FS (DK/EU): HP 83731A 1-20Ghz Signal Gen - Page 1
Forum section: electronics / general

author: Stigaard
author_rank: Contributor
timestamp: April 09, 2017, 05:32:33 pm
content: I won an military auction lot recently which included a HP 83731A signal generator as I have no use for it or even much idea of what to use it for (other than from Shahriar's awesome videos) I thought it might as well find a new home where it could see actual use.The unit has the following options installed83731A - 1E1 ADD 90DB OUTPUT STEP ATTENUATOR83731A - 1E5 ADD HIGH-STABILITY TIMEBASE83731A - 1E8 ADDS 1HZ FREQUENCY RESOLUTIONAnd was last calibrated by Trescal on the 22-09-2014 and passes the self test.A quick browse on google gives the following linksDatasheet:http://www.axiomtest.com/documents/models/Keysight%2083731A%20Data%20Sheet.pdfManual:https://www.topdogtest.com/inventorypdf/83731AOpGuide_usr,ops.pdfService manual:http://exodus.poly.edu/~kurt/manuals/manuals/HP%20Agilent/HP%2083731A,%2031B,%2032A,%2032B%20Service%20Guide.pdfI honestly have no idea of the value of this instrument, however browsing on ebay have the cheapest buy it now for 3700 €, that unit does however not have the high resolution option but instead has a modulation option so not fully comparable.Just to start somewhere let us say 3000 €, but please if you have any intelligent input on this feel free to sent me a pm or leave a post, especially if you are not looking to buy yourself

author: G0HZU
author_rank: Super Contributor
timestamp: April 13, 2017, 12:56:31 am
content: The prices for these tends to vary a lot. If you sell one untested (as yours appears to be) then I think you may struggle to get 1800 euros for it. But if you had it calibrated and verified and offered a short warranty with it then you would attract the buyers with much deeper pockets. You could easily get 5000 euros for it maybe much more.These things are not always easy to service or repair especially if there is a fault with the RF output section. So if there is an issue with the ALC or the attenuator or the synthesiser then the unit could be classed as beyond economic repair.I have the HP 83752A synthesised 20GHz sweep generator which is in a similar performance class and it is a wonderful piece of test equipment. My advice would be to try and find a way to verify/guarantee the performance if you want 3000 euros for it. However, you might get lucky and find a keen buyer willing to take a risk. At auction they tend to sell for about 1500 euros if there is no indication that they are fully working.

author: Stigaard
author_rank: Contributor
timestamp: April 13, 2017, 06:44:54 am
content: Quote from: G0HZU on April 13, 2017, 12:56:31 amThank you for your elaborate answer I really appreciate it.I have requested a quote from Trescal for calibration as I have every reason to believe the unit is perfectly fine since the papers states "decommissioned due to it no longer being needed, but too good to throw away" and besides passes self-test.Depending on how steep the quote is, I can then make a informed decision of whether it makes sense to have it calibrated.

author: petemate
author_rank: Regular Contributor
timestamp: April 13, 2017, 07:59:38 pm
content: Hi, just out of curiosity - where do you find these kind of auctions in Denmark? I'd like to get in on it

author: Neganur
author_rank: Unknown
timestamp: April 14, 2017, 10:13:55 am
content: Quote from: Stigaard on April 13, 2017, 06:44:54 amKeysight takes USD 988 to cal this unit and they are able to do alignments. (I'm sure Trescal DK does a fine job too)

author: G0HZU
author_rank: Super Contributor
timestamp: April 14, 2017, 11:15:29 pm
content: One potential issue with sending it for calibration is if it fails to meet the calibration limits. You end up paying money for a failed calibration. The choice then is to pay for a repair (massive money) or lose money on a failed calibration.I think there are various types of buyer for instruments like this. The buyer with the deepest pockets will be a company that already has one of these on an ATE production line. If their generator has failed then they will want a repair or replacement asap. But they will generally go to a reputable dealer for a replacement and they will want a fresh calibration and a warranty. They would pay >5000 euros.The next type of buyer would be a company who wants one of these for research and dev work. So they would pay maybe 3500 euros for an instrument that has been properly tested with a recent cal certificate.The next would be a dealer who would probably want to pay 1500-1800 euros with the hope it can be calibrated and sold to a company with deep pockets once calibrated etc.Further down the chain would be a private buyer who probably only wants to pay 1000-1500 euros.

author: Stigaard
author_rank: Contributor
timestamp: April 17, 2017, 03:37:44 pm
content: Quote from: petemate on April 13, 2017, 07:59:38 pmI am afraid I have not found a nirvana of cheap test equipment, this particular lot was bought from retrade.dk which is a general auction site, which does however seem to get some gear from the Danish military, but as I said do not get your hopes up test gear is really rare

author: Stigaard
author_rank: Contributor
timestamp: April 17, 2017, 03:42:44 pm
content: Quote from: G0HZU on April 14, 2017, 11:15:29 pmI hear you, the dealer is probably gonna be hard to find, my current thoughts are to order the calibration when and if I have a buyer lined up.Clearly as you said there is always the risk of the calibration failing, and me having to pay anyway however as I have a fairly good confidence in the gear I would be willing to make that bet.

