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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
3.5mm connector for SD24 sampling head...

Chuck Harris <cfharris@...>
 

Hi,

I have an SD24 sampling head that is otherwise ok, but has a
3.5mm connector that was banged into a wall by the previous
owner. The connector leading edge is peened over a little bit.

Finding a new connector seems unlikely.

Does anyone out there have a parts unit SD24 or 26 that has a
spare connector?

Thanks!

-Chuck Harris
want to buy 4S3

Brian
 

Hi everyone , I would like to buy or maybe trade for a 4S3 plug-in . I dont mind if it is non-functional or even if it has no probes with it , it is the one part of my 661 system that I have not been able collect yet .

thanks in advance for any help
OFF TOPIC- Fluke handhelds

greenboxmaven
 

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
WTB: 214, 224 handheld scopes and accessories for others

greenboxmaven
 

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: Tek 576 Curve Tracer HV Transformer winding

Mlynch001
 

My wife is not that hard to get along with. She knew what was going on and was letting me know that the core was probably ready to attempt to separate. All she wanted to know after that was “did it work?” . She is a keeper.
--
Michael Lynch
Dardanelle, AR
Re: 11801 NVRAM

Chuck Harris <cfharris@...>
 

Hey Reg,

Unless you actually mean an 11801, you should not
abbreviate the model number of your scope, 11801.

The 11801 is far less capable than your 11801C.
Especially in as far as GPIB programming goes.

-Chuck Harris

Reginald Beardsley via Groups.Io wrote:

FWIW I set up my 11801 using the internal trigger and feeding a ~100 kHz ramp from my 33622A. By making slight adjustments to the ramp frequency I get a straight line which intersects the graticule all the way across the screen at 5 ps/div and 2 mV/div using 5120 points and at 1 ps/div with 1024 points. The internal timebase is not as stable as the 33622A which, despite not having the high stability option, has *very* little drift relative to a GPSDO from Leo Bodnar.

I'm obviously severely aliased to get a single cycle image of a 100 kHz ramp in a 10 or 50 ps wide window. That corresponds to 10 femtosecond sampling.

If there is a time base correction that was lost I don't see how I can measure it or what effect it might have. The ramp appears dead straight though it jumps around a lot because of the 4 ps jitter of the 11801 clock. By continually fiddling with the ramp frequency I can stop the display for a single sweep with a diagonal line over the full screen from upper right to lower left when collecting 5120 points.

I'm going to puzzle over this while I fix a rather late lunch. But I can't see how there is a significant issue. I should be able to do better getting digits via the GPIB interface and supplying a trigger signal from the 33622A.

As I removed the NVRAM battery to get it to boot before I replaced the NVRAM chip, there's no question that if there were cal data in the NVRAM chip it was lost.

Have Fun!
Reg
Re: 11801 NVRAM

Chuck Harris <cfharris@...>
 

For what it's worth, the CSA803C, and the 11801C are
the same instrument, +/- two active ports for sampling
plugins, which are substituted for power only ports on
the CSA803C.

They are both covered in the 070-9970-00 Programmer Manual.

By inference, they both have the same command set, which
includes:

CALibrate <alpha> <ui> <link>: <arg>

which auto cal's the command in the argument.

With links,

AUTO: {All | Blowby | LOOpgain | OFFSet | ONUll or TDRAmplitude }

BLOwby:

CSTore: {All | Blowby | LOOpgain | OFFSet | ONUll or TDRAmplitude }

or,

DREcall: {All.....TDRAmplitude}

etc...

So, anything you can do with your CSA803A, you can do and more with
the much later 11801C....

Or, so it appears.... The Programmer Manual is about as clear as mud.

-Chuck Harris





Albert Otten wrote:

Hi Reg,

I think you refer to my message #158778. The GPIB command ccalcorrection does the job. That command was present in the CSA803A but not yet in the CSA803.This suggests that the calibration constants were introduced in the later models. So I suppose this feature is also not yet present in your 11801.

As far as I know there is no GPIB command to read memory contents. The Debug facility in the Extended Diagnostics menu can show memory contents at the scope screen; see also 11801 Diagnostics pdf, section 5.2.7. For viewing the time base NVRAM the Time Base subsystem should be selected in the E.D. menu. With Debug I could not find the GPIB commands in the firmware; probably some memory bank switching is needed to access the proper memory chips. I based my above mentioned conclusion on chip memory dumps obtained from elsewhere.

Albert
Re: 7403N questions

zenith5106
 

On Mon, Sep 16, 2019 at 05:51 AM, Ed Breya wrote:

. Does the 7403N have any chance at all to properly run these big two- or
three-wide plug-ins?
The 7403N uses the same mains transformer and LV pover supply as 7603 so
I assume the power specs are the same. http://www.hakanh.com/dl/docs/hardtofind/7k_PS_currents.pdf

2. Is it possible to field-add the readout function to this model? I
Introduction info from March 1971:
//
The 7403N/R7403N are designed to be low cost additions to our present
mainframes. Both mainframes allow the use of most 7000
series plug-ins for flexibility, while maintaining a total package
cost to be favorably competitive with the HP180 Series of instruments.
The only plug-ins that may not be used in this new line are those
requiring Auto Scale Factor Readout for an output such as the 7D Series.
In the present version of the 7403N, Auto Scale Factor Readout is not
available as an initial purchase, nor can it be later added to the
instrument if desired, because of completely different circuit design.
The 7403N together with its two low cost plug-in additions, the 7A18
and 7B53N, offer a "new gen", dual trace, delaying sweep, 50 MHz
laboratory scope at a low cost.
//

There is no official mod kit to be found to do that so the above would still be valid.

/Håkan
Re: 11801 NVRAM

Albert Otten
 

Hi Reg,

I think you refer to my message #158778. The GPIB command ccalcorrection does the job. That command was present in the CSA803A but not yet in the CSA803.This suggests that the calibration constants were introduced in the later models. So I suppose this feature is also not yet present in your 11801.

As far as I know there is no GPIB command to read memory contents. The Debug facility in the Extended Diagnostics menu can show memory contents at the scope screen; see also 11801 Diagnostics pdf, section 5.2.7. For viewing the time base NVRAM the Time Base subsystem should be selected in the E.D. menu. With Debug I could not find the GPIB commands in the firmware; probably some memory bank switching is needed to access the proper memory chips. I based my above mentioned conclusion on chip memory dumps obtained from elsewhere.

Albert

On Sun, Sep 15, 2019 at 07:59 PM, Reginald Beardsley wrote:


I'm very interested in how to derive and store the correction terms. There
has been discussion of a command to write them, but it appeared not to work
when attempted IIRC.

It would be very helpful to know where they are stored in the NVRAM. I've got
a programmer, but no idea where to put the data.

My Keysight 33622A is specified as <1 ps jitter. That's less than the 4 ps
jitter specified for the 11801. I think I'll play with that a bit and see if
I can persuade the 11801 to tell me what the uncalibrated errors are.

Having just built a GPIB-USB adapter using an Uno and AR488 I think I need to
read the programming manual for my 11801 to see if I can get digits out via
the GPIB port. That would allow removing the NVRAM one time to load the
correction values.

Have Fun!
Reg
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