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11801 is reassembled, up and running :-)

Reginald Beardsley
 

My ST NVRAM came today. As previously reported it took 3 boots to clear the T1331 error.

I now have both the 11810 User Manual and Service Manual in original Tek hardcopy.

I experienced a good bit of operator confusion after performing the Enhanced Accuracy procedure from the service manual. In particular it seemed to be aliasing the calibrator output. But now I'm getting 26-32 ps rise times which seems about right for an SD-20 head.

I tried to copy the A5-U300 ROM but I'm not sure that succeeded. The TNM5000 said it failed to identify it. Can anyone tell me what type of EPROMs are used in the scope?

As much as I hate to take it apart again, I would like to archive the ROMs in case I or anyone else needs them. I'll also scan the User Manual.

I'd like to thank all who helped but especially Tom for the tip about removing the DS1213s, Adrian for procuring the NVRAM replacements, Albert for general guidance and the person who sent me a link to a PDF scan of the 11801 manual. I've tried in vain to find out the name, but I may not be looking in the correct place.

BTW the upper knob has a crack where it pushes over the encoder shaft which resulted in it slipping a lot. I put a piece of heat shrink over it and it seems to be working fine now. But if anyone has a replacement, please contact me off list.

Have Fun!
Reg

Bob Koller
 

Great!

Calibrator risetime? Isn't the cal output specified at about 250ps? Both of my instrument measure it about 300ps.

Reginald Beardsley
 

11801 User manual p 42.

"The signal from the calibrator output us a 250 mV square wave with a rise time of approximately 20 ps and a period of approximately 10 microseconds."

After I did the Enhanced Accuracy cal process I got results similar to yours. I eventually got it to do something sensible after a bunch of semi-random button pushing. Pulse amplitude was not stable on the display among other weirdness. It is now behaving as one would expect.

Someone else has stated that the calibrator is the same as the pulse generator in the SD-24.

I am now getting the same results I got before I replaced the NVRAM.


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

On Mon, 3/25/19, Bob Koller via Groups.Io <testtech=yahoo.com@groups.io> wrote:

Subject: Re: [TekScopes] 11801 is reassembled, up and running :-)
To: TekScopes@groups.io
Date: Monday, March 25, 2019, 7:08 PM

Great!

Calibrator risetime? Isn't the cal output
specified at about 250ps? Both of my instrument measure it
about 300ps.

 

On Mon, Mar 25, 2019 at 10:52 PM, Reginald Beardsley wrote:

I tried to copy the A5-U300 ROM but I'm not sure that succeeded. The TNM5000
said it failed to identify it. Can anyone tell me what type of EPROMs are used
in the scope?
27C010 and 27C512

/Håkan

 

On Tue, Mar 26, 2019 at 10:49 AM, zenith5106 wrote:



I tried to copy the A5-U300 ROM but I'm not sure that succeeded. The
TNM5000
said it failed to identify it. Can anyone tell me what type of EPROMs are
used
in the scope?
27C010 and 27C512
I may have to take part of that back.
In my F/W EPROM collection I don't have 11801 but there is a note saying that 11801 can also use 11801A F/W
which I have and it uses both types. I now begin to think that is wrong and if so 11801, just like 11802 no letter,
use only 27C512.

/Håkan

Reginald Beardsley
 

Thanks. It will be a while before I take it apart again, but I'll make a note in my service manual.

Fortunately, most of my HP gear lists the parts in the manuals, so those will be easier to do.

I've attached a photo showing the calibrator output trace. The measured rise time is shown in the lower left at 32 ps. I've got smoothing on.



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

On Tue, 3/26/19, zenith5106 <hahi@...> wrote:

Subject: Re: [TekScopes] 11801 is reassembled, up and running :-)
To: TekScopes@groups.io
Date: Tuesday, March 26, 2019, 7:01 AM

On Tue, Mar 26, 2019 at 10:49 AM,
zenith5106 wrote:

>
> >
> > I tried to
copy the A5-U300 ROM but I'm not sure that succeeded.
The
> > TNM5000
>
> said it failed to identify it. Can anyone tell me what
type of EPROMs are
> > used
> > in the scope?
>

> 27C010 and 27C512
>
I may have to take part of
that back.
In my F/W EPROM collection I
don't have 11801 but there is a note saying that 11801
can also use 11801A F/W
which I have and it
uses both types. I now begin to think that is wrong and if
so 11801, just like 11802 no letter,
use
only 27C512.

/Håkan

Albert Otten
 

Attachments are not allowed here Reg. Via the website you can create a new Album in the Photos section and put your picture(s) there. If you do so, it's handy for "us" if you insert a link to the album in your messages.
Albert

On Tue, Mar 26, 2019 at 02:06 PM, Reginald Beardsley wrote:


I've attached a photo showing the calibrator output trace. The measured rise
time is shown in the lower left at 32 ps. I've got smoothing on.

Bob Koller
 

They must have changed the cal output circuitry on the later models.

Reginald Beardsley
 

The user manual I quoted has a revision date of May 1989. The August 1988 service manual states the calibrator is < 35 ps. The February 1989 revision page states the same rise time.

As I noted previously. I also got a 300 ps rise time from the calibrator due to something not being set properly. This persisted when I used autoset, but eventually went away after I power cycled it a couple of times and used the autoset again. The behavior suggested an off by 10x error in the timebase generator strobe line. But I have far too little experience with the instrument to be sure of anything.

Albert Otten
 

On Tue, Mar 26, 2019 at 03:28 PM, Reginald Beardsley wrote:


The user manual I quoted has a revision date of May 1989. The August 1988
service manual states the calibrator is < 35 ps. The February 1989 revision
page states the same rise time.

As I noted previously. I also got a 300 ps rise time from the calibrator due
to something not being set properly. This persisted when I used autoset, but
eventually went away after I power cycled it a couple of times and used the
autoset again. The behavior suggested an off by 10x error in the timebase
generator strobe line. But I have far too little experience with the
instrument to be sure of anything.