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Re: How to reach and remove 7633 SAVE INTEN/STORAGE LEVEL pot for cleaning?

unclebanjoman
 

Found the solution by myself.
Here are the steps:
1) Remove all the knobs from the front panel.
2) Unscrew all the bolts securing the pots.
3) Carefully pull out the front panel (take care do not drop the bushing surrounding each push button)
4) Unscrew two screws holding the three FAST/VAR PERSIST/BISTABLE pushbuttons. It's a little pcb, A17 storage mode switch board. Pull the harmonica connector that connect it to the storage board: connector P1400 (A17)<->P1404 (A14). Remove the assembly.
Now the R1472A/B pot can be carefully extracted from its recess for cleaning. Eventually pull out P1475 that connects the dual pot to the storage board for greater ease.

Max


Re: 2465B calibration temp?

 

On Sat, Dec 26, 2020 at 05:46 PM, victor.silva wrote:


I would warm it up with the cover off and a small muffin blowing at A1.
Hi Jon,
Warming up with case open would only apply to settings via trimcaps and R-trimmers. You may check if those are in cal by going to the applicable points in the adjustment routines. If they are in cal, don't change anything, put the case on and let it warm up. At that time, internal temp. should be close to normal operating temp, so do electronic adjustments under those real life conditions.

BTW, did you adjust power supply voltage(s)? If so, you've probably lost cal, also for image width and height (which is not the same as V/div and vertical (amplitude). Unless you really want to, there's no need to adjust PS voltage unless out of cal. and make a full recal. necessary.

Bonne journée,

Raymond


Re: 2465B calibration temp?

victor.silva
 

I would warm it up with the cover off and a small muffin blowing at A1.


Re: 2465B calibration temp?

victor.silva
 

Jon,

There are many more trimmers to adjust during a calibration.
You should pick up the service manual, you can find a useable free scan on the Tek site.
Chapter 5 lists the CAL steps 01 through 09.

There is a large drawing in the service manual that identifies the adjustable locations on the A1 assembly.
You are correct, the trimmers are on the LVPS, HVPS, A1 and A5.

--Victor


2465B calibration temp?

Jean-Paul
 

Bonjour a tous:

Have some 2465B that are out of VCAL only or HCAL perhaps a few percent. Been a while since did cals on these.

Do it with case closed after warmup 30 min to stabilize?

Are the only CALS internal on trims are PSU, HV, transient and DAC REF of A5 PCB?

MANY THANKS


Jon


Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603

Chuck Harris <cfharris@...>
 

A couple of things:

First, you don't have to get so worried about accidentally putting
DC on the mixer. It is safer, and better to be more conscious of
what you are doing when you make measurements with your SA. Sample
the measurement point with an oscilloscope, to determine the signal
composition, before connecting your SA. Always use the maximum
attenuation that allows you to get your measurement. Make prophylactic
use of probes and loops. Always discharge coaxial lines before you
attach them to the SA.

Second, DC blocks will *NOT* protect your SA against all such DC
abuses. When a discharged capacitor is connected to a high voltage
point, it will instantaneously behave as a dead short circuit. It
will transfer that high voltage point directly to your mixer, as if
it isn't there. Only as the capacitor begins to charge, will that
high voltage/current be removed from the mixer.

If you connect your DC block protected SA input to a 100V point inside
of a transmitter, it will toast your mixer very nicely, and quickly.

Train yourself to use your SA safely. Don't rely on crutches to protect
you from unsafe behavior.

-Chuck Harris

Attilio wrote:

Sorry if I ask some trivial questions, but I am worried by the writing on the RF input of the 7L13 regarding the absolute prohibition of applying a direct current voltage (0 Vdc). I am looking on the internet for a dc-blocking with BNC connectors to be applied on the RF input, but I cannot find the Tektronix part number 015-0221-00, I was thinking of using a small metallic box with BNC connectors and connecting a 1000 pF - 1 KV ceramic capacitor between the BNC connectors, what do you think?
I have seen other DC blockers use a 100nF capacitor but I doubt that when charging it will damage the 7L13's first mixer.
I should equip myself with some accessories, but I have no clear ideas, I should buy a power splitter or a combiner.
I would like to buy a TR502 tracking generator with its power supply in the future.

