Re: [volt-nuts] (New to me) 3458A Trivia
Per my conversation with Gary Biermann, the 4 ppm and the 2 ppm units are the same as the 8 ppm units except they perform better. Purely a selection of best performers and nothing to do with a special circuit. I don't know about Fluke. Joe -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of John Phillips Sent: Tuesday, October 30, 2012 11:07 AM To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] (New to me) 3458A Trivia I think the main thing they do is age and screen. On Tue, Oct 30, 2012 at 6:48 AM, Bill Gold wrote: > Speaking of the 03458-66529 reference board added to the HP 3458A by > Fluke (before Fluke offered the 8508A), has anyone ever seen a > schematic of that board or how Fluke could rate that reference at 2 > ppm? One person on this forum theorized that by lowering the > operating temperature of the LTZ1000A to around 70 degrees C, which is > what the LTC device specification note recommends, this might have > what was done to achieve the better drift specification. It was noted > that HP was running the LTZ1000A at around 105 degrees C which might > accelerate the aging rate. I lowered my references to around 70 C and > they have seemed to be a little more stable when checked against the > Fluke 732A DC Reference Standard. But I never started a project to > follow up on this theory. Just another project to play with when I "get a round toit" > Bill > ___ > 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. > -- John Phillips ___ 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.
Re: [volt-nuts] ESI 2100
Mark has it pretty much, toss in the keyboard switches go bad as well, and even the assembly quality was poor. The product was quite the low point for ESI and basically the end of their instrument line. A friend worked at ESI on their laser trimmer products and did not have many good things to say about their design follow through. -pete On Mon, Oct 29, 2012 at 11:44 PM, Mark Sims wrote: > > A common fault with these is the Mostek CPU/peripheral chips on the > motherboard. The pins corrode away. > Another common fault is with the video monitor. I had one where the socket > on the CRT was bad... intermittent connection to the filament. Another blew > a couple of transistors. Also the pots needed to be cleaned. > ManualsPlus.com has the service manual... $70 > ___ > 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.
Re: [volt-nuts] (New to me) 3458A Trivia
Speaking of the 03458-66529 reference board added to the HP 3458A by Fluke (before Fluke offered the 8508A), has anyone ever seen a schematic of that board or how Fluke could rate that reference at 2 ppm? One person on this forum theorized that by lowering the operating temperature of the LTZ1000A to around 70 degrees C, which is what the LTC device specification note recommends, this might have what was done to achieve the better drift specification. It was noted that HP was running the LTZ1000A at around 105 degrees C which might accelerate the aging rate. I lowered my references to around 70 C and they have seemed to be a little more stable when checked against the Fluke 732A DC Reference Standard. But I never started a project to follow up on this theory. Just another project to play with when I "get a round toit" Bill ___ 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.
