The Computer-free Automation of a Jukebox (Electromechanics)

In the modern world, when we want to make
something happen automatically, we use these newfangled computer things. Whether that means a huge industrial automation
system controlling robots in a factory, or an Arduino you learned how to program to do… whatever the kids do with Arduinos these days… our modern world is based on bits of silicon
executing instructions. It’s a pretty great place to be – for now – but to me it’s not all that interesting. What is much more interesting to me is the
wild world of electromechanical wonders that is… pretty much all general-purpose automation
from 1975-ish and before. Electromechanics is my favorite kind of automation. Why? Because using nothing but switches, some motors,
some relays, maybe a solenoid or two, and a heckuva lot of ingenuity, you can make surprisingly complex things happen, all without a single bit of code. For example, a jukebox! This here is the Statesman, by Wurlitzer. This beautifully brown beast hails from the
year 1970. I mean of course it does. This may be the ugliest jukebox ever produced. It’s… even as an outspoken fan of the
color brown, this is not very attractive. But! At least with the lights on we get some purple! Also known as the 3400 series, this jukebox introduced the new Wurlamatic record changer mechanism. Which, sadly, was a radical departure from
Wurlitzer’s previous designs which put the mechanism on full-display. Here it’s hidden, but luckily I have the
key to open it up. Now what this mechanism does is fairly obvious
upon a short glance. I mean, it’s got a carousel of records,
an arm to grab hold of one of them and place it on this little turntable, and so obviously the
carousel will rotate to a specific record, stop, the arm will grab it, put it on the
turntable with the selected side facing up, let go of it, then the tone arm will move
into position to play it, and once it’s done the tone arm will return to its resting
position, the record-grabby arm will grab it again, put it back, and we’re done. So, let’s see how that works in action. I’ll be selecting M3 which will play the
A side of the green record. Pay attention to the sounds it makes. [two clicks as buttons are pressed] [a whirring mechanical sound] [a clunk and a loud buzzing as the carousel moves] [another clunk, whirring] [two clicks] [another click] [whirring stops] ♫ Alright, and now that the record is over,
watch what happens. [a click, followed by the whirring again] [various mechanical sounds as the record is put back] [carousel buzzes as it moves] You might think that the carousel will stop
once it gets back to its starting position [faint double-click]
but it actually continues for one more rotation. Then, it comes to a halt. [clunk, and buzzing stops] Now you might ask, how does it know what record
to play? What was the point of that sound before the
carousel started to move? [button being pressed; whirring] [buzzing of carousel] And more generally, what are the brains of
this operation? If there isn’t a microcontroller controlling
things all micro-like, how can it be controlled? The answer is a whole bunch of weird, purpose-built
mechanisms, rats nests of wires, and a staggering number of switches. That’s it. Electromechanics are really quite simple as
a concept, but the applications can be a little complex at least on the surface. Before we get too far into the electro-side
of things, let’s look at the mechanics more closely. The heart of the Wurlamatic mechanism is right
here. This controls everything the jukebox does
aside from record selection. And all of its functions are performed by
a simple electric motor and a gear reduction drive. Here, I’ve re-wired the motor to a constant
power source. You’ll notice that it simply repeats the
same actions over and over again. Grab the record. Put it down. Move the tone-arm. Then the same thing in reverse. It’s just a constant back and forth. But notice how much it’s actually doing. It may look like it’s just moving the arm
back and forth but it’s a lot more than that. Most of everything that’s happening is happening
because of this one very complex mechanism. The mechanism is powered by the main cam
motor underneath it, and as the mechanism rotates, so do a series of cams. A cam is a sort of oddly-shaped wheel that
rotates around a shaft, and thanks to its odd shape, it translates rotational movement
into linear movement with the help of a cam follower which gets pushed as the cam rubs
against it. In fact built into the drive gear is a vaguely-heart-shaped
groove which serves as the cam that operates the record arm. It’s a little hard to see, but there’s
a little peg riding in this groove, and it causes the record arm to pivot backwards,
away from the record carousel with the help of this little ratchet and gear thing. At its pivot point, these three gears serve as the means by which each side of the record is selected. Pins on the two side gears will stop either
one of them from turning when they hit these catches. This then causes the arm to rotate sideways
as it continues to pivot backwards. Depending on which pin is stopped, it will
rotate in either one direction or the other, and this solenoid moves the catch points back
and forth, therefore its position determines which side is played. In its resting state, it will rotate to play
