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10 жыл бұрын

What's inside a vintage Fluke 5450A Resistance Calibrator used in cal labs to calibrate multimeters?
Schematic: assets.fluke.com/manuals/5450A...
Coto reed relay: www.farnell.com/datasheets/148...
High Resistance measurement with a relay matrix:
• EEVblog #38 - LCR Mete...
• EEVblog #38 2of2 - Sei...
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Пікірлер: 181

@crisdodds1864 10 жыл бұрын

I enjoyed your video alot. Especially the accent. I started working at Fluke almost 40 years ago next month. My Boss was one of the 5 original employees. My favorite part of my job has been the math, used to match resistors per drawings in order to make these instruments so precise. Thanks for admiring the dedication that I still put into all my jobs that I do here. Cris Dodds

@rsattahip 5 жыл бұрын

Wish I could afford your equipment. I have to settle for the best Chinese equipment I can find like Rigol.

@vishalpatil7974 2 жыл бұрын

You deserve respect 👏

@pezikon 7 жыл бұрын

I had my Fluke 5700A calibrated by Fluke just last year (2015). The cal cert includes a 5450A. So you could say it's still a relevant unit.

@Psychlist1972 10 жыл бұрын

Test equipment doesn't do a whole lot for me, but I really enjoy seeing what people go through to achieve high precision. Another great teardown, Dave.

@RobertBardos 10 жыл бұрын

I loved how u talked it down to a box of resistors in the beginning but it actually ended up being quite a work of art at the end. Good video pretty neat stuff.

@mushroomsamba82 10 жыл бұрын

One of the best teardowns yet, this thing is like a piece of art.

@EEVblog 10 жыл бұрын

Even if you used modern $20 resistors, you'd still need the special relays and careful design shown in this design to give the same functionality. The product may be vintage, but the design rules are not!

@NathonDalton 10 жыл бұрын

I love your videos. I'm new to the EEVBlog and have already learned so much! Thank you very much for taking time out of what I'm sure is a busy schedule to make these videos!

@kevincozens6837 5 жыл бұрын

My cat and I both enjoyed the video although the cat was more interested in pawing at the screen trying to catch the black pointer you were waving around. :) I also noticed at the 25 minute mark the schematic mentioned the use of special "telfon" standoffs.

@strangersound 8 жыл бұрын

"Each manufactured and hand assembled by nude virgins in Utopialand. Tested by graybeards. Beautiful." :D

@KenYOW Жыл бұрын

Those solder joints are beautiful.

@wetwingnut 10 жыл бұрын

"All the electrons are going to fall out." LOL Dave, you know why you're successful? Because even when I'm not particularly interested in the topic I still make time to watch you because I know I'll always be entertained. Thanks mate!

@MarkShannonroad_videos 10 жыл бұрын

Sprague is still around. Lots of people use them to restore old televisions and radios because they tend to last. Great video as always!

@vmiguel1988 5 жыл бұрын

Dave the plate in the 1ohm resistor is Mica not plastic.

@Damien.D 7 жыл бұрын

This thing is a serious piece of art.

@gglovato 10 жыл бұрын

lol @25:10 "telfon", 1979 original typo!

@Avionics1958 10 жыл бұрын

ah good old Zilog, Z-80 how much fun we had with these in 80's :-)

@theoryof9 10 жыл бұрын

The shielded wound resistors are wound on mica insulators that were also used in HV vacuum tubes, great insulation values.

@ryankelzenberg3453 10 жыл бұрын

Some of the "early" gear was sure built to last. Some great history and finds for the teardown tuesdays.

@rsutherland76 10 жыл бұрын

Yes it is, good catch!

@WooShell 9 жыл бұрын

Re 12:30 - Sprague joined Vishay a decade or two ago.. and I wouldn't be surprised if they were still behind their power elcap series.

@crocellian2972 9 жыл бұрын

Maybe your best ever. I will never have a chance to see this tech. Many thanks.

@twomorestars 10 жыл бұрын

Awesome video!

@treborrrrr 10 жыл бұрын

I always find it hilarious how Dave just can't quite resist poking at things. Not saying that the little taps with the plastic spudger would actually do anything but with all the talk prior to popping the lid off... :P

@edherdman9973 10 жыл бұрын

So, about that linear regulator, two ideas: 1) To keep the heat from bothering other parts? 2) To make sure that it was conducting heat out into the chassis, but they didn't want any stresses on the chassis being transferred into the linear regulator's soldering points, so they used the flexible cable for a standoff? I like the second idea better, could it be something else though?

@smbrob 10 жыл бұрын

One hot peace of electronics Dave.

@MrocznyTechnik 10 жыл бұрын

25nA half of a bee's dick - cannot stop from laughing :D

@materialsguy2002 7 жыл бұрын

MrocznyTechnik i

@MarkShannonroad_videos 10 жыл бұрын

I stand corrected. A lot has changed in the world of component makers over the last 25 years. At least the name hasn't been bastardized like some in the industry. Thank you for the correction.