Greetings and Merry Xmas to all






Details on 015-0670-00 Feed-Through Adapter for AM503B?

Jared Cabot
 

Hi all.

I'm looking to build an 015-0670-00 Feed-Through Adapter for testing the AM503B Current Probe Amplifier TM500 plugin modules.
I'm hoping someone has one they can take a peek inside and take some pictures so I can replicate one for myself.
I have the Amphenol 165-9 connector, I just need to know how the pins are connected inside...


Thanks!
Jared


Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603

Miguel Work
 

Tte cheap opción if bandwith os importante os a BNC ti SMA adaptar and a SMA DC blocker


need case for 067-0508-00 Amplitude Calibrator

Rick
 

Hi all, I just picked up a 067-0508-00 Amplitude Calibrator and I believe it was rack mounted. It doesn't have the outer cabinet. I don't know much about the interchangeability of mounting and cabinet systems from the late sixties. I'd like to find a cabinet or possibly a cab for a pair. I have a Type 284 Pusle Gen that I've seen sitting paired with the Amp Cali unit in the same cabinet. Does anyone know what Tek was doing back them? Was there a storage system of sorts? I've heard of type 1,2,3 but don't know if my two units mentioned here are part of those systems. I plan to use both to bring my 5S14 to spec assuming it out of whack when it arrives.

Thanks
Rick


Re: Added album 7004 bezel #photo-notice

Bruce Atwood
 

Sorry, that's 7904 not 7004


Added album 7004 bezel #photo-notice

TekScopes@groups.io Notification <noreply@...>
 

Bruce Atwood added the album 7004 bezel: Is this an add-on? Can it be removed? photo in https://groups.io/g/TekScopes/album?id=258576


Added album 7004 bezel #photo-notice

TekScopes@groups.io Notification <noreply@...>
 

Bruce Atwood added the album 7004 bezel: Is this an add-on? Can it be removed?


Re: Comments from Peter Keller on the 500 Series Scopes

Glydeck
 

First, Peter’s book is one of my favorites, and is a resource I reach for regularly.

My first experience with the 500 series was in the college lab in the late 70s. There was always a scramble to get the one 547 that was available. My first restoration, with the help of this group, was a 535 documented here in 2008.

http://www.lydecker.org/Tektronix_535A.htm

The favorite scope at work for documenting audio issues was a 547. Screen shots from the 547 appear in multiple Warner Music Group documents and decks. As I have mentioned in other posts my 570 and 575 were used regularly to check tubes and transistors. Again, all restored to usefulness with the help of this group:

http://glydeck.blogspot.com/2012/01/testing-dual-triodes-with-tek-575.html
My next restorations that I’ll be sharing with this group will be a 561 and a 555.

Happy holidays to all,

George

On Dec 24, 2020, at 9:23 AM, Don Bitters via groups.io <donbitters=yahoo.com@groups.io> wrote:

That sir, is a serious addiction! Have you considered counseling? (Tongue in cheek!! ;) !!). I probably have 30+ pieces of ETE, but I am diversified - no more than 5 spectrum analyzers, and 3 O-scopes.Best wishes and a Merry Christmas to you and yours.Don Bitters





Re: Mechanism of CRT Double Peaking (UPDATED)

Nenad Filipovic
 

I kind of confirmed my initial belief, Tektronix document 062-0852-01 (Cathode Ray Tubes by Chuck DeVere) clearly states on page 9 that CRT cathode is indirectly heated oxide based type.

However, a Tektronix submitted dispenser cathode patent exists indeed:
https://patents.google.com/patent/US4954745
but it appears to date 1989-1990, therefore the CRTs we're discussing are older than that.

Nenad FIlipovic


Tek 500 series scopes

ken chalfant
 

Greetings,

I lost track of the thread but I am glad to share some of my experiences with 500 series scope. Perhaps I have owned more than necessary, but they are amazing scopes and have been wonderful additions to my lab over the past half century.

To the best of my memory I have owned the following: 532, 535, 545, 556, 575 curve tracer and most fortunately a 547 with a 1A2 plug-in.

They were all good scopes but for several reasons the 547 was hands down my favorite.

