Peter, I did not work for Bell Labs directly But was a
design engineer with Western Electric and on loan to
the labs, both were owned by AT&T. That did not
matter though because we had workers from other
division of AT&T that came up for a day and they could
get parts like a Lab employee.
As you said about the man you knew, the electronic switching
phone system was developed by a man that had a hobby of
model trains and developed it to switch his large train system.
As you said you would get arrested today for that. But that
is why they were so good, you could get the OK to work on
new Idea (not just communications) if you could show
management you could do it.
Derward
----- Original Message -----

*From:* Peter Gottlieb <mailto:hpnpilot@verizon.net>
*To:* TekScopes@yahoogroups.com <mailto:TekScopes@yahoogroups.com>
*Sent:* Friday, May 17, 2013 6:45 PM
*Subject:* Re: [TekScopes] Re: Rant: Analog vs Digital

As a kid I knew someone who worked there. He had gotten several patents for
them from projects he created from parts he brought home. These days most
companies would instead fire you and have you arrested for theft. Those
stolen
parts don't help them this quarter, you know.

On 5/17/2013 2:54 PM, Derward Myrick wrote:
>
> 
>
> Brad, back in the 1960s I know that at Bell Labs all I had to do for
parts to
> build anything
> was go to the supply and get a cart and load it up. All you had to do was
> sign-out what you got so they
> could reorder it. That is why Bell Labs had so many patients. They did not
> restrain you on using parts
> at home. This is how a REAL progressive company worked.
> I was working on the Nike Zeus System.
> Derward Myrick KD5WWI
>
> ----- Original Message -----
> *From:* Brad Thompson <mailto:brad.thompson@valley.net
<mailto:brad.thompson%40valley.net>>

<snip>

--------------------------------------------------------------------------------

No virus found in this message.
Checked by AVG - www.avg.com <http://www.avg.com>
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Hello,

I read all the posts I could find on replacing or rebuilding the high voltage
transformer for the 576. So far I have found two options.

Chuck Harris

(I am not sure if he ever updated his winding machine to work for winding the 576
HV transformer).

Bill Schell, AA4AY 10102 Winder Trail Orlando, FL 32817 Phone (407) 282-4289

This contact is listed on Bill and Stan's Tektronix Resource site for rewinding
547 transformers. Can Bill Shell rewind 576 transformers?

Are there any other options out there (other than finding a replacement)?

The DS1250 looks a bit weird with the circle pattern on the top, but I don't think that's a problem (for now)

If you try to power up with with ribbon cable to the CRT assembly disconnected, does it power on then?

Have you checked for shorts on the power rails?

When you try to power on, does it briefly try then shut down?

After it's been off for awhile with the power cord disconnected, when you plug it in and toggle the rear switch to on, does it emit a little ticking sound once?

Jay

--- In TekScopes@yahoogroups.com, "alberto.vaudagna" <alberto.vaudagna@> wrote:

Yes I've arleady downloaded the manuale. Nothink change if I press the on board switch. Here there is a link the scope dissasambled.
Link: http://www.mediafire.com/?b3y1xxgguouod1d
There are any common failure in this psu or some test point into the cpu board?

--- In TekScopes@yahoogroups.com, "jayw_comark" <jayw_comark@> wrote:

Hello,

There is a component level service manual at http://www.ko4bb.com/
for a TDS520B. The power supply may be similar to yours if not the same. You could also try pressing the small button on the CPU board to see if it turns on in case your problem is with the front panel board.

Jay


--- In TekScopes@yahoogroups.com, "alberto.vaudagna" <alberto.vaudagna@> wrote:

Today I've got a TDS540 oscilloscope with options 13, 1M and I think 2F (I don't know exactly).
The problem is it doesn't turn on.
Despite I read a lot of comment regarding capacitor leaking in my unit none of the capicitora are leak. (A lot of fortune!!)
I think it is a psu problem.
When I plug in the power cord and turn on the instrument, nothing happens.
Near the psu I can hear tick-to sound.
Any one have a schematics for that power supply circuit?
The model is: 22904700 rev F.
Any body have some idea on what ca be wrong?
Thanks for the attention.
Best regards, Alberto Vaudagna.

