Date   

Re: Circuit boards used to demo scopes\ c]

Marvin Moss
 

As I recall, Tek used to give them to us free to take home with us. I would be happy to pay for your trouble and postage to me in GA. Thanks, Marv


Re: Morning fun - working scope with no tubes?

Chuck Harris
 

Then how can we get upset when a tube harvester
does what comes natural?

The price is related to demand and availability.
Each unit that is tube harvested, reduces the
availability.

The only part of the equation that is currently
stalled is the "increases the price" part. Thus
far, we treasure these scopes, but we value them
like they are trash.

We want them, but are too cheap to pay for them. We
just complain, but don't increase the prices we are
willing to pay.

-Chuck Harris

Jamie Ostrowski wrote:

And lastly, before I go close out my day and drown in a sea of random
youtube videos for the evening, as cool as they are, they are just
oscilloscopes, and there's just a lot of other cool vintage gear out there
to attract buyers. When they start hitting $500, people say "well, that's
really cool but...look at all the other cool vintage gear I could get for
that."... So...that has a big impact as well. Ultimately, you can really
increase the price, but people are going to look for other things to
restore.


Re: 11801C 11802 CSA803A

 

On Wed, Sep 18, 2019 at 09:15 PM, cmjones01 wrote:

Been there, done that ...

I had no use for the power-only slots but quite liked the idea of the
trigger prescaler, so I modified the acquisition module from the 11802,
adding SMA trigger outputs from the delay lines on the front
http://www.hakanh.com/dl/lab/csa.jpg

The high-speed calibrator from the 11802 is still in a safe place awaiting
its round tuit, when I will build it in to a useful housing.
http://www.hakanh.com/dl/fast_pg_2.htm

/Håkan


Re: 11801C 11802 CSA803A

cmjones01
 

On Thu, Sep 19, 2019 at 1:18 AM John Griessen <@jgriessen> wrote:

On 9/18/19 2:15 PM, cmjones01 wrote:
I had no use for the power-only slots but quite liked the idea of the
trigger prescaler, so I modified the acquisition module from the 11802,
adding SMA trigger outputs from the delay lines on the front of it (there's
no option to route these internally on the CSA803A) and fitted it to the
803A, creating a frankenscope with the features I wanted. I'm really
pleased with it.
Did the delay lines go into your frankenscope? Are the delay lines part of
the acquisition module from the 11802?
Yes, the delay lines are built in to the 11802's acquisition module.
They're very substantial, heavy pieces of plumbing. Each of them has a
power splitter on the input which sends part of the signal down the
delay line and the remaining part to a trigger output. On the 11802
the trigger signals are routed internally to the bottom board of the
mainframe. The CSA803A doesn't have the necessary connections so I
drilled holes in the front panel of the acquisition module and added
semi-rigid SMA pigtails to bring the trigger outputs to the front
panel so I can just hook them up externally to the CSA803A's trigger
input.

Chris


Re: A6302 current probe excessive offset

cmjones01
 

I've certainly used the degauss function on the AM503s lots of times,
and it's definitely working (the probe makes the characteristic
'boing' noise). However, perhaps the core or metalwork is more
magnetised than the internal degauss function can cope with. I'll try
an external degaussing wand. Thank you for the idea.

Chris

On Wed, Sep 18, 2019 at 10:56 PM Jean-Paul <jonpaul@...> wrote:

Chris you have throughly degaussed it?
A permanent magnetic field bias is one explanation
Jon



Re: PM for a working Tek 577 with D1 storage Curve Tracer

Kevin Oconnor
 

Thanks Chuck

Sent from kjo iPhone


Re: Morning fun - working scope with no tubes?

Jamie Ostrowski
 

And lastly, before I go close out my day and drown in a sea of random
youtube videos for the evening, as cool as they are, they are just
oscilloscopes, and there's just a lot of other cool vintage gear out there
to attract buyers. When they start hitting $500, people say "well, that's
really cool but...look at all the other cool vintage gear I could get for
that."... So...that has a big impact as well. Ultimately, you can really
increase the price, but people are going to look for other things to
restore.



On Wed, Sep 18, 2019 at 11:09 PM Jamie Ostrowski via Groups.Io
<jamie.ostrowski=gmail.com@groups.io> wrote:

I did give that plan some more thought. I don't think it would work. Let's
say everyone increases the price of the oscilloscopes to protect them from
tube hoarders. A 535 oscilloscope now goes for, say, $400 in tattered but
complete working order.

Now what will happen is the scavengers will buy it for $400, rip their
tubes out, and then put the remains back on the market for $300. And it
will sell at $300 because if audio tubes are added, it will become worth
$400 again.

So really, nothing would change, except for the going price level.

