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How would you make a scrolling-text sign............. in 1931????

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Krumlink

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I believe that it was a pre lit set of light bulbs that was pulled around the building.
 

arhi

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IIRC prom is here since '56 so in '3x the mechanical is the only way ...I think I saw a show where they used punched tape (like continuous punch card) .. for big text signs.

Do remember that in "those times" mechanical "memory" was present in many forms, you could purchase "drums" with notes actually punched into paper roll for your "self playing piano" for example... you could get metal drums with "pins" that will play music (still used in those music boxes) ...
 

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unclejed613

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a bank of stepper relays and a "pegboard" programming device. each stepper relay feeds a vertical column of bulbs, and the contact points are wired to the pegboard each of the stepper relays are 1 step out of sync with the next one, so each column of lights is connected to one column of the pegboard at a time.

stepper relays and relays in general were the "binary processors" of their time. when i was 10-14 yrs old i maintained a set of pinball machines that were owned by the youth department of my parent's church. it was amazing application of electromechanical "logic"...... there was a lot of use of stepper relays as decade counters, adders, shift registers, etc...
 
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mneary

New Member
We did a lot with steppers, before integrated circuits were invented. Telephone exchanges were full of them.
 

Mr RB

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Punched tape loop, pulled through contact sets. Looks like quite a wide tape, must have been an expensive setup.

I used to have some 5bit punched tape samples I aquired in the '70's but seem to have lost them. :(
 

unclejed613

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Do remember that in "those times" mechanical "memory" was present in many forms, you could purchase "drums" with notes actually punched into paper roll for your "self playing piano" for example... you could get metal drums with "pins" that will play music (still used in those music boxes) ...

gee..... would that be the mechanical equivalent of MIDI?????:D
 

Diver300

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In this electronic age, it is easy to forget what could be achieved without electronics, and in many cases without electrics.

Some examples:-

Automatic gear boxes on car. Up until about the 1980s these had no electrical components. A typical 3 speed auto would have about 10 - 15 valves, connected by what was in effect a printed circuit board for hydraulic oil.

Babbage's difference engine. Difference engine - Wikipedia, the free encyclopedia

Lucas/Girling/AP's anti-lock brake system.

Railway signalling systems that prevent "clear" signals being shown until all leading points (switches in american) are locked into position. (That has been a legal requirement for passenger train service in the UK since before 1900)

Temperature compensated time keepers.

P.S.
I had forgotten Strowger's automatic telephone exchange. I think that Strowger did more for mass communications than A G Bell did. Without Strowger, the telephone would have stayed a luxury item for many more decades.
 
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tcmtech

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Ah... The ever so pointlessly over engineered vehicle! :mad:

Mechanical fuel injection. Very reliable and still tunable. (With a screwdriver!)
Interior lights controlled by an actual door switch. They actually would stay turned off when the doors were closed!
Mechanical speedometer. never got glitchy or just decided it wanted to turn off/ on/ off/ on.
mechanical heater controls. hot was hot and cold was cold. and in between was in between.
direct connection between a control switch and its intended device. (no computer midpoint that decides one day that the blinkers should now flash the headlights!)
direct connection from the key switch to the starter solenoid. (now the vehicle can decide if it really wants to start or not)
Mechanical seat adjustments. No electric door mounted switch to break and lock the seat into midget mode!
Crank down windows. now electrical components die when its -30 f and the window is half down!

I could go on but I have to go and reprogram my vehicle so the... well, see the above list and pick one, works again!:(
 

unclejed613

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not to mention that during the cold war it was a possibility that the USSR could cripple the US by detonating 4 nukes 250 miles up. the high velocity surge of electrons from the nukes would hit the ionosphere and the Compton Effect would create a massive EMP that would kill every solid state device in north america. no burned cities or killer clouds of fallout, just a whole continent of people suddenly finding themselves back in the Stone Age within microseconds.
 

tcmtech

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I would still be going! We still have a few vehicles and farm machines that do not have modern electrical systems. points and condenser ignition dont care too much about EMP.
And as far a fuel is concerned gravity flow tanks dont need electricity!

I have a Friend that had his tractor get struck by lightning.
It Burnt a hole in in the hood, killed the lights and flattened one tire but it still started right up!

But yea, the rest of the country being in a panic would be a real pain to deal with!
Kids would have to go outside and play, and people would actually have to go and talk to each other in person!
But with 99% of the vehicles off the road traffic would be nonexistent!
 

Diver300

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I see big advantages and big disadvantages of the current electronics in cars.

On ignition advance control, I've seen centrifugal/diaphragm vacuum advance seize, jump from full advance to none and back again. I've helped repair a car where the centrifugal weights had overrun their end stops, and jam the distributor, breaking the camshaft drive.

On a mid-1990s Fiat, we had the vacuum sensor fail. A light lit on the dash, and when the new sensor arrived, my wife, who would struggle to change a wheel, was able to fit it. No adjustment was needed. Also the car has no distributor, and when a coil failed, it still drove on 3 cylinders.

That car has a mechanical speedo, and changing the speedo cables when they have worn out is a bloody nightmare. The speedo cable also makes getting the speedo out quite tricky. An electronic one would never need a new cable and doesn't impede getting the speedo out.

So those are all wins for electronics.

On the other hand, the electric windows and seat adjusters that won't work unless you have the ignition on. You can only operate the starter once each time you turn on the ignition, the headlights turn off when you turn off the ignition, so you flash the headlights between stalling the engine and restarting, confusing other drivers.

Air bag lights that won't turn off if a fault has been repaired, cars that need to be dragged to the dealer if you leave something running from the cigar lighter, immobilisers that rely on radio signals that can be interfered with, or fault reporting that is cryptic, vague or just plain wrong.

Those are all car manufacturers shooting themselves in the foot.

However car manufacturers manage that quite easily without the use of electronics.
 

Mosaic

Well-Known Member
But yea, the rest of the country being in a panic would be a real pain to deal with!
Kids would have to go outside and play, and people would actually have to go and talk to each other in person!
But with 99% of the vehicles off the road traffic would be nonexistent!
I am not so sure that the EMP will take out modern autos anymore.
ISO 7637 load dump transient capability is a requirement now for auto electronics.

Pre 1995 autos did not have such requirements.
 
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