Re: [volt-nuts] 3458A reference boards on ebay
http://www.ebay.com/itm/Agilent-Keysight-HP-3458A-Std-Ref-Board-NIST-certified-/310249132548?pt=LH_DefaultDomain_0&hash=item483c4a1204 Try this one... It has a 30 day return and you get a cal voltage with it. On Fri, Jan 30, 2015 at 9:21 PM, Joel Setton wrote: > I'll be happy to design a PCB, and have bare PCB prototypes made. > Sourcing parts and purchasing them will be another, larger project! > > Joel Setton > > > On 30/01/2015 14:24, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: > >> On 30 January 2015 at 12:25, Will wrote: >> >>> The boards are factory rejects. >>> >> I doubt all boards on eBay are in this category. Some are probably >> quite genuine, some may be rejects, and it would never surprise me if >> some are counterfeit. The problem is, I have no idea what ones are >> what. >> >> I don't know what the problems sourcing the parts for making a >> reference would be, but if a number of people wanted to make one from >> parts, perhaps someone could produce a PCB and people contribute >> towards the cost of it. Maybe leave people to get their own reference >> chip, as there are different grades of that. But things like the >> precision resistors may be easier to buy in a quantity of 10 rather >> than 1. >> >> I would certainly not mind buying one if a PCB was available. Even if >> it works out costing a bit more than a 3458A reference from eBay, I'd >> feel a bit happier. >> >> Dave >> ___ >> 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. > -- *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.
Re: [volt-nuts] 3458A reference boards on ebay
I'll be happy to design a PCB, and have bare PCB prototypes made. Sourcing parts and purchasing them will be another, larger project! Joel Setton On 30/01/2015 14:24, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: On 30 January 2015 at 12:25, Will wrote: The boards are factory rejects. I doubt all boards on eBay are in this category. Some are probably quite genuine, some may be rejects, and it would never surprise me if some are counterfeit. The problem is, I have no idea what ones are what. I don't know what the problems sourcing the parts for making a reference would be, but if a number of people wanted to make one from parts, perhaps someone could produce a PCB and people contribute towards the cost of it. Maybe leave people to get their own reference chip, as there are different grades of that. But things like the precision resistors may be easier to buy in a quantity of 10 rather than 1. I would certainly not mind buying one if a PCB was available. Even if it works out costing a bit more than a 3458A reference from eBay, I'd feel a bit happier. Dave ___ 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] 3458A reference boards on ebay
Most likely the boards are real, especially if the boards are from a seller in Colorado since that is where Keysight in the past manufactured and serviced all 3458A's. They still do all calibration in Loveland (I am not sure if Loveland is where service is done today) but this would mean the boards are pulls for either up grade to 002 or HFL boards or worse failed to meet spec. Further I would guess that working boards that meet spec would be retained for future replacements. That said the ones listed do appear genuine. If someone was thinking of duplicating the PCB I may be able to provide one to disassemble and repopulate afterwards. It would be interesting to have a few boards to experiment with. Cheers; Thomas Knox > Date: Fri, 30 Jan 2015 13:24:30 + > From: drkir...@kirkbymicrowave.co.uk > To: volt-nuts@febo.com > Subject: Re: [volt-nuts] 3458A reference boards on ebay > > On 30 January 2015 at 12:25, Will wrote: > > The boards are factory rejects. > > I doubt all boards on eBay are in this category. Some are probably > quite genuine, some may be rejects, and it would never surprise me if > some are counterfeit. The problem is, I have no idea what ones are > what. > > I don't know what the problems sourcing the parts for making a > reference would be, but if a number of people wanted to make one from > parts, perhaps someone could produce a PCB and people contribute > towards the cost of it. Maybe leave people to get their own reference > chip, as there are different grades of that. But things like the > precision resistors may be easier to buy in a quantity of 10 rather > than 1. > > I would certainly not mind buying one if a PCB was available. Even if > it works out costing a bit more than a 3458A reference from eBay, I'd > feel a bit happier. > > Dave > ___ > 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] 3458A reference boards on ebay