side B by default, and when the solenoid is energized, it catches the other pin to
play side A. Obviously the most noticeable thing this mechanism
does is move the record take-out arm, which is its official name, by the way. But thanks to a series of other cams adjacent
to the main drive gear, and the various linkages they attach to, it does much more, too. The single cam in front of the main drive
gear releases the record from the arm by way of this linkage, which also pulls the turntable
slightly to the left so the record can spin freely of the arm. Two of the cams behind the drive gear move
the tone arm to play the record, with one responsible for lifting it up and the other
for moving it left and right, and there’s even a cam just for activating this little
button which switches the amplifier from its auxiliary input to the phonograph input when
a record is being played. Take a look at this exploded diagram. This is everything going on inside the Wurlamatic
mechanism. There are 7 cams in total, though that’s
not perfectly true as you’ll see later. But anyway, these seven cams are the programming
of the physical actions that take place. Their shape and position dictate at what points
in the mechanism’s 360 degree rotation each action will occur. This may not look like a program, but it very
much is. Note that the cams could be made to cause one
action to happen multiple times per cycle, if required. However, this clever mechanical program doesn’t
make for a useful jukebox all by itself. If it just runs all the time, well then that
wouldn’t do anything but make a bizarre record flinging dance. We need a way to control when the program
starts. Of course we also need to pause the program
in the middle when the arm has reached the turntable so the record can actually play. And then we’ll need to restart the program to
put the record back. Of course, finally there needs to be a way to shut down
that program altogether once that task is complete. So we need some sort of additional control. Of course, before I re-wired the motor, it
didn’t start moving until the correct record was in place, and it was automatically stopping
in both the record playback and its resting positions. How did it do that? Well, what makes it automatic is the plethora
of micro-switches you see all over the place that function as interlocks, interrupts, start-stop
points, and triggers for other ancillary actions. OK, so here’s something that’s super common in electromechanics and is gonna come up a few times here. Self-latching circuits with interrupts. Using a relay, we can design a circuit that
will latch itself in a closed state until another action occurs. What is a relay? Well, a relay is an electrically operated
switch. A small electromagnet within the relay opens
or closes any number of switch contacts. One of the most common things we do with relays
is control high power devices with low voltage, low current control circuitry. But we can also be almost endlessly clever
with them. So, let’s say we want to turn on this light
bulb with a momentary pushbutton switch. We could wire the bulb right to the pushbutton,
but of course that means it’s only lit so long as the button is held in. And it also means the button has to handle
all of that current. What I want is for the button to turn the
light bulb on, and for it to stay on after the button is released. Here’s a simple circuit which will accomplish
that by latching itself closed. 12 volts DC power is used here on the control
side of the relay, but the load side of the relay can be whatever we want it to be. This relay is now the switch which turns the
light bulb on, and it will do so whenever the relay receives 12 volts DC power. So, we’ve got a 12 volt supply and a ground for the relay, with the bulb wired on a completely separate 120V circuit through one of the normally
open contacts of the relay. If I wire the 12 volt supply through the pushbuton,
now the relay will energize whenever the button is depressed, which closes the switch contacts
inside the relay, and turns on the light. This also has the benefit of making the button’s
electrical connections safe to touch, since they’re now just handling 12 volts. But, the light still goes out as soon as you
release the button because the relay loses its 12v power source. However, if I branch off the 12 volt supply to another of the normally open switch contacts of the relay, then feed the other side of
that back into the control side input, what now happens is that as soon as I push the
button, the 12 volt control side becomes self-powered. The button is now completely out of the picture,
as it becomes bypassed by the relay itself. The relay is now stuck in the closed position,
or latched… forever. At least, until the power supply is cut. Taking a closer look, we now have a second
power source coming from before the switch. This has 12 volts on it at all times. Again, it’s going to the second set of switch
contacts of the relay, and its output is being fed back to the control side. If there’s no power from the button, well nothing
happens. But as soon as the button supplies power,
that second wire snaps into action, bypassing the button, and keeping the relay energized. But, if I cut that second wire feeding the
relay and put a second button across it, this one with normally closed contacts, that means I
