[volt-nuts] 3458A - To Modify or Not To Modify?

[J. L. Trantham]

I had long conversation with the folks at Agilent in Loveland yesterday and
I think I understand their offerings.  For $552.57 they offer an 'Agilent
Calibration Per Incident' which includes determining if your meter is
operating correctly and is, indeed, 'calable'.  If it is, the cal is done
and the meter is returned.  If not, you are informed and an estimate of
repairs is made.  If repair is refused, you pay 'half price' for the failed
attempt at calibration and the meter is returned.  If you agree to repair,
you pay only the 'Repair Per Incident' charge of $2363.56 which includes the
'Agilent Calibration Per Incident' calibration.  

The repair would include replacing the DALLAS NVRAM's.  I don't recall if
they replace the EPROM to bring it up to the latest version of firmware
(9,2) or not.  In any event, for my meter, it would be a single EPROM, P/N
03458-88897, listed as $18.21 on the Agilent website.  Their approach is to
unsolder the chips, solder in new chips, complete the repair, do the
calibration and return the meter.  

Once a meter is successfully calibrated, either via the 'Agilent Calibration
Per Incident' path or the 'Repair Per Incident' path, the meter then becomes
eligible for their 'Repair Agreement' for $175.20 per year which would
include all the services of the 'Repair Per Incident' if and when needed.
Basically you purchase a warranty and can continue to do this year after
year.

My meter appears to be original with all date codes consistent with mid to
late August 1997 including the DALLAS NVRAM's so these are not long for this
world.  'CALNUM?' returns 'CALNUM 1'.  For my purposes and for ease of my
long term maintenance, I think it would be desirable to have sockets for the
EPROM and all three NVRAM's.  That requires 'modification' of an otherwise
pristine meter with the risk of converting my probably 'calable' meter to a
'non-calable' meter.  If I leave it 'un-modified', it is successfully
calibrated and I purchase the service agreement, when the 1997 DALLAS chips
finally die, it gets a nice trip back to Loveland for the 'full repair', all
for the price of $175.20 per year.  If I successfully place sockets without
damaging the A5 board and it is 'calable', I can harvest the data from all
the chips, reinstall the chips, send it in for calibration, harvest the new
data, buy new DALLAS chips (and possibly the latest firmware), program them,
install them and be ready to go for another 10 years or so.

So, the question is which to choose?  Send it in now, hope for 'calability'
and buy the service agreement or modify the A5 board to install sockets?

I would appreciate any and all thoughts.

Thanks in advance.

Joe