Date   

Re: Comments from Peter Keller on the 500 Series Scopes

Paul Amaranth
 

I have a 555 that followed me home just because it's an
iconic scope and I couldn't bear the thought of it going
for scrap or the tube harvesters.

I'll get to it one of these winters (at 1KW it's a little
much for working on in the summers).

I think nobody talks about them much since repair is pretty
straightforward; there's no esoteric technology that you
have to work around. All you need is some 2-3% silver solder
and you're good to go.

Paul

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


Re: Comments from Peter Keller on the 500 Series Scopes

Dave Wise
 

535, 545, 535A, 547. The 535 and 545 are daily runners; I should swap periodically.
B, C, CA, D, G, H, K, L, O, Z, 1A1, 1A2, 1A4, 1A5, 1A7, 1L5, 1S1, TU-7.

Dave Wise in Hillsboro Oregon
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Dennis Tillman W7pF via groups.io <dennis=ridesoft.com@groups.io>
Sent: Wednesday, December 23, 2020 11:47 AM
To: TekScopes@groups.io
Subject: [TekScopes] Comments from Peter Keller on the 500 Series Scopes

Since Sunday when I picked up 106 of Peter Keller's books we have spoken by
phone. During our conversation Peter mentioned a few things I thought I
should pass along since I thought he may have reached the wrong conclusion
from his brief time as a member of TekScopes.

Peter was disappointed that there didn't seem to be much interest in the 500
series of oscilloscopes. I thought it might be nice if Peter heard from how
many TekScopes members have 500 series scopes and what you like most about
your favorite model.

* Peter and I both agree that the pinnacle of the 500 series was the 547. I
was in love with the first one I got to use in 1967 shortly after it was
introduced. That was a fabulous scope!
* We both agree the 500 series was known worldwide for the incredibly tiny
CRT spot size.
* Peter felt the 500 series was the last scope anyone could fix since it
didn't use many specialized parts. I disagree about this because I have
spent years troubleshooting and repairing 7000 series plugins and
mainframes. Tektronix' fabulous documentation makes it just as easy to fix
these 7000 scopes as it does to fix the 500 series but that it just my
opinion.

From the volume of posts we receive it may appear that there is more
interest in the some of the portables but that is because they are so often
broken, replacement parts are impossible to find, they use a lot of surface
mount and custom parts, and Tek stopped providing Circuit Descriptions,
Parts Lists, and schematics to assist in calibrating and repairing them.

Dennis Tillman W7pF


Re: Comments from Peter Keller on the 500 Series Scopes

Timothy W. Koeth
 

Hi Dennis and All,

My Tek scope inventory at home exceeds 100 instruments. About half are of
the 500 series. Off the top of my head, I know the following are in my
collection.

three 310,
one 317,
two 502,
three RM503
one RM15
one 513,
one 514,
three 519,
two 535s,
one 536,
one 541,
one 545,
four 547s
one 549,
four 555,
three 556s
one RM564B,
one 575,
two 576,
one 577,
(and more...)
(and lots of 7000 series too)

Around 50% of these are operating and in cal.

It is funny that you mention the 547 specifically, it is certainly a superb
instrument. I have four that are my "winter projects," one has just been
overhauled and is now in fine working condition. The next one is on the
operating table as we speak... I've solved both time base A and B
unblanking issues (bad 2N2207s), and now troubleshooting an intensity
flickering issue that appears about 10 minutes after turn on... After that
one, two more to go. One was plucked of all its tubes, so it might be just
fine once repopulated.

A 547 testimonial: In March of 2018, Dr. Don Edwards, the husband of my
late PhD advisor (Dr. Helen Edwards) was in town and visited my house. He
also is an accelerator physicist, active at Cornell in the 1950s and 60's
before moving to the "National Accelerator Lab" (Fermilab) in Batavia IL in
1969. During his visit, I gave him a tour of my basement, and of all the
wonders it contains, Don (90 years old at the time) immediately gravitated
to the 547 sitting on a cart in the corner and exclaimed "You have a
547!?!?" To which I replied "No, I have three" Ahahahah, he was stunned,
and could not get over his 1960's mindset of that being the most coveted
oscilloscope. "You know, that is a very good oscilloscope," he chided. He
went on to tell me about how excited he was when his lab finally got one!
(For comparison, he was totally unimpressed by my collection of 7104s). I
knew that the 547s were good instruments, but that March day, they became
extra special to me.

