Date   

Re: 11801 NVRAM

Sergey Kubushyn
 

On Mon, 16 Sep 2019, Chuck Harris wrote:

Sorry for jumping in but is it somehow possible to share those ROMs?

I do have 11801C sitting on a shelf with difficult access to it and I'm not
sure it has 1T option that would've been nice to have...

My 11801C, with OPTS 1T (Telecom std masks),

has, Exec: 4.05, Disp: 4.00, Timebase/Controller: 4.03, ACQ1: 9.02, ACQ2: 9.02

-Chuck Harris

Reginald Beardsley via Groups.Io wrote:
My scope is an 11801. That should be visible in the screen photo I posted. Based on the dates on parts it is 1989 production. It is enough different from the 11801C that it was obvious from the meager information in the service manual for the 11801C that I needed an actual an 11801 manual. Zenith was kind enough to furnish a scan of the 11801 service manual, which is now available online, but I bought a paper copy.

I currently am triggering off a square wave on one channel of the 33622A while displaying a ramp from the other channel. There is a periodic jitter in the time base, so even with an external trigger I cannot get a stable sweep. In 1024 point mode at 1 ps/div it appears that there are 4-5 subsweeps before it repeats. As a result the trace oscillates back and forth over a span of about 1.3 ps as it drifts across the screen. In 5120 point mode it seems to have just 2 subsweeps with ~1 ps dither between them.

When the OXO heater kicks on everything jumps out of sync for a while. It may well be that the mystery NVRAM calibration constants are intended to correct the time offset between the sweeps. IIRC my timebase ROMS have a 1991 or 1992 date, so it is possible that my scope had a FW update and could be corrected if I knew where and what values to write with a PROM programmer.

If someone has an 11801C or other newer model open I'd appreciate version and date information on the timebase board ROMS. But if anyone knows *anything* about this I'm very interested in investigating. I've got another 11801x in CA at my sister's house which I'm waiting for her to ship to me. I have had more fun with my 11801 than any other piece of test gear I've bought. Being able to see reflections from each side of a high grade SMA-F to N-F adapter is quite amazing.

Have Fun!
Reg



---
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Re: From 2014: Tektronix Announces Winner of Europe’s Oldest Working Oscilloscope Contest

Chuck Harris <cfharris@...>
 

I plea guilty to my brain spontaneously emitting gas about the "D"
being for Distributed. It was, of course, an indication of the delay
line, that allowed you to see the triggering signal.

The 513D, however, announced back in 1949 had a distributed vertical
amplifier containing a host of 6CB6's. That was at least two years
before the 517 showed up in the catalogs.

-Chuck Harris

Dave Wise wrote:

That D suffix indicates Delay line, not Distributed amplifier. (So you could view the edge that triggered the sweep.) Tek's first distributed-amp scope was Type 517.

Dave Wise


Re: 11801 NVRAM

Chuck Harris <cfharris@...>
 

My 11801C, with OPTS 1T (Telecom std masks),

has, Exec: 4.05, Disp: 4.00, Timebase/Controller: 4.03, ACQ1: 9.02, ACQ2: 9.02

-Chuck Harris

Reginald Beardsley via Groups.Io wrote:

My scope is an 11801. That should be visible in the screen photo I posted. Based on the dates on parts it is 1989 production. It is enough different from the 11801C that it was obvious from the meager information in the service manual for the 11801C that I needed an actual an 11801 manual. Zenith was kind enough to furnish a scan of the 11801 service manual, which is now available online, but I bought a paper copy.

I currently am triggering off a square wave on one channel of the 33622A while displaying a ramp from the other channel. There is a periodic jitter in the time base, so even with an external trigger I cannot get a stable sweep. In 1024 point mode at 1 ps/div it appears that there are 4-5 subsweeps before it repeats. As a result the trace oscillates back and forth over a span of about 1.3 ps as it drifts across the screen. In 5120 point mode it seems to have just 2 subsweeps with ~1 ps dither between them.