can interrupt the 12v supply that’s keeping the relay energized in order to deactivate it. Now, I press the “on” button, which energizes
the relay. This of course turns on the light bulb, but
also creates that new 12-volt supply for the relay to stay on indefinitely, but that new supply
now travels through this second button. When I press it, it momentarily breaks the
12-volt supply to the relay, which de-energizes it, and the light goes out. However, as soon as the green button supplies
12 volts again, even for just a tiny fraction of a second, the relay provides a bypass
for itself once more, and the light stays on. Pretty clever, huh? There are all sorts of applications for a
circuit like this. For example, a garage door opener! Push one button, the motor starts, and it
doesn’t stop until a limit switch at the end of the door’s travel opens the circuit. Of course, you’ll also want to design in
some safety interlocks, and other stuff, but hey. It would work. It might also kill someone. But it would work! So then, how does this apply to the jukebox? Well, the Wurlamatic has a microswitch that
serves as an interrupt to a latched relay. It’s the red button in our previous example. It rides along the edge of the main gear. That’s why I said there are more than seven
cams, because this is also its own kind of cam. Once the program is started, it will continue
to run on its own because a relay, specifically the Main Cam Relay, is latched in. But it’s latched through this, the transfer
switch. Now, you’ll notice that the switch doesn’t
actually get actuated… ♫ abruptly slow jazzy blues kinda music ♫ Ooh, twangy! Now, you’ll notice that the switch doesn’t
actually get actuated until the main cam has moved a little bit. Why is that? Well, because at first, either the Side 1
or Side 2 relay serves as the power source for the main cam relay. Electromechanics can get a little complicated. The same device can receive power from multiple
places, but so long as you sequence things correctly, you can manage it. When the carousel has reached the correct
selection, either the side one or side two relay will be activated. That starts the main cam program, just like
pushing the green button. However, the signal from the first relay will
disappear shortly after the record arm has moved from its resting position. We’ll get into the specifics of why that
happens when we get to the delightfully named Selection Accumulator. To put it more simply, a signal caused this
motor to start turning, just like the green button turned on the relay. But to keep it turning we need to generate
a new signal because we’re gonna lose the first one, just like releasing the green button. And that’s what this switch does. The transfer switch keeps the main cam relay
energized, and thus the main cam motor running, all the way through its rotation, until the
record is put back at which point it is released. But wait. That’s… a problem. Doesn’t it need to stop midway through to
actually play the record? Indeed, it does! So, there is another switch at play here,
appropriately called the Play Switch. This is actually a sort-of second red button
in this scenario, but it’s not going to totally kill the circuit. Instead, it will just sort of pause it. Ironic for a switch named Play. Whenever the transfer switch is engaged, the
main cam relay is, too. So it wants to move the mechanism. But, once the play switch is activated by
this cam, it interrupts the flow of power from the transfer switch and de-energizes
the main cam relay. This then causes the entire Wurlamatic mechanism
to stop. And now the record can play. Incidentally, this switch does double-duty
and the same switch which mutes the amplifier’s auxiliary input to give priority
to whatever record is playing. The key difference here is that the transfer
switch is still trying to sending power to the main cam relay, but it’s being interrupted
by the play switch. So what happens when the record is over? If this circuit was designed like our red
and green button thingy, well if the red button’s being held in, we would need another green button to provide power and start it back up. Do we have one? Well, yes! That’s the trip switch, located right here. It’s activated by the tone arm once it’s
near to the run-out groove of the record. This then bypasses the play switch, allowing
current to go around it, and thus re-energize the Main Cam relay to restart the program. Now here’s a bit of nuance which is very neat and I want to highlight it. The trip switch works as a bypass for the
play switch, right? Which, again, the play switch stops everything
so the *record* can play. The play switch isn’t letting power through
to the main cam relay, but the trip switch provides a workaround. But that means that the programming of all
these cams needs to be done such that the play switch gets released before the tone
arm is pulled back to its resting position. Otherwise, the play switch would just cause
things to come to a halt once more as soon as the tone arm moved away from the trip switch. You can see that things were programmed just perfectly so that the play switch gets released, then the tone arm moves This is why electromechanics are so fascinating
to me. It’s a delicate ballet of logical circuit
design and physical interactions. You need to make this action to stop? Well, just make it hit a switch that kills