Of course, I personally really like the 500 series scopes, I use them when
I can. For work (and for fun) I do a lot of single shot pulsed work (HV
and nuclear signals), so it is tough not to use a digital scope.
Nevertheless, if it is really something cool, that "deserves" to be
displayed on a CRT, I make the effort to capture the signal with a
photograph - this gives me perspective of the previous generations of
nuclear physicists and the tools they had to work with. For example, the
header photograph of this page of my basement measurement of the muon
lifetime starts of with the 555 P-11 phosphor image of the "capture and
death" signature of a muon:

http://www.nuclearphysicslab.com/npl/npl-home/experiments/muons/muon-lifetime-measurment/

An unreasonable amount of time was put into setting up the timing just to
display this on the 555 - but it was worth it!

I should post some photos of my "equipement pool."

73,
Tim


Dr. Timothy Koeth
Assistant Professor
Material Science & Engineering
Institute for Research in Electronics and Applied Physics
University of Maryland
301-405-4952 (office)
609-577-8790 (cell)

https://mse.umd.edu/clark/faculty/676/Timothy-W-Koeth

radiation.umd.edu

Amateur radio call sign K0ETH "K-zero-ETH" (formerly N2LPN)


On Wed, Dec 23, 2020 at 2:47 PM Dennis Tillman W7pF <dennis@ridesoft.com>
wrote:

Since Sunday when I picked up 106 of Peter Keller's books we have spoken by
phone. During our conversation Peter mentioned a few things I thought I
should pass along since I thought he may have reached the wrong conclusion
from his brief time as a member of TekScopes.

Peter was disappointed that there didn't seem to be much interest in the
500
series of oscilloscopes. I thought it might be nice if Peter heard from how
many TekScopes members have 500 series scopes and what you like most about
your favorite model.

* Peter and I both agree that the pinnacle of the 500 series was the 547. I
was in love with the first one I got to use in 1967 shortly after it was
introduced. That was a fabulous scope!
* We both agree the 500 series was known worldwide for the incredibly tiny
CRT spot size.
* Peter felt the 500 series was the last scope anyone could fix since it
didn't use many specialized parts. I disagree about this because I have
spent years troubleshooting and repairing 7000 series plugins and
mainframes. Tektronix' fabulous documentation makes it just as easy to fix
these 7000 scopes as it does to fix the 500 series but that it just my
opinion.

From the volume of posts we receive it may appear that there is more
interest in the some of the portables but that is because they are so often
broken, replacement parts are impossible to find, they use a lot of surface
mount and custom parts, and Tek stopped providing Circuit Descriptions,
Parts Lists, and schematics to assist in calibrating and repairing them.

Dennis Tillman W7pF






Re: Comments from Peter Keller on the 500 Series Scopes

Jokken Feldhaar
 

Hi all,

I own a small herd of 5xx scopes, starting with a 567, more than 30
years ago. To me, one of the most fascinating reads on this planet is
the patent bunch on the 54x and 58x series, the name John Kobbe stands
out to me. Reading his description of the vertical chain amplifier and
the termination was like reading a thriller by Grisham, likewise. I
admire the knowledge and superb engineering that has gone into these
scopes. If I have a question about these scopes, this group is my
resource for maintaining these fine instruments!

Cheers, Jochen DH6FAZ

Am 23.12.2020 um 20:47 schrieb Dennis Tillman W7pF:

Since Sunday when I picked up 106 of Peter Keller's books we have spoken by
phone. During our conversation Peter mentioned a few things I thought I
should pass along since I thought he may have reached the wrong conclusion
from his brief time as a member of TekScopes.

Peter was disappointed that there didn't seem to be much interest in the 500
series of oscilloscopes. I thought it might be nice if Peter heard from how
many TekScopes members have 500 series scopes and what you like most about
your favorite model.