Yes I've arleady downloaded the manuale. Nothink change if I press the on board switch. Here there is a link the scope dissasambled.
Link: http://www.mediafire.com/?b3y1xxgguouod1d
There are any common failure in this psu or some test point into the cpu board?

--- In TekScopes@yahoogroups.com, "jayw_comark" <jayw_comark@> wrote:

Hello,

There is a component level service manual at http://www.ko4bb.com/
for a TDS520B. The power supply may be similar to yours if not the same. You could also try pressing the small button on the CPU board to see if it turns on in case your problem is with the front panel board.

Jay


--- In TekScopes@yahoogroups.com, "alberto.vaudagna" <alberto.vaudagna@> wrote:

Today I've got a TDS540 oscilloscope with options 13, 1M and I think 2F (I don't know exactly).
The problem is it doesn't turn on.
Despite I read a lot of comment regarding capacitor leaking in my unit none of the capicitora are leak. (A lot of fortune!!)
I think it is a psu problem.
When I plug in the power cord and turn on the instrument, nothing happens.
Near the psu I can hear tick-to sound.
Any one have a schematics for that power supply circuit?
The model is: 22904700 rev F.
Any body have some idea on what ca be wrong?
Thanks for the attention.
Best regards, Alberto Vaudagna.

I was able to calibrate some parts of the DMM : DCV, ACV, HI OHMS, and LO Ohms. I don't have equipment to generate more than 15VAC so I'm stuck there. Does anybody from the group live in Arizona and has a Fluke 5101 or similar Calibrator? of course A leveled sine wave generator and a time mark generator would be great too :)

Still have to calibrate quite a few things on the scope side. The vertical is very good but the horizontal has some scales that are out of cal.

--- In TekScopes@yahoogroups.com, "lazystrings" <casinada@> wrote:

I repaired the broken trace and programed the new DS1225AD and now the scope works fine but is out of calibration. The vertical measurements are fine but the frequency measurements are off on some scales and always off when measured automatically or with the cursors.
The DMM is out of Cal as well.
--- In TekScopes@yahoogroups.com, "lazystrings" <casinada@> wrote:

Just a quick update:
C1034 Measured 4.74uF and the ESR was 1.1 ohms. I don't think the cap was bad but it was part of the recap.

I found that A9 trace pin 24 was severed right between the pad and the trace. I will repair it tonight.
I also found that there is a resistance of 38 Ohm between +5V and GND coming from the LVPS Connector J251 but the voltage is correct.
Thank you
Daniel




--- In TekScopes@yahoogroups.com, "vdonisa" <vdonisa@> wrote:

Hi Daniel,

Do you remember the ESR of C1034? I'm asking since I've seen several reports on this however by looking at several datasheets of capacitors of this type, I've seen ESRs of 2 to 8 Ohms mentioned, depending on manufacturer / series.

And a question for the group: I've seen R1010 open too, and I've seen it mentioned several times by other people. What exactly is the failure mechanism? Mine didn't have any (dis)coloration that would suggest sustained high temperatures (photo here: http://groups.yahoo.com/group/TekScopes/photos/album/1314606778/pic/708477577/view ). I believe it's happening through some fast mechanism - a transient high current that helps evaporate the metal film in a very short time. Anyone that has a good theory about what's going on there?

Thanks,
Valentin VE3VDO

--- In TekScopes@yahoogroups.com, "lazystrings" <casinada@> wrote:

I got a Tek 2465B DM to repair just for fun. The tantalum capacitor C1034 had high ESR and R1010 was open (15ohm)

Hello,

There is a component level service manual at http://www.ko4bb.com/
for a TDS520B. The power supply may be similar to yours if not the same. You could also try pressing the small button on the CPU board to see if it turns on in case your problem is with the front panel board.

Jay


--- In TekScopes@yahoogroups.com, "alberto.vaudagna" <alberto.vaudagna@> wrote:

Today I've got a TDS540 oscilloscope with options 13, 1M and I think 2F (I don't know exactly).
The problem is it doesn't turn on.
Despite I read a lot of comment regarding capacitor leaking in my unit none of the capicitora are leak. (A lot of fortune!!)
I think it is a psu problem.
When I plug in the power cord and turn on the instrument, nothing happens.
Near the psu I can hear tick-to sound.
Any one have a schematics for that power supply circuit?
The model is: 22904700 rev F.
Any body have some idea on what ca be wrong?
Thanks for the attention.
Best regards, Alberto Vaudagna.