When the OXO heater kicks on everything jumps out of sync for a while. It may well be that the mystery NVRAM calibration constants are intended to correct the time offset between the sweeps. IIRC my timebase ROMS have a 1991 or 1992 date, so it is possible that my scope had a FW update and could be corrected if I knew where and what values to write with a PROM programmer.

If someone has an 11801C or other newer model open I'd appreciate version and date information on the timebase board ROMS. But if anyone knows *anything* about this I'm very interested in investigating. I've got another 11801x in CA at my sister's house which I'm waiting for her to ship to me. I have had more fun with my 11801 than any other piece of test gear I've bought. Being able to see reflections from each side of a high grade SMA-F to N-F adapter is quite amazing.

Have Fun!
Reg




Re: 11801 NVRAM

Chuck Harris <cfharris@...>
 

I'm sorry Reg, I thought you had a "C" model.

I agree, they are fun to play with.

I will try to check my "C" for the information
you need.

-Chuck Harris

Reginald Beardsley via Groups.Io wrote:

My scope is an 11801. That should be visible in the screen photo I posted. Based on the dates on parts it is 1989 production. It is enough different from the 11801C that it was obvious from the meager information in the service manual for the 11801C that I needed an actual an 11801 manual. Zenith was kind enough to furnish a scan of the 11801 service manual, which is now available online, but I bought a paper copy.

I currently am triggering off a square wave on one channel of the 33622A while displaying a ramp from the other channel. There is a periodic jitter in the time base, so even with an external trigger I cannot get a stable sweep. In 1024 point mode at 1 ps/div it appears that there are 4-5 subsweeps before it repeats. As a result the trace oscillates back and forth over a span of about 1.3 ps as it drifts across the screen. In 5120 point mode it seems to have just 2 subsweeps with ~1 ps dither between them.

When the OXO heater kicks on everything jumps out of sync for a while. It may well be that the mystery NVRAM calibration constants are intended to correct the time offset between the sweeps. IIRC my timebase ROMS have a 1991 or 1992 date, so it is possible that my scope had a FW update and could be corrected if I knew where and what values to write with a PROM programmer.

If someone has an 11801C or other newer model open I'd appreciate version and date information on the timebase board ROMS. But if anyone knows *anything* about this I'm very interested in investigating. I've got another 11801x in CA at my sister's house which I'm waiting for her to ship to me. I have had more fun with my 11801 than any other piece of test gear I've bought. Being able to see reflections from each side of a high grade SMA-F to N-F adapter is quite amazing.

Have Fun!
Reg




Re: Tek 576 Curve Tracer HV Transformer winding

Dave Wise
 

I made the bobbin flanges for my 453 rewind out of sanded-off CD's. Cheap abundant source of 0.050" polycarbonate sheet.

FWIW,
Dave Wise

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Mlynch001
Sent: Sunday, September 15, 2019 5:53 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek 576 Curve Tracer HV Transformer winding

Success! I jacked the oven up to 350 and went for broke. My wife yelled "I smell something" so I figured it was hot enough. Gave it a twist as instructed and it popped apart. One outer leg had already fallen off, so I am thinking that the core was already cracked by the earlier attempt. No harm, no foul, super glue to the rescue.

I APPRECIATE all the advice that was given. A special thanks to Chuck Harris for his concise instructions. Now to figure out how to make and wind a new bobbin.

Sincerely,

--
Michael Lynch
Dardanelle, AR


Re: 561B Recapping

widgethunter <tubesnthings@...>
 

If it aint broke don't fix it!!!Running several 561As & 565 in original condition with NO issues.That is the norm for 500 series gear.Bernie Schroder

-----Original Message-----
From: Glydeck via Groups.Io <glydeck=aol.com@groups.io>
To: TekScopes <TekScopes@groups.io>
Sent: Sun, Sep 15, 2019 5:15 pm
Subject: Re: [TekScopes] 561B Recapping

I would be interested as well. — George
On Sep 15, 2019, at 1:17 PM, David Holland <david.w.holland@gmail.com> wrote:

Anyone recapped a Tektronix 561B, and have some pointers for capacitor
replacement specifications?  (ESR/DF & ripple current ratings
particularly)

Looking up the Tektronix part numbers will lead to NSN numbers, which
will give original manufacturers, (Sprague/Mallory), and purported
original part numbers, that I can not find references to.