author: Stigaard
author_rank: Contributor
timestamp: April 17, 2017, 03:45:28 pm
content: Quote from: Neganur on April 14, 2017, 10:13:55 amThanks, that will give me some reference once Trescal gets back to me after the holidays. The reason for Trescal is that it is currently their sticker on the unit and therefore I am hoping that they can also provide the calibration history of the unit

author: G0HZU
author_rank: Super Contributor
timestamp: April 17, 2017, 04:24:33 pm
content: QuoteYes, that's probably the best way to do it, especially if you can afford to wait to find the right (desperate?) buyer with deep pockets. Offer them an agreed price subject to it passing a calibration at Trescal.You could end up getting much more than 3000 euros this way, especially with the desirable options it has. However, you have to be able to find that buyer and also compete with real dealers who may offer a warranty.

author: nctnico
author_rank: Super Contributor
timestamp: April 17, 2017, 05:17:47 pm
content: I don't think having it calibrated will be worth it. It will be much like putting new tires on a car you are going to sell. You won't recoup the money. An equipment dealer may be able to offer a replacement in case something turns out to be wrong. If you aren't an equipment dealer then all you can do is offer a money back guarantee and who is going to pay for the return shipping?I'd try to get some screenshots from a spectrum analyser showing it works and put it on Ebay with a 30 warranty. This HP 83731A has all the desireable options and a fairly recent calibration so it will fetch a nice sum of money anyway.

author: G0HZU
author_rank: Super Contributor
timestamp: April 17, 2017, 06:15:10 pm
content: Quote from: nctnico on April 17, 2017, 05:17:47 pmYour strategy will alienate the best buyers and this then degrades to be an ebay sale of a generator that might work but the seller can't test it properly. So it becomes 'untested' to the best buyers and a huge risk. To test it properly needs some decent test gear and a knowledgeable operator and this would cost time and money similar to a calibration.QuoteDo you understand how special this generator is? This is a fabulous and extremely complex and fragile piece of test gear. Have a look at the spread in prices on ebay or from specialist test equipment retailers. A working one is worth a lot of money. One that kind of works is worth a lot less. One that has a fault with the ALC or attenuator will become a money pit if you want to repair it. If you want to pry away my 20GHz HP 83752A from me you would need to offer me huge money. But it isn't for sale. I'd be just as reluctant to sell a fully working HP 83731A if I had one. I'd want huge money. Way more than the numbers being discussed here.

author: Stigaard
author_rank: Contributor
timestamp: April 17, 2017, 06:27:31 pm
content: Quote from: nctnico on April 17, 2017, 05:17:47 pmThe plan I have so far is to get a quote on the testing and make the sale of the unit such that the buyer have the choice of either paying for a new calibration at a known price in which I take the risk should the unit not pass, it is of cause always a risk but on the other hand I am not interested in cheating anyone. Alternatively the buyer can choose not to have the unit verified any further than self-test as I do not have the equipment to do the proper testing myself, (not even a spectrum analyzer, frequency counter or power meter in this frequency range), in this case the buyer has the risk as I would be unable to verify any claims.

author: nctnico
author_rank: Super Contributor
timestamp: April 17, 2017, 06:56:59 pm
content: Quote from: G0HZU on April 17, 2017, 06:15:10 pmThe best buyers will be alienated anyway if the seller isn't a reputable test equipment dealer which can offer a decent (1 year?) warranty. Just look at the prices near brand new high end Keysight scopes sell for when sold by an individual.

author: G0HZU
author_rank: Super Contributor
timestamp: April 17, 2017, 07:05:26 pm
content: Quote from: nctnico on April 17, 2017, 06:56:59 pmThat's true but I think this generator will lose a lot of potential value if sold as seen and untested.My own impression of this generator is that it looks to be in nice condition. Some of them see a hard life and can be battle scarred and scruffy. The biggest negative for me is that the Trescal 'tamper' seals have vanished from the rear of the instrument indicating the possibility that someone has taken the covers off it since it was last calibrated. Why would they do this? To look inside or to try and fix a fault? This ramps up the risk factor for a serious buyer.

author: G0HZU
author_rank: Super Contributor
timestamp: April 17, 2017, 07:22:15 pm
content: My HP83752A was last calibrated in 2014 and it still has the anti tamper seals on it as you can see below. I know the history of my generator over several calibrations so I know the tamper seals are genuine even though they are starting to fall off...I'm assuming that your generator once had seals over the screws like these ones?

author: Stigaard
author_rank: Contributor
timestamp: April 17, 2017, 07:41:48 pm
content: Quote from: G0HZU on April 17, 2017, 07:22:15 pmThat would make sense, however I never saw such stickers on there and neither does there seem to be any sticky residue on there, but I would expect Trescal to leave some sort of seal on there.