No.041 - HP3457A DMM Repair & GPIB Software Overview
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- Опубликовано: 22 дек 2018
- Purchased from Ebay as "doesn't power up", in this video I get to the bottom of the 'fault', fix it, and then give an overview of the GPIB software I wrote to use with it and other test instruments.
UPDATE: There are theories appearing regarding the 'snipped/broken' wire.....but just to put it out there, it wasn't me as some appear to be saying! Here's a screenshot of the Ebay Ad:
www.ianjohnston.com/images/st...
I don't think it was 'worn' through though, bare minimum the wire was damaged/broken maybe years ago and 'finally' broke on rubbing with the pillar.......which is what I was trying to get at.
GPIB Software (free for Windows) available here:
www.eevblog.com/forum/metrolo...
Also available here:
www.ianjohnston.com/index.php...
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Nice easy repair! I see what you mean by you’re having fun playing around with gpib! Awesome bit of software. Certainly tempting me now to finally give it a go too!
Superb work with the GPIB software Ian.
Wow. I’m blown away. Your software looks amazing. I am going to give it a whirl.
Excellent!!! This video was a nice early XMAS present! Great work on the software you wrote there for the GPIB too =D
Not sure why it took me so long to find your channel: Subscribed.
You can change the LCD display bias to find the sweet spot where the display looks great under your angle view.
Niki
Super, excellent!! thanks a lot!
Slick software!!! Is this Visual basic as well?
Nice repair as well, most of the time it's something plain and simple like this, I find, but I'm sure you would've gotten to the bottom of this anyhow. Please keep the repair videos coming. I learn a lot from those.
Thanks!
It's written in VB written using visual studio.
I have had a couple of bits of gear now which had very obvious “failures” such as a Racal Dana frequency counter where the reference crystal wasn’t plugged in, so yes I am sure that some service people are faking broken gear in order to get new upgraded equipment ! Personally I wished more people did that to give us more stuff on eBay to buy.
Hello Ian what a fantastic video. I really enjoyed the way you explained the fault finding procedure around the PSU. I generally go right to checking for smoke signals but your way is infinitely better. Thanks for the intro to GPIB. I have been thinking of trying to automate frequency sweeps on the 8903, I note Simon Spiers has got his setup that way but I’m perhaps more tempted to purchase a USB based audio analyser. I did buy a HP USB to GPIB interface last your and have not yet unpacked it but could be interesting to have ago in the new year. I liked your control software does it have the option to make the X axis have a log scale? Nice to chat with you and RadioCruncher Graham the other day. Thanks for sharing have a great Christmas and a Happy New Year.
No log scale......however, once I am done making my mods to the code I will publish the source code warts n all.....so if your handy with Visual Studio VB then........
Regarding the clean interior and lack of a fan, Dave Jones mentions in his teardown that you don't want air flow through one of these precision meters as that upsets the thermal stability. Keep it sealed up and the internal temperature stays constant. These 3457A units are pretty nice and sometimes you can get them for good prices.
I guess I was comparing to my 3458A which is an 8.5 digit DMM and it has a fan on the rear, albeit it does have a pretty good micro filter on it which stops a lot of the dust.
Snipped to get it out of company 'salvage' but made it into the wrong hands who didn't use the sidecutters? Merry Christmas and thanks for the videos :) Looking forward to having a play with the software too 👍
These units do tend to be clean whatever else might be going on inside them.
That broken wire was big surprise..
Sometimes, on repairs, i'm to spotted strange faults.. One time i get TV for repair with factory warranty sticker still as new and not broken - TV was 5 years old.. Surprise was when i started closer inspection on PCB - one leg on capacitor was bend and only one was soldered in.. :D I don't remember TV brand and exactly which capacitor was affected, i find it with capacitance tester, start to desolder it because tester can't seen it.. and surprise - i get this capacitor out by desoldering one leg, at first moment i think, that leg is broken and then i spotted bend, uncut leg when turn around capacitor.. :D I straightened leg, soldered it back and all worked fine.. in reality, i don't understand how that TV worked 5 years because no other big capacitors was in the same line.. And in reality, i don't have a time for closer investigation.. But i take picture that's now is laying somewhere in photo archive..
That's for fun.. ;)
I think that, yellow wire may be broken during some hit from back side, during transportation or someone before try to plug in power cable very hard way till the end multiple times and, from eclosure deformations, cut the wire with transformer case.. History of device, anyway, is unknown..
Spotted EEVblog multimeter on the table. :)
Very good explanation of GPIB software. Looks nice! ;)
Hi Ian. I'm a big fan, keep up the good work! Quick question, is the link to the download already modded on EEV for the 3457A (currently using LabVIEW with it which is overkill and I also use the same Excel program because I have 3456A also)? Thanks in advance!
Doesn't need modded as such, you just need to enter the correct gpib commands. The Notepad button opens up a list of sample devices with sample commands, I think i added 3457a in there already. There are soooooo many devices with their own command subset!!
nice software! What do you use to get gpib on PC? something expensive?
You can use 82357B, E5810A as I have tested both. 82357B ebay knock offs seem to work ok.
When did you get the 3458A? I didn't know you had one.
A couple of years ago, I use it to calibrate PDVS2's. I've had two 3458A's actually, I recently bought a faulty one cheap which I fixed and then sold. Wasn't worthy of a video.
Congrats on an easy fix on some nice gear for cheap.