* Peter and I both agree that the pinnacle of the 500 series was the 547. I
was in love with the first one I got to use in 1967 shortly after it was
introduced. That was a fabulous scope!
* We both agree the 500 series was known worldwide for the incredibly tiny
CRT spot size.
* Peter felt the 500 series was the last scope anyone could fix since it
didn't use many specialized parts. I disagree about this because I have
spent years troubleshooting and repairing 7000 series plugins and
mainframes. Tektronix' fabulous documentation makes it just as easy to fix
these 7000 scopes as it does to fix the 500 series but that it just my
opinion.

From the volume of posts we receive it may appear that there is more
interest in the some of the portables but that is because they are so often
broken, replacement parts are impossible to find, they use a lot of surface
mount and custom parts, and Tek stopped providing Circuit Descriptions,
Parts Lists, and schematics to assist in calibrating and repairing them.

Dennis Tillman W7pF




Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603

Attilio
 

Thanks a lot to everyone
Brian clarified my doubts, Miguel you are light years ahead of me, Chuck thanks for the support.
I took a look at Morris Engelson's book "Spectrum Analyzer Measurement - Theory and Pratice" and felt like a caveman, but how much do these engineers know?

Greetings
Attilio


Re: Backlash/Play in the Delta Time Position Control on a 2236

 

On Wed, Dec 23, 2020 at 09:19 PM, Ed Breya wrote:


I think the coarse/fine action is normal, and built into the pot.
My 2236 (S/N 200731) doesn't have such a pot.

Raymond


Re: Backlash/Play in the Delta Time Position Control on a 2236

Roger Evans
 

In the short wave radio receivers of my youth there was a common two speed tuning mechanism that used an epicyclic ball drive for maybe 6:1 reduction but there was also a peg and slot arrangement that forced the inner and outer to lock together after about 3/4 turn. The locked setting had a lot more friction.

I daresay there are other ingenious mechanisms for the same effect.

Roger


Re: Backlash/Play in the Delta Time Position Control on a 2236

Ed Breya
 

I think the coarse/fine action is normal, and built into the pot.This kind of action is usually provided by two pots ganged together, with a slip mechanism between, to disengage the coarse pot. The schematic may show them explicitly, or not, depending on how the pot is built and pinned out.

You can see if it seems to work and is beneficial by using it in a setup. Rotate it to overshoot the desired spot a little, then reverse direction, and it should be much easier to set.When you reach the other limit, the coarse pot will kick in again.

Ed


Re: Comments from Peter Keller on the 500 Series Scopes

Tom Lee
 

Well, as the proud owner of a 541, 545, 547, 585 and several other 500-series scopes, I can say that the relatively low volume of posts might be attributable to how relatively simple they are to repair. SOS's are transmitted fairly rarely, as the most common ailments (and their cures) seem to be well documented at tekwiki and other places.

My 547 has a special place of honor in my home lab. For years I'd been on the lookout for one here in the Valley, but I could not find any other than stripped hulks that weren't worth hauling home as parts queens. The rumor was that Jim Williams had picked up all the good ones. At one of the eFleas here, I teased him about the rumor. He was shocked that I did not have a 547. So right after the eFlea, he had me follow him to Linear and then to his famous bench. Hidden underneath a huge tangle of cables was a dusty but otherwise pristine 547. "If you can liberate it from that mess, it's yours." Quite a guy he was, and quite a scope it still is. The jug's electron optics are impressive. Every time I fire it up, I'm reminded of exquisite engineering, and of Jim's kindness.

--Tom


--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 12/23/2020 11:47, Dennis Tillman W7pF wrote:
Since Sunday when I picked up 106 of Peter Keller's books we have spoken by
phone. During our conversation Peter mentioned a few things I thought I
should pass along since I thought he may have reached the wrong conclusion
from his brief time as a member of TekScopes.

Peter was disappointed that there didn't seem to be much interest in the 500
series of oscilloscopes. I thought it might be nice if Peter heard from how
many TekScopes members have 500 series scopes and what you like most about
your favorite model.

