Date   
Type 184 questions

bill K7WXW
 

I am refurbishing a type 184 time mark generator to go with the 109 and 191. The 0.5us marker has a little extra stub that I have to figure out but other than that the basic functions work and the 10HMz oscillator is well within specification and not drifting. But all is not well. There is 10MHz noise on the DC rails, about 200mV pp on 30VDC and 12VDC, 120mV pp on 125VDC. There is also noise on the trigger output that appears to be a combination of the 10MHz oscillator and the marker output, at least when the marker is set to 0.1us or faster. This noise varies between 60 and 100mV pp. I am pretty sure that's not how it is supposed to look.

Other than the usual tracking it back from the BNC, any good places to start looking for noise injection points? There's no obvious physical problems with the unit, though it was clearly not stored carefully and the switches were in need of a good cleaning. Other than trying to track the noise down, any hints where to start?

I bought this as a project, and I guess I got one. ;)

Re: Tek 576 noise and looping

Kevin Oconnor
 

Is the looping truly visible in every day transistor measurement?
Mine is a virgin. It has some looping under some conditions but others the sweep lines are fine. Knobs & switches are somewhat noisy but not worth putting unit into the ER.
There is a line of thought that says sometimes you should leave well enough alone. Are you there or is major surgery called for?

Kjo KO3Y

Re: 2465 Fan Collet Thingy

 

Shapeways will "print" brass as a lost wax casting.  Their process is to print the wax on a 3D printer, then use lost wax casting to produce the part.  They don't give specs on the precision of their process however and I have not tried it.

On Sunday, November 10, 2019, 08:23:18 AM CST, Chuck Harris <cfharris@...> wrote:

Hi Tom,

Ahh!  My fervent wish is to be able to 3D print brass, aluminum,
or steel... But alas, that won't be for a while.

What I see that says it is 3D printed brass, or aluminum, is in
actuality a slurry of brass flakes, or aluminum flakes, and some
organic (plastic) meltable binder.  The brass or aluminum comes
to the surface in a way that makes it appear to be brass or aluminum,
but the strength is all plastic.

I read an article of a M1911A2 being entirely printed in steel, but
I never heard how they did that, only that they would happily sell
you one of their printed guns for $30K.... To help fund research,
of course.

I suppose something like a mig welder controlled by a 3D mechanism
would do something... but it would be brutally inefficient.

-Chuck Harris

Tom Gardner wrote:
I've no doubt you are correct.

When I stated "parts could be manufactured in brass or aluminium", I was thinking of
3D printing them. It would have helped if I had been more precise.

Sorry for the confusion.



On 10/11/19 13:20, Chuck Harris wrote:
I had several collets made from the Tom Jobe, etal prints that
are in the file section of this group, and they were made from
a single piece of brass rod... threaded section and all.  They
worked perfectly.

Re: 7S14 7S11 SAMPLER bias QUESTION

 

On Mon, Nov 11, 2019 at 12:29 AM, Miguel Work wrote:


Yes, but I don´t find the answer. Why 7S14 can´t work as the S1?
Hi Miguel,

- The 7S11 wasn't made specifically for the relatively slow S1 but supports discrete samplers that are 14 times as fast.
- The 7S14's vertical input is much simpler and therefore of lower cost than a 7S11 plus sampler setup. See the documents referred to earlier.

As I said in msg #161516, I think the 7S14 can "get away with" the simpler (battery) solution because of the relatively low BW.

To describe my thoughts differently again: The 7S14's solution is cheaper than the 7S11 + Sx sampler solution, so it's less attractive for the 7S14 to be built as an integrated 7S11 + sampler. Rather the opposite from your thoughts that it would be desirable for the 7S14 to be designed like the 7S11 + sampler general solution.

Raymond

Re: 7S14 7S11 SAMPLER bias QUESTION

 

On Mon, Nov 11, 2019 at 12:02 AM, Raymond Domp Frank wrote:




:), and now the question, why one works with cells and the other no.
Again, did you read previous replies to your question?
Have a look at msgs #161506 and #161516
Specifically, msg #161516 contains a possible explanation. Also, for any particular functionality, several design solutions usually exist.
Please let us know what you think of my suggestion and if maybe you disagree.
In connection with that, msgs #161506 and #161510 may help.