Back in 1971 or 72 I was a junior technician on my first full time job with a local company. The same month they hired me they also bought a brand new 547. It was absolutely amazing and so advanced over any other scope I had ever used. Of course, being rather new to electronics I had only used scopes made by EICO, Heathkit, RCA, Dumont and some army/navy surplus - but never anything like the 547.

The senior tech I worked for showed me a little about how to use it and he let me use for my work sometimes. Hands down it was the most amazing scope I had ever seen or used.

Well time moves on, I had gone to work for other companies and gained experience but along the way I stayed in touch with the friends I had made at my first work place. One day I learned that company was going out of business and fortune smiled upon me and I was able to buy that 547.

I used it well into the early 2000’s when I finally replaced it with 7000 series scopes as well as a TDS 620 or 640 (I’ve forgotten which).

But the 547 holds a special place in my memory because it and I were “new” at about the same time, I knew its history for more than 30 years and used it for much of that time. Additionally, it had one of the smallest spot sizes and sharpest traces of any scope I have used before or since and with its tunnel diode trigger circuit it would trigger on anything!

The 547 was, and remains, a true engineering masterpiece.

I was lucky to own one!

Regards,

Ken


How to reach and remove 7633 SAVE INTEN/STORAGE LEVEL pot for cleaning?

unclebanjoman
 

Hi all,
on my 7633 I have very noisy SAVE INTEN / STORAGE LEVEL pots.
Seem it is practically unreachable without having to disassemble many other parts. Anyone know the correct procedure on how to disassemble this damn pot from the front panel?
I searched the manual but there is no explanation on how to disassemble this part.
It looks like I should remove the storage board and all the associated cables. A tedious and complicated procedure. Urgh!
Any suggestion?

Regards and.. Merry Christmas!
Max


Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603

Attilio
 

Sorry if I ask some trivial questions, but I am worried by the writing on the RF input of the 7L13 regarding the absolute prohibition of applying a direct current voltage (0 Vdc). I am looking on the internet for a dc-blocking with BNC connectors to be applied on the RF input, but I cannot find the Tektronix part number 015-0221-00, I was thinking of using a small metallic box with BNC connectors and connecting a 1000 pF - 1 KV ceramic capacitor between the BNC connectors, what do you think?
I have seen other DC blockers use a 100nF capacitor but I doubt that when charging it will damage the 7L13's first mixer.
I should equip myself with some accessories, but I have no clear ideas, I should buy a power splitter or a combiner.
I would like to buy a TR502 tracking generator with its power supply in the future.

Greetings and Merry Xmas to all


Re: Thoughts About Modern Tek Scopes

 

On Fri, Dec 25, 2020 at 03:51 PM, amirb wrote:

Hi Amir,
Thanks for your response.



There's a risk of mixing up sampling rate (MSa/s) and capture rate (wfm/s)

here. There are several ways to make these more or less "independent".
I didnt say anything about sampling rate
I wasn't saying you did...

Raymond


Re: Mechanism of CRT Double Peaking (UPDATED)

Chuck Harris <cfharris@...>
 

The CRT cathodes are not thoriated tungsten, but
rather a dispenser cathode.

Think of a tiny thimble cup that has its outer
bottom dipped in a cathode emitter material, and
has a heater element inside.

-Chuck Harris

SCMenasian wrote:

This is a very complex subject and the correct explanation of what is going on depends critically on what type of cathode is involved. I do not know exactly what types of cathode Tektronix used. They probably used several in various generations of tubes. Two types, in addition to coated cathodes come to mind. Both can respond to higher than normal heater current.

The first is the dispenser cathode, familiar to many experimental atomic physicists. These cathodes (which are extended in nature and probably not suitable for CRTs) are consist of a pellet of sintered material in which the active electron emitting oxides are actually in the body of the cathode. The must be "activated" by raising the temperature high enough to diffuse the active material to the surface. If, for example, Tektronix developed a dispenser cathode in which, initially, the activated surface was only a tiny point and, in which, subsequent overheating would cause active material to diffuse, not only to that point, but to the entire anode facing surface, the behavior might be as described.

Another cathode material, often used in vacuum tube filaments, is thoriated tungsten. In this material, thorium is, initially, distributed through the body of the material and initial (and subsequent) heatings serve to diffuse the thorium to the surface, with, possibly, similar results.