* Peter and I both agree that the pinnacle of the 500 series was the 547. I
was in love with the first one I got to use in 1967 shortly after it was
introduced. That was a fabulous scope!
* We both agree the 500 series was known worldwide for the incredibly tiny
CRT spot size.
* Peter felt the 500 series was the last scope anyone could fix since it
didn't use many specialized parts. I disagree about this because I have
spent years troubleshooting and repairing 7000 series plugins and
mainframes. Tektronix' fabulous documentation makes it just as easy to fix
these 7000 scopes as it does to fix the 500 series but that it just my
opinion.

From the volume of posts we receive it may appear that there is more
interest in the some of the portables but that is because they are so often
broken, replacement parts are impossible to find, they use a lot of surface
mount and custom parts, and Tek stopped providing Circuit Descriptions,
Parts Lists, and schematics to assist in calibrating and repairing them.

Dennis Tillman W7pF




Re: Backlash/Play in the Delta Time Position Control on a 2236

 

On Wed, Dec 23, 2020 at 08:36 PM, Jeff Dutky wrote:


I've also noticed that the play in the shaft still results in some change of
the pot value, you get a small amount of adjustment over that 45 degrees of
motion before you it the higher "stiffness" rotation that results in a much
greater amount of adjustment. I've checked the operators manual and there is
no mention of the find-vs-coarse feature in the (very short) discussion of the
delta time position control. Is this how the delta time knob on the 2236 is
supposed to work?
Tek (and others) used pots with that behavior in some instruments, though usually over more than 45 degrees, I'd say about 90. I'm not sure if they did in some 2236's. Not in my 2236 at least. Looking at the pot's body, you may be able to distinguish to mechanisms in tandem.

Raymond


Comments from Peter Keller on the 500 Series Scopes

 

Since Sunday when I picked up 106 of Peter Keller's books we have spoken by
phone. During our conversation Peter mentioned a few things I thought I
should pass along since I thought he may have reached the wrong conclusion
from his brief time as a member of TekScopes.

Peter was disappointed that there didn't seem to be much interest in the 500
series of oscilloscopes. I thought it might be nice if Peter heard from how
many TekScopes members have 500 series scopes and what you like most about
your favorite model.

* Peter and I both agree that the pinnacle of the 500 series was the 547. I
was in love with the first one I got to use in 1967 shortly after it was
introduced. That was a fabulous scope!
* We both agree the 500 series was known worldwide for the incredibly tiny
CRT spot size.
* Peter felt the 500 series was the last scope anyone could fix since it
didn't use many specialized parts. I disagree about this because I have
spent years troubleshooting and repairing 7000 series plugins and
mainframes. Tektronix' fabulous documentation makes it just as easy to fix
these 7000 scopes as it does to fix the 500 series but that it just my
opinion.

From the volume of posts we receive it may appear that there is more
interest in the some of the portables but that is because they are so often
broken, replacement parts are impossible to find, they use a lot of surface
mount and custom parts, and Tek stopped providing Circuit Descriptions,
Parts Lists, and schematics to assist in calibrating and repairing them.

Dennis Tillman W7pF


Backlash/Play in the Delta Time Position Control on a 2236

 

I have an otherwise pristine 2236 that has a lot of play/backlash in the delta time knob. I had expected that the extension shaft was loose, but when I opened it up to have a look it turns out that the play is in the pot itself. So I ordered a replacement from QService, and it just arrived. The pot from QService is a perfect match for the one in my 2236, and appears to be NOS, never used (the pins show no sign of ever having known the touch of solder), but when I turn the shaft there is some play in it (about 45 degrees).

I've also noticed that the play in the shaft still results in some change of the pot value, you get a small amount of adjustment over that 45 degrees of motion before you it the higher "stiffness" rotation that results in a much greater amount of adjustment. I've checked the operators manual and there is no mention of the find-vs-coarse feature in the (very short) discussion of the delta time position control. Is this how the delta time knob on the 2236 is supposed to work?

