Topics

11403A as bench scope, how useful is it?

satbeginner
 

Hi all,

I have the opportunity to acquire an 11403A with some errors. (I am optimistic about reparability)

My question is:

How useful is this beast, compared to my 2465B, when my main usage is repair and troubleshooting of amplifiers, other oscilloscopes, playing with Arduino etc.

Are there other advantages that I did not see yet?

I think I like the idea of being able of making a print screen to a printer and having a color screen.

Are there members who actually have one of these for daily use who can comment on this?

Thanks,

Leo

David DiGiacomo
 

On Tue, Jun 20, 2017 at 9:33 AM, satbeginner@... [TekScopes]
<TekScopes@...> wrote:

I have the opportunity to acquire an 11403A with some errors. (I am optimistic about reparability)
I wonder why you are optimistic. I think it is very challenging to
repair the 11400 series.

My question is:

How useful is this beast, compared to my 2465B, when my main usage is repair and troubleshooting of amplifiers, other oscilloscopes, playing with Arduino etc.
The biggest weak spot is the 20MSPS maximum sample rate. The short
record length is not so great either.

Many people dislike the UI, but that's a matter of taste.

Chris Wilkson
 

The biggest weak spot is the 20MSPS maximum sample rate. The short
record length is not so great either.


Is it really that low? Wow.
Using my typical rules of thumb that gives you a good look at square waves up to about 2MHz (5th harmonic is 10MHz, Nyquist rate -> 20MSPS).


Not great at all. Surely it has some tricks to be better for non repetitive signals?

 

Hi,

You are taking Nyquist too literally. If all you had was one chance to
sample a waveform the Nyquist Criteria would apply but if the waveform is
repetitive then you have an infinite amount of time to sample it or to build
up a set of samples. This is like the difference between a waveform that is
a single shot or a waveform that repeats.

These were the early days of digital scopes and many clever schemes were
needed to achieve excellent bandwidth (1GHz to 3Ghz) with the relatively
slow sampling speed available in those days. The 11403A is capable of GHz
bandwidth on several channels as long as you are measuring repetitive
signals.

A single shot waveform only gives you one chance to sample it (or one chance
to display it on the CRT of an analog scope). Your eye has to be really fast
to see the entire one shot waveform or to study any part in detail. A
repetitive waveform refreshes the phosphor of the CRT over and over and you
eye has a chance to study any part of it in detail for as long as you like.

Dennis Tillman W7PF

-----Original Message-----
Sent: Tuesday, June 20, 2017 2:00 PM
Subject: [TekScopes] Re: 11403A as bench scope, how useful is it?

The biggest weak spot is the 20MSPS maximum sample rate. The short
record length is not so great either.

Is it really that low? Wow.
Using my typical rules of thumb that gives you a good look at square
waves up to about 2MHz (5th harmonic is 10MHz, Nyquist rate -> 20MSPS).

Not great at all. Surely it has some tricks to be better for non
repetitive signals?
------------------------------------
Posted by: cwilkson@...
------------------------------------

Tom Gardner
 

Not only digitising scopes, of course.

As an extreme example, the Tek 1502 TDR has a sampling
rate of ~10kS/s, but can display 140ps risetimes since its
front-end bandwidth is >2.5GHz. That's why it is beneficial
to specify both the sampling rate and the front-end bandwidth.

And the first sampling scope I saw used a XY pen plotter
as an output device :)

Note that for digital signals the period/frequency is irrelevant.
All that matters is the transition time, since that's the principal
influence on the "signal integrity".

On 20/06/17 23:53, 'Dennis Tillman' @Dennis_Tillman_W7PF [TekScopes] wrote:

Hi,

You are taking Nyquist too literally. If all you had was one chance to
sample a waveform the Nyquist Criteria would apply but if the waveform is
repetitive then you have an infinite amount of time to sample it or to build
up a set of samples. This is like the difference between a waveform that is
a single shot or a waveform that repeats.

These were the early days of digital scopes and many clever schemes were
needed to achieve excellent bandwidth (1GHz to 3Ghz) with the relatively
slow sampling speed available in those days. The 11403A is capable of GHz
bandwidth on several channels as long as you are measuring repetitive
signals.