Today I've got a TDS540 oscilloscope with options 13, 1M and I think 2F (I don't know exactly).
The problem is it doesn't turn on.
Despite I read a lot of comment regarding capacitor leaking in my unit none of the capicitora are leak. (A lot of fortune!!)
I think it is a psu problem.
When I plug in the power cord and turn on the instrument, nothing happens.
Near the psu I can hear tick-to sound.
Any one have a schematics for that power supply circuit?
The model is: 22904700 rev F.
Any body have some idea on what ca be wrong?
Thanks for the attention.
Best regards, Alberto Vaudagna.

 

Don: Ah, so they were just LC filters, and used the phase shift for delaying?

I wonder if such a 3M dropout compensator could be modified to be used with an analog scope? What do you think?

Cheers,
D.

On Sat, May 18, 2013 at 9:17 AM, Don Black <donald_black@...> wrote:

What I call lumped (artificial) delay lines are delays made of a number of discrete inductors in series with capacitors to ground (or the complimentary side) rather than a cable using its natural inductance and capacitance. In the case of the deflection plates, they are made of a number of short segments coupled with small coils and trimmer capacitors from each one (segment) to trim them). Of course you need a special vacuum screwdriver to adjust them through the glass without losing the vacuum (joke). Tektronix usually used a coiled coaxial delay line for the signal delay to allow viewing the leading edge of a signal. However artificial delays can also be used. We used to have a 3M dropout compensator for video recorders which had to delay one horizontal line of signal. I was switchable for the different standards, up to 100 µs for 405 lines and it had row upon row of coils making up the delay lines.
Others more familiar with Tektronix please jump in and add or correct me as you see fit please.

Don Black.

On 17-May-13 7:19 PM, cheater00 . wrote:

 

Regarding delayed deflection plates.

What is the basic operation of the lumped delay line circuits? Is it
just a long delay cable with a network which compensates the
impedance?

Regarding the digital vs analogue cancer that spread into this conversation:

On Fri, May 17, 2013 at 6:10 AM, Steve <ditter2@...> wrote:
> Modern real time scope run up to 65 GHz. No analog scope could get within an order of magnitude of that. And few applications simply look at a Y-T waveform. I use fast RT scopes every week for tasks such as decomposing jitter components in serial data streams running at 28 gigabits per second. I can easily measure these down to 300 femtoseconds, with an accurate resolution of 50 femtoseconds or so. Users buy digital scopes for their analysis capability, seldom as a replacement just to look at waveforms that an analog scope could do.
>
> I love old analog scopes for their place in history. They are fun to restore. It is not different then people who restore antique autos. May of these had design features that were decades ahead of their time. But no one claims that an antique auto has the utility or reliability of a modern car that gets you to work every day.
>
> The tasks that design engineers need to perform today simply can not be performed by an analog scope.


Because everyone is just like you and has exactly your job, right? Let
me tell you, in 100% of my use of an oscilloscope I don't need *any*
of the doohickeys you mentioned. And even if I took the technical
level of my work to the very frontier of what's being done today, I
still wouldn't need any of it. Who cares about 300 picosecond jitter
when designing analogue audio circuits? You've got to be out of your
mind to think everyone needs 65 GHz bandwidth (so why bring it up at
all). My area, audio circuit design, will forever be fine with a 200
MHz bandwidth analog scope, maybe with minimal digital or analogue
storage capabilities. There are loads, loads, loads other areas in
technology which don't need *anything* provided by digital scopes.
Electrical and electronic engineers of all kinds and types have needs
that are simply not provided for by a digital scope, while the digital
scope provides a lot of stuff they expressly do *not* need. The same
goes for hobbyists: very few end up needing high bandwidth; if an eval
board or kit is provided you don't need to care about clock lines
being bad. There's a huge amount of those people, and I dare say many
more than those who need 65 GHz scopes.

It seems like you think the moment NASA started building the space
shuttle everyone stopped building, using, and servicing bicycles. What
a load of junk. Look at your wrist watch or your mobile phone. Think
that needs a 65GHz scope to build?