Raymond

Re: 7S14 7S11 SAMPLER bias QUESTION

Miguel Work
 

Yes, but I don´t find the answer. Why 7S14 can´t work as the S1?

Re: 7S14 7S11 SAMPLER bias QUESTION

 

On Sun, Nov 10, 2019 at 11:57 PM, Miguel Work wrote:


:), and now the question, why one works with cells and the other no.
Again, did you read previous replies to your question?
Have a look at msgs #161506 and #161516

Raymond

Re: 7S14 7S11 SAMPLER bias QUESTION

Miguel Work
 

On Sun, Nov 10, 2019 at 02:47 PM, Raymond Domp Frank wrote:


Found that! The voltages on the sampler diodes in the S4 (e.g.) are derived
from it. Effectively about +/- 2.3 V to the sampler diode circuits.
:), and now the question, why one works with cells and the other no.

Re: TEK 2430A Changing settings

frank carcia
 

Bob,My 7904 could see a 1GHz sine wave so really miss it. I turned on the 2430A today to record the faults and it came up. I looked at a square wave signal that was very rounded off. I cycled the power and next time it came up with faults. I recorded all the faults so I can check the manual. I almost bought a TDS a while back.  I think I will check the battery and cycle all the boards and connectors. Maybe just dirty contacts somewhere. Frank WA1GFZ

On Sunday, November 10, 2019, 04:03:42 PM EST, Bob Self via Groups.Io <bobmiscmail=yahoo.com@groups.io> wrote:

Hi Frank,
Similar to your aquistion, my 2465B was a company scope that lost horiz drive so I paid a few bucks and took a chance on it. Fortunately I had a late friend who repaired HP & Tek products on the side, so with some parts from his junk pile I had a working scope. He also gifted me the 2430A which I don't use very much but it does come in handy once in a while. The 1990 date code Dallas NVRam modules lasted until now, not too bad for 10 yr guaranteed parts.
Bob


    On Sunday, November 10, 2019, 10:09:48 AM PST, frank carcia <carcia@...> wrote:

  Hi Bob,A couple years ago a VP at work signed a 2430A slated for the dumpster to me. It worked fine for a while and then started pulling faults.Reading these threats I learned about the battery and found a service manual on line. Then my beautiful 7904 died that appears to be a power supply issue. I'm debating unloading all of them and picking up a modern light weight scope. I have about 5 different 7000 series scopes and only one works. Not sure how much time I want to put into repairing these things. I have a couple NOS CRTs that I think go in a 7404 and maybe 7904. Frank WA1GFZ
    On Sunday, November 10, 2019, 10:52:02 AM EST, Bob Self via Groups.Io <bobmiscmail=yahoo.com@groups.io> wrote:

I have a 2430A that I just replaced the NVRAM modules on and all is well relative to that, but I'm wondering if anyone has any thoughts on another problem that it has had for several years.  The settings keep changing on the scope, the longer it has gone without use, the worse it is.  If it has been on for hours, the problem becomes very infrequent and is tolerable.  I worked on it months ago to no avail.  I checked all the power supplies and re-seated all the connectors and also the eproms.  I monitored the voltage on the bezel switches for a while and did not see any unexpected voltages.  I am open to any ideas on where to look.  I don't have another digital scope to catch occasional events, only a voltmeter and 2465 scope.

Thanks,
Bob WB6OFS

Re: 7S14 7S11 SAMPLER bias QUESTION

 

On Sun, Nov 10, 2019 at 11:26 PM, Raymond Domp Frank wrote:


And where do you see +/- 50V going to the sampler in the 7S11?
Found that! The voltages on the sampler diodes in the S4 (e.g.) are derived from it. Effectively about +/- 2.3 V to the sampler diode circuits.

Raymond

Re: 7S14 7S11 SAMPLER bias QUESTION

 

On Sun, Nov 10, 2019 at 07:15 PM, Miguel Work wrote:

Hi Miguel,


Can you explain the reason please?, thanks
Did you read and understand previous replies to your initial question? And where do you see +/- 50V going to the sampler in the 7S11?