There's nothing I'm aware of specifically wrong with the scope at the
moment, other than 47 years on those caps - based on the 1972 date
codes, and a serial # in the B19xxx range.

There is also 2 (of 3) tantalum capacitors that don't seem to be
de-rated particularly well (C11 & C31). - (Yes, they look like
tantalum, the NSN's say they are tant., and their tiny physical size
strongly implies it as well.)

I've a DER DE-5000 and a HV supply (Eico 950B) so I could pull them
and measure DF/ESR/leakage/etc to my hearts content, but if I'm going
to remove them, I'd just as soon put new caps back in circuit.

Suggestions? Comments? Cries of Derision?

Thanks,

David



Re: 3.5mm connector for SD24 sampling head...

Reginald Beardsley
 

How extensive is the damage? If it's just the thread, a fine triangular needle file will fix that.

If the side has been pushed in so it is no longer round, but not too badly damaged, it's a bit more complex, but still a fairly simple repair if you have access to a small lathe with which to make a plug expander to fit inside the connector.

I made one once to fix a friend's flute foot joint which was worn and allowed the foot to fall off. It took a couple of tries to make one that worked, but I'm not a machinist and had no experience. All I had to go on was the concept of a conical plug being pulled into a conical hole which then forced the outer cylinder to expand.

Would you post a close up photo to the files section?

Have Fun!
Reg


Re: From 2014: Tektronix Announces Winner of Europe’s Oldest Working Oscilloscope Contest

Dave Wise
 

That D suffix indicates Delay line, not Distributed amplifier. (So you could view the edge that triggered the sweep.) Tek's first distributed-amp scope was Type 517.

Dave Wise

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Chuck Harris
Sent: Sunday, September 15, 2019 6:57 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] From 2014: Tektronix Announces Winner of Europe’s Oldest Working Oscilloscope Contest

The 310 is close, but no cigar.

The 511 was the original Tek scope, the 511AD was a
later refined model, with a distributed vertical amplifier.

My working (?) 513D is probably older than Alan's 511AD.

I give it a ? because although I went over it completely
about 30 years ago, it has the selenium rectifiers, which
tend to turn into insulators.

According to Stan G's book:

511 last catalog 1952
511AD last catalog 1955
513 last catalog 1953
513D last catalog 1953

310 last catalog 1958
310A last catalod 1971

-Chuck Harris

Dave Daniel wrote:
Hmmm.. I have (and had back in 2014) a working 310.

As cool as an MDO would be, and not that I want a 'scope that I can't repair when
(not if) it breaks, but there have to be hundreds of owners of vintage Tektronix
'scopes out there that own working 'scopes that are older than the 511 cited in the
post, Europe or not.

I don't recall hearing of this "contest". It is weird that it did not come to light
while it was in progress. Does anyone have any information about the the contest itself?

DaveD


Re: 11801 NVRAM

Reginald Beardsley
 

Albert,

The signal is 20 mVpp, so that is the full ramp in the image. I just posted more in response to Bob Koller.

My calculation of the frequencies required is not correct. Not sure what I got wrong. With the settings I gave I get a flat trace across the screen which slowly rises and then starts over at the bottom. I'm guessing I calculated the frequencies such that each sweep was a constant offset from the trigger.

With a 100 kHz ramp I need a trigger around 99.989 kHz to display the full ramp for a single cycle. That's a difference in period of ~1.1 ns. Or with a 100 kHz trigger, I need a 100.0108 kHz ramp.

I've never dealt with such extreme aliasing before and normally I am considering the frequency domain effects. So this will take some thought.

