Date   

Re: 577 step generator troubleshoot

DW
 

My hope was replacing the thermal pad would at least have me with something I can work with. I should point out the step generator was partially working when Q386 did not have a thermal insulator pad. When I have thermal pads on both Q384 Q386 I am getting no indications of step generator function on the screen. This is weird that the step generator would show some forms of life on the screen with Q386 without a thermal pad


577 step generator troubleshoot

DW
 

Recently I had Q386 that was shorted to the frame of the 577. I have replaced both thermal pads so now there should be no short.

I reassembled this instrument and proceeded to test a transistor but it appears I get no response from the step generator when I turn it on. I probed test points 305 and counting the horizontal lines on the staircase pattern I see about 12 horizontal lines from the very bottom to the very top. I probed test point 360 and found I get similar results like 305 but the staircase pattern is either negative or positive depending on what I select.

I checked power supply voltages and they seem to be reasonable on the +-12V +-30V +200V

I notice R300 Step Zero seems to have a burn mark on it, it sparks when I fully turn it, I reset it to its default position, maybe defective

Any suggestions what I should probe or check, thanks


Re: OT - Any members in Czechia or Poland who can help me with parts?

 

Tam and all the other generous members who came forward to help.
Thank you so much!

A member in Czechia has already helped me.

Great to know that there are so many upstanding people here!

Menahem


Re: Morning fun - working scope with no tubes?

Keith Erickson
 

At least you know where an in town parts depot is! LOL

Keitj

On Sep 19, 2019, at 9:59 AM, Jamie Ostrowski <jamie.ostrowski@...> wrote:

Yes, that is a good point, Chuck. I guess I am being a bit unfair and
selfish. Unfortunately right now I'm in a situation where I have to be
pretty frugal and it's frustrating but that's nobody else's problem but
mine.

I guess it wouldn't be such a bad thing to buy a unit that has had just the
audio tubes removed and to buy a replacement set. I suppose the unit would
have to be calibrated again.



On Thu, Sep 19, 2019 at 6:39 AM Chuck Harris <cfharris@...> wrote:

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.




577 R300 pot

DW
 

On the main board of the 577 R300 "Step Zero" appears burned and I would like to replace it.

It is a 100k 30% 0.25W pot. Preferably I would like to replace it with the same type if possible.

Also I will look around and submit replacement parts which might work for review

71450 201--YA5549


Re: A6302 current probe excessive offset

Jean-Paul
 

Chris if vibrations affect the offset I suspect a hairline crack in the core half.

Any signs of dropping?

Use a magnifying lens on the shiny mating surfaces of the core.

Jon


Re: Morning fun - working scope with no tubes?

bobkrassa
 

Some tube scavengers are good for our hobby. They are the ones who are set up to market the rest of the parts of a scope back to us. With the aging of folks like Stan who acuumulated lots of Tektronix parts early on, our sources of parts are diminishing. Given the time involved in disassembly, organizing and selling, I doubt that a tube scavenger can pay for than $100 for a scope.

An example would be ebay seller mercedesman6572. I have bought a few parts from him over the years and note that his principal business appears to be tubes. Most of the tubes are in original boxes so not harvested, but other tubes may well be from scopes. Even though a few tubes have high prices, the whole endeavor must be as much a hobby as a business. If you look at his website, there are a lot of Tektronix parts under $10. I will say that I have parted out a couple of 500 series scopes myself to have a parts supply, but it is a real challenge to keep track of those parts and the time I would have to spend to organize and sell them would be impractical.

One approach that I would like to suggest is to inquire whether a purchaser actually has a business website where one can confirm that they are not just discarding the rest of the scope. If so, selling the scope to them for $100 or less is better than our family throwing it out when we can't remember what a scope is.

73s Bob Krassa ACØJL


Re: Morning fun - working scope with no tubes?

Jamie Ostrowski
 

Yes, that is a good point, Chuck. I guess I am being a bit unfair and
selfish. Unfortunately right now I'm in a situation where I have to be
pretty frugal and it's frustrating but that's nobody else's problem but
mine.

I guess it wouldn't be such a bad thing to buy a unit that has had just the
audio tubes removed and to buy a replacement set. I suppose the unit would
have to be calibrated again.

On Thu, Sep 19, 2019 at 6:39 AM Chuck Harris <cfharris@...> wrote:

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: Morning fun - working scope with no tubes?

Harvey White
 

Perhaps we don't have the money?

How much is a used 535 worth?

Firstly as a scope.

Secondly as a collector's object to be restored.

Thirdly a source of oh so valuable tubes.

Fourth as a source of spare parts for a working unit.

What would you suggest as "reasonable" prices we might pay....?

Harvey

On 9/19/2019 7:38 AM, Chuck Harris wrote:
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: A6302 current probe excessive offset

cmjones01
 

I've tried manually degaussing the probe with the wand I normally use
for tape head degaussing, and it doesn't seem to have had any
noticeable effect on the offset. One thing I do observe is that the
probe seems sensitive to vibration and the offset jumps around
slightly. I wonder if there's a wiring problem somewhere within the
potted part.

Chris

On Thu, Sep 19, 2019 at 9:09 AM cmjones01 <chris@...> wrote:

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: 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.