I plan on doing a complete cal as well.
On Thu, Aug 21, 2014 at 8:49 AM, Bill Gold <[email protected]> wrote: > Correct, I didn't read the NVRAMS. I didn't have a prom reader/writer that > would handle these devices anyhow and no GPIB interface that worked > anymore. > Actually I have two 3458A. Once I was completely done with the first one > including the cal I didn't even try to put the original NVRAMS removed from > the second meter, just put in the new ones and proceeded to the cal > procedure. > > Bill > > ----- Original Message ----- > From: "J. L. Trantham" <[email protected]> > To: "'Discussion of precise voltage measurement'" <[email protected]> > Sent: Thursday, August 21, 2014 7:53 AM > Subject: Re: [volt-nuts] HP 3458A Mem test 1 hight. How do youread 32K > memorychips? > > > > Bill, > > > > Thanks for the insight. > > > > I always thought that I lost my CALRAM data by trying to read the chip in > my > > programmer while the chip was still warm. What you are saying is that > you > > did not try to read your chip, just unsoldered, installed a socket, > plugged > > it back in and the data was corrupted. > > > > Very interesting. > > > > I have done this to three 3458A's and only lost the data on one of the > > units. > > > > This further supports the need to be able to read the contents before > > unsoldering and have that data be able to be used to program a new chip. > > > > Thanks for the insight and I would love to try some programs to do that. > I > > only have Windows systems but I have several USB to GPIB adapter choices, > > PCI to HPIB adapter choices, and RS232 to GPIB adapter choices. > > > > Joe > > > > -----Original Message----- > > From: [email protected] [mailto:[email protected]] On > > Behalf Of Bill Gold > > Sent: Thursday, August 21, 2014 9:33 AM > > To: Discussion of precise voltage measurement > > Subject: Re: [volt-nuts] HP 3458A Mem test 1 hight. How do you read 32K > > memorychips? > > > > When I removed the original NVRAM devices and then put in sockets, I > plugged > > the original devices back in just to see if everything worked. > Apparently > > some cal data was lost just desoldering the devices as I got error > messages. > > It really didn't concern me as I intended to completely recal the meter > with > > my local "standards" anyhow. It was hours before I plugged the original > > devices back in so they were completely at room temp. My guess was that > > since the date codes were 1992 and I did this in 2010 the batteries were > > almost dead after 18 years and just the shock of desoldering caused "the > > end". > > > > Bill > > ----- Original Message ----- > > From: "Mark Sims" <[email protected]> > > To: <[email protected]> > > Sent: Wednesday, August 20, 2014 7:20 PM > > Subject: [volt-nuts] HP 3458A Mem test 1 hight. How do you read 32K > > memorychips? > > > > > > > The problem with removing the chip and copying it is the very real > chance > > of glitching the contents in the process. Much better to make a backup > copy > > first. > > > > > > The 32Kx8 NVRAMS are used for system memory and things like storage of > > user programs and data. > > > > > > Note that the two 32Kx8 devices are form a 16-bit word. The 2kx8 cal > ram > > is only on the high byte of the data bus. MREAD returns memory contents > as > > a signed integer value (-32768..32767) in ASCII. > > > _______________________________________________ > > > volt-nuts mailing list -- [email protected] > > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > > > and follow the instructions there. > > > > _______________________________________________ > > volt-nuts mailing list -- [email protected] > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > > and follow the instructions there. > > > > _______________________________________________ > > volt-nuts mailing list -- [email protected] > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > > and follow the instructions there. > > _______________________________________________ > volt-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > -- *John Phillips* _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
