Beautiful TEC Digital Switch Display Module
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- เผยแพร่เมื่อ 3 มิ.ย. 2024
- Another TEClite display, this one bought just because it looked like it would be cool - and it is! Really a piece of beautiful design from a time when reliability and ruggedness really mattered. Enjoy!
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These displays were used on Burroughs mainframes like the B3500 and B4700 to display state information. They plugged onto connectors on the back of circuit cards and could be installed / removed while running. The clips are for right angle metal pieces ("brackets") embossed with signal names for each card location. There was a full set of brackets supplied with each system but a lesser quantity of display modules as [the theory was] only those required for a specific trouble shooting task were required at any given time. The associated flip flops for each switch / indicator could be set by pushing the switches and, IIRC, the yellow buttons cleared / reset the associated flip flops for each indicator bank on the connected card.
that style of resistors were the nicest looking of any resistors ever made. Neat perfect cylinders with precisely applied, bright and distinct color bands.
Yes... Carbon Composite for the win.
NOT like the resistors of today with LIGHT BLUE bodies, making ORANGE and RED bands nearly indistinguishable from each other :(
I prefer my resistors to be the size of a rice grain.😂
Sesame sized SMD resistors 😳
Those Allen-Bradley carbon-comp resistors were arguably the pinnacle of wire-lead component design and manufacture. (Something that is perhaps obvious only in hind-sight.) By contrast, the SMD components in the modern era are nearly indistinguishable microscopic rectangular lumps of whatever. The popular vintage electronic repair channel "Mr Carlson's Lab" frequently comments on those rectangular A-B resistors and their superiority to the other resistors of the era (porus-looking gray bodies with rounded ends). The crisp A-B resistors are almost always able to faithfully hold their value for decades even in harsh environments. Whereas the other "roundie" resistors have very frequently drifted and will require replacement when reviving an old circuit.
I can imagine the magnetic switches would also make it very useful in a ‘dirty’ or otherwise sensitive environment where you need a reliable switch no matter what’s in the air.
I love that it’s from Eden Prairie! Still tons of very high-end tech manufacturing and engineering going on there, like a tiny cold version of Mountain View.
Awwwww! A thing of beauty, a joy for ever. Very simple and reliable. Looks like you could flip bits on two bytes, haha!
Agreed that the sealed magnetic reed switches promise extra-long life expectancy. And the mechanical design is just short of elegant. However, those incandescent lamps really negate the expectation of long functional lifetime. And their deep internal location and soldered-in deployment make for a very repair-hostile product. PROUD PATREON SUPPORTER OF FRAN LAB
The limiting resistor and standby state would mean that these lamps would last a very long time in operation.
For some reason this brought Fritz Lang's "Metropolis" movie to my mind. Its a real beauty!
the vacume sealed magnetic reed switches are also explosion safe, and can be used in environments with volatile gasses present!!
I noticed that each lamp lens had a tiny Fresnel lens inside to better direct the light from the bulb in a forward direction, and probably to even out the tendency to have a hot spot of light.
They’re called magnetic reed switches. The Western Electric 1ESS telephone switch used thousands of them in their speech pathway switch matrix because they were so low noise.
Yeah Reed switches are still used in guard switches.
That is fabulous. Really artsy too as you point out.I've got some reed switches on a breadboard right now so this was so cool to see.
Hi Fran I’m a sci-fi fan. The clear indicators remind me of the fingers on the hand computer in “Demon with a glass hand” 1964 “The Outer Limits”. Love the look.
That OL Episode Featured Robert Culp as
The Man w/The Glass Hand Computer😊👍🏼😎💥🆒🧐
I suspect the yellow switches might reset the byte so that you can enter a different value.
Are there any lamps under the opaque buttons?
That's what I was yelling at the screen at the end of the video too
That's cool! This would be the first time I've seen power applied to a lamp while it's "off" to keep the filament warm, but makes sense. Did I miss the NASA modules doing anything of that sort?
as others stated, used to test running peripheral cards on Burroughs mainframe systems
Light it up!
Love the curvy traces. And so precise, it makes me wonder if they really were hand-taped or drafted using French curves.
UpLateGeek, almost certainly taped using black crepe tape, which easy made bends.
That's lovely! I kind of want to make one now. :D
Man, thats quite clever.
thing of beauty, joy forever
Those reed switches looked very neat all lined up like that, the whole assembly looked like it was made to last.
I once had a nixie tube calculator that had reed switches for all the buttons, it lasted since the early sixties up until it exploded in the late nineties because of being left plugged in and switched on for a fortnight whilst I was on holiday, and it wasn't even me that had used it last and left it powered on.
But I was a youngster then so it had to come apart ofcourse.
thought the fact that they used reed switches was awesome also.
I have heard of Vacuum tubes having the filament to stay warm, for
instant on:
but never indicator lights. I guess because they're data lights, they need to
be able to switch on and off quickly. and also it would not be such a physical
shock on the filaments, so they would have a long life.
