard solder used in making mechanical joints such as
in jewellery. It melts at a relatively high temperature and is akin to
brazing, i.e. "hard soldering". It contains silver, copper and zinc and
maybe a little cadmium to get a lower melting-point. The "silver bearing"
solder is akin to soft solder (used in making electrical joints) and
contains a relatively low proportion of silver.
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David
Kuhn
Sent: 22 June 2020 12:32
To: TekScopes@groups.io
Subject: Re: [TekScopes] 2% Silver

"The tektronix solder is definitely not lead free, and you definitely
do not want to be using lead free solder on the terminal strips in
a tektronix 500 series scope. "

Hello Chuck. I thought they used "silver" solder on those? Is that not
lead free? If not, what does "Silver" solder mean?

Sorry, just curious.

Dave

On Mon, Jun 22, 2020 at 12:07 AM Chuck Harris <cfharris@erols.com> wrote:

The tektronix solder is definitely not lead free, and you definitely
do not want to be using lead free solder on the terminal strips in
a tektronix 500 series scope.

The Kester Sn62 solder makes beautiful joints, though.

-Chuck Harris

Randy.AB9GO wrote:
I purchased a 1 lb roll of Multicore 2% at of all things a farm
equipment
show 4-5 years ago for $3.00! No one wanted because it was too thin.
You
just never know where stuff like this is going to show up. I will
probably
bite the bullet and buy a new roll when I need it. It makes some of
the
prettiest joints you've ever seen. I use it on everything. On the
other
end of the spectrum is lead free and unless I have to work on something
that is already lead free I'm just not buying it or using it. Awful
awful
stuff.

randy.ab9go@gmail.com







--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
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: Obfusctated email adresses in archive

David DiGiacomo
 

On Mon, Jun 22, 2020 at 6:53 AM David C. Partridge
<david.partridge@perdrix.co.uk> wrote:

Dennis,

It's possible to change the group settings to not hide email addresses in
the archive. If anyone is concerned about exposing their email address,
they probably already use a "throw-away" email address to post to the group.

Please could I request that you change the setting?
What is the reason for this request? Why can't you just use the
private message/email function of the groups.io website?

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