A single shot waveform only gives you one chance to sample it (or one chance
to display it on the CRT of an analog scope). Your eye has to be really fast
to see the entire one shot waveform or to study any part in detail. A
repetitive waveform refreshes the phosphor of the CRT over and over and you
eye has a chance to study any part of it in detail for as long as you like.

Dennis Tillman W7PF

-----Original Message-----
Sent: Tuesday, June 20, 2017 2:00 PM
Subject: [TekScopes] Re: 11403A as bench scope, how useful is it?

The biggest weak spot is the 20MSPS maximum sample rate. The short
record length is not so great either.

Is it really that low? Wow.
Using my typical rules of thumb that gives you a good look at square
waves up to about 2MHz (5th harmonic is 10MHz, Nyquist rate -> 20MSPS).

Not great at all. Surely it has some tricks to be better for non
repetitive signals?

Jerry
 

make sure you can get the operating and service manuals. I recently was given a 11301 which has some issues and I haven't been able to find the service manual. I have it working, it must have a ROM problem as I have to play with the focus/astig and the brightness of the various traces every time I power it on.

No big deal. Oh, and by the way, the 11301 heats my garage nicely and I suspect the 1140x will do the same.

ArtekManuals
 

I have service manuals for both the 11301 and 11403A ...sadly neither
has schematics which would be in something entitled "Extended Service
manual" ..which I have never been able to find ( though I do have the
extended manual for the 11401 ...go figure)

Dave
manuals@...

On 6/20/2017 8:18 PM, jerry@... [TekScopes] wrote:

make sure you can get the operating and service manuals. I recently
was given a 11301 which has some issues and I haven't been able to
find the service manual. I have it working, it must have a ROM problem
as I have to play with the focus/astig and the brightness of the
various traces every time I power it on.

No big deal. Oh, and by the way, the 11301 heats my garage nicely and
I suspect the 1140x will do the same.

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

--
Dave
Manuals@...
www.ArtekManuals.com

Chris Wilkson
 

Hi Dennis,

No not really. I'm just a lazy typist. I did imply that I was referring to non-repetitive signals and was content with that lever of "CYA". Of course if you're willing to wait "long enough" and the analog front end has enough bandwidth, then you can get quite good rise time performance for repetitive signals even with a low sample rate by using an equivalent time sampling. But or single shot events I think my math is accurate within the limitations of the under lying assumptions.


I agree with what you said. Thank you for expanding it out for me! :)


-Chris

 

On 20 Jun 2017 15:33:19 +0000, you wrote:

I have the opportunity to acquire an 11403A with some errors. (I am optimistic about reparability)

My question is:

How useful is this beast, compared to my 2465B, when my main usage is repair and troubleshooting of amplifiers, other oscilloscopes, playing with Arduino etc.
I think it would work great for these applications. 20 MS/s is plenty
fast for a real time updated display and I bet it has a better update
rate than the 20 MS/s 2230 which itself is completely useable for
general purpose work.

Common power supply troubleshooting includes watching the start-up
behavior and 20 MS/s is fast enough for that as well.

The only thing it is missing is peak detection.

Are there other advantages that I did not see yet?
An 11403A would be especially useful anywhere transient response is
important because it supports differentiation and phase/magnitude FFTs
which allows for easy network analysis. There are only a few DSOs
which can do this and very few modern ones.

It has a 10 bit ADC and with self calibration, higher accuracy than
most DSOs and even 3.5 digit voltmeters.

The dual timebases support delayed and delta delays displays with
200ps timing resolution in single shot mode and 10ps resolution for
repetitive signals. This largely makes up for the lack of huge record
lengths.

With one of the faster vertical plug-ins, this DSO might be good
enough to make jitter measurements on low performance logic and
Tektronix even had option 1S to support this so I suspect they thought
so also.

satbeginner
 

Hi all,

thanks for all the feedback, ideas and suggestions.
Today I received the shipping information, so "The Beast" is on its way to me, all 21kg... :-)


Keep you posted when it arrives and I have powered it on for the first time.


Un saludo,


Leo

satbeginner
 

Hi all,

here my first update on this Tek 11403A, it came with:
1x 11A52 dual channel plug in, 600MHz
1x 11A72 dual channel plug in, 1GHz
1x 11T5H Multi Standard Video Trigger plug in.