Very common in incandescent animated display signs and such. If you looked closely at those bulb based signs, the bulbs are ever so faintly on when "off" .
@@FranLab never actually noticed that b4, they flash on and off so quickly. but sometimes my brain is a 8086 processor, in a Intel Core i9 world 😁
GothGuy885, in industrial control panels, back when incandescent bulbs were used in pilot & indicator lamps, it was quite common to drive them from 120VAC, or 24VAC, etc; via TRIAC switches, and there were RC snubbers across the TRIACs, so that even when there was no command for a lamp to be on, and thus the associated TRIAC was off/not conducting, the small leakage through the snubber would keep the bulb filament energized at a low voltage, keeping it warm but not hot enough to incandesce, Thus the thermal shock of each activation of the lamp would be kept to a minimum, and there were few burnt out bulbs in them.
This became a real problem when industry switched over to LED-based lamps, which would glow dimly with the leakage current; nobody had changed the design of the TRIAC modules and such to eliminate the snubbers. In a less than brightly lit room, it could be hard to tell sometimes of such a lamp was on or off, if there was no clearly ON lamp to compare the brightness with. A common, kuldgy 'fix' was to wire a power resistor across each affected LED-based pilot light, to bypass much of the leakage current to the point where the LED wold not make visible light. Then you were left with panels full of smokin' hot resistors, which were merely uncomfortably warm when the lamp was supposed to be off.
Take a close look at the PCB. That circuit trace that connects together many resistor ends needs to be insulated from the traces going to the edge connector. There were many ways companies used to make multi layer PCBs.
It is a two sided PCB, but one layer.
Good use of reed switches. Never wear out and a good positive contact.
I was thinking 8bit Address and Data inputs with a reset/enter each, or 16bit with upper reset/enter and lower reset/enter. (?)
You aren't going to power it up?
Disappointed you didn't fire up the lamps though.
yes, would have loved to see them glowing.
Really nice! Makes me wonder if that was made for navy ship's computers.
Nice.
Inside circuit board and connector looks like one of 2 plug-in key contact assemblies from a Hammond organ solid-state era. 22 contacts times 2, 44 note spinet style. Same factory? Is the spacing of the buttons the same as musical keys?
Considering the number and arrangement of the switches, I'm wondering if this was a code entry module of some sort. In the early days, they often entered data directly by keying them in by hand.
Magnetic switchs are usually called reed relays - used in early telephone exchanges for switching.
No.
A relay is a device that uses an electromagnet to actuate a magnetic switch of some type.
A reed switch is just one type of magnetic switch.
A reed switch can be used to make a reed relay, but can also be used for other things, like this switch module.
Reed relays were used in _later_ analog telephone exchanges. Early ones used open-frame relays that required vastly more maintenance.
@@tookitogo Fair comment - I worked in telephone exchanges in the uk in the 1970's and they wecalled reed relays in the configuration. Tamato tomato :)
@@TerryMurrayTalks Yes, modern telephone exchanges in the 70s would have been chock full of reed relays. My point is that a reed SWITCH is not the same as a reed RELAY, and that reed switches are a subset of magnetic switches. That is not a trivial “tomato tomahtoh” distinction.
No problem, the course of Western history is not dependant on this. I stand corrected :).
It looks like an application specific design. Wonder what it was used for?
Why didnt you light one up so we can see how it looks powered on
Wow, that is such a beautiful design of the circuit board layout. Thank you for sharing it Fran!
What's under the solid yellow buttons ? 🤔🥰
Juke box selector 🙃
That is a really neat switch! Thanks Fran!
I’m confused what turns on the bulb to indicate the reed switch is engaged. Unless the reed switch puts the filament in series with whatever your turning on, which is messy. Perhaps there are mechanical connections for the bulb independent of the reed switch.
I expect they’re completely independent of each other.
This is a display module with switches - it does not actually perform any other function, all that is done outside through the interface.
Fran explores all those old lighted indicator technologies used before LEDs made it trivially easy.
🤔 21 contacts on the connector. Maybe 16 for the lights. Then 4 bits for the switches. And one for ground? To encode the switches into bits i expect some traces on the back...
Why don't you call them Reed switches?
I love your display videos 😍
what does it smell like?
You vids are fun interesting informative
Thank you, Fran! I would have liked to see them glowing or dimming, those beautiful little lamps. 😮
Love the content
That time long ago when things could be taken apart with a simple screw driver.
Great video, Fran...👍
magnetic reed switches
💚🐪☀️🌴👍🏽
Hi fen , We’re over this side , I’m sent back to get you across this leap of faith : “ And if you believe , wasteve Austin that we wouldn’t go back For Fran . “ Como Fran , It’s Time to Leap Of Faith Baby Girl, Just hold on to me And Voila We’re Other Side Heading Home Again( Unwaxed And Clive: Got Fran , Safe , didn’t notice , no interrupts . Let’s get out of here..
Fantastic vintage dysplays!😍