Date   

Engine Analyzer Plug-In Modification

Gary Robert Bosworth
 

Does anyone know the specific modification that was done to the 2B67 horizontal sweep plug-in to make it work with the Engine Analyzer that Tektronix offered back in the 1960's and 1970's? Physically, does it show on the outside of the plug-in?


Re: DIY TD Pulser

Chuck Harris <cfharris@...>
 

I have two of them. One has a bad TD, the other works, but
is easily 10 times slower than the spec's say it should be.

I had heard that when tektronix made them they had no real
way of measuring the pulse risetime, so they guessed.

-Chuck Harris

David davidwhess@gmail.com [TekScopes] wrote:

Why can't you use the random sampling capability on the 7T11? Then at
least no delay line should be required. A power divider might still
be desirable to separate the sampling kickout from the trigger.

Tektronix had a slightly more complex tunnel diode pulse generator
which generated a pretrigger:

<http://w140.com/tekwiki/wiki/067-0513-00>

It would be interesting to see the inside to see how it was
constructed.

On Mon, 13 Nov 2017 23:53:05 +0000, you wrote:

Hey Joseph,

I built one of those, and the complexity/value is not in the circuit. It's
mostly in the characterization of the behavior of the physical construction
of the circuit. Mine has a rise time of ~200ps, as determined by my TDS
784D and some maths. Plenty good to calibrate the transient response of my
485 and 2467, though I do worry about the pre-shoot and overshoot I see on
the TDS.
I'll need to look closer one day, now that I have a 7834, 7S11/7T11 - just
need a decent power splitter and a delay line, and a few more little things
:).

Siggi

------------------------------------
Posted by: David <davidwhess@gmail.com>
------------------------------------


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

Yahoo Groups Links




317 in Lyons, Colorado

Kurt Rosenfeld
 


Re: A fool and his money ...OR ... moneywell spent

 

On 13 Nov 2017 18:11:41 +0000, you wrote:

The test is to coaxially connect the probe tip through a 50 ohm feedthrough termination (Tektronix made this as a special adapter) to
a fast reference level pulse generator like a PG506 (not quite fast enough) or tunnel diode pulser like the Tektronix 067-0681-01 which is what was actually recommended for the 2465 calibration. Then the transient response can be compared with and without the probe on the oscilloscope itself.
I got the Agilent probes and they seem to be performing well with the Tek 2465 CTS but I really can't check the upper part of the bandwidth. I looked at getting a Tektronix 067-0681-01 (Calibration fixture / tunnel diode pulser) and was quite shocked on the availability and cost - more than I paid for the scope, shipping, and three of the four probes. Guess I'll be on the lookout for one of these. Not going to pay $250 that some folks want for these.
The Tektronix 067-0681-01 in particular is pretty expensive but I
think that is because there is high demand from those who do not know
of alternatives.

The Tektronix 067-0513-00 and Type 284 tunnel diode pulse generators
could also be used with a GR874 adapter. Tektronix even made GR874
feedthrough termination to coaxial probe tip adapters which are
intended for exactly this application; the part numbers are
017-0088-00 for miniature probe tips and 017-0520-00 for subminiature
probe tips. They were intended for low-z and active probes much
faster than 300 MHz so would be overkill for your application.

There are some other hobby level fast edge pulse generators available
which could be used. Some are avalanche transistor based and others
use the output signal from a CML or ECL gate.

<https://www.eevblog.com/forum/projects/yet-another-fast-edge-pulse-generator/>
<http://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=124&products_id=295>


Tektronix 485s for sale

Dave Daniel
 

All,

Due to mounting pressures to sell my property I need to unload a few test equipment items.

I have two Tektronix 485s that I think I need to sell. I have powered them up and performed very basic testing. I have limited time and don't plan to do any exhaustive testing on either of them. They are not in calibration.

Below are descriptions:

1. Tektronix 485. It has serial number B192687. It has Option 78 - P11 phosphor. It is in good cosmetic shape. Channel 1 is rock-solid while channel 2 is a bit jittery; I suspect the front panel controls need cleaning. It has the rare front panel snap-on plastic cover. $300.

