EEVblog

Teardown and calibration checking of a Keithley 480 Picoammeter Dave got from ebay.
This was supposed to be a repair and troubleshooting as well, but Murphy had other ideas.
Keithley 480 User & Service Manual: www.ko4bb.com/Manuals/09)_Misc...
Forum Topic: www.eevblog.com/forum/blog/eev...
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[@mrkv4k]

Dave, it's easy... You've just cleaned the main switch conectors from oxidation by switching it on and off few times.

[@timbersrcadventures]

Also short cords are the best

[@LouieMcConnell26]

only EEs are bummed when a product works.

[@friedmule5403]

How do you define a real electronic geek? He is disappointed if things work:-)

[@Pow3llMorgan]

I think Dave is the only person I see on YT who gets upset when things suddenly decide to work after having been seemingly broken ^^

[@billysgeo]

I think the right angle mains cable "strap" on the bottom is there to help the cable wound around the legs (they double as "wound posts" probably).

[@dregenius]

When I was a student at Penn State University the EE stockroom had piles and piles of what appeared to be an early 80's version of that meter. I asked if they didn't replace them with something newer because of budget cuts, and they said it was actually because they'd yet to find a replacement worth their time. I guess these old "Yank-made" Keithley instruments really are worthy of bringing tears to our eyes.. you know, when we actually made good stuff! :|

[@CyrusBrinkworthRAS]

as old it is it is really accurate... they knew what there doing back in 70's, simple & crisp!

[@sbreheny]

Dave: in your explanation of the offset voltage getting multiplied as the feedback resistor goes up - I don't understand why that should produce an increasing error, since the scale factor of the output of the op-amp (i.e., volts per amp) is also going up. I suspect that the reason for the increasing error has something to do with the way they implemented the FET-input buffer on the op-amp but I have not checked the schematic to develop that theory further.

[@AspectOfTheStorm]

24:06 "I'd be a fool to even touch this thing" Huh, the video still has 25 minutes. I feel some touching will be going on

[@pbaemedan]

Thanks for a great video. We have 3 of these meters at our facility. They are used in our Electrostatics lab. You referenced the sheilding contact to the lid. The lid is a carbon load polymer about 1 to 5 Gohms. The shield contact provides a discharge path for the surface charge built-up on the plastic lid. Again, thanks for the effort you put into your productions.

[@foxyrollouts]

I love to watch uncle dave fix stuff b4 my nap time

[@arcadeuk]

It amazes me how accurate alot of your old kit is from this video and some of your others

[@sammy5043]

The A/D chips are in the 177 Microvolt too. That same A/D converter showed up again after 2 years in #777 in another precision Keithley instrument. Tripped me out for a sec

[@JaySmith-cd1ln]

Grabbing my popcorn, I love these videos :)

[@SolidStateWorkshop]

Awesome video Dave. Happy new year!

[@G1BJN]

Memories :) Used these on a daily basis when I worked for IPL (Photodiode manufacturer), great instrument, indispensable :)

[@ViperFallenAngel]

That cord is at the bottom because it was meant to be wrapped around the slotted raised feet :3

[@PinkTurtleFart]

Happy new years!

[@CH_Pechiar]

Dave, the right angled power cable coming out from the bottom of the unit is because the cable can be stored by winding it into the groves molded on the unit's feet.

[@ebmmdawguy]

I like these repair videos, most educational.

[@WayneJohnsonZastil]

Happy New year mate

[@illustriouschin]

i really like the aesthetics of this device

[@thegoodies2]

I've never seen someone so disappointed that a piece of equipment does work.

[@maccartier7287]

I've never heard anybody so disappointed by a device working. XD I see where you're coming from though!

[@digital4282]

I live about 10 minutes from them, they've still got their headquarters at 28775 Aurora Rd Solon, OH 44139 which is kinda cool! I guess they used to make these there too? I don't think they do any manufacturing there anymore. I'll have to drive over there and maybe stop in and see what they do!

[@chrisgreece52]

I think Dave is the only guy on youtube that is dissapointed when a thing works...

[@maeanderdev]

I've had the same idea. I think it's really the most plausible reason which I can hardly believe.

[@rafflesmaos]

Happy New Year Dave! Oddly enough, I got a Keithley 197 from ebay a few days ago that was also shown as powering on and functional, but when it came in it had the same problem! A few hours later, it too started working just fine - after a few power button presses that initially displayed some character errors on the LCD. Wonky switch or overly temperature sensitive soldering joint somewhere, maybe?

[@TheProCactus]

I sure, You knew it wasent going to be much problem. However nice video. Its good to see something I can watch 2 or 3 times :)

[@javiergonzales8487]

Great detailed videos, Thanks ! I have the same problem on many of my sensitive instruments when I use an input bnc cable with leads. Any ideas on how to avoid/minimize the input signal distortion ? An extra grounding capacitor ?

