Changing battery in a HP 3478A - can i use a 3v Lithium ? - Page 1
Forum section: electronics / beginners

author: bingo600
author_rank: Super Contributor
timestamp: March 21, 2013, 11:19:31 am
content: Inspired by these nice pictures of a 3468a battery changehttps://www.eevblog.com/forum/testgear/quick-question-about-hp-3468a/msg197337/#msg197337http://mrmodemhead.com/blog/hp-3468a-battery-replacement/I decided to check/change the battery in my HP 3478ASN : 2911A66xxx - Means : (29+60 = 89) = 1989 , Week 11 , A(merica)My serial is almost the same as Daves , and i have the same yellow battery in.https://www.eevblog.com/forum/blog/eevblog-427-hp-3478a-multimeter-teardown/msg194349/#msg194349I just measured the battery to 3.4170v - with a Agilent 34401A , and Bravo said "watch out" here.https://www.eevblog.com/forum/blog/eevblog-427-hp-3478a-multimeter-teardown/msg195033/#msg195033I have been preparing a bit , and have gotten som Lithiums from the "net" , even 2 Taradians.But they have the "reverse polarity" , meaning - on the dual pins and + on the single pin.I also have a "perfect fit" but it's only a 3v Lithium , could i use that ?.I have attached some pics , and "snipped" 3 pages from the service manual to give an idea of the buildup.The Ramchip (U512) in pg. 154 , and the battery circuit with CR764 on pg. 156.On the schematic they say 3.0v , so i hope i can use the 3v Lithium.But will not if anyone says its really a bad idea.Hope to get some advice now that i have the "lid off" and is all "warmed up".I have prepared a spare Taradrian with an 1n4148 on + , have a propane solder iron ready.I'll leave the meter powered on mains and solder the spare taradrian across C510 , and then desolder the original battery , and solder the new one in.Edit: I just found this with the same part£ as in HP's manualhttp://www.ebay.com/itm/1420-0278-Agilent-HP-Lithium-Battery-3V-95A-for-3478A-/350546682442It's a 3v Lithium , so i think i should be ok or ?TIA/Bingo

author: bingo600
author_rank: Super Contributor
timestamp: March 21, 2013, 01:17:19 pm
content: Well being impatient ....I performed the surgery , and the patient survivedThe new battery delivers 3.0587v across C510 , sorry i didn't measure what the old one delivered across there.I took a pict of the old battery , and it's a Panasonic BR-2/3A 3v cell.So that's the one , also in Daves reviewed meter.Ohh this is the battery i used : SANYO / FDK CR17335SE - 2/3A "med loddeflig (1 stk.)" ... the "xxxx" means with solder tabshttp://www.batteribyen.dk/sanyo-fdk-cr17335se-23a-med-loddeflig-1-stk-3112Specshttp://www.fdk.com/battery/lithium_e/pdf/data_sheet/hcc_type/CR17335SE_spec-sheet.pdfIf i read it correctly , it should be good for 10+ years (@23 C) , the curves shows 10y with a 20uA load , and the Ram DS says it uses 10uA/Bingo

author: ModemHead
author_rank: Frequent Contributor
timestamp: March 21, 2013, 01:39:58 pm
content: I've attached the datasheet I dug up for the uPD5101L SRAM chip. It indicates that the minimum voltage needed for data retention is 2.0V (third page). So the 3.0V battery should be OK, as you've already figured out...

author: bingo600
author_rank: Super Contributor
timestamp: March 21, 2013, 01:47:54 pm
content: ThanxI did see that, before i changed my battery.I performed the "surgery" with mains on , and also with a 3v6 taradian soldered to C510 , via an 1n4148.C510 is the silver cap seen here , just above the ram chip - on sIMG_0513.jpghttps://www.eevblog.com/forum/beginners/changing-battery-in-a-hp-3478a-can-i-use-a-3v-lithium/?action=dlattach;attach=41988Note "-" on the cap is towards the frontpanel , and "+" is towards the rear , it makes sense as it's pin-22 that's vcc.I suggest always confirming with a DMM before soldering wires on.

author: bingo600
author_rank: Super Contributor
timestamp: March 21, 2013, 02:09:03 pm
content: Ohh...Does the Agilent 34401A also have a battery for calibration data retention ? (i'm lazy) ...I'd really hate to loose my cal on that one./Bingo

author: ConKbot
author_rank: Super Contributor
timestamp: March 21, 2013, 06:40:36 pm
content: Is that section of the board floating/not ground referenced? You wouldnt want to short the battery out with a grounded soldering iron tip. Or is that why you used the propane soldering iron?Even if it doesnt reset the memory, shorting out a lithium battery isnt exactly a good thing.