2. Tektronix 485. It has serial number B155872. Some of the button legends are worn off; I placed white label-printer labels with the legends on most of the buttons where the legends were missing. The mode buttons on this 'scope are in serious need of electrical cleaning. They operate stiffly and do not fully switch between modes (for instance, when the mode is set to CH1 or CH2, there is a second trace on the screen, as if the mode is really "sort of" ALT or "sort of" CHOP; putting additional pressure on the CH1/CH2 mode button eliminates the second trace). It also has the rare front panel snap-on plastic cover. I think I might have a few button caps that could be used to replace the ones on this 'scope where the legends are worn off; I will need to check. If so, I will include whatever I have with the 'scope. If not, Walter at Sphere or Qservice (or someplace else) may have them. $250.

I would like to sell these for the prices listed above plus the cost of shipping (and maybe for packaging materials if I have to buy them), more or less. The prices are negotiable; we'll see what responses I get. I will endeavor to pack them well so that they are not damaged in transit (I've shipped several largish Tektronix products around the globe and have not had any complaints, and received one compliment). I would use either USPS or UPS (not FedEx) at the buyer's discretion. Local pickup in the Lyons, Colorado (front range) area would be preferable. Payment would be by PayPal or cleared personal check.

I have one original manual which I would include for $10 with one of the 485s. I believe I have a printed copy of a PDF of the manual and, if I can find it, I would include that with the other 485. If not, then the other 485 would come without a manual.

If you are interested PLEASE CONTACT ME PRIVATELY using "kc0wjn at gmail dot com". Please do not reply to the list (I will ignore any such replies).

I am not at all pleased about having to sell these, as I had a 485 as one of my two "personal" 'scopes for many years at StorageTek many years ago and these 'scopes are old friends. But I think this is probably the right thing to do.

I also have a partially-working HP 8558B/853A spec an combo that I also need to sell, if anyone is interested in that.

Thanks for the bandwidth.

DaveD


Re: New member and owner of a dead 2225

n4mf_sc
 

I have the 1982 version I think and one from a website that is no longer there called Tek-cross-ref-free. It has a sig in the pdf of www.aa4df.com http://www.aa4df.com which is available for someone to purchase but no longer online. I can't post either because they are way past the limit on upload sizes. Transistors and IC's are in both..

Mitch
N4MF


Re: New member and owner of a dead 2225

Tom Jobe <tomjobe@...>
 

Hi Phillip.
I see you are getting some very good help on this problem, and when you
combine that with the fact that your voltages are only down by half, I'd
say the 2225 is only lightly wounded and that you will have it working
perfectly very soon. In order for the low voltages to be half there,
most of the power supply must be fundamentally sound.
The 2225 needs all of the aluminum electrolytic capacitors 10 uF and
larger changed anyway to regain that sharp trace you once had, and the
new ones might possibly help with your current problem as well. Get
brand new high quality 105 degree caps from a major electronics parts
supplier if you can.
There are several variations of the architecture of the small 22xx power
supplies but there are not many problems with the 2225 type of power
supply that ever show up on the Tekscopes Group .
When I read your original post about your 2225 problem, I looked on
YouTube to see what kinds of videos were available about the 2225.
Take a look at these two when you have time. This 2225 Dave Jones bought
worked just as it was received, and he gives you quite a nice lesson on
its use and claibration, as well as a tour of much of it's inner
workings (less the power supply unfortunately). He also gives you some
good common sense tips about working around the high voltages present in
the oscilloscope.

EEVBlog #196 operational review of the 2225
https://www.youtube.com/watch?v=8GR_6QH3uZk

EEVBlog #208 teardown and calibration of the 2225
https://www.youtube.com/watch?v=mHODWDBcQDg

Best of luck!
tom jobe...




On 11/12/2017 3:29 PM, phillip.lyne.barrett@gmail.com [TekScopes] wrote:

Long term electronics hobbyist. I've had a Tek 2225 for about 15 years
and used it a lot. The other day I turned it on to test a circuit I'm
prototyping and nothing. Dead. Check outlet, fuse, power cord. Nope.
The only sign of life is a little blip on the power and leds - maybe
half a second. I'm guessing it's the power supply. This scope has been
an old friend.