it. Oh, you need it to start up again? Well, just add another switch that un-does
the first one. And make sure you get the timing right or
it won’t work at all! Basically, there are a ton of if/then statements
in here, but manifested as wires and switches. It’s a form of logic, but very rudimentary. When you combine that with crazy mechanisms
like the Wurlamatic, you find yourself with a machine that can do surprisingly complex
things all through whatsists and doodads. None of that there computery business. And you’ll also find some important safety interlocks,
too. For example, notice how when the record grabby
thing grabs the record from the carousel, it ends up between the two records surrounding the one it’s grabbing. Well, what if the record carousel were to
move with it in that position? A bunch of records would be broken by the
little hook. To keep that from happening, the motor which
turns the carousel is wired through this microswitch, which is only depressed when the Wurlamatic
mechanism has opened the jaw of the… right, the take out arm. That’s what it’s called. This prevents what we in the business call
“a bad day”. And of course you’ll find some other switches
here that do other groovy things, like the Side 2 Release Switch. This is what actually releases the side 2
relay. There’s another one, of course, for the
side 1 relay, and these function just like the red buttons in our little demo rig. Both the side 1 and 2 relays are self-latching
to get the main cam relay, and thus the entire mechanism going, and these two switches are
responsible for releasing them. You’ll notice that it’s the same pins
which are used to turn the take-out arm that actually actuate these two switches. But of course, we haven’t answered perhaps
the most important question about this machine. What gets this all started? How does it know to start turning the carousel, and how does the carousel know what record to stop at? Or what side to play? Well, I’m gonna save that for the next video. Yeah I know, I know, I’m sorry, but this
is already, what, [NINETEEN] minutes long? Or thereabouts? But before I go, let’s look at one more
thing. I bet you didn’t think you could just remove
the record carousel, but you can. It’s actually just sitting in here. Just select a record to be played, then shut
if off. [sound of music stopping[ Now, the carousel can simply be lifted up
and out. Look at what’s underneath. It’s connected to this black arm which can
be spun around. This is clearly going to some sort of mechanism
below it. That mechanism is the Read-out Arm and it,
along with the Selection Accumulator, are perhaps the most amazing parts of this entire
machine. The Selection Accumulator is what made the sound you
heard before everything got started. This one. [rapid clicking, followed by whirring] [click] [carousel spinny-buzz begins] Notice when I select a record that the buttons
stay depressed until that sound stops. Then they pop back out. That’s actually the reason there’s a reset button in the middle, so that way if you press the wrong button you can pop it out. Now, listen closely as I select a series
of records. A1 [whirring] [clunk as it stops] C1 [whirring] [click] [whirring] [clunk as it stops] E1 [whirring] [click] [whirring] [clunk as it stops] G1 [whirring] [click] [whirring] [clunk as it stops] and J1. [whirring] [click] [clunk as it stops] Did you notice something changing with each selection? [whirr… [whirr… click] [whirr… click] [whirr… click] [whirr… click] What’s going on? Well, stay tuned because in the next video
we’ll find out. Thanks for watching. I really hope you enjoyed this video and that
my explanations were easy enough to follow. Electromechanics are really quite simple,
but they can be a little confusing. When you use switches and relays to make sequences
and interlocks, it can seem to get out of hand. In fact, these here are the schematics for
this machine. They’re super easy to read! You might have thought this was a pretty simple
device with what you’ve seen up ‘till now, but trust me. When we explain where these buttons go, it’s
gonna get a lot more complicated. I think I’ll play some music now. How about… T1? [ buttons being pressed ] [ selection accumulator whirring ] [ buzzing as carousel moves ] this is gonna take a while… shoulda picked something in the C’s or D’s… [ clunk, followed by various mechanical sounds ] [a low hum] ♫ scratchy low-fidelity smooth jazz ♫ ♫ audibly improved smooth jazz ♫ I liked that delivery so much and then it
fell apart! And a staggering number of switches, rel … ooh. Ha, that’s the, that’s the end of the
sentence! [laughs] oops. Did I say “of course” weirdly? It’s a little late now, ‘cause I’m already
moving it back, but I think I did. However, this clever mechanical program wouldn’t
make for a useful jukebox… it’s later than you think it is, I’m kinda tired. When I press it, it morment… [weird stress
sounds] Those are fun words! They aren’t words, they’re just sounds So what happens when the record is over? Oh. It’s not phrased as a question that I know
the answer to. I should have added a paragraph here. I need to… I need to say something that’s not in the
script. That’ll go well. Stay tuned for next time when we
ACCUMULATE SOME SELECTIONS I’m very excited for the next video. I think you’re gonna like it. doo doo doo doo