I'd go for a deal like that as well. I have a small number of LM399s that I'd like to put to use, as well as a couple LTZ1000A references. A project using either type of reference would be very exciting for me. I have a few old Fluke differential meters that have lots of nice low tempco, high quality resistors that might finally find a useful project such as this. Count me in, Dave M. Dr. David Kirkby (Kirkby Microwave Ltd) wrote: On 30 January 2015 at 12:25, Will wrote: The boards are factory rejects. I doubt all boards on eBay are in this category. Some are probably quite genuine, some may be rejects, and it would never surprise me if some are counterfeit. The problem is, I have no idea what ones are what. I don't know what the problems sourcing the parts for making a reference would be, but if a number of people wanted to make one from parts, perhaps someone could produce a PCB and people contribute towards the cost of it. Maybe leave people to get their own reference chip, as there are different grades of that. But things like the precision resistors may be easier to buy in a quantity of 10 rather than 1. I would certainly not mind buying one if a PCB was available. Even if it works out costing a bit more than a 3458A reference from eBay, I'd feel a bit happier. Dave ___ 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] 3458A reference boards on ebay
There is currently a thread on EEVBlog where one has already been built. I believe it can be purchased once the final layout is completed. http://www.eevblog.com/forum/projects/project-kx-diy-calibrator-reference-sourcemeter/ Todd On Fri, Jan 30, 2015 at 8:24 AM, Dr. David Kirkby (Kirkby Microwave Ltd) < drkir...@kirkbymicrowave.co.uk> wrote: > On 30 January 2015 at 12:25, Will wrote: > > The boards are factory rejects. > > I doubt all boards on eBay are in this category. Some are probably > quite genuine, some may be rejects, and it would never surprise me if > some are counterfeit. The problem is, I have no idea what ones are > what. > > I don't know what the problems sourcing the parts for making a > reference would be, but if a number of people wanted to make one from > parts, perhaps someone could produce a PCB and people contribute > towards the cost of it. Maybe leave people to get their own reference > chip, as there are different grades of that. But things like the > precision resistors may be easier to buy in a quantity of 10 rather > than 1. > > I would certainly not mind buying one if a PCB was available. Even if > it works out costing a bit more than a 3458A reference from eBay, I'd > feel a bit happier. > > Dave > ___ > 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] 3458A reference boards on ebay
On 30 January 2015 at 12:25, Will wrote: > The boards are factory rejects. I doubt all boards on eBay are in this category. Some are probably quite genuine, some may be rejects, and it would never surprise me if some are counterfeit. The problem is, I have no idea what ones are what. I don't know what the problems sourcing the parts for making a reference would be, but if a number of people wanted to make one from parts, perhaps someone could produce a PCB and people contribute towards the cost of it. Maybe leave people to get their own reference chip, as there are different grades of that. But things like the precision resistors may be easier to buy in a quantity of 10 rather than 1. I would certainly not mind buying one if a PCB was available. Even if it works out costing a bit more than a 3458A reference from eBay, I'd feel a bit happier. Dave ___ 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] 3458A reference boards on ebay
The boards are factory rejects. I bought five of them several years ago when the price was around $40. One of them had the heater transistor flipped. Worked fine after reversing the transistor. One had misaligned connector, which would have been easy to repair but the HP policy seems to be reject rather than repair small boards. One had corner of the Vishay resistor cracked. Two of them were cosmetically perfect but had much higher noise than others. Be prepared that there is always something wrong. Could be a good idea to prefer those with some obvious cosmetic problem... > I am puzzled why there are so many reference boards that are supposed to > come from 3458As on the used market. It makes me wonder if they are > genuine. > > One seller, with the two high stability reference boards at $750, claims > that they come from working and recently calibrated 3458As. Why would > anyone wreck a working and recently calibrated 3458A? > > It is not beyond the bounds of possibility that a 3458A might be worth more > in parts than as a complete unit. I know this is true for some HP items, > but I doubt that is the case with a 3458A. > > Another seller, who has them at $395 "or offer", has sold 17 and has 11 > left. > > Although expensive, having two and monitoring the difference between them > would probably allow their stability to be measured with a DVM of modest > specification. > > There are lots of counterfeit components around, and I fear that it could > be some of these boards could fall into that category. This makes the > building a board from new components more attractive. In the short term it > is likely to be less stable than an old reference, but at least one would > know the history of it. If the components were sourced from reliable > sources, it would get around the potential counterfeit problem. > > Dave. > ___ > 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.