I got the service manual and pulled the chassis out of the case. Found
a loose torx screw inside though It didn't appear to be shorting
anything and after removing it the symptoms persist. The scope had
been sitting on the bench in the same spot for a couple of years so I
doubt the screw was the problem. Inspection didn't show anything
obvious - burnt components, bulging caps, blue smoke. In fact, it was
surprisingly clean for 30 year old scope.


Anyway, I took some test point measurements on the bottom of the main
baord and all the voltage levels were around half what they were
supposed to be. More confident it's the PS. Looked at the mains input
board. rectifiers (CR901-CR904) are ok. Pulled the board and pulled
the big @ss 2200 uF cap (C900). It tested out ok (2270 uF).


Next step is to look at the preregulator section after I put the mains
input board back.


I'm just following a fairly logical path here but thought there might
be smarter people than me here that could help short cut the process.
Any suggestions of where to look would be greatly appreciated.


Phil

[Non-text portions of this message have been removed]



[Non-text portions of this message have been removed]


Re: DIY TD Pulser

 

Why can't you use the random sampling capability on the 7T11? Then at
least no delay line should be required. A power divider might still
be desirable to separate the sampling kickout from the trigger.

Tektronix had a slightly more complex tunnel diode pulse generator
which generated a pretrigger:

<http://w140.com/tekwiki/wiki/067-0513-00>

It would be interesting to see the inside to see how it was
constructed.

On Mon, 13 Nov 2017 23:53:05 +0000, you wrote:

Hey Joseph,

I built one of those, and the complexity/value is not in the circuit. It's
mostly in the characterization of the behavior of the physical construction
of the circuit. Mine has a rise time of ~200ps, as determined by my TDS
784D and some maths. Plenty good to calibrate the transient response of my
485 and 2467, though I do worry about the pre-shoot and overshoot I see on
the TDS.
I'll need to look closer one day, now that I have a 7834, 7S11/7T11 - just
need a decent power splitter and a delay line, and a few more little things
:).

Siggi


Re: New member and owner of a dead 2225

 

I think U940 would have been overvoltaged. Max is 41 volts. It would have seen 67 - 15 or 52 volts. But those are very cheap and available. C972, 470/50v could have survived a 17 volt overvoltage. But they are cheap and available. I agree Q912 is probably ok as long as the stressor didn't get it before 913 shorted.

Hell, I would sure try to bring it back to life.

Tom

----- Original Message -----
From: David davidwhess@gmail.com [TekScopes]
To: TekScopes@yahoogroups.com
Sent: Monday, November 13, 2017 6:12 PM
Subject: Re: [TekScopes] New member and owner of a dead 2225



A shorted Q913 should have protected driver Q912. Q911 should have
protected TL594 U910.

The linear series regulator would have tried to control the output
voltages until Q923 overheated and likely failed shorted. Switching
regulator controller U940, another TL594, operates open loop to drive
the inverter but uses one of its error amplifiers to detect the supply
voltage to the inverter and if it rises above 42.5 volts, it shuts
down so the rest of the oscilloscope circuits should be protected.

I am not sure about how the +40 volt supply rising to +67.5 volts is
going to affect the sweep circuit on schematic 5 and the vertical CRT
amplifier on schematic 5. Normally both circuits should be able to
protect themselves until they overheat but when the low voltage
outputs shut off, they may not be able to. I am inclined to believe
Tektronix took this into account but the theory section says nothing
about Q913 failing as a short.

On Mon, 13 Nov 2017 01:01:56 -0500, you wrote:

>That's not good. The Q913 is a TIP30C and is available pretty cheap. The analog pass xistor Q923 is also on ebay. You should also check the driver to Q913, Q912. Probably pull Q913 to double check it and follow up with some other measurements.
>
>The switching regulator is a TL594. They are common. Two are used. probably both are now toast.
>
>You will need to check everything that is supplied the pre-regulated voltage (38 volts) as it would have exceeded many ratings. Besides the power supply schematic #7, check schematics 2 and 5 as this overvoltage goes to those sections.
>
>Good luck,
>Tom M


Re: DIY TD Pulser

Siggi
 

Hey Joseph,

I built one of those, and the complexity/value is not in the circuit. It's
mostly in the characterization of the behavior of the physical construction
of the circuit. Mine has a rise time of ~200ps, as determined by my TDS
784D and some maths. Plenty good to calibrate the transient response of my
485 and 2467, though I do worry about the pre-shoot and overshoot I see on
the TDS.
I'll need to look closer one day, now that I have a 7834, 7S11/7T11 - just
need a decent power splitter and a delay line, and a few more little things
:).