Have Fun!
Reg


Re: PM for a working Tek 577 with D1 storage Curve Tracer

Mlynch001
 

Kevin,

My 577 had been sitting for some time in storage. It had some balky switches. I have found that cleaning those switches with non-working latches will bring them back to proper function. This is a common switch, used in almost all Contemporary TEK instruments. I buy many so called "non-working" instruments that need only thorough cleaning of these type switches to restore their function.

--
Michael Lynch
Dardanelle, AR


Re: 11801 NVRAM

Bob Koller <testtech@...>
 

These patents may provide some information, Google will get you there:

US4755742, US4678345A, US 4727340A


Re: 11801 NVRAM

Reginald Beardsley
 

Your 11801 version and date match my recollection.

I've been pondering how they generate signals at differential increments of 10 femtoseconds. At 1024 points and 1 ps/div I'm seeing a sequence of 4 sweeps separated by jitter of about 200 femtoseconds. It's so quick that the only way to count them is to look at the time between the first and the last on the graticule.

It's quite interesting to watch the behavior of the internal timebase relative to the ramp and trigger from the 33622A.

I wish the Tek Museum would release at least board schematics for these. I hate to think of them going away for want of enough information to track down a failed part in a reasonable amount of time.

Thanks,
Reg


Re: 11801 NVRAM

Albert Otten
 

On Mon, Sep 16, 2019 at 12:22 AM, Reginald Beardsley wrote:


FYI I created a photo album and posted a picture of the 33622A ramp displayed
on my 11801 using an SD-26 head at 1 ps/div and 2 mV/div with 1024 samples.

With a trigger signal at 100 kHz, you need a ramp at 100.0001 kHz to test the
linearity of the time base. I'm just using the internal timebase, the 33622A
set as close as I could and taking the photo at the right moment. It took a
couple of tries. I'll try for more rigorous results later.

I'd like to thank be_moulton for suggesting the idea. I had pondered the
subject, but lacked the insight needed. It's a great pleasure to have such
excellent company join us.

Have Fun!
Reg
Hi Reg,

I try to understand what's going on but don't see it. What is wrong in the following reasoning?
The trigger and ramp periods are equal to and almost equal to 10 us, with a difference of 10^-6 period or 10 ps. So per sample the time shift of ramp w.r.t. trigger is 10 ps while at 1 ps/div the time base adds only 10 fs per sample to the shift. If my view is correct then the time base accuracy plays no role in your display.
Another concern is the following. The total time shift during one trace is 10 ns, only 1/1000 period. The display shows a very small portion of the ramp. You measure at 2 mV/div. The total of 20 mV difference during one trace would correspond to 0.001 x total ramp amplitude. Hence total ramp amplitude would be 20 V, obviously way to high for the sampling head. Apart from that, the displayed ramp would nearly always be vertically off screen.

Something must be wrong in my reasoning, but what?

Albert


Re: 11801 NVRAM

Bob Koller <testtech@...>
 

Regarding TB board EPROM:

My 11801B has 1993 and 1994 dated FW v 4.01 and 4.03 respectively.
I have an 11801 TB board from a parts unit with FW date 1991, v10.11

These two sets of FW have very different part numbers as well, so they don't seem to be simple revisions of FW.


Re: 11801 NVRAM

Reginald Beardsley
 

My scope is an 11801. That should be visible in the screen photo I posted. Based on the dates on parts it is 1989 production. It is enough different from the 11801C that it was obvious from the meager information in the service manual for the 11801C that I needed an actual an 11801 manual. Zenith was kind enough to furnish a scan of the 11801 service manual, which is now available online, but I bought a paper copy.

I currently am triggering off a square wave on one channel of the 33622A while displaying a ramp from the other channel. There is a periodic jitter in the time base, so even with an external trigger I cannot get a stable sweep. In 1024 point mode at 1 ps/div it appears that there are 4-5 subsweeps before it repeats. As a result the trace oscillates back and forth over a span of about 1.3 ps as it drifts across the screen. In 5120 point mode it seems to have just 2 subsweeps with ~1 ps dither between them.