author: bingo600
author_rank: Super Contributor
timestamp: March 21, 2013, 07:13:16 pm
content: Quote from: ConKbot on March 21, 2013, 06:40:36 pmI used the Propane iron just for that reason./Bingo

author: johnh
author_rank: Regular Contributor
timestamp: March 21, 2013, 10:17:27 pm
content: I was just wondering if its possible to build an adaptor to read the contents of the memory. So you could back it up

author: nukie
author_rank: Frequent Contributor
timestamp: March 27, 2013, 11:38:00 pm
content: No it doesn't. Don't worry bout it.Quote from: bingo600 on March 21, 2013, 02:09:03 pm

author: nukie
author_rank: Frequent Contributor
timestamp: March 27, 2013, 11:39:32 pm
content: Hello Bingo what's the date code on your new battery?

author: bingo600
author_rank: Super Contributor
timestamp: March 29, 2013, 08:50:31 am
content: Quote from: nukie on March 27, 2013, 11:39:32 pmI don't really knowI couldn't find any sensible printing saying that./Bingo

author: nukie
author_rank: Frequent Contributor
timestamp: April 02, 2013, 05:24:54 am
content: Have a look at the original yellow cell, it is usually printed on the battery sleeve or stamped letters. Or contact your seller for date code. I know Sanyo usually has date code on the battery sleeve.

author: free_electron
author_rank: Super Contributor
timestamp: April 03, 2013, 02:07:14 pm
content: Quote from: johnh on March 21, 2013, 10:17:27 pmYou can dump it through gpib....

author: eliocor
author_rank: Unknown
timestamp: April 03, 2013, 05:23:57 pm
content: Quote from: free_electron on April 03, 2013, 02:07:14 pmPlease can you state the GPIB commands required to dump the calibration parameters?I have taken a look to the Operator's and Service manuals with no avail....Manuals at thefollowinglink

author: bingo600
author_rank: Super Contributor
timestamp: April 03, 2013, 09:02:17 pm
content: Quote from: free_electron on April 03, 2013, 02:07:14 pmIsn't that only the 3458A ?I have never heard about a "hidden command" for the 3478A , or for my upcomming 3457A (hint..hint)/Bingo

author: radiogeek97
author_rank: Regular Contributor
timestamp: April 12, 2013, 06:58:27 pm
content: well folks I found a resonably priced 3478a on fleabay for 99$ including shipping. It arrived the other day and I just replaced the battery sucessfullyThe battery installed in it was a saft LX1634, i measured the voltage across the battery and it was about 3.04xxvdc the voltage across the c510 cap was about 2.8xxxvdc. I installed a battery pack across c510 and I left the unit under power. I used my gas soldering iron and took my time. Stupid design but I am hopefully good for many years now. The voltage across the c510 post replacement was 3.04xxx so there was a noticeable boost in voltave with the new battery. The red and black tape was to remind me of which end was which I didn't want to take any chances on shorting anything. Thanks to dave and all the rest of you for the valueable info.PS has anybody a link on the adaptors to allow me to use my fluke and or pamona leads on this? I hate to cut a $$ pair of leads. I saw a link somewhere on here but cant find it anywhere not.take care alljohn

author: Monkeh
author_rank: Super Contributor
timestamp: April 12, 2013, 07:03:00 pm
content: I have no idea where else stocks them, but:http://www.rapidonline.com/cables-connectors/4mm-shrouded-socket-adaptors-63902/

author: Unknown
author_rank: Unknown
timestamp: April 12, 2013, 07:12:01 pm
content: I think Frankie (iloveelectronics on this forum) sells them. Send him a PM and you should get a better price than in his EBay store. Pomona also sells them, but at quite a high price if I remember correctly.

author: bingo600
author_rank: Super Contributor
timestamp: April 12, 2013, 07:25:56 pm
content: I might like some too ...For my 3478A , and my newly arrived 3457AMaybe Frankie can chip i here/BingoPs: I just bought batts for the 3457A , i might start another thread on that one ...