Siggi

On Mon, 13 Nov 2017 at 18:14 joseph@danyabutter.com [TekScopes] <
TekScopes@yahoogroups.com> wrote:



Sergey - thanks for the information. I looked at the schematic from the
data sheet and you are correct, this is not a very complex circuit. Not
sure why folks want over $200 for it. Guess they are hard to come by - law
of supply and demand.


Re: New member and owner of a dead 2225

 

If I had to order any parts, then I would include replacement aluminum
electrolytic capacitors.

On 13 Nov 2017 18:34:01 +0000, you wrote:

I'm wondering if I should just replace all the electrolytics and be done with it.


Re: New member and owner of a dead 2225

 

Absolutely there is; it is called the Tektronix Semiconductors Common
Parts Design Catalog and a search for that will turn up scans.

On 13 Nov 2017 19:20:14 +0000, you wrote:

One other question, is there an authoritative cross reference between the tektronix PN and the actual part number? I see a goodgle search on the tektronix part number typically gives at least one hit that shows it. A lot of places just show the Tek PN and list an amazing high price (one I saw was $8 for $0.50 part). I'll buy from Mouser, if I can.


Re: 7854 sticky keyboard buttons repair

Siggi
 

On Mon, 13 Nov 2017 at 15:14 Nenad Filipovic ilmuerte@gmail.com [TekScopes]
<TekScopes@yahoogroups.com> wrote:



Hi Everyone,

Sorry to hear you're having trouble looking at the photos. I tried to open
my own link both at home and from work (using Firefox), and images loaded
fairly quickly.
I had no luck loading images from Yahoo's albums all weekend, works fine
now. Guess something derailed over the weekend, and only got fixed bright'n
early Monday morn'.


Re: A fool and his money ...OR ... moneywell spent

Joseph Butter
 

Thanks Jeff
BTW - I think I inadvertently responded to that earlier thread.
Great information.


Re: DIY TD Pulser

Joseph Butter
 

Sergey - thanks for the information. I looked at the schematic from the data sheet and you are correct, this is not a very complex circuit. Not sure why folks want over $200 for it. Guess they are hard to come by - law of supply and demand.


Re: New member and owner of a dead 2225

 

A shorted Q913 should have protected driver Q912. Q911 should have
protected TL594 U910.

The linear series regulator would have tried to control the output
voltages until Q923 overheated and likely failed shorted. Switching
regulator controller U940, another TL594, operates open loop to drive
the inverter but uses one of its error amplifiers to detect the supply
voltage to the inverter and if it rises above 42.5 volts, it shuts
down so the rest of the oscilloscope circuits should be protected.

I am not sure about how the +40 volt supply rising to +67.5 volts is
going to affect the sweep circuit on schematic 5 and the vertical CRT
amplifier on schematic 5. Normally both circuits should be able to
protect themselves until they overheat but when the low voltage
outputs shut off, they may not be able to. I am inclined to believe
Tektronix took this into account but the theory section says nothing
about Q913 failing as a short.

On Mon, 13 Nov 2017 01:01:56 -0500, you wrote:

That's not good. The Q913 is a TIP30C and is available pretty cheap. The analog pass xistor Q923 is also on ebay. You should also check the driver to Q913, Q912. Probably pull Q913 to double check it and follow up with some other measurements.

The switching regulator is a TL594. They are common. Two are used. probably both are now toast.

You will need to check everything that is supplied the pre-regulated voltage (38 volts) as it would have exceeded many ratings. Besides the power supply schematic #7, check schematics 2 and 5 as this overvoltage goes to those sections.

Good luck,
Tom M


Re: Ebay seller playing shenanigans on scope auction

Ovidiu Popa [Business]
 

The funniest GSP happening with P-B was when they slapped one of those colorful eBay round stickers right on the nicely printed address. It took one month until a genius from the local postal service (so after arriving in Canada) had the brilliant idea to lift the %$^%&^ sticker and retrieve the stinkin' house number and postal code for delivery.


