[volt-nuts] 3458A Questions - The Sequel

Electronics and Books electronicsandbooks at yahoo.com
Sat Oct 29 10:52:46 UTC 2011

Best is to solder out the Dallas RAMs and the EPROM. You can then put sockets in. The Dallas RAMs are readable as an eprom and on an eprom programmer also writable. Desoldering and soldering new sockets took me an hour. My firmware is marked 9017. Does anyone has a newer version on file.


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From: J. L. Trantham <jltran at att.net>

To: volt-nuts at febo.com
Sent: Saturday, October 29, 2011 5:41 AM
Subject: [volt-nuts] 3458A Questions - The Sequel

Considering all the info this group supplied, I wound up with a new (to me)
3458A that was offered on theBay as a BIN or Best Offer.  We negotiated back
and forth and I wound up with SN 2823A18533, no options, delivered for less
than $3800.  Perhaps more than the $2500 suggested by other list members but
I am happy.

It has been on for about a month now and reads my two Fluke 731B's about 15
uV apart and it drifts up and down about 10 uV, P-P, at 10V, but with a
relatively stable 15 uV difference between the 731B's.  It has ver 8.2
firmware and all the date codes on the chips along with the dates stamped on
the various covers and boards are all around Aug 1997.  The bottom cover has
'Aug 20 1997' and the top cover has 'AUG 22 1997' stamped on.  IIRC, Agilent
was born around 1999.  Later, in the early 2000's, manufacturing was moved
from the US to Malaysia.

I talked to the folks at Agilent regarding 'new vs. a fine vintage' and they
suggested, similar to others on the list, that a 'fine vintage' at the right
price coupled with their 'Repair Per Incident' at $2363.56 would be the
preferred approach.  They basically disassemble the unit, check everything,
including the 'crimps' on the cables, repair or replace whatever is needed,
test it 'to new standards', do a 'Gold Cal' (IIRC), and return it basically
as a 'new unit' including the option to purchase a 3 year extended warranty
on the meter.

The 'drift' issue of the reference is not tested for a non Option 002 unit
but when the next 'Gold Cal' is done, the drift would be provided as
compared to the first 'Gold Cal'.

List members suggested that I back up 'CALRAM' ASAP.  I would agree.  How do
I do it?  The Dallas chips are soldered in place.  By HPIB I presume?  That
means that I am finally going to have to solve the 'HPIB issue'.  Or is it
available from the front panel?

Of course, if I send it back to Agilent, backing up 'CALRAM' is less
important, at this time at least.

My A5 board is 03458-66505 Rev C.  I note that the Option 001 board is
03458-66515.  Other than the installation of the four HM66256LP-12 chips,
which would appear to be about a $30 investment, is there any difference
between the boards?  Does the firmware need to be changed to acknowledge the
presence of Option 001?  Is there a way to tell if the chips are installed
using front panel controls?  Using HPIB?  I notice that there are two
'jumpers' in the vicinity, JM600 and JM132.  Are these involved?  On my
board, both jumpers connect the center pin and the pin to the left, as
viewed from the front, and as shown on the labeling on the board.

I also note that on my A5 board, there is a single ST M27C4002-12F1 chip,
soldered in place, instead of the six TM27C512's shown in the CLIP and the
ALRM.  Unless there is a way to read the chip, installed, erase it,
installed, and reprogram it, installed, to upgrade the firmware to ver 9
would require the removal of the chip, installation of a socket, then
installing a new chip with the latest data programmed in.  I don't know if
this is done or not.  When I spoke with the folks at Agilent, I was given
the impression that part of the 'repair' was to upgrade everything to the
latest version by replacing the appropriate components rather than replacing
the various boards, citing the desire not to change the 'character' of the
meter by virtue of keeping all the 'aged' components possible.

Therefore, the question arises as to how practical is it to remove the three
Dallas chips (perhaps it is only one that needs to be archived) and the
single EPROM with a hot air rework station, install sockets, archive the
data, then reinstall the chips in the newly installed sockets?  Is the board
just a dual level board or multiple layers?  If I am going to send it back
to Agilent for their 'repair', would it be desirable to make the attempt

Again, thanks to everyone on the list for their input and I look forward to
more input.


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