100 comments on “The Computer-free Automation of a Jukebox (Electromechanics)”

  1. Technology Connections says:

    Those of you with eagle eyes will have noticed that the transfer switch is a double-pole switch. This added to the messiness of the "red button" analogy so… I ignored that bit of nuance! Yeah. Pretend it's a red button just like in the demo. But that gets pressed when it's let go. Easy, right?

    Seriously, I can't say I'm happy with how I explained that. So here's a (perhaps) better after-the-fact clarification;

    The Wurlamatic (main cam) really has two red buttons and two green buttons. The side 1/2 relays are the first green button. The transfer switch is the first red button. When the machine is at rest, the red button is still being held in and the side 1/2 relays need to get around that to start it moving. Once that happens then the red button is "let go".

    The play switch is the second red button which stops the program mid-run. Then the trip switch becomes a second green button, which re-starts the program. Finally, when the machine is back to the starting point, the transfer switch is released and therefore the original "red button" is pressed to shut it down.

    Hope that helps!

  2. jlpland says:

    Very like Video for UK, techmoan Guy !!!

  3. ShadowZero27 says:

    when you said we were going to save that for the next video my heart stopped

  4. Andrew Micallef says:

    Relays are pretty awesome CuriousMarc had a video on a Japanese computer that used relays instead of vacuum tubes for logic – the 1958 FACOM 128B. Apparently made of old telephone switchboards from after the war if I remember correctly

  5. RaptureFilm says:

    You are a gift

  6. Goon124 says:

    20:00 Petition to release the 14+ hour video of you brute forcing every record combo with narration on the second channel.

  7. MrSmitheroons says:

    The click happens later when you select a "later" letter in the alphabet. (Given it's A to V, I think that's 22 records.) It probably spins through all 22 records (spins through "the whole thing,") but there's some kind of trick to click the record selection mechanism at the right time in all this, to mark out the actual record we want.

  8. Aaron G says:

    And I thought my 360 was noisy…

  9. CmonSoundz says:

    next time: Pinball machnines!

  10. Evan Doorbell says:

    The way you explain stuff is great! (I know it ain't easy) I'm "taking notes" on how to do that better myself.

  11. FixerUK says:

    As soon as the tone arm dropped on that record inside my head I heard "Sunday, Monday, Happy Days" 😂

  12. Dylan Davies says:

    Ah a differential 🙂 like on a car – the speed of both outside gears must average to the speed of the middle. By stopping one the other has to rotate twice as fast to compensate, and the middle thus rotates one way or the other.

    Similar thing happens on a car- if you rais both wheels off the ground, you can stop one with a finger, and the other will rotate twice as fast- it's why regular cars are kinda bad off-road.

    They're useful in mechanical computers as a way to implement addition/subtraction

    Arstechnica did an article a while back explaining how those old analogue computers worked mathematically – well worth the read

  13. Austin Allmond says:

    Interestingly enough, all those micro switches are name-brand Micro-Switches

  14. Jari-Pekka Haataja says:

    It took me some time to realize that your end tune is actually instumental (elevator) version of this finnish song…
    Not my favorite type of music but your channel is amazing! Keep up the good work!

  15. David Kempton says:

    You lost me after the first 5 minutes. But I still watched it to the end. Well done Alec!

  16. TheAlby87Project says:

    18:50 "And this is, kids, how I meet your jukebox"

  17. Calder Niven says:

    2:08 may have been the best unused rick roll setup of all time.

  18. Eric Larkin says:

    Your unsolved Rubik's cube bothers me.

  19. normantor says:

    Wish I could show you how styrofoam cups get made. All electro mechanical.

  20. Евгений Рыжаков says:

    Resistor-contactor control system used in my tram. Welcome onboard!