@antonioferraoneto6681 7 жыл бұрын

Very nice video! Thanks!

@johnclawed 6 жыл бұрын

Never heard of Potter Brumfield? They were huge in relays.

@scottgfx 10 жыл бұрын

I'm not sure why they exist, but they do make GPIB 488 to USB adapters! 25 years ago we had a Tek plotter with a GPIB interface donated to the art lab at my college. Sadly, we didn't have anything that would talk to it. Didn't have the internet back then to look up Microchannel GPIB cards! :)

@martinda7446 9 жыл бұрын

That was wonderful stuff.

@douro20 10 жыл бұрын

It's probably a silver-tin alloy with high silver content, and I would imagine that it was soldered without flux, in a glove box under an argon atmosphere.

@matthewrichardson828 6 жыл бұрын

This thing is beautiful

@pigpenpete 10 жыл бұрын

In our lab we're still using a vintage Wavetek 4808 multifunction calibrator but we've characterized it over a fair few years and we can get fairly good uncertainties exceeding the original specification, good enough for most 8.5 digit long scale DMMs anyway.

@johantoftling5518 6 ай бұрын

One of those should be nice to have in my collection 😊

@excavatoree 10 жыл бұрын

The bus company I worked for used them for the chassis power circuits. P&B "ice cube" relays were rated at 40 Amperes, while the rest were 30A or 20A. We only used P&B and Bosch. Now, my current company uses Tyco relays that I believe are no longer made in the USA.

@AmirHakimiRezaei 10 жыл бұрын

your screwdrivers still amaze me

@paulbendel 10 жыл бұрын

I didn't know boards had care factors! Awesome :)

@LawrenceDuffy477 10 жыл бұрын

Always a fun time

@topxe. 10 жыл бұрын

Very cool. I would love to see the inside of those various relays and resistors. Obviously this would be destructive but hey... :)

@mtravnik84 2 жыл бұрын

We have 4 of these still in use at the NASA Marshall Space Flight Center. They still serve their purpose.

@bazathemanyoungG0SCI 10 жыл бұрын

Hi Dave the Screened area is a ribbon wound resistor on a mica former

@Eman2000 10 жыл бұрын

i have heard of Potter and Burmfield (P&B) i have a 4PDT relay from them in the original box. the box says that they make electromechanical relays, solid state relays, time delay relays, specialty sensors, circuit breakers, solenoids, contactors, sockets and accessories at least at the time this was made, the box also says made in the USA

@travisbigelow823 10 жыл бұрын

@10:57-"you're only talking ten nanoamps... it's naff all, half a bees dick" HAHAHA! I love Aussie slang. Thanks for the video Dave. You're just as entertaining as you are informative, as usual :D

@matthew3p 7 жыл бұрын

Travis Bigelow 10:57

@CoolMusicToMyEars 2 жыл бұрын

I always wanted the Fluke 5450A resistance standard, but what a cost in those days & these days, I like it, but 4 Terminal Resistors in oil bath are far better

@anachrocomputer 8 жыл бұрын

Not only are the relay poles in parallel, they're in inverse parallel. The wiper end on one pole connects to the fixed contact on the other pole. I wonder if that's for easier PCB layout? Or is it done that way to minimise the effects of the metal-to-metal contact in the relay? Thermal EMFs? Differences in contact resistance with polarity?

@cryptsys 10 жыл бұрын

What EEVblog means is "if someone would kindly loan/donate an extender card, i could go further" :]

@whitcwa 10 жыл бұрын

I worked on pro VTRs and one maker abbreviated "Record Tally" as "rectally".

@NickMoore 10 жыл бұрын

Tohms? Where i work we just call that "open"

@Bubu567 3 жыл бұрын

What is that, the resistance of 1 foot of vaccuum on the moon?

@ericsbuds 9 жыл бұрын

whats a moldymeter?? sounds nasty!

@anuragsaha9641 7 жыл бұрын

ericsbuds This accent is one of the may rsns i watch eevblog regularly😂😂😂

@ericsbuds 7 жыл бұрын

agreed. I was trying to make a joke but I am no comedian.

@alpcns 10 жыл бұрын

Now THAT's a horrible thought:-) Thanks for another great video, Dave! How is that impressive back-to-the-future display doing? I would love to see it working!

@simoncrabb 10 жыл бұрын

Fascinating! Telfon!

@EEVblog 10 жыл бұрын

Yes, ULN2003 drivers.

@skonkfactory 10 жыл бұрын

The resistance wire used is probably constantan or manganin or something like that. Low tempco alloy.

@JosefdeJoanelli 10 жыл бұрын

14:55 Potter and Brumfield also make LOTS of resetable circuit breakers and switch breakers for aircraft.

@ve2zzz 10 жыл бұрын

27:00.... Now you know where the zig-zagged resistor symbol comes from...

@matthew3p 7 жыл бұрын

ve2zzz 27:00

@TheHuesSciTech 7 жыл бұрын

The relays do NOT have to have ultra low or ultra consistent contact resistance in 4-wire mode. The inherent advantages of 4-wire mode apply to relay contacts as well, as long as you invest in double the number of relays, or dual-throw relays (since you need to switch both sense and force).

