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CHECKSUM
I would kindly like to know, assuming I dumped correctly the CAL 02 values, if there is a sound method to verify the checksum for my scope before fiddling with the battery.
Any pointer before I get mad with X-Way forensics editor?

I found a guy that could re calibrate it for 300EUR (maybe 250, we have two scopes) so I could just avoid the hassle to change the battery myself and/or switch to FRAM. It seems it could even be a reasonable price, I don't know.

RECAPPING
Of course, if I have someone to recalibrate it, I may well think of recalibrating it AFTER recapping.

Is there any current BOM for Digikey/Mouser available?

TIA.

--
Giuseppe Marullo
IW2JWW - JN45RQ

Old A 5 bd, battery backup, easy to change

Use EXER function to read RAM cal.values, or gpib bus f has the option

CAL requires correct test equipment, see service manual

Usually a complete Cal is required

On forums many threads on 2465/7/AB cal.

Jon

Giuseppe,

I did post a photo of the parts list for my higher s/n B model. The part prices and some parts will be different. Maybe some parts will have to have a different series due to Nichicon stopping production of some series.

Mark

Giuseppe

For the parts, contact me
yachadm AT gmail DOT com

Menahem

What do you do with the values read from CAL/EXEC function. is there a way to enter/change them?

I am asking as I have a 2465 as well that just had 04 10 which is describes by Tektronix as just out of cal (guessing old data or checksum fails. ER1400 can hold data for 10+ years) but TBH the cost of calibration if you dont have the very specialised TMG is not worth it for a scope this age (my opinion as you can by newer versions for 3-500GBP) or go crazy old skool and aim for 4xx series IF BW is the issue.

I am for fun experimenting with reading the data out of the ER1400 (potentially replacing is if it is bad - I got like 10 spare ones). I am not too fuzzed about accuracy as I have digital never scope as well if needed).

Just curious to understand the logic behind what is stored in ER1400, checksums, etc and if it can be trigged into thinking it is calibrated and don't fail on selfcheck.

Cheers.

Jon,
many thanks but:
1) I have hopefully a good capture video of all the CAL 02 values.
2) I found a lab that claims they have all the required equipment to fully calibrate it

I was wondering:

a) if there is a method to be certain that the values I captured in video can be checked against the checksum(no GPIB card). I have found a source code for the spiral checksum but not sure how to apply to the data. Not much of a cryptologist, but still can code something.

b) assuming I will make recalibrate it in the lab (still deciding about it) I would like to recap the scope prior to recalibrate it. So I am looking for a BOM for Digikey or Mouser. a reasonably priced kit (price+customs and so on, shipped to Italy) can be a viable option.

Hope it is more clear.

--
Giuseppe Marullo
IW2JWW - JN45RQ

If you have an A or B series, you can get the calibration values back in the NVRAM with this utility (or with GPIB, if you have the equipment):

/g/TekScopes/files/24xxAB-writecal-1.1.zip

The only way to get them back into a 2445/2465 (plain) that I know of at the moment is via the optional GPIB interface (OPT 10). A similar utility to the above for A/B versions could be developed for 2445/2465 scopes, but ER1400 failures are far and few between (unlike dead batteries), and virtually no one has backed up their 2445/2465 cal data so it can be used with such a utility. If you have a backup of your cal data and are trying to get it back in the ER1400, please speak up!

The above zip archive has demonstration code in ./related/earom.c on how the Tek "spiral add" checksum algorithm works on the 2445/2465, plus how parity is calculated for the range of locations that include parity. So, you might be able to determine the offending entry by putting your EXER 02 data in the code.

If you want to post your 2465 EXER 02 data, we could also look at it together in this thread.

Theoretically, you could force the scope to recalculate the checksum by performing a calibration step, such as CAL 04, where you don't actually modify anything and then exit the cal procedure. I haven't tried this, but keep in mind if you do you're ignoring bad cal data that could affect the scope's operation.

From a reliable source, I am told there is an undocumented screen utility similar to EXER 02 for *entering* the data, but the person I spoke to can't recall how it was done. More work with a better logic analyzer (which I have now), and/or analysis with Siggi's 2465 Ghidra image and 2465 MAME simulator may find the answer. It's on my to-do list.

-mark

On Wed, Apr 9, 2025 at 11:53 AM, Giuseppe Marullo[iw2jww] wrote:

RECAPPING
Of course, if I have someone to recalibrate it, I may well think of
recalibrating it AFTER recapping.

I'm very interested in the topic of 'recapping.'
I know there was a problem with some brands of electrolytic capacitors, coming from China, circa 1999... and that has an effect on those things manufactured that used them... mostly from China.
Yet...IME... what I have seen is more damage to the PCB, then good.

What's the motivation for ordering a capacitor 'kit'... and doing 'shotgun' replacement of capacitors?

IMO... if one does not take the time to test... for a bad component... and then to identify, and specify the appropriate component....
Well how do you know, you are not replacing something, with something that is worse?
Also... but importantly, using inappropriate de-soldering, and soldering tools, and supplies, risks damage to the pcb... which might not be trivial.

--
Roy Thistle