[@hanie1601]

Watching this yesterday I thought maybe I can try fix the faulty ones we have at work. I managed to fix one today. The ranges were all overranged except the 2micro A.

[@andymouse]

I would love it if you did a deep dive into low current measurement.

[@AmericanLocomotive1]

The right angle power cord is so you can easily wrap the cord around the feet for storage/transport.

[@yesitsdawid]

Normal person who recieves a non-functional product: Refund! Dave: Yes! Score!

[@ChuckCLJ]

Thanks Dave!

[@Falcrist]

“Bummer, it works!” I know you wanted a troubleshooting video, but that's just too funny. :D

[@EEVblog]

I've had confirmation that the mains switch in these vintage Keithley instruments is notorious for this problem.

[@jaapweel1]

The Keithley measurement book is available online. KZbin won't let me post a URL, but it's the top hit on Google for "keithley measurement handbook".

[@ElectronicsPubVideos]

Yes dave current leakkage is a absoloute killer for performance of this kind of instruments. I did design a automated capacitor current leakage measurement with a newer model with help of kithey low current switching relay board. Pain in th arse but result came out good. Now they test all the capacitors in europe in my pervious company (which is mother of test and quality of electronics in europe). this brought me good memories of employment time :(

[@davidhoekje7842]

Neat piece. Would you want to short the input terminals to zero out the current meter?

[@MadScientistsLair]

Tektronix bought Keithley at some point....my 2015 THD Multimeter, a relatively recent product, is made in the USA.

[@bionh]

Great video! Do you know how we can pull an output from one of these babies into an arduino or raspi to get an online current trace?

[@jan.tichavsky]

10 picoampere /(charge of electron) = 6.241509×10^7 per second. That's still quite a lot. Now you can get opamps which have input bias currents in femtoampere range and that's really low.

[@Aeduo]

The front panel reminds me of a 70s digital alarm clock combined with a 70s blender. :p

[@laharl2k]

repairing computers i've seen that syndrome lots of times, just live it unpowered to discharge some time (say a month or a week) then plug it. It might not work at first but after a couple of times it will magically start working and after some more power cycles (sometimes wont start) it will stabilize and continue working till the end of times.

[@mrcrud5]

I was told Dave appears in the comments if you say his name three times. Dave, Dave, Dave

[@bertoid]

46:30 Figure 3-1. I just wonder what possessed them to draw it like that. I would have put the resistors and Ohms switch at the top, directly between the polarity switch and the BNC...?

[@ExStaticBass]

I believe the power switch has gone a bit dodgy and needs to be cleaned. It makes sense if you think about it that it wouldn't work if it wasn't making proper contact...

[@AiOinc1]

9:03 Does... Does that fuse have a *resistor* inside of it?

[@sd4dfg2]

Dave should talk to his mailman, and make sure all of his deliveries are dropped at least once before he gets them.

[@aiden1015]

When you look for test equipment on ebay do you look for specific items or do you just do a generic search for "test equipment"?

[@EEVblog]

That Murphy ensures were metric instead of imperial that are needed to tighten the knob grub screw...

[@ivanv754]

EEVBlog: the only place where people get disappointed when things work.

[@Nikkuuu69]

10 picoamps! How many electrons would that be every second? These devices are just awesome for measuring/sourcing currents that small! :)

[@arcadeuk]

The front panel on that looks in great condition for an old lab device

[@elboa8]

Very nice. Happy new year. No hangover!! You're sure you are Australian?

[@tkarlmann]

Inspiring!

[@illustriouschin]

What are a few common electronic devices that might require testing on this scale?

[@speffex]

A LOT- 'round about 62,415,093 electrons per second. An inexpensive LMC6062 typically leaks about 10fA or about 62,415 electrons a second. A modern meter has a bias that is a fraction of that, even. LM6001 is guaranteed to be less than 25fA (same 10fA typical as the much cheaper 6062)

[@barbasbandas6665]

In 2022 who need netflix when you can watch dave dowing a teardown 9 years ago!?

[@twjonckheere]

When it comes to electronics/computers Einstein's saying of "Insanity is doing the same thing over and over again and expecting different results" isn't always true. In this case, the device turning on and working after the Nth try proves that. :)

[@maemaisagat]

Im a bit dissapointed.. i have problems with a display also.. but a my dont work when i test the rezistance on the powercable :))).. btw my is showing OL on rezistance meter.. is that normal?

[@SirBunghole]

The equipment fears you. It knows what you did to that xray machine!

[@MrJohnDevour]

and most other metals would tarnish over time that would change the resistance between the contact points, gold doesn't tarnish.

[@alynicholls3230]

what was that unpopulated dip socket for?.

[@cyberjacob]

gotta ask, what's with the 'Dutatime' licence plate on the shelves?

[@dmarman]

thanks!

