HP 3457a rear panel label - Page 1
Forum section: electronics / testgear

author: BradC
author_rank: Super Contributor
timestamp: August 24, 2017, 05:07:23 am
content: Does anyone know what this yellow label is on the back of my 3457a? I know it's not the serial number label.I'm trying to have Keysight in Australia calibrate the meter, and they are telling me they can't do it without the serial number (which I don't have). Awkward and inconvenient.Unfortunately I bought the meter from an old guy who was closing his shop back in early 2010 while I was in the US, so I've got zero hope of tracing it back from him.I'm hoping that tag is some form of traceable test they might be able to use to dig out the serial number, but it's a kinda vain last-resort sort of hope. I have noticed that a majority of units for sale on-line seem to have that tag, so I'm keeping my fingers crossed it's useful.Anyone have any ideas?

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: August 24, 2017, 08:28:55 am
content: CSACanadian Standards Association, safety certification registration number (for type of product I guess)these guys:ww.csagroup.org/service/certification/Useless for calibration and not related to serial number,Maybe it is useful; on mine the number is A 687 359 so those labels could be serialized after all but that would be strange.The HP serial number tag should be immediately to left of the yellow, it is on mine. I see you have glue residue there so it is off.

author: BradC
author_rank: Super Contributor
timestamp: August 25, 2017, 02:34:22 am
content: Much appreciated. Yeah, the label is long gone.Keysight have said to send it anyway and they'll see what they can do. Not terribly confidence inspiring when you have to send your meter across the country, but I don't really have any other options so I'll roll the dice.

author: AlfBaz
author_rank: Super Contributor
timestamp: August 25, 2017, 11:33:01 am
content: Hey Brad, if you don't mind me asking, how much is it going to cost you, including postage. Also is it just checking to see if it's in spec or is it for adjustment as well?

author: BradC
author_rank: Super Contributor
timestamp: August 25, 2017, 11:39:02 am
content: Quote was for 455+gst for the cal. Paperwork says that is a measure only and adjustment (which it will need) is probably extra.Freight is 135 one way by road. Keysight will return ship as part of the cal.So ultimately I don't know what will wash out.Freight would have been cheaper if I had a decent way of packing it up myself. As I didn't have and couldn't find a suitable box, I paid Pack and Send in Balcatta to do what their name says they do. I had several recommendations for them packing and shipping fragile electronics, so it should get there in one piece.This is a first for me, so it'll be a learning curve.If I need it done again I'll schedule it for June when Keysight have their mobile cal lab in Perth.

author: AlfBaz
author_rank: Super Contributor
timestamp: August 25, 2017, 06:16:40 pm
content: Thanks for the infoPrices aren't as bad as I thought so I might as well go down the same path

author: BradC
author_rank: Super Contributor
timestamp: September 14, 2017, 02:04:02 am
content: Quote from: AlfBaz on August 25, 2017, 06:16:40 pmIt arrived yesterday. Invoice value was as quoted, so they performed a full check & adjustment to reset all cal values, packed it up and shipped it back.I'm pretty impressed with their service actually, the lab was communicative and helpful throughout the whole process.It's nice to turn it on and not have the little error indicator reminding me it's out of whack.

author: AlfBaz
author_rank: Super Contributor
timestamp: September 14, 2017, 12:34:55 pm
content: Good stuff. Thanks for the updateWasn't aware it had an error, did they tell you what it was?

author: BradC
author_rank: Super Contributor
timestamp: September 15, 2017, 12:10:02 am
content: The error was that the battery had gone mostly flat and it had dropped some of its calibration constants. Every power on or self test resulted in the blinking error indicator and further interrogation showed "9 NOT CALD".Interesting tidbit I didn't know before. On power up or test it checks the cal constants for validity and then when you select each function and range it checks the individual values, so if you do see the error you can roll through each range on each function until the error pops up which will tell you which element needs to be recalibrated. My meter failed everything except DCV, 2W ohms and frequency, and a full adjustment was required to clear the cal errors.

author: AlfBaz
author_rank: Super Contributor
timestamp: September 15, 2017, 07:22:07 am
content: Not that I've searched thoroughly but it appears people have found ways to back up cal data on nearly all old hp meters except this one. If only there was more spare time available I'd have a crack at it

author: BradC
author_rank: Super Contributor
timestamp: September 15, 2017, 07:26:51 am
content: Quote from: AlfBaz on September 15, 2017, 07:22:07 amDon't bother. Even if you get it out you'll never get it back in again. Read the manual section on enabling the cal ram /WE line. The designers *really* didn't want any accidental writes to that bit of memory.

author: AlfBaz
author_rank: Super Contributor
timestamp: September 15, 2017, 07:33:06 am
content: Makes sense why it hasnt been done then

author: BradC
author_rank: Super Contributor
timestamp: September 21, 2017, 01:13:51 pm
content: I had some spare time tonight so I grabbed an EPROM dump of the 3457a and thought I'd be clever and run it through the disassembler.Got plenty of valid 6809 code, most of which turned out to be a FORTH machine. The bloody firmware is mostly implemented in a customised version of FIG FORTH.I did find the startup code that determines if it has experienced a reset as part of a calibration sequence and then goes off to unprotect the cal-ram, but it looks like it disappears into a different part of the FORTH machine.I'll add it to my list of things to look at when I next have a couple of hours to burn, but either writing a disassembler for the FORTH code or finding one that might apply is probably more work than I feel like getting into for the sake of it.