author: radiogeek97
author_rank: Regular Contributor
timestamp: April 12, 2013, 08:22:06 pm
content: digi-key has what looks like an exact fit the batteries were only like 5 bucks each however the shiping fedex or ups was 10$ i told the lady forget it. upps wont take lithium batteries so you are stuck with paying a premium

author: iloveelectronics
author_rank: Frequent Contributor
timestamp: April 13, 2013, 01:31:39 am
content: Quote from: bingo600 on April 12, 2013, 07:25:56 pmI hope it is ok to post a link to my eBay store here in this case. Here is the shrouded to unshrouded banana adapter:http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200904597758I do offer 7% discount to all members who buy direct from me outside of eBay, as I will save some eBay fees that way. Just PM me what you want and your paypal address etc. Thanks!Cheers,Franky

author: radiogeek97
author_rank: Regular Contributor
timestamp: April 23, 2013, 12:21:28 pm
content: just recieved my adaptors today Thanks

author: BillyD
author_rank: Regular Contributor
timestamp: April 23, 2013, 12:43:27 pm
content: Sorry for going a little off topic here, but this made me curious. Given that the meter is basically screwed if this battery dies, is there any safeguard against this happening? i.e. do you get any sort of low battery warning or equivalent before it's too late?

author: nukie
author_rank: Frequent Contributor
timestamp: April 25, 2013, 11:40:30 am
content: Microbattery sells them very good international shipping rates.

author: nukie
author_rank: Frequent Contributor
timestamp: April 25, 2013, 11:42:00 am
content: Send it in for calibration, or replace battery every 8 years or so. Note battery date code.Quote from: BillyD on April 23, 2013, 12:43:27 pm

author: bingo600
author_rank: Super Contributor
timestamp: June 06, 2013, 05:11:09 pm
content: Quote from: iloveelectronics on April 13, 2013, 01:31:39 amI ordered on sunday via *Bay , Franky shipped monday and the adapters arrived today ...I think i got lucky with China mail , so does Franky.Thats expedite/Bingo

author: iloveelectronics
author_rank: Frequent Contributor
timestamp: June 07, 2013, 04:16:49 am
content: Quote from: bingo600 on June 06, 2013, 05:11:09 pmThat was certainly a record delivery time from Hong Kong to Denmark! And FYI, it's Hong Kong Post, not China PostAlthough technically HK is part of China now, we have separate systems in many ways.

author: mrflibble
author_rank: Super Contributor
timestamp: March 14, 2014, 09:54:31 pm
content: Quote from: eliocor on April 03, 2013, 05:23:57 pmBump!Any chance of the commands? I'd love to back up those constants, just to be sure.

author: Unelma
author_rank: Contributor
timestamp: May 25, 2014, 02:55:28 pm
content: Thanks for the info guys. Used isolation transformer and meter was powered all the time.Replacement battery was Sanyo 3v Lithium CR23500SEhttp://www.houseofbatteries.com/documents/CR23500SE.pdf.

author: cellularmitosis
author_rank: Unknown
timestamp: May 02, 2017, 01:33:36 am
content: Just replaced the battery in my 3478A and all seems well!Summary of the procedure:Order this battery:https://www.digikey.com/product-detail/en/fdk-america-inc-a-member-of-fujitsu-group/CR17335SET-FT/SY609-ND/3662227Prepare an emergency 3V battery with diode (e.g., 2 AA's in a holder with a 1N4148 diode on the positive lead) in case the power fails while you are performing the battery swap.Measure the voltage of your emergency battery to ensure you got the diode polarity correct.Remove the case from your HP 3478APlug your 3478A in and turn it on (it will remain powered up during the entire battery swap)Unplug your soldering iron and plug it into a charged UPS which is NOT PLUGGED INTO THE WALL (your soldering iron must not be grounded or you will short out the RAM when you solder the positive lead of the battery).Locate capacitor C510. Use a multimeter to determine which end is positive.Tape your emergency battery to the side of the case of your 3478A.Solder in your emergency batteryDesolder the existing battery. I did this with the 3478A on its side, so that I could grab the battery while soldering from the backside.User solder wick / solder sucker to clear out the battery terminal holes.Solder in the new batteryDesolder your emergency batterySanity check: power cycle your 3478A and ensure it didn't lose calibrationPower your 3478A down and reassemble.

author: SvanGool
author_rank: Regular Contributor
timestamp: May 02, 2017, 01:38:34 pm
content: Thanks! If you have a GPIB adapter, then I also would read out the CAL-SRAM as one of the first steps.https://www.eevblog.com/forum/repair/hp-3478a-how-to-readwrite-cal-sram/msg1182436/#msg1182436

author: sprintcarfan
author_rank: Contributor
timestamp: September 26, 2017, 01:20:04 am
content: Another successful 3478A battery replacement here. I more or less followed the directions listed above. I used a Digi-key P226ND battery. I left the 3478A powered on, but used a normal soldering iron and just plugged/unplugged as needed. I soldered the battery across some different points than what I've seen so far. I didn't use C510 as I was a bit worried I might overheat the cap, so I used one side of R765, and one leg of an RFI shield.

