HP 3456A from EBAY has no serial sticker / plate. How can i retrieve the serial  - Page 1
Forum section: electronics / testgear

author: voltampere
author_rank: Regular Contributor
timestamp: May 02, 2017, 10:18:39 pm
content: Dear eevblog community.I bought an HP 3456A on ebay.After some research and reading through the manuals i wanted to check if the model needs any modfications according to the service manual.I found an empty place at the back of the instrument where the serial should be.I already contacted the seller and asked him to provide a proof of ownership and the serial number.No answer so far.Is there any other way to find out the serial number?Is it somewhere coded inside the instrument?I couldnt find any command to read it from the internal memory.I was thinking about getting the instrument calibrated, but the keysight online form for a calibration request needs a model and serial number.Any help or hint is very much appreciated.Thank youjoerg

author: Vgkid
author_rank: Super Contributor
timestamp: May 02, 2017, 10:23:08 pm
content: Open it up, and take pictures, does it have a fan? That way we can determine the age, which affects whether the mod was done, has been done, needs to be done.Might as well any ways, those power supply caps will need to be replaced, unless it had already happened.Realize that HP changed serial number ranges(added a digit), my 34401a apparently doesn't exist according to KS, despite the Agilent Cal sticker.

author: DaJMasta
author_rank: Super Contributor
timestamp: May 02, 2017, 10:33:14 pm
content: A proof of ownership for such an old instrument is a pretty tall order, but I suspect the serial number can be found inside in at least one place. If you really don't want to open it up, instead of using their online calibration request, maybe ask if there's a way to get it calibrated without a visible SN through their customer service.Better yet, find a third party cal lab and ask how much it will be. You can probably get a reasonable price for a 6.5 digit meter and they probably don't care if there isn't a serial number on a 35 year old instrument.

author: plesa
author_rank: Frequent Contributor
timestamp: May 02, 2017, 10:34:28 pm
content: Keysight calibration should not require serial number. They will needs to make sure the instrument is passing self test and/or functional tests.It is pity that there is no serial number, but at the active period of 3456A/3457A the amount of data available based on serial number was limited.This instrument can be calibrated in almost any cal lab near by cheaper I suppose. Here are few member who can help you with calibration.

author: coromonadalix
author_rank: Super Contributor
timestamp: May 03, 2017, 12:52:15 am
content: Interesting link :https://xdevs.com/fix/hp3456a/

author: voltampere
author_rank: Regular Contributor
timestamp: May 03, 2017, 10:02:53 am
content: Thank you for all the fast replies so far!I am not su much worried about the necessary modifications.I agree it should be no problem to look at the pcb and see if those had been performed.The instrument has no fan, i opened it once already to take a peek inside. when i´m back home i will make some pictures.Thanks for the link to xdevs.com, that was already in my bookmark list. Very detailed and informative site!I am planning to renew the capacitors of the power supply.Regarding the calibration i think you are right, it should be cheaper to have it calibrated by a company nearby. Or maybe find somebody nearby with an calibrated meter with sufficient accuracy.As i had no idea about the prices i was wondering how much keysight would charge for that job. So i went to their website and tried the online form. But they are asking for a serial number. I will contact them by mail and explain my problem.My biggest concern is that the serial sticker/plate did not drop off by accident. There is some probability that it was done for a reason. That is why i asked the seller about the serial number and proof of ownership.He did not answer yet. Don't know what that means!Actually i feel a bit stupid because i should have checked the serial right away when the meter arrived.And the ebay description did not have a picture from the back of the meter.Lesson learned!Thanks so farjoerg

author: nctnico
author_rank: Super Contributor
timestamp: May 03, 2017, 11:47:10 am
content: Come on, this is a 35 year old instrument so no need to get all worked up about a serial number. I also strongly doubt a calibration lab still has the equipment to adjust it if it turns out to be out if spec. And if they do it will be terribly expensive.

author: Tony_G
author_rank: Super Contributor
timestamp: May 03, 2017, 02:31:31 pm
content: Keysight US will cal a 3456A for $210 - Not sure what the German cost would be though (I tried changing my country to Germany but the calibration search didn't seem to work)They also seem to get caught up on the serial number thing - I've had them call me because I mistyped the serial number on an 11792A and their process simply couldn't move forward until it was corrected.You might want to drop them an email at "contactcenter_germany@keysight.com" with the subject "Reparatur/Kalibrierung" and ask them about the missing serial number.I've always found them helpful, if it does take a day or two for them to respond.TonyG

author: TimInCanada
author_rank: Regular Contributor
timestamp: May 03, 2017, 09:58:04 pm
content: In answer to an earlier question, there is no serial number inside the meter.It will be useful to go through all the boards anyway because even if you had the serial number that doesn't mean someone didn't swap in older boards from other units.Traceability is the basic reason calibration is done in industry, so cal labs are very big on serial numbers. If you need traceable calibration you could always put your own serial number on the meter. If you don't need traceability you may even be able to find a lab that will do the cal at a lower price.Whether or not the meter is stolen will never be answered. HP made many of these meters and by now most have gone through many hands.Tim

author: voltampere
author_rank: Regular Contributor
timestamp: May 05, 2017, 08:18:49 pm
content: I had email contact with keysight germany.They are asking 245 € for the calibration.They will assign a "new" serial-number so that they can store it in their database.Quote from: TimInCanada on May 03, 2017, 09:58:04 pmI somehow expected that.As it looks right now that should not be a problem.Anyhow, this will be the last piece that i bought without a serial!Thanks for helping so far....joerg

author: free_electron
author_rank: Super Contributor
timestamp: May 05, 2017, 09:31:44 pm
content: Calibrations need ot be traceable.. to do that you need ... a serial number. how else can you verify that particular machine has been calibrated ?the cal certificate lists the identifying number.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 05, 2017, 10:32:20 pm
content: Quote from: free_electron on May 05, 2017, 09:31:44 pmTrue enough. But several cal labs afix their own serial number to an instrument for traceability reasons. It need not be the manufacturer serial number. It sucks to not have a calibration history going back to the date of manufacture, but it beats having nothing.I also don't think you need to assume foul play for a missing serial number. In instruments of this age you find knobs broken off, BNC connectors broken off, frames cracked or broken and handles broken. All due to rough handling. The serial number plate is less exposed than some other things, but can get broken off either when something is dropped and lands wrong or when something is dropped on it. Something as simple as a heavy connector on a cable swinging down and striking the back of the instrument.While some of that abuse is malicious (if I break this thing bad enough maybe they will finally buy me something new and shiny) I really believe most is just carelessness.