Please let's not derail this topic further. If you or anyone else
wants to continue the DSO vs CRO conversation, open up your own thread
(which I likely won't take part in).

Kill it with fire.

From: d.seiter@comcast.net
Sent: May 18, 2013 3:35 AM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] Re: Rant: Analog vs Digital

The first "computer" I bought was a Commodore VIC-20, but by the time that came out, my friends and I had top of the line Commodore CBM systems, mostly 8032's, that we built from scrap out of the Commodore dumpster. Saturday morning was always an adventure!


-Dave

----- Original Message -----
From: "Michael A. Terrell" <mike.terrell@earthlink.net>
To: TekScopes@yahoogroups.com
Sent: Friday, May 17, 2013 8:39:57 PM
Subject: Re: [TekScopes] Re: Rant: Analog vs Digital






My favorite was the Commodore 64, SX64, 128 & 128D computers, and I did a lot of writing with a freeware program called Speedscript.

-----Original Message-----

From: "Kenneth G. Gordon" < kgordon2006@frontier.com >
Sent: May 17, 2013 12:33 PM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] Re: Rant: Analog vs Digital

I understand that the entire Space Shuttle runs on what amounts to a '286
and the complete system software amounts to 300,000 lines of code.

MS-Word requires 3 million lines of code.

One of my most useful computers was a TRS-80 Model 4P. It had 64 K of
RAM. I used a word-processor named AllWrite, which did everything
MS-Word and Wordperfect would do, and then some, with room left over in
RAM for large files. I never ran out of enough RAM.

The very first microcomputer I ever worked with was a Southwest Technical
Products job. 1 K of RAM for that thing cost $1500.00 at the time.

A bit later, Radio Shack brought out a HUGE 5 MB (!) Hard drive system
which cost $4995.99.

Gee....

Ken W7EKB

Michael A. Terrell

Mike,

Thank you for your tip. Having read the thread I just wanted one and I
didn't pay attention to the schematic details (it was around 03 AM here).
So I can modify the pulser input circuit and use it with the 555
oscillator or I can drive it with my Tek 50 Ohm calibrator fixture which
gives up to 2 V or my SD 100A pulse generator that outputs up to 10 volts.
Or build it HP style and make it a stand alone unit.

Regards,
Ignacio


On 17/05/2013 2:52, Mike wrote

The full datasheet was already linked on tekwiki.

The transistor is simply a current limiter to prevent blowing up the
TD. As far as I can tell it could have nothing to do with risetime.

I can't fathom why you would want to build an exact copy which
requires 100V drive (to trigger a half-volt device!), and then have to
build another thing to provide said 100V which is very inconvenient!

The originals (TU-5, 067-0681-01, etc) were originally designed to be
driven by the calibrator on a 5xx (vacuum tube) scope, which can put
out up to 100V. The current-limiting resistance was chosen so that you
would not blow your TD up by setting the calibrator knob wrong. The
PNP current limiter was probably further insurance against abuse by
other possible drive sources (like a PG505 or Type 106) once 5xx
scopes were not the only possible test subjects.

Mike

From: Steve <ditter2@yahoo.com>
Sent: May 17, 2013 11:03 PM
To: TekScopes@yahoogroups.com
Subject: [TekScopes] Re: Rant: Analog vs Digital

Interesting historical note on the Space Shuttle - the original version had so little compute power, it could not navigate a landing. Look at the old news clips of the landing and you always saw a military aircraft - usually a F15, as a chase plane close behind. It followed all the way to touchdown, but it did not land and instead flew off over the shuttle after is landed. I originally thought this was for security. It turns out that the limited compute power in the shuttle would not support simple instrument landing. Any computer expansion had to be "space qualified" a lengthy process. The chase plane had extra computer power on board which did not need to be "space qualified". It was fed telemetry data from shuttle sensors, performed the flight control computations, and radioed those back to the shuttle in front of it. Without the chase plane, the shuttle could only be landed with manual control, a very difficult and risky method if visibility or weather conditions are impaired.

Somewhere during the life of the shuttle, updated "space qualified" computers were installed which eliminated the need for the chase plane in landing.