  21. Robert Clausecker says:

    If you like electromechanic devices, make a video about the Zuse Z3!

  22. FixerUK says:

    I'm just wondering why the numbers and letters are reverse/mirror imaged along the edge of the record carousel or will that be answered in part 2?

  23. Tartrazine says:

    11:57 Why would a safety stop function kill someone?

  24. Ray Kent says:

    Very good presentation of a surprisingly complex automaton. Well done!

  25. Lawn Fascist says:

    years ago, I worked at a radio station. They had an old automation system from the early 70's back in the back. It had a record player and system to play commercials on cartridges. We didnt use it at the time, but it was there and functional. I used to go back and load it up with commercials and records just to watch it do what it does. That thing was great.

  26. Henry Dorsett says:

    If you only knew how many of those bit-shiftin Ardu-eeno kids watch your channel, eyes gazing in awe 🙂

  27. vidprodcts says:

    You mention how the timing of cams and switches had to be exact. This reminds me that back in the day all the traffic lights at an intersection went from red to green exactly at the same time…they were on a cam in that little box by the curb. Now days I can detect a slight delay as the electronics change the lights from red to green independently at some intersections.

  28. Uriah Garcia says:

    Song name on green record?

  29. AntneeUK says:

    "SIDE 1 RLY"

    Honest, guv'nor, it really is side 1

    I wasn't suspicious until it said rly…

  30. Howard Jones says:

    Also check out thang010146's Youtube channel for things that mostly only need motors. It's quite impressive what you can do with just a rotating motion source.

  31. Fly Beep says:

    2:40 Oh man, I recognize the song from the first few beats, it's Tarzan's Boy from Baltimora, an early 1980s small hit. Must be getting old.

  32. inund8 says:

    I definitely thought I was going to get rick rolled while that first record was queueing up.

  33. kalsan15 says:

    I've always wanted to know how these old things work. Thank you for enlightening me!

  34. Thomas Eastman says:

    I have a 1969 Pinball machine. Talk about cams, switches, and relays!

  35. Nathan Miller says:

    A hands on experience with switch based programming can be found in Bomb Squad Academy. Supports Android, iOS, and Steam.

  36. Nuts n Proud says:

    Thanks for the video. I have a Rock-Ola Princess II and I love it. It's been converted to play UK small centre hole records at 45 rpm instead of 33rpm.

  37. Frodo TheHobo says:

    Great video! Just one minor thought.
    At 12:45 instead of talking about a pressed and released switch i think it might be clearer to everybody if you talked about an open or closed switch/circuit instead.

  38. Chris Robot says:

    Oh RLY………???

  39. TheDrunkenMug says:

    Yet another awesome video, really enjoyed watching it. Very clever engineering in one of those old Jukeboxes..!
    But I have to point out that you made a mistake:
    The selection- and control-mechanism inside actually IS a computer, just not a pure Electronic computer like the ones we have today.
    Rather; a Electro-mechanical computer.
    Now I hear you think: Wow, thats old-school…!
    Well no, not really. Because before the invention of electricity there already exist purely Mechanical computers. Best known example being the 'Abacus'.
    Oh and this one too;
    "Babbage's Analytical Engine"
    A fully functional design from the 1830's.
    It had RAM, a CPU, a BUS, could do loops, handle IF-statements, and qualifies as 'Turing-complete'.
    (It was however never built), great video briefly explaining this fully functional design nevertheless:

    Did I mention this design dates from the 1830's ?

  40. Shawn Johns says:

    Don't you mean the color orange?

  41. niqhtt says:

    I didn't hear you use the terms Normally Open and Normally Closed. That is needed to explain your switches.

  42. Fahrenheight says:

    What is the song that plays at 2:36?

  43. Jimbo says:

    13:37 a short snippet is a certain song plays… I hope you do not get a copystrike! The owners of, uh, that particular band's music are notorious for abusing YouTube creators.

  44. realvanman1 says:

    The folks who design modern day automation just using micro computers have nothing on the engineers of yesteryear. A level of critical thinking that is nearly lost. The engineers who design the microcomputers themselves have got to be pretty high level thinkers though!

  45. ColdSig says:

    This video was kind of all over the place was it a jukebox vid or an electromechanics vid? Idk but I watched the orange gears on that record move a thousand times.