It powers on an shows the typical graticule, so that's a good thing, I spend some time in the Menu's to find and get acquainted with the diagnostics.
There it basically gives several errors, none in the system, memory, etc, but 4 errors in the Acquisition module, 2 errors in the 1st plug in and 2 errors in the second plug in, none in the Video trigger module.


It seems there are no schematics available for the 11k series?? Does anybody have additional schematics??
The "Service Manual" only points to FRU's (Field Replaceable Unit's), so that does not help....


But after some "googling" and reading, I do think the plug in errors are caused by the acquisition errors.
The acquisition errors are grouped in 2 errors in the Voltage tests and two errors in the AD Converter tests.


Although this does not sound well at all, I started probing with a second scope (using my 2465B) and found that there is communication between the acquisition board and the data board by means of the bottom flat cable.


It seems that most/all of the logic on the acquisition board is ECL so are the signals going over this flat cable.
On the data board they go into ECL -> TTL converters.


Running the AD converter Voltages tests (+0,8V, 0,0V and -0,8V) it is always hard stuck on 0,034V in all three tests.


Probing around these signals showed that some of the ECL output signals did not comply with the specified ECL levels, so I think that (one of) these ECL Flip-Flops, used as a driver, is gone since the data is always hard on 0,034V


I removed the suspicious chip and put a 16-pin socket on the board, so I can easily put the new ECL chip in when it arrives. (MC10H131L)
Testing with the old chip still in place made me think that it could be the inputs of the ECL -> TTL converter as well, so I removed that as well and put there a socket as well. (MC10125L)


The funny thing is, that running the Voltage Test in a loop without the cable between the 2 boards installed (so none of the bits get to the other end) the voltage showed -0,1024 V and +0,1024 V, so that looks like the 10 bit data we are looking for, so maybe the digital parts following the AD data is still working.
Also the tests related to the calibration generator are looking good.


I'll try to put some pictures on.


Un saludo,


Satbeginner (Leo)

satbeginner
 

Hi all,

here my first update on this Tek 11403A, it came with:
1x 11A52 dual channel plug in, 600MHz
1x 11A72 dual channel plug in, 1GHz
1x 11T5H Multi Standard Video Trigger plug in.


It powers on an shows the typical graticule, so that's a good thing, I spend some time in the Menu's to find and get acquainted with the diagnostics.
There it basically gives several errors, none in the system, memory, etc, but 4 errors in the Acquisition module, 2 errors in the 1st plug in and 2 errors in the second plug in, none in the Video trigger module.


It seems there are no schematics available for the 11k series?? Does anybody have additional schematics??
The "Service Manual" only points to FRU's (Field Replaceable Unit's), so that does not help....


But after some "googling" and reading, I do think the plug in errors are caused by the acquisition errors.
The acquisition errors are grouped in 2 errors in the Voltage tests and two errors in the AD Converter tests.


Although this does not sound well at all, I started probing with a second scope (using my 2465B) and found that there is communication between the acquisition board and the data board by means of the bottom flat cable.


It seems that most/all of the logic on the acquisition board is ECL so are the signals going over this flat cable.
On the data board they go into ECL -> TTL converters.


Running the AD converter Voltages tests (+0,8V, 0,0V and -0,8V) it is always hard stuck on 0,034V in all three tests.


Probing around these signals showed that some of the ECL output signals did not comply with the specified ECL levels, so I think that (one of) these ECL Flip-Flops, used as a driver, is gone since the data is always hard on 0,034V


I removed the suspicious chip and put a 16-pin socket on the board, so I can easily put the new ECL chip in when it arrives. (MC10H131L)
Testing with the old chip still in place made me think that it could be the inputs of the ECL -> TTL converter as well, so I removed that as well and put there a socket as well. (MC10125L)


The funny thing is, that running the Voltage Test in a loop without the cable between the 2 boards installed (so none of the bits get to the other end) the voltage showed -0,1024 V and +0,1024 V, so that looks like the 10 bit data we are looking for, so maybe the digital parts following the AD data is still working.
Also the tests related to the calibration generator are looking good.


I'll try to put some pictures on.