@TestTubeBabySpy 6 жыл бұрын

would have been cool to hear the relays

@EEVblog 10 жыл бұрын

I need an extender card before I can further do anything useful

@rsnilssen 10 жыл бұрын

considering its a ten year old design at the guesstimated date of production maybe the flatflex was added to accomodate some change in production at some point during the lifetime of the design

@EEVblog 10 жыл бұрын

You be surprised!

@cemx86 10 жыл бұрын

Potter & Brumfield was *THE* name in relays here in the states. At least they were when I cut my teeth electronics-wise.

@rustyrebar9647 4 жыл бұрын

That 'plastic see through former' is mica sheeting!

@whitcwa 10 жыл бұрын

Unlike modern DMMs, most meters at that time read up to 2, 20, 200, etc. I guess 1.9 was near full scale.

@bain5872 10 жыл бұрын

As always enjoyed it. Do you think the clear 10 ohm former cards could have been Mica?

@rcleveacp 10 жыл бұрын

I wish I could offer 2 thumbs up! Very Neat.

@douro20 10 жыл бұрын

The Coto equivalent for that is 1240-0177, according to NSN Now.

@aphexteknol 10 жыл бұрын

14:15 "Alright, lets lift the skirt up, this is what we wanna see! I better not breathe on this thing, I better not sneeze, because we could be in trouble if I do that. I definitely won't be touching anything inside here, I'll have a poke around..." Wow Dave, innuendo much? Just kidding! Loving the teardowns as usual.....

@berni8k 10 жыл бұрын

While it is nice to see the guts of modern gear, those teardowns are usually not as fun since its alaways some BGA SOC processor, meaby a FPGA and varius tiny SMD bits around. While in vintage gear you always see some neat tricks they used to get around the limitations of technology back then(I absolutely loved the vintage high speed camera teardowns that tesla500 did)

@crisdodds1864 10 жыл бұрын

PS- I'm not a nude virgin.

@baroque_engineer 10 жыл бұрын

And there was none of them involved in assembly process? I'm kinda disappointed... :D

@MaxKoschuh 9 жыл бұрын

Cris Dodds Hahahaha. Great work, Chris.

@digital4282 10 жыл бұрын

Dave, Does the amount of dust on that board cause any issues with the resistors? Thanks!

@TheOriginalEviltech 10 жыл бұрын

Those 1 and 1.9 ohm resistors are wound on mica sheets. Same as normal heating elements.

@williamsquires3070 10 жыл бұрын

Okay, but what I didn't see are the back-EMF protection diodes for the relay coils... or, for that matter, driver transistors. Dave, did you note any ULN-series driver ICs for these things?!?

@cemx86 10 жыл бұрын

The spare fuses was a nice touch. I also noticed next to the huge blue Sprague cap (look at the size of the bracket!) something held in what looks like a fuse clips but it has leads and is soldered in place. What was that? Why the clips?

@robber576 6 жыл бұрын

I wonder if you would need to use a special high conductivity solder for such a unit? , and what would that be? , high in silver?

@archonc 10 жыл бұрын

15:15 low right corner XD

@sheldonholy 10 жыл бұрын

"Upside-down, all the electrons are going to fall out..." I wonder how many people would actually fall for that :)

@kcasc_hd 2 жыл бұрын

19:42 I found a website that could give informations concerning the electrol relays

@calmarcalmar 10 жыл бұрын

not sure guessing: 0.1 + 0.9 = 1 1 + 9 = 10 10 + 90 = 100 100 + 900 = 1000 So when you connect all the small ohm together with the bigger ones, .you get 1.. stuff.

@chrisandcarleen 10 жыл бұрын

potter and brumfeild some of the best relays you can get.

@Q8Police777 10 жыл бұрын

I still dont understand anything one bit, but i watch the entire thing.

@EEVblog 10 жыл бұрын

For some crude stuff, yes.

@Razor2048 10 жыл бұрын

Can those resistors and other parts be re purposed for other devices? eg repairing cheap electronics :) One thing I wonder, how do they get the initial calibration for the first ever device, eg who made the first ever resistance standard and how did they know when that was accurate when there is no other calibration device to compare it to?

@chemtype 10 жыл бұрын

Are you giving up on the DSA? I believe in you! I know you can do it.

@wetwingnut 10 жыл бұрын

That's a really good idea. What brand do you use? ;)

@oetken007 7 жыл бұрын

28:00 I think it's Glimmer. It is a very good insulator and can handle temperatures around 600°C (soldering).

@bur1t0 7 жыл бұрын

TIL: "Glimmer" is the German word for "Mica".

@SergeiKotikov 6 жыл бұрын

Aren't those mica sheets at 27:17?

@petersage5157 6 жыл бұрын

28:00 With the solder connections to those resistors, I doubt they're nicrhome. Basic metallurgy - solder takes to nichrome about as well as it does to aluminum. Of course Dave probably realized this moments after he said "nichrome".