-- Jeff Dutky


Re: Asking for Help with Verifying Genuineness of 2465B from Ebay

ka7hqp@...
 

ebay feedback in no way represents actual feedback as I have left feedback
for a seller that was misrepresenting a small fan that did not have an
oscillating feature yet the description mentioned that it did. I purchased
the fan and no refund was given and ebay removed my feedback and the same
item is still available with the same description. ebay at first denied the
act of removing the feedback saying that they could not, then admitted that
they did remove it.

So what good is feedback if you can't rely on it...

Once they make their decision, there is no one to elevate it to, so I had
to take the loss and purchase another fan with the feature I desired.

Dennis

On Tue, Dec 22, 2020 at 8:22 PM Tom Lee <tomlee@ee.stanford.edu> wrote:

Thanks for that—the second reference has exactly the error that I was
recalling. The implication that a single-pole system has a Gaussian
response is one of the rare mistakes Tek allowed in print.

Cheers
Tom

Sent from my iThing, so please forgive brevity and typos

On Dec 22, 2020, at 20:11, Mr. Eric <engr.eric@gmail.com> wrote:

Tom,

I loved the idea, I hadn't thought about leaving it calibrated although
that's what I would have done on my DSO or what I would have done even just
a year ago on an analog scope. Unfortunately I tried it and the result was
exactly the same, 1.09ns. So I realize that this BW approximation technique
is not the end all be all. But it is a very interesting experiment in and
of itself that allows me to learn a lot more. So in that aspect, I think
it's absolutely awesome. So I can't thank everyone enough for their help,
ideas, and knowledge!!!! I'm a Computer Engineer by trade and degree, which
means my skill lies somewhere between a bad EE and a bad Software
Developer. But these are all the little aspects that contribute to my
growth =)









Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603

Miguel Work
 

I use external mixer and CW generator, 1Ghz in this example, to go at higher frequencies.

For example, a DECT signal from cordless phone:

https://www.youtube.com/watch?v=8fp1UvMKQPI




-----Mensaje original-----
De: TekScopes@groups.io [mailto:TekScopes@groups.io] En nombre de Brian J. Henry
Enviado el: miércoles, 23 de diciembre de 2020 17:54
Para: a.alovisetti@alice.it; TekScopes@groups.io
Asunto: Re: [TekScopes] Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603

Hi Attilio,

The 7L13 is spec’d down to 1 kHz. It is able to go down this low because the first mixer is DC coupled to the RF input. The downside to this is that any DC at the RF input will destroy the first mixer. Unless you are specifically using it for very low frequencies, it is a good idea to place a DC block in series with the RF input in order to afford it some protection.

To protect the first mixer, Tektronix added a “limiter” to the RF input circuitry when they introduced the 7L14. The 7L14 is spec’d down to 10 kHz with the option of deleting the “limiter” and DC coupling the input to bring it down to 1 kHz.

The 2.5 GHz option for the 7L13 is designated “MOD 139U”. I don’t believe that it was ever listed as an option in a Tektronix catalog. It was offered as a option for the 7L14, however. Chuck pretty much calls it right as to how it was implemented and what the downsides are.

To take advantage of the 7L13’s narrow resolution bandwidth filter capabilities, you will want to install it into a storage oscilloscope as it is next to impossible to use the 30 Hz resolution bandwidth filter without one.

The 7L14 resolved this necessity with the introduction of digital storage. For all practical purposes, the 7L14 is identical to the 7L13 except for the inclusion of digital storage.

There is an early and a late version of the 7L13. They are differentiated by the introduction of an LED readout for the reference level.

I believe that the earliest 7L13’s (or prototypes) used the push/pull knob arrangement for selecting the fast/slow tuning that is described in the manual. I have never actually seen one. Every one that I have seen uses the innovative dual clutch system to engage and disengage the two tuning potentiometers.

When the frequency span is 100 kHz/division and greater it operates in the fast tune mode. At 50 kHz/division and below, it operates in the slow tune mode when the spectrum analyzer is phase locked.

The phase lock circuitry can be disabled with a front panel switch. When this is done, the analyzer reverts to the fast tune mode.