Re: 7854 adding more memory.

Dave Daniel
 

IIRC, option 2D added an extra 4 kB to the 'scope.

Look in the archives for the thread entitled "7854 RAM card upgrade only
- any interest?" Starting March 4, 2016. There are over a hundred posts
in that thread on the subject of upgrading the memory in a 7854.

DaveD

On 11/13/2017 1:08 PM, 'Max Vaughan' maxvon@bendcable.com [TekScopes] wrote:

I believe this was discussed before, but I am finding thousands of
hits to wade through.

Some do not seem to be really relevant to the email subject.

Looking to add more memory to my 7854.

Older model, says version 04 on the service tag on the back.

I believe it only has the basic options.

Thanks in advance…

Max

KF7MAX

[Non-text portions of this message have been removed]


Re: 7854 sticky keyboard buttons repair

Nenad Filipovic
 

Hi Everyone,

Sorry to hear you're having trouble looking at the photos. I tried to open
my own link both at home and from work (using Firefox), and images loaded
fairly quickly. However, back when I was uploading them the process
struggled a lot, each image uploaded only after a dozen failed (reason?)
attempts (the loading "script" automatically retries the failed upload of
selected files). I reduced all images to 1600x1200 resolution (file size
being approx. 500kB), I'd say this is pretty modest for today's standards,
even blurry cell phone images are many times larger. Don't know if there is
a guideline for photo upload (size/resolution) here on the group? I still
think there must be something wrong with Yahoo's servers.

Best regards,
Nenad FIlipovic


On Mon, Nov 13, 2017 at 8:56 PM, Dave Daniel kc0wjn@gmail.com [TekScopes] <
TekScopes@yahoogroups.com> wrote:



This morning, I took a look at the cited URL and the only one the photos
would load, even after a half-hour or so.

A few minutes ago, I looked again and all the photos loaded immediately.
I suspect that the photos are high-resolution photos with large file
sizes and that my internet connection was behaving badly this morning as
it sometimes does.

DaveD


On 11/13/2017 12:39 PM, Daniel Koller kaboomdk@yahoo.com [TekScopes]
wrote:

I'm not getting the "minutes later" part. Maybe hours later, but I
can't wait that long. Exceedingly slow for me. I get blank frames
in all the photo albums. Could it be some mystery setting in my browser?
...ok, FINALLY. As I was writing up this message, I went back to
double check, and I can view the photos. Something is deathly wrong
with Yahoo's servers. Maybe they are trying to emulate the dial-up
days? wow, how I don't miss those days.
Dan
On Monday, November 13, 2017, 10:37:23 AM EST, bobh bobh@joba.com
[TekScopes] <TekScopes@yahoogroups.com> wrote:


I logged in to Yahoo, went to the TekScopes group area and to
photos/albums – the frames and filenames were there but no pictures. I
looked at some files and then came back to the photos and they
(finally) appeared minutes later. Very slow.
Bob.

Sent from Mail for Windows 10

From: Daniel Koller kaboomdk@yahoo.com [TekScopes]
Sent: Monday, November 13, 2017 6:48 AM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] 7854 sticky keyboard buttons repair


Is anyone else having trouble viewing these photos?
Dan


Re: 7854 adding more memory.

Dave Casey
 

If you can source the correct chips (old stock from eBay), you can add them
to the empty spots on the existing RAM card to get the extra space. I may
have a couple of chips, but not enough for a full upgrade (bought ten,
needed eight, or something like that).

Dave Casey

On Mon, Nov 13, 2017 at 2:08 PM, 'Max Vaughan' maxvon@bendcable.com
[TekScopes] <TekScopes@yahoogroups.com> wrote:



I believe this was discussed before, but I am finding thousands of hits to
wade through.

Some do not seem to be really relevant to the email subject.

Looking to add more memory to my 7854.

Older model, says version 04 on the service tag on the back.

I believe it only has the basic options.

Thanks in advance…

Max

KF7MAX





[Non-text portions of this message have been removed]

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