On Wed, Sep 18, 2019 at 10:31 PM Jamie Ostrowski via Groups.Io
<jamie.ostrowski=gmail.com@groups.io> wrote:

Perhaps, but that solution is probably much easier to accept by folks who
have a couple hundred in their basement as compared to others just
beginning to collect.

On Wed, Sep 18, 2019 at 10:27 PM Chuck Harris <cfharris@...>
wrote:

The easiest way is to pay real money, and to charge real money
for them.

Anything short of that is giving them to the tube harvesters.

-Chuck Harris

Jamie Ostrowski wrote:
I wish there was a way to find a way to keep the classic scopes out
of
the
hands of the tube harvesters. I know when it comes to sell any of my
classic equipment, I'd offer it up here on the Tekscopes list first
long
before I would ever list it on e-pay, just because I know that people
here
are enthusiastic about the classic scopes.

I have given some consideration to putting up some kind of free site
on
my
server just for collectors to advertise their scopes/plugins, but not
sure
how to keep the site from becoming a target for harvesters. Maybe I
could
do something like manually approve accounts to the site for people
who
have
demonstrated a sincere enthusiasm for the classics in one form or
another
in the past via tekscopes mail archives or something like that. Not
sure.

It wouldn't have to be a big/complicated site, nor generate a lot of
traffic. Just more for a circle of collectors to trade gear.

Ebay has become mostly ridiculous, in my opinion.








Re: Morning fun - working scope with no tubes?

Jamie Ostrowski
 

I did give that plan some more thought. I don't think it would work. Let's
say everyone increases the price of the oscilloscopes to protect them from
tube hoarders. A 535 oscilloscope now goes for, say, $400 in tattered but
complete working order.

Now what will happen is the scavengers will buy it for $400, rip their
tubes out, and then put the remains back on the market for $300. And it
will sell at $300 because if audio tubes are added, it will become worth
$400 again.

So really, nothing would change, except for the going price level.

On Wed, Sep 18, 2019 at 10:31 PM Jamie Ostrowski via Groups.Io
<jamie.ostrowski=gmail.com@groups.io> wrote:

Perhaps, but that solution is probably much easier to accept by folks who
have a couple hundred in their basement as compared to others just
beginning to collect.

On Wed, Sep 18, 2019 at 10:27 PM Chuck Harris <cfharris@...> wrote:

The easiest way is to pay real money, and to charge real money
for them.

Anything short of that is giving them to the tube harvesters.

-Chuck Harris

Jamie Ostrowski wrote:
I wish there was a way to find a way to keep the classic scopes out of
the
hands of the tube harvesters. I know when it comes to sell any of my
classic equipment, I'd offer it up here on the Tekscopes list first
long
before I would ever list it on e-pay, just because I know that people
here
are enthusiastic about the classic scopes.

I have given some consideration to putting up some kind of free site on
my
server just for collectors to advertise their scopes/plugins, but not
sure
how to keep the site from becoming a target for harvesters. Maybe I
could
do something like manually approve accounts to the site for people who
have
demonstrated a sincere enthusiasm for the classics in one form or
another
in the past via tekscopes mail archives or something like that. Not
sure.

It wouldn't have to be a big/complicated site, nor generate a lot of
traffic. Just more for a circle of collectors to trade gear.

Ebay has become mostly ridiculous, in my opinion.






Re: Morning fun - working scope with no tubes?

Jamie Ostrowski
 

Perhaps, but that solution is probably much easier to accept by folks who
have a couple hundred in their basement as compared to others just
beginning to collect.

On Wed, Sep 18, 2019 at 10:27 PM Chuck Harris <cfharris@...> wrote:

The easiest way is to pay real money, and to charge real money
for them.

Anything short of that is giving them to the tube harvesters.

-Chuck Harris

Jamie Ostrowski wrote:
I wish there was a way to find a way to keep the classic scopes out of
the
hands of the tube harvesters. I know when it comes to sell any of my
classic equipment, I'd offer it up here on the Tekscopes list first long
before I would ever list it on e-pay, just because I know that people
here
are enthusiastic about the classic scopes.

I have given some consideration to putting up some kind of free site on
my
server just for collectors to advertise their scopes/plugins, but not
sure
how to keep the site from becoming a target for harvesters. Maybe I could
do something like manually approve accounts to the site for people who
have
demonstrated a sincere enthusiasm for the classics in one form or another
in the past via tekscopes mail archives or something like that. Not sure.

It wouldn't have to be a big/complicated site, nor generate a lot of
traffic. Just more for a circle of collectors to trade gear.

Ebay has become mostly ridiculous, in my opinion.




Re: Morning fun - working scope with no tubes?

Chuck Harris
 

The easiest way is to pay real money, and to charge real money
for them.

Anything short of that is giving them to the tube harvesters.