Each iteration of the 7L series spectrum analyzers brought with it new innovations that are well documented in the Tekscopes articles that accompanied their introductions that are quite informative. Tektronix managed to package a considerable amount of functionality into relatively small spaces for the time. It isn’t really fair to compare them with the huge HP spectrum analyzers that were their contemporaries.

I hope that you find some of this information to be of help.

Brian Henry







Scanned by McAfee and confirmed virus-free.
Find out more here: https://bit.ly/2zCJMrO


Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603

Brian J. Henry
 

Hi Attilio,

The 7L13 is spec’d down to 1 kHz. It is able to go down this low because the first mixer is DC coupled to the RF input. The downside to this is that any DC at the RF input will destroy the first mixer. Unless you are specifically using it for very low frequencies, it is a good idea to place a DC block in series with the RF input in order to afford it some protection.

To protect the first mixer, Tektronix added a “limiter” to the RF input circuitry when they introduced the 7L14. The 7L14 is spec’d down to 10 kHz with the option of deleting the “limiter” and DC coupling the input to bring it down to 1 kHz.

The 2.5 GHz option for the 7L13 is designated “MOD 139U”. I don’t believe that it was ever listed as an option in a Tektronix catalog. It was offered as a option for the 7L14, however. Chuck pretty much calls it right as to how it was implemented and what the downsides are.

To take advantage of the 7L13’s narrow resolution bandwidth filter capabilities, you will want to install it into a storage oscilloscope as it is next to impossible to use the 30 Hz resolution bandwidth filter without one.

The 7L14 resolved this necessity with the introduction of digital storage. For all practical purposes, the 7L14 is identical to the 7L13 except for the inclusion of digital storage.

There is an early and a late version of the 7L13. They are differentiated by the introduction of an LED readout for the reference level.

I believe that the earliest 7L13’s (or prototypes) used the push/pull knob arrangement for selecting the fast/slow tuning that is described in the manual. I have never actually seen one. Every one that I have seen uses the innovative dual clutch system to engage and disengage the two tuning potentiometers.

When the frequency span is 100 kHz/division and greater it operates in the fast tune mode. At 50 kHz/division and below, it operates in the slow tune mode when the spectrum analyzer is phase locked.

The phase lock circuitry can be disabled with a front panel switch. When this is done, the analyzer reverts to the fast tune mode.

Each iteration of the 7L series spectrum analyzers brought with it new innovations that are well documented in the Tekscopes articles that accompanied their introductions that are quite informative. Tektronix managed to package a considerable amount of functionality into relatively small spaces for the time. It isn’t really fair to compare them with the huge HP spectrum analyzers that were their contemporaries.

I hope that you find some of this information to be of help.

Brian Henry


Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603

Chuck Harris <cfharris@...>
 

You are of course right. My recollection of a fancy knob
on the 7L13 was the time/division knob, which is similar to
the time/division knobs on all of the other scopes of the
era.

I think the OP's 7L13 is typical of all 7L13's. If there is
a push/pull notation in the manual, it is probably wrong.

-Chuck Harris

Miguel Work wrote:

If you look inside the 7l13 there are two multiturn pots, fine and coarse, mechanically connected to the tuning knob. Each pot has a electromagnet clutch. The pot engaged depends of span resolution position, or pll on/off position. For a low span the fine pot is automatically engaged, but if you switch off pll, coarse pot is engaged, so tuning knob will move more frequency. For large span coarse pot is used.

7L12 and 491 has PLL too, but the PLL in 491 isn´t automatic



https://www.youtube.com/watch?v=832QaqG7OPI
https://www.youtube.com/watch?v=G3A-4Jrtv3s



Regards!




-----Mensaje original-----
De: TekScopes@groups.io [mailto:TekScopes@groups.io] En nombre de Attilio
Enviado el: lunes, 21 de diciembre de 2020 19:28
Para: TekScopes@groups.io
Asunto: [TekScopes] Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603

Dear Sirs,
I got hold of a 7L13 spectrum analyzer in a 7603 mainframe and I have two questions to ask you, first from the manual the tuning knob can be pushed or pulled to change the tuning speed, but on my 7L13 the tuning knob is fixed and there is only the word tuning, Do you know when this modification was made and why ?
Second question: Is it possible to extend the maximum frequency from 1.8 GHz to 2.5 GHz ?
If so, what are the changes to be made ?