When the OXO heater kicks on everything jumps out of sync for a while. It may well be that the mystery NVRAM calibration constants are intended to correct the time offset between the sweeps. IIRC my timebase ROMS have a 1991 or 1992 date, so it is possible that my scope had a FW update and could be corrected if I knew where and what values to write with a PROM programmer.

If someone has an 11801C or other newer model open I'd appreciate version and date information on the timebase board ROMS. But if anyone knows *anything* about this I'm very interested in investigating. I've got another 11801x in CA at my sister's house which I'm waiting for her to ship to me. I have had more fun with my 11801 than any other piece of test gear I've bought. Being able to see reflections from each side of a high grade SMA-F to N-F adapter is quite amazing.

Have Fun!
Reg


Re: WTB: 214, 224 handheld scopes and accessories for others

Miguel Work
 

Hi, I have a lilttle collection of these scopes too, two 221, two 213, two 214, one 222, and a THS730, and a Fluke97.
I have experience fixing power supplies from 221 and 213.

Regards

Miguel

-----Mensaje original-----
De: TekScopes@groups.io [mailto:TekScopes@groups.io] En nombre de greenboxmaven via Groups.Io
Enviado el: lunes, 16 de septiembre de 2019 16:10
Para: TekScopes@groups.io
Asunto: [TekScopes] WTB: 214, 224 handheld scopes and accessories for others

Thanks to responses from others on this list, I now have a few Tektronix hand held scope projects, and looking for a few more. I would like to add a 214 and 224 to my collection. I am also looking for carrying cases or bags, as well as parts for the 2XX series. The scopes don't need to be working, I prefer to restore them. Bruce, KA2IVY


Re: PM for a working Tek 577 with D1 storage Curve Tracer

Chuck Harris <cfharris@...>
 

Generally speaking, there are no must do's for the 577.

They are very reliable.

Well, perhaps a few, if you have the storage version:

1) learn how to use it without burning the storage mesh
when in non store mode.
2) learn how to adjust the storage system for optimal
performance.
3) learn that even when performing optimally, storage
tubes aren't as nice as digital storage.

-Chuck Harris

Kevin Oconnor wrote:

There has been frequent postings on various repairs for broken 577 CTs. However, mine is working ok, given its age and typical senior citizen arthritis issues.
I don’t want to fix what ain’t broken, but it would be nice to have a list of:
1) must do - or it will explode
2) should do
3) when you have the time do

My 577 issues are buttons that don’t want to latch, pots that are scratchy, display zero moving around with selector setting changes. All things that I can live with.

Kevin KO3Y




Re: OFF TOPIC- Fluke handhelds

Dave Daniel
 

There is “fluke-dmm@groups.io”.

There is also a Yahoo fluke group. I don’t know the name of it offhand.

DaveD


Sent from a small flat thingy

On Sep 16, 2019, at 10:15, greenboxmaven via Groups.Io <ka2ivy=verizon.net@groups.io> wrote:

I am also interested in project Fluke "Scopemeter" hand helds. If anyone has a project or two for sale, please let me know. If anyone knows of a group similar to this one but devoted to Fluke, please let me know about it as well. Thanks, Bruce KA2IVY




Re: OFF TOPIC- Fluke handhelds

Kevin Oconnor
 

Check out the Fluke-DMM group here.


PM for a working Tek 577 with D1 storage Curve Tracer

Kevin Oconnor
 

There has been frequent postings on various repairs for broken 577 CTs. However, mine is working ok, given its age and typical senior citizen arthritis issues.
I don’t want to fix what ain’t broken, but it would be nice to have a list of:
1) must do - or it will explode
2) should do
3) when you have the time do

My 577 issues are buttons that don’t want to latch, pots that are scratchy, display zero moving around with selector setting changes. All things that I can live with.

Kevin KO3Y

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