HP / Agilent 3458A SNAPHAT ZeroPower Battery Replacement
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HP / Agilent 3458A SNAPHAT ZeroPower / TimeKeeper Battery Replacement on the A5 Outguard Controller.
HP 3458A 8.5-digit metrology-grade DMM restoration by Illya Tsemenko: xdevs.com/fix/...
Some history and background on the 3458A:
hackaday.com/20...
www.hpl.hp.com/...
ST Micro application note on their ZEROPOWER® and TIMEKEEPER® NVRAM devices:
www.st.com/web/...
www.st.com/web/...
Application note on date codes:
application-not...
Spartan-II 2.5V FPGA Family Data Sheet:
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I learned my lesson the hard way with the old Dallas 1220Y NV RAM battery in a couple of Hal ST-8000 HF Modems; one of the "big" providers was actually providing knock-off units that didn't function and I ended up ordering them direct from (then) Dallas (turned out they were cheaper to boot!). And Deja Vu all over again when I discovered recently that the backup battery in my TenTec RX-340 receiver was a "Snaphat" battery as well. Martin, you should have seen me shaking my head up and down throughout your video saying "...yep, been there, done that!". Thanks for sharing, great info! 73 - Dino KL0S
+Dino Papas Thanks for your post and the support of the community Dino.
Thanks Martin. That was a lot easier than replacing the backup battery in my Tek 2465 ADV oscilloscope. I'm glad it worked out well for you.
+Robert Calk Jr. Thanks Robert.
Nice vid, thanks for credits, appreciate.
Recalibration by Keysight would be more like 2600$ calibration minimum exercise, if to do it right for 3458A-002 grade specs. ;)
Also you can backup calibration ROM using various software, so even if NVRAM dies, you can have data safe and reprogram it back after chip replacements.
Very interesting. Have never seen a SnapHat battery. Hats off the tinkers!
2004 or 2014 will still have the same date code digit. Will need a destructive opening of the device to see the datecode of the internal cell. Best storage is polystyrene foam sheet. Then wrap in some more ( also known as the worst practise in static management) and include a big block of silica gel well dried just before. Then seal in a bag, do again then put in Tupperware with another pack in the fridge. Mark as not to be opened and do not eat.
You can see in the sawed off one the cell is mounted positive side down. Would be interesting to peel it apart further and see if there is a real manufacturers datecode on there, ST does not make these cells, but they are assembled in Malaysia and finla assembly is done in Mauritius. Seen by the MAL and 99 on the bottom line.
+SeanBZA Thanks for all your input Sean, it been a great help.
Cool! I found one of these inside the controllers of a IBM storage server (a DS6800, to be exact)
Thanks for the video Martin. NVRAM is something that annoys me slightly on modern equipment, but I guess in something like this, it's expected to go for calibration yearly anyway.
+SDG Electronics Indeed, thanks for your post.
this guy is driving me nuts with his hand movements
***** LOL but I Think he is trying his best
i have replaced snaphat battery. it is causing my 3458 meter , however it requires recalibrations. can i use my multimeter without snaphat battery ?
Hey Martin, +mjlorton
in such cases I connected a Logic Analyzer parallel to the Memory while powering up. So (aver a little work combining the addresses and data to create a .hex) I have a hardcopy of the contents if something is going horribly wrong. Not everytime it is a dead NV-Battery - sometimes it's very handy to have the EEPROM data of your Notebooks if one of your clients sets a password while forgetting it... ;-)
All ROMs of the older gear I own is preserved in that way.
Nevertheless: good video.
If those we're meant to be replaced every 10 years on the lower capacity rating with these new higher capacity ones that you installed I'm confident you will get 10 years plus of service out of them.
Why can't they just design the chips with 2 battery compartments in parallel so that when they were low, you could replace one at a time in order to avoid losing the data?
Or have a single large coin cell at the top that can be replaced, in addition to a secondary small slot where you just stuff a temporary coin cell battery in while you replace the main coin cell?
Razor2048 I would prefer the latter
I'll keep my 4.5 dig Fluke, this made me nervous! lol but wow 8.5 dig...cool, thanks for sharing.
is it possible that for exemple 452 is 14 week 52 because they wanted to stick to 3 digits format?
Thank Your, for very good video! The next question is were the ram memory deleted because of dead battery or not :D
If they are a lithium cell couldn't they be recharged?. If there were no diode inside, forcing some current through it might extend their life? Or am I missing something?
+Pete Bloggs
Lithium cells aren't rechargeable (unless you want an explosion).
these are primary batteries, that's how they get their shelf life
Very good and interesting
Not too sure why Agilent went with SnapHats, have the same design in my Agilent SA, but they are no dummies. A 2032 coin cell is around 220 mAH, but has nowhere near the shelf life of the STM solution.
Why did they not use EEPROM?
afroninjadeluxe limited write cycle and speed
RAM TEST HIGH and RAM TEST LOW erros on 3458A, it´s the same issue?
yes it can causes that errors
even mov j132
Thanks for all the pictures / video of the modern A5 PCB. Very interesting, also for future battery replacement on older boards with the DALLAS nv-RAMs. Would like have seen the SRAM types..This exchange is feasible for private owners only, as companies would always let Keysight calibrate or adjust the instrument routinely, at least every two years, and therefore, could replace the nv-RAMs w/o such an elaborate effort.Therefore, I find your demonstration video highly questionable, as you do not save the CAL constants at all, neither over GPIB with the MREAD command, nor by simply writing down the CAL constants. You would have had at least the possibility to reconstruct the 10V and 10kOhm calibration, so that for amateur use, the instrument would have been usable in case of a failure during exchange of the batteries.Also, the datasheet for the battery clearly states a 3-digit date code, that means, there's a 10 year wrap-around for the production date. So it's more probable, that it's really 2014, but not 2004, as the cell voltage is a full 3.4V. 12 years old Li cells usually have lower no-load voltages, due to self-discharge.. and I just don't trust the 50 years storage claim of STM. You might ask STM directly about the age of the cells, by presenting them the lot number in the first line.