Thanks a lot to everyone, a greeting
Attilio








Scanned by McAfee and confirmed virus-free.
Find out more here: https://bit.ly/2zCJMrO





Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603

Miguel Work
 

If you look inside the 7l13 there are two multiturn pots, fine and coarse, mechanically connected to the tuning knob. Each pot has a electromagnet clutch. The pot engaged depends of span resolution position, or pll on/off position. For a low span the fine pot is automatically engaged, but if you switch off pll, coarse pot is engaged, so tuning knob will move more frequency. For large span coarse pot is used.

7L12 and 491 has PLL too, but the PLL in 491 isn´t automatic



https://www.youtube.com/watch?v=832QaqG7OPI
https://www.youtube.com/watch?v=G3A-4Jrtv3s



Regards!




-----Mensaje original-----
De: TekScopes@groups.io [mailto:TekScopes@groups.io] En nombre de Attilio
Enviado el: lunes, 21 de diciembre de 2020 19:28
Para: TekScopes@groups.io
Asunto: [TekScopes] Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603

Dear Sirs,
I got hold of a 7L13 spectrum analyzer in a 7603 mainframe and I have two questions to ask you, first from the manual the tuning knob can be pushed or pulled to change the tuning speed, but on my 7L13 the tuning knob is fixed and there is only the word tuning, Do you know when this modification was made and why ?
Second question: Is it possible to extend the maximum frequency from 1.8 GHz to 2.5 GHz ?
If so, what are the changes to be made ?

Thanks a lot to everyone, a greeting
Attilio








Scanned by McAfee and confirmed virus-free.
Find out more here: https://bit.ly/2zCJMrO


Re: Asking for Help with Verifying Genuineness of 2465B from Ebay

Chuck Harris <cfharris@...>
 

Fundamentally, the problem with making such documents is the
people that might need them, don't know to look for them. It
doesn't fit the usual expected mode of behavior for a group.
(eg. Ask question, expect answer...)

I have written extensively about the 2465 family, but only those
that remember those writings bother to reference them. Those that
don't know, don't search.

The tekwiki is a better layout for such reference material.

-Chuck Harris

Brian Cockburn wrote:

Chuck et al,

Perhaps this list of what's what in various models (2445, 2445A, 2445B, 2465, 2465A, and 2465B) could be made into a document stored here in groups.io and in the tekwiki. It would have textual descriptions of the salient differences, a set of pictures of the parts that vary so that identifying what is in front of you on the bench becomes a 'look and match' experience. This issue of scopes sold as things they are not has been raised before and will no doubt be again. Maybe a google docs shared spreadsheet would be a suitable starting point?

Cheers, Brian.






Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603

Chuck Harris <cfharris@...>
 

Another way, possibly, is to scan through the catalogs
from about 1978 through 1981.

I looked in my 1981 catalog, and I find that I am misremembering
a lot of things about the 7L13 and 12.

-Chuck Harris

Attilio wrote:

You're right Chuck, I think it's great from 1 MHz and that at very high frequencies there is the problem of not being able to see the harmonics.
But I fell in love with the 7L13 and will use it in HF, VHF and UHF where I think it gives its best.

I took off the TUNING knob and noticed that it is heavy so it acts like a flywheel when tuning.
I think the only way to find out the truth is to ask someone who worked at Tektronix and knows the whole story of 7L13.

Thanks a lot Chuck.
Greetings
Attilio







Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603

Attilio
 

You're right Chuck, I think it's great from 1 MHz and that at very high frequencies there is the problem of not being able to see the harmonics.
But I fell in love with the 7L13 and will use it in HF, VHF and UHF where I think it gives its best.

I took off the TUNING knob and noticed that it is heavy so it acts like a flywheel when tuning.
I think the only way to find out the truth is to ask someone who worked at Tektronix and knows the whole story of 7L13.

Thanks a lot Chuck.
Greetings
Attilio

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