So is there a bottom line here? I have ordered replacement NVRAM modules
but now am leery of installing them, as I may lose calibration, which seems
to be good even though the batteries are down.
Bob
On Saturday, November 9, 2019, 01:26:28 PM PST, Raymond Domp Frank <
hewpatek@gmail.com> wrote:

On Sat, Nov 9, 2019 at 08:39 PM, Szabolcs Szigeti wrote:

I think what the SM says here is when you press the button, it

recalculates some values and

writes it to the nvram.

Quite likely.

But this needs to be done after every change in setting the pots.

True for the operational settings, not true for the Adjustment (chapter 5)
data that is stored in the "store..." menus during Adjustment.

So for the original question of is there a real need to save the 2440

nvram

when _it is in cal_ but the nvram needs to be changed, the answer is no,

as

the scope can be brought back to calibrated state by running the self

cal and ext cal.

Here I disagree.
If this were true, what purpose would the menu-supported adjustments (like
setting numbers, turning external pots) and storing by pressing keys etc.,
see msg #161473, during manual calibration ("Adjustment", chapter 5) serve?
They are quite different from the saving of operational settings, which
happen all the time during use.
In these respects, the NVRAM function is quite comparable to that in
'scopes like the 2445/65 series. Calibration constants are stored in NVRAM,
as are the operational settings. The latter change all the time when
working with the 'scope, whereas the former cannot be restored by just
pressing a button: The scope needs to be Adjusted as per SM chapter 5.
Many 'scopes also store user-initiated attenuator offset corrections in
NVRAM.

...the scope can be brought back to calibrated state by running the self

cal and ext cal.

Not if the constants that were set during Adjustment (chapter 5) were lost
because of exchanging the NVRAM , unless the 'scope does have another place
to store them. It seems that we don't know where that would be in this
model.

Raymond

I think what the SM says here is when you press the button, it recalculates some values and
writes it to the nvram.

But this needs to be done after every change in setting the pots.

So for the original question of is there a real need to save the 2440 nvram
when _it is in cal_ but the nvram needs to be changed, the answer is no, as
the scope can be brought back to calibrated state by running the self cal and ext cal.

...the scope can be brought back to calibrated state by running the self cal and ext cal.

On Fri, Nov 8, 2019 at 02:45 PM, Szabolcs Szigeti wrote:

But these are all adjustments requiring turning trimmer pots.

I had a quick look in the SM. The Adjustments chapter (5) mentions e.g. on
pages 5-8 and 5-10 (in my manual) "WRITE TO CAL STORE" and on page 5-13
"Pushing A HORIZONTAL MODE causes the instrument to make firmware
corrections...".
I assumed that those writes and corrections were to the NVRAM. If you're
right, the 2440 has yet another kind of "writable ROM" than the NVRAM. Do
you know if that's true and if so, what kind of storage it is?

Raymond

On Nov 7, 2019, at 6:29 AM, Daniel Koller via Groups.Io <kaboomdk=yahoo.com@groups.io> wrote:

I'm no nuclear science history expert, but wrt the original post, that 535 seems out of place. The criticality experiments were generally carried out in the 1940's and the 5 series was not available till the 1950's. Afterall, by 1945 they knew what it took to make a pile of uranium go off.
But in the 1950's the techniques of Nuclear spectroscopy were being developed and that scope would have been at home reading the pulse outputs of scintilation counters. I used such scopes in Columbia University's undergraduate physics labs in the 1980's for just such pulse counting. they had not updated the labs in 30 years (!!) so it was very much like working in the 1950s
Someone correct me if I am wrong in my time estimates.
Dan

On Wednesday, November 6, 2019, 10:02:59 PM EST, <sdturne@q.com> wrote:

On Sat, Nov 2, 2019 at 01:10 AM, battyhugh wrote:

If you are in Minneapolis - on the S side of the bridge across the river on
the W side (if I remember correctly) - there is another relic - you have to
decend about 6 stories down - there are masses of HB spec analysers and a
rather large Van de Graffe generator - - very strange (I saw it in early 90's)
- A Dr Weiblen was working at that time on using high voltage pulses to bust
up moon rock. It would be rather interesting to document the remaining
residues of the 50's and 60's (on the marshes near Palo Alto is an old radio
transmission facility - might be interesting... but wait.. there's more!

Hmmm, is it an abandoned site or is someone taking care of it?

The cell voltage was 2.74 V, now it is 3.23 V.
I just successfully replaced.
I followed your advice, using a second cell soldered to pins 4-8 of DS1210.
My wife saw me during the work and told me: you put it in extracorporeal circulation. She is a nurse.
I had several heart strokes (pin removed from the original cell, positive battery terminal near gnd and the like) but I did it!
At the end I drank a large glass of red wine.
Next replacement scheduled for November 9, 2029.

Reading the manual I have understood that after data loss in the NVRAM, you can do a simple re-calibration using the internal calibrator.
This can allow to make just qualitative measures. All linearization data must be re-entered with a complete calibration using very precise signal generator and power meter at different values of amplitude and frequency. This is necessary to get a good amplitude responce on the whole freq. range. The bad thing is that an elusive "271X Flatness Tests" original software is necessary to carry on this procedure.... and a working very old PC.
This is the reason why my hands are shaking to change a battery!