Changing battery in a HP 3478A - can i use a 3v Lithium ?

[bingo600]

I might like some too ...

For my 3478A , and my newly arrived 3457A

Maybe Frankie can chip i here

/Bingo

I 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=200904597758

I 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

I 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

[iloveelectronics]

I might like some too ...

For my 3478A , and my newly arrived 3457A

Maybe Frankie can chip i here

/Bingo

I 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=200904597758

I 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

I 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

That was certainly a record delivery time from Hong Kong to Denmark! And FYI, it's Hong Kong Post, not China Post Although technically HK is part of China now, we have separate systems in many ways.

[mrflibble]

I was just wondering if its possible to build an adaptor to read the contents of the memory. So you could back it up

You can dump it through gpib....

Please 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 the following link

Bump!

Any chance of the commands? I'd love to back up those constants, just to be sure.

[Unelma]

Thanks for the info guys. Used isolation transformer and meter was powered all the time.
Replacement battery was Sanyo 3v Lithium CR23500SE  http://www.houseofbatteries.com/documents/CR23500SE.pdf.

[cellularmitosis]

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/3662227
• Prepare 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 3478A
• Plug 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 battery
• Desolder 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 battery
• Desolder your emergency battery
• Sanity check: power cycle your 3478A and ensure it didn't lose calibration
• Power your 3478A down and reassemble.

[SvanGool]

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

[sprintcarfan]

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.

[agaelema]

Hi guys, a question

Today 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 CR764

Are this values good or I need replace the battery?

Thanks!

[cellularmitosis]

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?

[agaelema]

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.

[agaelema]

There is another type of battery (no lithium) that can be used? Stores like Digikey not send theses batteries outside USA.

[kelchm]

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-2/3AE5SPN
3V / 1.2Ah
$5.68

FDK SY609-ND
3V / 1.8Ah
$5.89

Tadiran TLH-5955/P
3.6V / 1.4Ah
$10.41

[PepaZdepa]

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)

[sprintcarfan]

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.

[agaelema]

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

[pinpassion]

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