[@FlashEF]

Woah, it is clear that you don't drink. Half the Europe has a hangover now, not able to do a teardown :D

[@mikeselectricstuff]

About 50% of things people give me to repair magically start working as soon as I go near them...!

[@frollard]

10:50 battery retainer clip?

[@Desmaad]

What would you need a picoammeter for?

[@GenosetScentia]

This! Happens all the time. Them: "Fix this for me" I go up to it. Me: "But it's working....." Them: "I swear it wasn't working!"

[@iamtemo]

What is the disadvantages of square traces?

[@Arabhacks]

I like looking at how the US product might have this US plug but the otherwise same product has this Huge Australian plug and socket! In the US the flip down plugs. Would that even be possible with Aussie stuff? Enjoy!

[@TheHuesSciTech]

14:33 What's the point of guard rings covered in solder mask? Doesn't that make them completely pointless? A bit of a misstep on the part of the board designer there -- or am I missing something?

[@BaileyWootn]

15:16 That's what she said!

[@AxelWerner]

What did ya payed for this device at ebuy ? whenever i check ebay in germany/europe i feel ripped off. even "kaputt" test equipment there seems to be enormous expensive compared to your prices over there.

[@EEVblog]

Only when he's back from a canyon trip.

[@richardcommins4926]

I watch a lot of your videos and you don't make many mistakes, but you blew it with this video! You are correct that (1V-100uV)/10K = 99.99 uA but (10mV-100uV)/10K = 0.990 uA or 990 nA not 990 uA and (1mV-100uV)/10K = 0.090 uA or 90nA not 90uA . I make electrometers for a living and work down from 1uA to 1fA. Look at my video that measures femtoamps if you want to see really small currents.

[@bertoid]

And doesn't the 1Meg resistor in the input path affect Dave's calculations? I've just built the Gyro@EEVBlog picoammeter adapter (1mV/pA) , and doing what Dave was showing, with 1mV driving through 1G, 1 read 1pA. It reads V/1G for all voltages to well within 1%. It can even resolve 100fA reliably as I change the voltage in 100uV steps. More experimenting is required, but it seems to work really, really well.

[@elektropiragmenos8280]

this picoA ..endering the lab....learned what happend to the Lecrisp with that 40A PS...and thought about it again.....

[@CH_Pechiar]

your avatar explains it all :)

[@Reincarnitor]

Were can one get that t shirt u wear ^^ ?

[@BersekViking]

Ground loop via the mains?

[@38911bytefree]

Happy not meeting Mr Scapel this time !!!!

[@erlendse]

So... Do you take jobs just involving going near stuff? as in the job itself is to just to go near, not looking more closely at stuff..?

[@HennerZeller]

Even if you just once mention the name "Dave", then "Dave" shows up in your comment. Works as well with "XuzJ5Z3".

[@FrankSiler]

It's okay Dave, the "Star Spangled Banner" is quite difficult to sing anyway. ;)

[@MrClaudiodonate]

Only Dave gets disappointed when stuff he bought works.

[@wernertrptube]

congratulation I like your presentations. I also like Keithley. Today I got an ebay Keithley 179A for 50 euro bugs in a perfekt condition only the batteries are down.

[@jan.tichavsky]

check urban dictionary, they have good explanation there

[@4dirt2racer0]

im pretty sure thiss the first time i heard somebody genuinely get upset about something randomly "start" working lol i do get it its jus funny :p

[@remontlive]

somebody tell (spell) me please a word, I can't understand from video. Dave said "shmeeg one" or smeek or shmig. How to write it right? I'm studying English, and can't find out what word is it.

[@SimoWill75]

I don't recall hearing him say it, and I'm not going to go back thru 48 mins, but you may have heard 'Schmick'? It's an Australian saying so would make it likely. It's another way of saying 'very good'.

[@remontlive]

SimoWill75 ou yes! You absolutely right! Thank you very much! I did not know that word. Schmick is right! Good word! Schmick word!)))

[@elboa8]

The word is "Bummer" Noun: A thing that is annoying or disappointing. Exclamation:Used to express frustration or disappointment, typically sympathetically. Enjoy

[@202Electrics]

Sounds familiar here ;)

[@dylanm36]

Haha these are going for $1,125 on some online retailers.

[@EletronManiacos]

Why don't you Teardown your Keithley current source?

[@dmarman]

Hey! English isn't my mother tongue and I'm curious about the word "bama", could anybody tell me how to write it or just the meaning? thanks!

[@fumitakahayashi]

your trouble shooting videos seem to go haywire and the thing starts working on its own. Perhaps you can do a troubleshooting video on the world economy or US healthcare system.

[@Deckardsvr]

the white coat syndrome is strong with you !

[@ChipGuy]

Bummer it is !

[@R4MP4G3RXD]

flying sphagetti monster :DDD