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- เผยแพร่เมื่อ 3 ต.ค. 2024
- What's inside a vintage Fluke 5450A Resistance Calibrator used in cal labs to calibrate multimeters?
Schematic: assets.fluke.co...
Coto reed relay: www.farnell.com...
High Resistance measurement with a relay matrix:
• EEVblog #38 - LCR Mete...
• EEVblog #38 2of2 - Sei...
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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
Wish I could afford your equipment. I have to settle for the best Chinese equipment I can find like Rigol.
You deserve respect 👏
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.
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.
One of the best teardowns yet, this thing is like a piece of art.
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!
"Each manufactured and hand assembled by nude virgins in Utopialand. Tested by graybeards. Beautiful." :D
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.
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!
25nA half of a bee's dick - cannot stop from laughing :D
MrocznyTechnik i
Those solder joints are beautiful.
Sprague is still around. Lots of people use them to restore old televisions and radios because they tend to last. Great video as always!
Dave the plate in the 1ohm resistor is Mica not plastic.
"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!
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.
The shielded wound resistors are wound on mica insulators that were also used in HV vacuum tubes, great insulation values.
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
ah good old Zilog, Z-80 how much fun we had with these in 80's :-)
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.
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.
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.
Hi Dave the Screened area is a ribbon wound resistor on a mica former
This thing is a serious piece of art.
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
Some of the "early" gear was sure built to last. Some great history and finds for the teardown tuesdays.
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?
Maybe your best ever. I will never have a chance to see this tech. Many thanks.
@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
Travis Bigelow 10:57
lol @25:10 "telfon", 1979 original typo!
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.
Never heard of Potter Brumfield? They were huge in relays.
Yes, ULN2003 drivers.
One hot peace of electronics Dave.
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.
your screwdrivers still amaze me
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! :)
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).
One of those should be nice to have in my collection 😊
Very cool. I would love to see the inside of those various relays and resistors. Obviously this would be destructive but hey... :)
Yes it is, good catch!
The resistance wire used is probably constantan or manganin or something like that. Low tempco alloy.
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
I worked on pro VTRs and one maker abbreviated "Record Tally" as "rectally".
I need an extender card before I can further do anything useful
I didn't know boards had care factors! Awesome :)
Tohms? Where i work we just call that "open"
What is that, the resistance of 1 foot of vaccuum on the moon?
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?
14:55 Potter and Brumfield also make LOTS of resetable circuit breakers and switch breakers for aircraft.
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
We have 4 of these still in use at the NASA Marshall Space Flight Center. They still serve their purpose.
What EEVblog means is "if someone would kindly loan/donate an extender card, i could go further" :]
This thing is beautiful
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.
Those 1 and 1.9 ohm resistors are wound on mica sheets. Same as normal heating elements.
27:00.... Now you know where the zig-zagged resistor symbol comes from...
ve2zzz 27:00
whats a moldymeter?? sounds nasty!
ericsbuds This accent is one of the may rsns i watch eevblog regularly😂😂😂
agreed. I was trying to make a joke but I am no comedian.
That 'plastic see through former' is mica sheeting!
Unlike modern DMMs, most meters at that time read up to 2, 20, 200, etc. I guess 1.9 was near full scale.
You be surprised!
PS- I'm not a nude virgin.
And there was none of them involved in assembly process? I'm kinda disappointed... :D
Cris Dodds Hahahaha. Great work, Chris.
The Coto equivalent for that is 1240-0177, according to NSN Now.
Awesome video!
Always a fun time
That was wonderful stuff.
It's probably a mica, not acrylic boards (on which 1 and 1.9 resistors are wound).
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)
would have been cool to hear the relays
Potter & Brumfield was *THE* name in relays here in the states. At least they were when I cut my teeth electronics-wise.
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.....
For some crude stuff, yes.
*grin*
On the top shelf porn Tek are still doing ok, but the bottom end peep-show stuff is just old and saggy.
Fascinating! Telfon!
I still dont understand anything one bit, but i watch the entire thing.
19:42 I found a website that could give informations concerning the electrol relays
Very nice video! Thanks!
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?!?
"Upside-down, all the electrons are going to fall out..."
I wonder how many people would actually fall for that :)
28:00 I think it's Glimmer. It is a very good insulator and can handle temperatures around 600°C (soldering).
TIL: "Glimmer" is the German word for "Mica".
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!
I am afraid of asking, but how many arms and legs do you have to pay for such a thing, new?
15:15 low right corner XD
you have to be careful with that,its really hard to put them back in if they fall!
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".
Aren't those mica sheets at 27:17?
Dave,
Does the amount of dust on that board cause any issues with the resistors? Thanks!
potter and brumfeild some of the best relays you can get.
I wish I could offer 2 thumbs up! Very Neat.
Schrodinger's resistors under the can, looking at them changes their value...
You make a good point. I just feel that half of this stuff sometimes obsolete. Like this video when Dave says that a 20 dollar resistor today has the same specs. I'm still watching, but I much prefer something like the Kindle tear down, or a relative modern oscilloscope. I feel that the vintage ones a more for entertainment than practical, useful information.
Are you giving up on the DSA? I believe in you! I know you can do it.
how does a relay with two pins work and what's the point of it?
+Sam Brooks You can't see it in the video but there are 2 additional pins below the main body to energize the coil.
"All the electrons fall out" lol
"That's half a bee's dick...."
So funny! Love your videos!
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?
Is there a reason they would use 162 ohm resistors in parallel when that results in 81 ohm? 81+10+10=101 but on the board it had 100 written?
That's what I was thinking.
In a teardown, is anything in this piece of machinery reusable or worth any money? It is a helluv an engineered piece no doubt.
As always enjoyed it. Do you think the clear 10 ohm former cards could have been Mica?
Have you heard of American Relay?
Hahah! "Half a bee's dick" I love your colloquialisms/sayings
Moldy meter?
Did anyone else notice the rude word at 15:15 ?