Raymond

Re: anyone have 310 or 360 parts machine?

oliver johnson
 

I have the same scope that i will repair some time in the future,  can you send me a diagram of each interconnect cable , i have the ends but not sure is its a one to one connection. 
On Sun, Nov 10, 2019 at 11:00 AM, Dennis Tillman W7PF<@Dennis_Tillman_W7PF> wrote: Hi Phil,
I MAY have one. I am on the road until Friday so you will have to wait until then.

Next Saturday send me an email off list to dennis at ridesoft dot com to remind me and I will take a look.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Phil Cirocco
Sent: Saturday, November 09, 2019 9:40 PM
To: TekScopes@groups.io
Subject: [TekScopes] anyone have 310 or 360 parts machine?

I am looking for a graticule lens for my Tektronix 360 indicator module. This is the old scope module for the 160 series with the round CRT.The 310 scope used the same part. Tektronix part #331-0027-00. I will gladly pay for it and shipping. Any help would be appreciated.

Thanks

Phil Cirocco





--
Dennis Tillman W7PF
TekScopes Moderator

Re: 2465 Fan Collet Thingy

Vince Vielhaber
 

Here ya go Chuck. https://www.micromark.com/search?keywords=filament

The magnetic iron filament will actually rust! They have stainless, iron and copper.

Vince.

On 11/10/2019 09:22 AM, Chuck Harris wrote:
Hi Tom,

Ahh! My fervent wish is to be able to 3D print brass, aluminum,
or steel... But alas, that won't be for a while.

What I see that says it is 3D printed brass, or aluminum, is in
actuality a slurry of brass flakes, or aluminum flakes, and some
organic (plastic) meltable binder. The brass or aluminum comes
to the surface in a way that makes it appear to be brass or aluminum,
but the strength is all plastic.

I read an article of a M1911A2 being entirely printed in steel, but
I never heard how they did that, only that they would happily sell
you one of their printed guns for $30K.... To help fund research,
of course.

I suppose something like a mig welder controlled by a 3D mechanism
would do something... but it would be brutally inefficient.

-Chuck Harris

Tom Gardner wrote:
I've no doubt you are correct.

When I stated "parts could be manufactured in brass or aluminium", I was thinking of
3D printing them. It would have helped if I had been more precise.

Sorry for the confusion.



On 10/11/19 13:20, Chuck Harris wrote:
I had several collets made from the Tom Jobe, etal prints that
are in the file section of this group, and they were made from
a single piece of brass rod... threaded section and all. They
worked perfectly.

Tek 576 noise and looping

peter bunge
 

The performance check/calibration that starts on page 5-4 was perfect up to step 16. Check Horizontal and Vertical Displayed Noise on page 5-15. The noise is twice what it should be for the horizontal and four times for the vertical. I 'scoped the power supplies and there is no ripple. Any suggestions?
I then switched to step 3. Locating Malfunctioning Circuits on page 4-5. Step D revealed that the rectified sine wave is flattened at the top and distorted on the right. This may be a cause of looping but not the noise problem. Any suggestions?
I have a parts unit that I decided to repair so I could compare signals. I had to remove the Collector switch box to repair shaft couplings so got to find out where the collector bridge rectifiers are and how to set up the shafts of the switches. I was surprised to find that the floating 50 volt supply is only 5 volts checked on both units with a 'scope and DVM. There is no ripple. It is plainly marked 50 volts in several places. Any comments?
I am going through the calibration on the second 576 but it is not looking good either.
Too bad I cannot show the photos here but if anyone wants my notes to get involved please ask off line.
PeterB

Re: TEK 2430A Changing settings

Bob Self
 

Hi Frank,
Similar to your aquistion, my 2465B was a company scope that lost horiz drive so I paid a few bucks and took a chance on it. Fortunately I had a late friend who repaired HP & Tek products on the side, so with some parts from his junk pile I had a working scope. He also gifted me the 2430A which I don't use very much but it does come in handy once in a while. The 1990 date code Dallas NVRam modules lasted until now, not too bad for 10 yr guaranteed parts.
Bob

On Sunday, November 10, 2019, 10:09:48 AM PST, frank carcia <carcia@...> wrote:

Hi Bob,A couple years ago a VP at work signed a 2430A slated for the dumpster to me. It worked fine for a while and then started pulling faults.Reading these threats I learned about the battery and found a service manual on line. Then my beautiful 7904 died that appears to be a power supply issue. I'm debating unloading all of them and picking up a modern light weight scope. I have about 5 different 7000 series scopes and only one works. Not sure how much time I want to put into repairing these things. I have a couple NOS CRTs that I think go in a 7404 and maybe 7904. Frank WA1GFZ
    On Sunday, November 10, 2019, 10:52:02 AM EST, Bob Self via Groups.Io <bobmiscmail=yahoo.com@groups.io> wrote:

I have a 2430A that I just replaced the NVRAM modules on and all is well relative to that, but I'm wondering if anyone has any thoughts on another problem that it has had for several years.  The settings keep changing on the scope, the longer it has gone without use, the worse it is.  If it has been on for hours, the problem becomes very infrequent and is tolerable.  I worked on it months ago to no avail.  I checked all the power supplies and re-seated all the connectors and also the eproms.  I monitored the voltage on the bezel switches for a while and did not see any unexpected voltages.  I am open to any ideas on where to look.  I don't have another digital scope to catch occasional events, only a voltmeter and 2465 scope.

Thanks,
Bob WB6OFS

Re: 2445 CH 3 and CH 4 vertical setting - volts/ div where ?

Chuck Harris
 

A free pdf file can be found on the BAMA site. You can find it by using
your favorite search engine.

Do you have real probes on those inputs? 10x probes have a resistor that
will identify the attenuation factor to the scope, and the scope will change
its scale readings to be 10x.

There is one selection button for each channel. If pressing one button causes
both channels to change their attenuation, you have a CPU board problem.

-Chuck Harris

vaclav_sal via Groups.Io wrote:

Thanks,I sort-of figured that out by myself late at night.I was using calibrator as a source and that of course is of fixed level.Basically these channels could be used to read 5V logic signals.
But the selection buttons seems to work on botch channels , not on individual channel.That is OK.

Right now I have some kind of vertical magnifier selected since the display on the CRT actually read 1 or 5 volts.I need to find free PDF manual.
Thanks



On Saturday, November 9, 2019, 9:51:53 PM CST, TomC <tomc@...> wrote:

Re: TEK 2430A Changing settings

Harvey White
 

Both of those scopes are very worth saving.  The 7904 is my go-to 7000 series scope.  You may want to look to see which ones have similar power supplies to the 7904, and then do a swap,

I have a 2430A, which was my go-to digital scope until I got a TDS540A, which has the same bandwidth as the 7904.

You  may want to see if you can find a 7904 that can become a donor unit for parts, always recommended.

Harvey

On 11/10/2019 1:05 PM, frank carcia wrote:
Hi Bob,A couple years ago a VP at work signed a 2430A slated for the dumpster to me. It worked fine for a while and then started pulling faults.Reading these threats I learned about the battery and found a service manual on line. Then my beautiful 7904 died that appears to be a power supply issue. I'm debating unloading all of them and picking up a modern light weight scope. I have about 5 different 7000 series scopes and only one works. Not sure how much time I want to put into repairing these things. I have a couple NOS CRTs that I think go in a 7404 and maybe 7904. Frank WA1GFZ
On Sunday, November 10, 2019, 10:52:02 AM EST, Bob Self via Groups.Io <bobmiscmail=yahoo.com@groups.io> wrote:
I have a 2430A that I just replaced the NVRAM modules on and all is well relative to that, but I'm wondering if anyone has any thoughts on another problem that it has had for several years.  The settings keep changing on the scope, the longer it has gone without use, the worse it is.  If it has been on for hours, the problem becomes very infrequent and is tolerable.  I worked on it months ago to no avail.  I checked all the power supplies and re-seated all the connectors and also the eproms.  I monitored the voltage on the bezel switches for a while and did not see any unexpected voltages.  I am open to any ideas on where to look.  I don't have another digital scope to catch occasional events, only a voltmeter and 2465 scope.