-Chuck Harris

Jamie Ostrowski wrote:

I wish there was a way to find a way to keep the classic scopes out of the
hands of the tube harvesters. I know when it comes to sell any of my
classic equipment, I'd offer it up here on the Tekscopes list first long
before I would ever list it on e-pay, just because I know that people here
are enthusiastic about the classic scopes.

I have given some consideration to putting up some kind of free site on my
server just for collectors to advertise their scopes/plugins, but not sure
how to keep the site from becoming a target for harvesters. Maybe I could
do something like manually approve accounts to the site for people who have
demonstrated a sincere enthusiasm for the classics in one form or another
in the past via tekscopes mail archives or something like that. Not sure.

It wouldn't have to be a big/complicated site, nor generate a lot of
traffic. Just more for a circle of collectors to trade gear.

Ebay has become mostly ridiculous, in my opinion.


Re: Morning fun - working scope with no tubes?

John Williams
 

No danger of any Tek gear I own being subject to sale. To paraphrase, you can have my scopes when you pry them from my cold dead hands. Not entirely joking.


Re: Circuit boards used to demo scopes\ c]

Oz-in-DFW
 

I have at least one. I'll dig out this weekend and try and check it out.


Re: Morning fun - working scope with no tubes?

Jamie Ostrowski
 

I wish there was a way to find a way to keep the classic scopes out of the
hands of the tube harvesters. I know when it comes to sell any of my
classic equipment, I'd offer it up here on the Tekscopes list first long
before I would ever list it on e-pay, just because I know that people here
are enthusiastic about the classic scopes.

I have given some consideration to putting up some kind of free site on my
server just for collectors to advertise their scopes/plugins, but not sure
how to keep the site from becoming a target for harvesters. Maybe I could
do something like manually approve accounts to the site for people who have
demonstrated a sincere enthusiasm for the classics in one form or another
in the past via tekscopes mail archives or something like that. Not sure.

It wouldn't have to be a big/complicated site, nor generate a lot of
traffic. Just more for a circle of collectors to trade gear.

Ebay has become mostly ridiculous, in my opinion.

On Wed, Sep 18, 2019 at 8:47 AM Dave Voorhis <voorhis@...> wrote:

On 18 Sep 2019, at 13:54, Jamie Ostrowski <jamie.ostrowski@...>
wrote:

https://www.ebay.com/itm/264469242144?ul_noapp=true

Tektronix Type 533 Oscilloscope TESTED . Condition is Used. The unit
does work and is in great shape. (No tubes in the scope) If interested in
the scope itself we can work something out. You are buying this with no
tubes. The unit works with tubes.

And it's only $400.
Sad that it’s sold sans tubes, but better that way than what some of the
audiophools do: pull the 6DJ8 tubes to sell them and discard the rest. :-(




Re: Working Tek 585A (Laurel MD USA) for $250 on Craigslist

Leon Robinson
 

The Type 81 is an adapter to use any of the 530 & 540 series plugins in the 585.In have 2 for my 585, one came with the scope and the other came with another plugin.


Leon Robinson    K5JLR

Political Correctness is a Political Disease.

Politicians and Diapers should be changed
often and for the same reasons.

On Wednesday, September 18, 2019, 9:31:48 AM CDT, Mike Dinolfo <@mdinolfo> wrote:

I am not affiliated with the seller, and I am not interested in this 'scope, but the seller apparently includes a type 82 plugin, and claims "with 81A plug in" (adapter, maybe?): https://washingtondc.craigslist.org/mld/ele/d/laurel-vintage-oscilloscope-585a/6979916583.html

I'd hate for it to go to a tube harvester.

Mike Dinolfo N4MWP


Re: 11801C 11802 CSA803A

John Griessen
 

On 9/18/19 2:15 PM, cmjones01 wrote:
I had no use for the power-only slots but quite liked the idea of the
trigger prescaler, so I modified the acquisition module from the 11802,
adding SMA trigger outputs from the delay lines on the front of it (there's
no option to route these internally on the CSA803A) and fitted it to the
803A, creating a frankenscope with the features I wanted. I'm really
pleased with it.
Did the delay lines go into your frankenscope? Are the delay lines part of
the acquisition module from the 11802?


Re: Transistor solder dwell time

Harvey White
 

Thanks.  I can only afford the older ones, used.  It's my favorite (and just about only) soldering system.

I'd be far less happy (and productive in SMT soldering, let alone anything else) without it.

Harvey

On 9/18/2019 5:06 PM, Jean-Paul wrote:
Hello all

I designed the Metcal SP-200 back before 1992.
The curie point tip combines the heater and temperature regulation.
The result is much less temp overshoot especially if the work has a big thermal mass.
The thermal overshoot of conventional irons is one issue in damages to the work.