Stephen Menasian






Re: Thoughts About Modern Tek Scopes

amirb
 

Agilent started (invented?) the idea of double buffering (I think it was
introduced in MegaZoom FPGA) so that they already capture the next waveform
while they are processing and displaying the previous one.
I remember having read about that Agilent development, which increased the no.
of wfm/s very significantly. First introduced in high-end 'scopes, later
trickled down to low-ends. I would be interested in a source for reading more
about it.
Not sure if it is available in low end scopes. It was a particular feature of their custom made MegaZoom FPGA and they had patented it I guess...



Thus the actual record length is half of what is "advertised" in the scope
datasheet
(Why) is that so? "Record length" isn't acquisition memory length, see below.
"Memory depth" as it's often called in specs, is display memory length, not
acquisition memory depth.

except for single shot capture where the whole memory is recorded for one
waveform
This would prohibit a single-shot acquisition where one would want to see
(part of) what happened before the trigger event so I don't think that's
correct.
yes it is. Read the Agilent manual for some of their scopes (I guess DSO6000A series would talk about this)


I am not sure other brand scopes use this idea, maybe they do but I have not
seen them saying that
one thing that makes me suspicious that perhaps Tek also uses this is that
in
several modern scopes that I have repaired from DPO4000 series
the amount of acquisition memory on board seems to be much larger than the
advertised "record length"
That would be interleaving, which is neither double buffering nor
dual-porting.
No, I meant each channel has a "LOT" more physical acq memory on board than the advertised record length (multiple times, I dont remember how many times more)
and DPO4000 do not do any interleaving. They have 4 separate set of ADC and memory chips for each channel.


Come to think of it, such interleaving *does* allow very high wfm/s, because
acquisition could be alternating between two or more fractions of total
acquisition memory, with reading from a momentarily inactive (not-acquiring)
part and filling display memory from that.
well, the Agilent scopes, use half the memory of that channel to do that (double buffering)
so the actual record length is half the advertised depth. They also do interleaving (unlike "most" (not all) Tek scopes DPO4000 or DPO3000)
for single shot capture however they use the whole memory because there is nothing coming after that


Using such a method, almost zero dead time is possible, with display memory
looking at alternating (non-active) parts of acquisition memory. I'm pretty
sure now (at least at the moment), that's how this works. Also, "alternating"
yes that's how it works, Agilent first introduced that in MegaZoom FPGA.
eplained a little bit briefly in DSO6000 manual IIRC


may be more than between two, in this case. BTW, the "memory depth" in specs
is not the depth of acquisition memory but of display memory.
It's been "good practice" to fill boards with (display) memory and enable the
fraction that the client paid for, as was done with firmware features, which
no this does not apply to what I have seen in DPO4000 at least. The physical acq memory was much much larger
than the 10M record length for each channel and the system memory (computer part) is a totally different thing on another part of the board
and there are no options to unlock any memory at all.
They must be using that amount of memory either for the same idea explained above
or for storing and accessing reference and math waveforms.... it is much more than twice the advertised 10M per channel.
let me see if I can find pictures and see how much memory per ADC they had in DPO4000....

usually were just unlocking keys to enable firmware already present. You
mentioned that the other day. I have been surprised about the memory because
of the cost of fast memory. LeCroy did it and I think so did Tek.


However, still it does not mean they do
this double buffering idea, they probably still work in the same traditional
straightforward capturing/displaying sequence and maybe using that
extra acq memory for other purposes for instance for storing reference
waveforms (2 or 4 of them are possible)
Reference waveforms usually are stored in non-volatile RAM, not in the much
faster, volatile acquisition RAM.
I think in DPO4000 they are sitting int the acquisition memory. Probably also in DPO3000...

or for math waveform (for sure)
in any event that dead time between the captures is miniscule in modern
scopes
and is much smaller than analog scopes
Is that so (esp. re. analog 'scopes), as a general fact in all circumstances?


not to mention the capture rate has increased significantly even in cheap
chinese scopes something like 100000 wfm/sec and more is available
and there are several tools for capturing rare events or very tiny glitches
that even with slower capture rate you will not really face any problem
There's a risk of mixing up sampling rate (MSa/s) and capture rate (wfm/s)
here. There are several ways to make these more or less "independent".
I didnt say anything about sampling rate




Raymond

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