Thanks,
Bob WB6OFS






Re: 2465 Fan Collet Thingy

Chuck Harris
 

Hi Siggi,

One thing to think of, if the collet is drawn vertically
by the printer, it is certain to break, but if you draw
it horizontally with long strokes, and in halves, it might
be strong enough.

Especially if it is ABS.

No matter what, I would expect that the threaded section
will have to be done manually with a tap and a short chunk
of threaded rod.

Most slicers will allow you to draw your own paths, if you
wish to go to the effort. Done once, it can be replicated
by anyone.

It wouldn't even be all that hard to build a custom printer
that had an X, Y and R axis. Like a 3d printer lathe.

-Chuck Harris

Siggi wrote:

On Sun, Nov 10, 2019 at 12:15 AM Chuck Harris <cfharris@...> wrote:

I am not sure that an all plastic printed solution will
work... tektronix didn't think so, and made a much more
expensive metal/plastic hybrid.
A home-printed plastic fused-filament collet almost certainly won't work,
those things will delaminate at the shade of a hint of a threat of any
stress in my experience. I'd be surprised if Shapeways and other commercial
services couldn't produce a usable part using SLS in nylon-like plastics
<https://www.shapeways.com/materials/versatile-plastic>.
I did machine a batch of these collets from delrin/acetal, and those will
work just fine - delrin will hold the thread just dandy. (I've been
shipping these out for postage, but I'm out of stock now - alas).
The reason Tektronix used an insert is IMHO not for strength, but because
you can't injection-mold threads, and a secondary machining step on this
collet would be awkward.
Injection molding around an insert is however no big deal, and you can
potentially use the same insert in many different injection-molded parts.
Machining the part from raw stock would also have been expensive in the
day, but the inserts would have dropped out of a screw machine by the
hundreds/minute.

Siggi



Re: So long...

widgethunter
 

Nothing is forever, and, I used to enjoy this group more in the past, myself.Though I am no fan of Facebook, I do enjoy our "Old Tekscopes" group, there.The visual interface is a nice alternative and less demanding to interact with, than composing novels in this text based environment.
Hope to see you there, Craig.Bernd Schroder

-----Original Message-----
From: Craig Sawyers <c.sawyers@...>
To: TekScopes <TekScopes@groups.io>
Sent: Tue, Nov 5, 2019 4:51 pm
Subject: [TekScopes] So long...

Hi all



I've been thinking about this for quite a while. But I think after 18 years on Tekscopes it is
finally time to sign off. In part it is because I think I have said all there is that I can possibly
say on Tekscopes, and in part because I just figured out that I have posted over 4,600 times - an
exceptionally depressing number, even more so when it represents 14% of all posts to Tekscopes ever.
That is one in every seven posts, heaven help us all, that I reckon to be over 800 hours of typing,
not counting the thinking time.



So to the many people who are on this list who have helped me to figure out problems in my stable of
Tektronix gear - my heartfelt thanks. There have been notable assistance above and beyond the call -
as an example, while describing a particular fault in my 7854, one of the list members disconnected
the sampling bridge in his own unit to mimic the fault! And yes, my vertical sampling bridge was
indeed toast. You have all been an inspiration, and I hope that some of you think of me as a friend.
I also hope that over the years I have been able to contribute something to others.



Anyhow - cheers all



Signing off



Craig Sawyers

Re: 3D printed metal

Chuck Harris
 

I am aware that the custom jewelry folks have been
using conventional 3d plastic printers with wax to
make lost wax investment casting patterns.

But...

Have you ever done metal casting? I have, and it
is a whole avocation in and of itself.

I have all the necessary furnaces, ovens, and other
supplies to do it... everything but the time and will.

99% of the time, I can do what I need using my 2-1/2D
router table.

But, I would still like to one day be able to 3d print
a brass widget... without having to sinter it, or investment
cast the part.

Not today, but someday, I am certain.

-Chuck Harris

Ed Breya via Groups.Io wrote:

You could possibly mix old and new technologies by 3D printing the desired part in a lost-wax type of deal. Put a clay mold around it, then melt or burn out the printed stuff, and cast it with metal. Depending on your foundry skills and materials, you can make all sorts of things. Steel and brass would be tricky due to high temperatures needed. Zinc and some of its alloys (pot metal) would be fairly easy.

Ed