Thanks Martin: Very informative and helps a bit to 'Gird My Loins' to tackle the Dallas Memory chip in my TEK 2465B. If anyone has word of wisdom or links please comment.
Cheers, Mark
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They are still producing this meter, although not for the EU market.
That KS statement is no longer true - these have been re-initated for the EU market:
EU3458A standard model
EU3458AX with Option 002 and 001
www.keysight.com/en/pd-2831253-pn-EU3458A/digital-multimeter-8-digit-for-eu-sales-only?nid=-536902435.1217937&cc=US&lc=eng
why don't they just use coin batteries like other devices that need to preserve data? I bet those devices aren't cheap either.
+Rubus Roo I wouldn't want to store my few thousand dollars of calibration data using a coin cell. Cost of these Dallas NV RAMs is neglible comparing to calibration cost, and they are ultra-reliable for much longer than typical calibration period. It's like buying Formula 1 car and asking why car battery ain't standard;)
+kroplaaaa I had no idea calibration was that expensive.
Kent A. Vander Velden For your typical portable multimeter, or even 5 1/2 digit bench meter one? Not so much. But for something like 3458A it's a pretty serious business:) Very much work goes to it, stuff like calibrators (made mainly for Fluke, HP doesn't make callibrators), constant measuring of drifts, whole network of comparing results between labs and so on. Most standard cal labs would use 3458A & some callibrator as a reference to calibrate all other meters, and, well, if you need that kind of accuracy, resolution and stability you gotta prepare your wallet;) Everyone can get few voltage references and good grade resistors and put some numbers into 8 1/2 digit meter and call it "done", but to maintain consistency, any level of confidence and credibility it requires a lot more work (and money). It's not like you'll become a millionaire from running a cal lab ;) For this instrument it also depends on the application, you can run it in 4 1/2 digits mode (like a typical portable DMM), then it will do 100000 readings/s, it's incredible if you need some kind of automated testing measurement setup, then you can probably get away with not having it so often calibrated, but still - new 3458A costs around 10000$ (for basic set, without increased stability addons etc), 2500$ for example every two years is acceptable cost, it pays for itself anyways. Only people that have real problem with NVRAM chips are hobbyists that buy some retired 15 year old ones and try to use it at home on a budget (for which there are much more pleasant meters to use, really;p):)
+Rubus Roo
Good idea, but where is the point of preverving the calibration data (by changing the battery) if you void your calibration by opening the case? Yes, for Home-Users it would be fine but I think HP/Agilent/Keysight is more interested in the business clients...
+kroplaaaa
Did you watch the video to the end? You *ARE* storing your calibration data using a coin cell. They just potted one in a case. So why didn't they use a normal non-cased one like most other devices?
I'm getting 204 Hardware Failure Flatness Dac Convergence 198. Any ideas anybody?
multimeter uni-t 61E
Totally crazy circuit design. Buyer beware.
I personally don`t see any sane justification for those snaphat batteries except for squeezing money from their owners. Flash, EEPROM anyone? Why not make it the way it should be done? Buyers beware!
+Piotr Szarański This device goes for at least annual calibration anyways, who cares? And it was designed in 1989 or something like that. NVRAM with battery included was always the best option (until Flash), they're designed to last reliably for 10 years, ridiculously longer than calibration cycle.
+kroplaaaa I don`t agree. World has seen way older lab equipment, where callibration is stored within EEPROM. And considering EEPROM erase/write cycles before wear out, I personally find it always better option than RAM with external battery suport. If you put it on the shelf for 15 years, it`s still going to retain it`s data in EEPROM, whereas snaphat will be plain dead (or even earlier if you buy unit with factory defect).Besides all of that, I would be very unhappy to pay $2600, when my little battery goes flat. Annual callibration considering this price would be Keysight`s dream, but again - unjustified. Just keep your tools in good condition and use it in proper environment (temperature, humidity, etc) - you won`t have to callibrate it so often.
Piotr Szarański It's metrology grade instrument. It's useless for its purposes (mainly being a transfer standard in a lab) without valid calibration certificate. They will gladly replace the chip during the cal procedure. And, well, most metrology instruments used batteries before the Flash era, much easier to use and design with calibration from the front panel or over GPIB than EEPROMs :) Cal sticker used to has something like "calibrated 03/85, change battery before 03/95".
+Piotr Szarański Selling this device in France, for example, would be illegal. They have a clause against planned obsolescence.
DPortain You're funny person. You can buy 3458A in France or every other EU country without any issue. Just call your local Keysight dealer and ask for a quote ;)
With those shaking hands you can do brain surgery on the fly.
"I don't believe it"', he says. Have you no faith?
Don't get involved with old overpriced junk.
+Dan Frederiksen Hey, it's a current model :)
+kroplaaaa, and that's the really offensive part. Fluke 87 is also current. Equally old overpriced 'tech'.
+Dan Frederiksen They do the job well though. The amount of engineering that went into this justifies the cost.
+Dan Frederiksen Did you ever design your low cost multimeter?
+SDG Electronics, you're a good sheep.
change with the machine powerd on??? are you people insaine? you could put a battery wired in paralel and desolder the old one with no data loss... I do it all the time. if you ask me is way better than working with the machine powered on...
That's how it's designed to be done.
ElectronicMarine wait what? these are clip in batteries that to on top of the IC
Bro relax it’s a battery your not gonna get zapped poor fella