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" <jlt...@att.net> To: "'Discussion of precise voltage measurement'" <volt-nuts@febo.com> 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: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] 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" <hol...@hotmail.com> > To: <volt-nuts@febo.com> > 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 -- volt-nuts@febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > > and follow the instructions there. > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