Hi Ian....Is it still possible to source the Keysight IO Libraries for download...It appears that Keysight have decided to charge a License fee per instrument since 2019...This previously came as a bundle with Command Expert.
I have no idea......mone has been loaded on my pc forever. I guess you could google it, somebody may have an older version. Saying that, was there not an option to download the libraries on their own?
@12:19 my suspicious mind wonders if that cut wire was someone's attempt at getting this "faulty" equipment cheap or even free from their place of work. I think it takes a lot of force to completely cut a wire and the break would not be so perfectly clean.
Thanks Ian. You scored.. heh heh, heh heh heh...
Just bought the same meter. Watch out for the mains filter.
Simon Spiers yup, saw your vid just after I had one the auction for this one. Plan is to change the filter when I open her up again. I am hoping to do an LED display conversion.......the current LCD is kinda hopeless. Might be fun.
@@IanScottJohnston Yes u was thinking the same. It looks like the led is held in by a plastic frame that could be cut to allow maybe 4 led's to be fitted. There is a page on the net somewhere of someone modding a 3457a with lots of (in my mind ) unnecessary component changes and hacks. He fitted led's to the edges of the display and it seemed to be worse than before.
This is the one I was thinking off. End result with the yellow is really nice (have tried to contact the guy - no answer yet).......
www.eevblog.com/forum/projects/led-display-for-hp-3457a-multimeter-i-did-it-)/?all
There are others, :
www.eevblog.com/forum/projects/hp-3457a-lcd-backlight-mod-(also-for-3478a)/
xdevs.com/article/hp3457a/#backlight
@@IanScottJohnston That would transform the meter. I wonder if he does a kit ?
@@SoddingaboutSi He talked about developing one but nothing as yet. However, I just bought a spare 3457a LCD and will try converting it from reflective to transmissive and mounting an led backlight behind it.
Not sure if you will read this but do you still use this software for talking all things GPIB please ?...cheers.
I do still use it. Much changed since the video mind you......see EEVBlog thread.
@@IanScottJohnston I will and thanks Ian ! I wasn't sure if youtube told you about comments on old videos
best way to get the boss to buy new equipment for your lab is sabotage cut a wire and its replaced )
That´s rather a clean cut, that´s not done by plastic, I do not buy it that simply. So If we assume your honesty then I would say is that it´s probably an institute, probably but not definitely publicly funded, trying to find an excuse to buy new equipment. These stories are like common secrets...
Thats a good point.......So I went off and looked up the Ebay seller (USA) and it's a seller that just sells anything and everything, not just test instruments and they have a pretty low feedback score. Here's a screenshot of the Ad......I can't believe my honesty is being 'questioned' - www.ianjohnston.com/images/stories/IanJ/GPIB/3457Aebay.png
@@IanScottJohnston
I could well believe your theory about the plastic cutting the wire.
Especially if the transformer isn't on a secure mount, or the case itself is quite pliable.
I've seen the very same thing happen on a few CRTs and VCRs over the years. The cuts can be surprisingly clean if the device had a short sharp knock at some point.
Or, yep, the previous owner or institute did it on purpose. I've seen that sort of thing happen with my own eyes. ie. engineers trying to get an RMA on things. It wouldn't surprise me at all. lol
I personally don't question your honesty at all. If you just wanted to make a repair vid, I know you would have made a far more interesting fault. lol ;)
(but sometimes the simplest faults are fun to find, too, especially if it was a bargain.)
Re. the eBay listing.
The device certainly isn't in Kansas any more. ;)
(I was going to do a joke about the Wichita Lineman, but it was too obvious.)
After re-watching the first part of the vid, I can see now that the trafo is bolted to the backplate, and I'm guessing it simply fits into a slot in the main case?
If the pillar is fairly sturdy when it's all back together, then I think your theory is far more likely.
Somebody has probably plonked the unit down on its corner too roughly, or even dropped it from a short height (maybe onto a workbench.)
One of the signs that the plastic may have cut the wire is when the conductor has retracted very slightly into the insulation on one side of the cut, which is how it seemed in the vid.
(since the cut probably wasn't straight-on when it happened, and could have stretched the insulation slightly, before the conductor itself broke.)
Failure modes like that are often quite interesting, and far more common than people might think.
It came from Shakopee , MN (from the tracking), maybe the seller was in Kansas. I don't think it was 'worn' through, bare minimum the wire was damaged/broken maybe years ago and 'finally' broke on rubbing with the pillar (which I was trying to get at). But the theory about an institute purposely breaking it to gain a budget seems very plausuble and not unheard of.
That cut is too clean to not have been made with a wire cutter.
There was no sign of crushing whatsoever.
You cut this before the video to be able to call it a "repair"
No chance!.........If I ever (which I wouldn't.......) had a mind to do that I would be a lot more inventive.
www.ianjohnston.com/images/stories/IanJ/GPIB/3457Aebay.png
@@IanScottJohnston Kudos, I'm sure you can appreciate it being very suspect plus the fact "repair" is a buzzword.
aqib2000
I can't believe that you said that!
Ian replied, ".If I ever (which I wouldn't.......) had a mind to do that I would be a lot more inventive"
Perhaps you could try following his example and maybe think about the bigger picture here.
@@jonka1 without viewers attracted via use of buzzwords there is no picture. Think
aqib2000
This has nothing to do with buzzwords and everything to do with your shitty comment."You cut this before the video to be able to call it a "repair""