I can personally vouch that the Metcal is far superior for work on ground planes, large conductors and TO-3.
Beware, there's two different Metcal irons, old style has a coaxial connection and ran at 12.5 MHz.
My more recent design was a 500 kHz resonant mode current source and uses a 4 pin DIN connector.
Irons and tips are on epay but the newer SP-200 is less prevalent.

Just the ramblings of an old retired EE.......

Jon




Re: Transistor solder dwell time

Jean-Paul
 

Hello all

I designed the Metcal SP-200 back before 1992.
The curie point tip combines the heater and temperature regulation.
The result is much less temp overshoot especially if the work has a big thermal mass.
The thermal overshoot of conventional irons is one issue in damages to the work.

I can personally vouch that the Metcal is far superior for work on ground planes, large conductors and TO-3.
Beware, there's two different Metcal irons, old style has a coaxial connection and ran at 12.5 MHz.
My more recent design was a 500 kHz resonant mode current source and uses a 4 pin DIN connector.
Irons and tips are on epay but the newer SP-200 is less prevalent.

Just the ramblings of an old retired EE.......

Jon


Re: A6302 current probe excessive offset

Jean-Paul
 

Chris you have throughly degaussed it?
A permanent magnetic field bias is one explanation
Jon


Re: Conclusion to Need Help troubleshooting Tektronix PS280 powersupply

Siggi
 

Congrats on the fix - it still gives me a buzz to get a nice bit of test
gear back into action!

On Wed, Sep 18, 2019 at 2:17 PM daven9ooq via Groups.Io <daven9ooq=
yahoo.com@groups.io> wrote:

Hi Everyone,

I am very happy to report my tektronix PS 280 is now working beautifully!
Many Thanks to Siggi, Larry, Harvey, John, Chuck, If I forgot anyone my
apoligies!

Let me say that timing is somewhat important when posting, Who gets to see
it first, I'm pretty much a night owl, but I have to get up early CDT to
drop my wife at work.

My first hemorrhagic stroke in my brain stem, Feb 2002 , took away the
use of my left arm, and weakened my entire left side, nearly killed me. it
was an allergic reaction to Cartizem a family of blood pressure
medications, one pill one time, doctors say there is no way to screen for
this! I was only 47 at the time.

You are at the mercy of your doctor and who's on call at the ER of your
hospital!

I could go on, but don't want to get off topic.

To refresh everyone , I started looking for a Dual Channel power supply
around 7-30 volts @ at least 2amps for my bench projects, I'm a ham , that
is Amateur Radio op, and belong to the EMRFD group , Experimental Methods
in RF Design.

My second stroke also hemorrhagic , a burst aneurism, most likely left
from the first stroke, took out my short term memory. So cant remember if
it's still a yahoo group or .io .

The very first thing I did after checking the power supply was to check
the voltages, as I recall there was some voltage on one of the channels but
way low and the other was dead, So recapped both variable supplies, the
fixed 5 volt was working , so left it alone.

after the recap, things were better but still not working correctly,
actually the first thing I did was download the manual from the TekWiki
W140.com ,I think.

in checking the schematic, and parts list I found no special IC's or
semiconductors, I often wondered over the years what regulator was used to
get it down to 0 volts , in fact it can be adjusted to go slightly negative.

AS it turned out had some loose connections , when I removed the board for
recap, So my initial assessment of the recap was correct.

while I did get some help from the group , I was hoping to turn this into
a learning experience both for me and other less experienced members, which
unfortunately did not happen.

I have checked it under load I get a little better than 2 amps on the Main
side and 1.68 amps on the Slave side, I have yet to do the adjustments, and
check for ripple yet, but I'm getting a nice smooth 0-31 volts under load
on both sides.

AS for the metering I inadvertently reversed the meter connections. my
fault.

took at lot longer than I had hoped for but got it working! it will make a
nice addition to the rest of my TM500/ 5000 equipment and 2246 mod A scope.

Many thanks again!
73's
Dave N9ooq

















A6302 current probe excessive offset

cmjones01
 

I have here an A6302 current probe which has a DC offset too big to be
corrected by the AM503's balance control. I've had it apart and it doesn't
seem to be damaged, and indeed appears to work fine apart from the offset.
Its behaviour is the same on all 3 of my AM503's, each of which has also
been successfully tested on another probe (A6303).

I played with reducing the value of the resistor which feeds the offset
correction in to one pin of the amplifier, but even that wasn't enough. I
have now added a 3k3 resistor from the offset adjust pot's wiper to one end
of the hall sensor's output, and that allows me to bring the offset down
but at the expense of a very fussy offset adjustment and slight reduction
in gain. I could probably correct the latter by increasing the hall current
a bit, or devoting one AM503 to it with increased gain.

Does anyone have an idea what might cause this? Presumably the hall sensor
is damaged in some way, but the whole thing is of course potted so I can't
do much to it.

Chris