The battery looks like it is original, so it could theoretically be up
to 25 years old based on the oft-quoted adage that adding 60 to the
first two digits of the sn prefix gives the year of the revision the
unit was built to. It could be much newer if that revision was in
production for many years, as is more likely the case. 25 years seems a
long time for that generation of battery technology. It is quite
possible the battery was replaced as recently as 2004/2005, just before
I got the unit. If that's the case whoever replaced it did an excellent
job as it looks like it's never been touched.
Your confidence check sounds reasonable. It would be interesting to the
group to see how your results compare with the "as received" numbers if
you do decide to sent your unit to Agilent.
Steve K.
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On 12/31/2012 11:44 AM, Jeff Machesky wrote:
Thanks for the information Steve. Hopefully mine will have the 3.6 volt
battery seeing as how it has the newer serial number prefix. How old
do you figure your battery is to still have that voltage ?
On another note I think I'll get a 3.000 volt reference from
voltagestandard.com and build up really carefully a 0.1x and 0.01x Hamon
divider to check the 300mv and 30mv ranges. Just as confidence check
until I can get it in for calibration. I could in theory check the
30v and 300v ranges by using 0.1x and 0.01x against those voltages
adjusting until the division matches the 3.000v reference and then
checking the results. So for the lower voltages I would divide by 10
or 100 the precision reference and for anything above the reference I
would divide and adjust until it matches the reference and take the
remainder. Hope that all makes sense.
3.00v * 0.01 for 30mv
3.00v * 0.1 for 300mv
3.00v * 1 for 3.00v
adj 30v * 0.1 until equal to 3.00v
adj 300v * 0.01 until equal to 3.00v
Thanks,
Jeff
On 12/31/2012 10:20 AM, Steve Krull wrote:
Joe and all,
I just had a quick look inside my 3457A again. Mine has the 3.0 volt
lithium battery, SAFT LX-1634. Obsolete at Agilent, as is the newer
battery. Google was no help either. Mine measures 3.03 volts and there's
no evidence of corrosion so that's good. I couldn't see a date code on
it; probably on the underneath side. I've replaced batteries by
paralleling the existing connections with an appropriate power supply
and then unsoldering the old battery with an isolated-tip iron and
soldering in the new battery. I've also carefully soldered a new battery
in parallel with the old and then clipped out the old one. No problems
with lost data so far.
I'm not sure how the cal numbers increment. I'll have to experiment with
that sometime. Right now I need to repair the 1349D display in my 8757A
so I can get on with a sweeper plug in project, so the volt-nuttery is
on hold for awhile.
Happy New Year to all!
Steve
On 12/30/2012 5:34 PM, J. L. Trantham wrote:
Steve,
Thanks for the data. Mine is also 2703A prefix with REV?:6,0 and
CALNUM?:98. Not a multiple of 34. Would be interesting to see what the
CALNUM increments by after an Agilent CAL.
I, too, need to look at the battery condition. I have not looked
at the
manual regarding replacing the battery. Has anyone done that without
losing
the CAL Constants?
Joe
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Subject: Re: [hp_agilent_equipment] 3457a on the way
It would be interesting to see if a newer rev is out there. My 3457A
is s.n.
prefix 2703, with rev 6,0 and option 0, CALNUM=34. I wonder if
that's a
default number for anything less than a full cal at Agilent? The last
calibration was at least 6 years ago and performed by what was then
Boeing
Military Airplane Company's metrology lab. I need to open it up and
check
the battery condition.
Steve