author: agaelema
author_rank: Contributor
timestamp: January 09, 2018, 03:09:25 am
content: Hi guys, a questionToday I opened my HP3478A to verify the battery. I bought this meter used but it was calibrated in 2013 and probably the battery was replaced (there is a little flux residue around the battery solder).The measured voltages are:- 3.036V on battery (bt701)- 2.847v on cathode of CR764Are this values good or I need replace the battery?Thanks!

author: cellularmitosis
author_rank: Unknown
timestamp: January 09, 2018, 08:08:24 am
content: The discharge curve of that battery is very flat, so I'm not sure a voltage reading will tell you much, unfortunately. Perhaps there is a date code somewhere on the battery?

author: agaelema
author_rank: Contributor
timestamp: January 09, 2018, 02:32:30 pm
content: Hi cellularmitosis,I couldn't see any date on the battery. I this case I think I will buy a new battery and change it.

author: agaelema
author_rank: Contributor
timestamp: January 21, 2018, 06:05:26 pm
content: There is another type of battery (no lithium) that can be used? Stores like Digikey not send theses batteries outside USA.

author: kelchm
author_rank: Regular Contributor
timestamp: January 24, 2018, 02:45:26 am
content: Recently picked up a 3478A in very nice condition on eBay. Still appears to have the original battery, so I will be replacing it sometime next week. Already ordered a TS100 soldering iron which I will power from a lipo battery.There are a few lithium battery options in stock at Digikey that should work work well. Anyone have any thoughts?Panasonic BR-2/3AE5SPN3V / 1.2Ah$5.68FDK SY609-ND3V / 1.8Ah$5.89Tadiran TLH-5955/P3.6V / 1.4Ah$10.41

author: PepaZdepa
author_rank: Contributor
timestamp: February 12, 2018, 09:06:17 pm
content: Hi, here's a good explanation why to change the old battery even when you think the voltage is still OK. The end may be very quick(example from SAFT Primary lithium battery LS 14250C datasheet)

author: sprintcarfan
author_rank: Contributor
timestamp: February 13, 2018, 05:29:09 pm
content: The Panasonic BR-2/3AE5SPN (Digi-key PN P226-ND) is what I used, and it dropped right in place of the old battery with no modification.

author: agaelema
author_rank: Contributor
timestamp: April 29, 2018, 07:05:06 am
content: There is some problem in use the battery below (CR17450SE) instead of CR17335SE? The series resistor will disrupt something?-https://pt.aliexpress.com/item/2-pcs-Nova-bateria-Original-CR8-LHC-3-V-CR17450SE-PLC-baterias-De-L-tio-com/32839375206.html?spm=a2g03.search0104.3.15.8c05618exzcJ0M&ws_ab_test=searchweb0_0%2Csearchweb201602_2_10152_10065_10709_10151_10344_10068_10342_5722912_10547_10343_10340_10341_5722612_10548_10697_10696_5722812_10084_10083_10618_5722712_10710_10307_5711212_10059_308_100031_522_10103_441_10624_10623_10622_10621_10620_5722512_5711312%2Csearchweb201603_31%2CppcSwitch_3&algo_expid=59df3717-a52b-4b80-984e-1c7dca08ad26-2&algo_pvid=59df3717-a52b-4b80-984e-1c7dca08ad26&priceBeautifyAB=0

author: pinpassion
author_rank: Contributor
timestamp: July 07, 2020, 06:04:32 pm
content: Hi Gang,I received the battery I ordered from DigiKey (BR-2/3AE5SPN) as suggested in this thread as a nice drop in replacement. I installed it today and can say it worked great. The battery is meant to sit on a PC Board, so the leads are just long enough to go through the board and be bent back somewhat to remain on the board for soldering.I had the 3478A plugged in and powered on during the replacement connected to a UPS. My soldering station is not connected to earth mains, so no worries about shorting out the battery during replacement, As a sanity check, I checked the voltage on pin 22 of the ram chip (U512) prior to battery removal and verified it was receiving power from the 5 volt rail and NOT the battery. I did not bother with soldering on a backup battery since I was using the UPS to power the meter. I was VERY careful. After replacement, I powered off and back on, all is good!My meter was made late 85 and probably left the factory first quarter 86. I removed the original battery (Eternacell), so it was in the meter for 34 years!! It still measures 3.02 volts out of circuit. It certainly was time to change it out!!My next step is to replace the 4 Rifa caps on the AC input. Those are ordered and on the way.Mike