Un saludo,


Satbeginner (Leo)

n4mf_sc
 

The Plugins 11A52 and 11A72 both have DALLAS NVRAM chips on them and the errors on the plugins could be from invalid cal data.

Mitch
N4MF

satbeginner
 

Thanks for the heads-up, a 11k series is new to me, so I will concentrate on getting the mainframe free of errors first, and then go on with the plugin's.

The Dallas in in my 2465B was still working when I replaced it, after 28+ year.

Most of the chip in the mainframe have s '91 timestamp, but I did not looked at the plugin's yet.

Parts are ordered, as soon as they get here I will update again.

Leo

 

Hi Leo,
A 1991 IC date code is consistent with when these 11000 series was being manufactured by Tek. Sadly, Tek decided by the late 1980s not to provide schematics and all of the other useful information we are so used to in the manuals for these instruments. Since the instrument is well past the point where Tek is obliged to support it with parts and repair services I don't think there is any support of any kind for the 11000 series scopes.

In the archives some where there is a description of how to deal with the Dallas Chip and, if I am correct, the errors coming from the plugins.

Dennis Tillman W7PF

-----Original Message-----
Sent: Friday, July 07, 2017 11:22 AM
Subject: [TekScopes] Re: 11403A as bench scope, how useful is it?

Thanks for the heads-up, a 11k series is new to me, so I will concentrate on getting the mainframe free of errors first, and then go on with the plugin's.

The Dallas in in my 2465B was still working when I replaced it, after 28+ year.

Most of the chip in the mainframe have s '91 timestamp, but I did not looked at the plugin's yet.

Parts are ordered, as soon as they get here I will update again.

Leo

------------------------------------
Posted by: satbeginner@...
------------------------------------

David DiGiacomo
 

On Fri, Jul 7, 2017 at 10:30 AM, satbeginner@... [TekScopes]
<TekScopes@...> wrote:
It seems there are no schematics available for the 11k series?? Does anybody have additional schematics??
The "Service Manual" only points to FRU's (Field Replaceable Unit's), so that does not help....
Didn't you read the previous replies? Artek has the 11401/11402
extended service manual.

satbeginner
 

Sorry David, I obviously missed that. :-(
I will contact him right away.

Thanks for reminding me,

Leo

 

On 07 Jul 2017 16:30:36 +0000, you wrote:

here my first update on this Tek 11403A, it came with:
1x 11A52 dual channel plug in, 600MHz
1x 11A72 dual channel plug in, 1GHz
1x 11T5H Multi Standard Video Trigger plug in.
The Tektronix 1991 catalog includes all of these. The 11A52 and 11A72
have 50 ohm inputs only making them less universal than the slower 11k
vertical plug-ins but of course they sure are fast. Combined with a
fast 50 ohm pulse generator, these would be great for characterizing
the speed of diodes and transistors.

Probing around these signals showed that some of the ECL output signals did not comply with the specified ECL levels, so I think that (one of) these ECL Flip-Flops, used as a driver, is gone since the data is always hard on 0,034V
Be careful about the ECL levels. While normally this family of ECL
would be operated between ground and -5.2 volts, Tektronix sometimes
ran it off of the same positive supply as the 5 volt TTL logic.

satbeginner
 

Hi all,

thanks for your support and thinking with me on this.

As far as I can see there is a group of D-type flip flops sending the data bits from the acquisition board to the data board, and it's just one of the dual flip-flops having the failing levels, so that's why I removed that one and also the matching receiver on the other board.

Bad luck about the schematic, Dave at Artek has the same service manual I found online, so no schematics yet.

I keep looking, many thanks for the feedback,

Leo

Brent Watson <brentleew2003@...>
 

Seems like Tek would eventually release the original schematics, not having interest in the 11000's any longer. You'dthink someone would know where they were, and let them out. They must be somewhere, right ?  Were they intentionally destroyed?
I guess they want us to buy disposable, and stop repairing vintage equipment.


My DSA602 works great thanks to help from generous forum members, but my 11A71 has Atten Gain, High and Low errors.    Service manual; says -1421, -1431, -1441 as error index IC "FRU's"   The Att Hybrid FRU is suspect for the Atten Gain error, and the main board suspect for the Gain High and Gain Low errors. Sounds like a write off to me.

Cheers,   Brent


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