  46. selforganisation says:

    Wah, it gives me anxiety when you point your fingers around a circuit with AC. I'm also fascinated by electromechanics and one place where it was popular for a long time was automatic washing machines. Cams are also used in music boxes for example, this time with no electronics. However, there's a step between microprocessors and electromechanical systems, and that's simple logic circuits, which you can do automation with. Back in the day I made a stop-watch out of a dozen 74 series logic chips (and of course you can do the same with single transistors or lamps).

  47. Nachtfalke says:

    Baltimora with Tarzan Boy!

  48. thezfunk says:

    Back when Electrical Engineering was all just Mechanical Engineering.

  49. Dong Harvey says:

    That 70s era disk carousel definitely outlasted the 2011 Kaleidescape Blu-Ray Vault carousel that just burns out it's roller motors 4 years in

  50. phalxor says:

    I love the amount of detail and then hearing "record grabby thing"

  51. 1kreature says:

    Look at it this way: Modern automation using electronics still use switches.They are just much smaller.
    See! Now you can love modern electronics as well 🙂

  52. DoktorFrankenstein says:

    21:44 – For a second, I thought you actually got Floaters cut into a record, but I'm guessing the tune is actually coming in through aux?

  53. Black70Fastback says:


  54. Watchandjewelryloft says:

    I repair watches. Even 100 years ago, mechanisms were quite impressive. To this day I can service and clean a 100+ year old movement and it will run as well as it did when it was made. And, even longer and more consistent today with the use of modern lubricants.

  55. Evan G. Srinath Das says:

    Superb video! Absolute viewing pleasure! Fascinating topic. 😁

  56. Calvin Schuster says:

    It is pretty crazy to think that because these people hadnt yet even considered computer style automation that they got to the point of doing a lot of things we use software today to do by simply using anologue machinery, using timing, anologue logic gates/electricity, and a little slight of hand as it were to do those jobs and it worked.

    It makes you wonder if there is another thing we could be doing that could do a lot of classical computing does but 10× more efficient. Perhaps quantum computing will be my generations classical computing. Heres hopping!

  57. TheHelado36 says:

    That system was beautiful, My grandad had one and as a kid I spend hours looking at that thing work !

  58. Beige-o-Vision says:

    Thanks for this. I'm looking forward to the next episode. BTW if you've not watched The Secret Life of Machines before, you'll get a real kick out of it. For instance this episode

  59. MrDurronko says:

    I expected to be Rick rolled. I'm disappointed

  60. Lord Zordid says:

    That's all fine and dandy. But can it run Crysis?

  61. WarWeasel says:

    The year is 2072, the meta channel called
    Teknologiaj Ligoj (Translated to Esperanto in compliance with the World Congress Bill 29491: Communication Simplification Act) uplinks a feed titled "The Quantum-free Automation of a Smartphone (Electronics)".

  62. EssenceofPureFlavor says:

    Incredibly interesting

  63. pmailkeey says:

    11:25 If I've understood your wiring correctly, you've wired it 'wrong' !

    If you decide to have a fight and press both buttons, the light will come on (unsafe) – so ideally, the feed to the green button should be through the red button so whenever the red button is held pressed the light is off no matter what happens to the green button !

  64. Spencer Bean says:

    11:00 literally the most basic LVP controller. It's actually a great explanation of how they work.

  65. Limbrat says:

    Mind blown!

  66. dscrive says:

    I had to learn quite a bit about this sort of stuff while in technical school, turns out that as technology progressed a lot of factories switched over to PLCs, programmable logic controls, which use a special form of coding called "ladder logic" to better emulate old school relays to control industrial equipment.

    programming the non PLC robots arms later was actually quite easy, we were able to put them in program mode and manually move the arms around and it learned from that, of course, we weren't allowed to do it that easy way till after we learned the manual coding method, I don't recall if it was G-code or something else.

  67. Joey Mormann says:

    DARK ORANGE BEAST! Now you have to make up a word that rhymes with orange!

  68. pmailkeey says:

    "Ever wonder how we made all these crazy machines do all their crazy machine things before computers came along?"

    No, not really. They used computers, that's all. They just weren't electronic – or even necessarily electric. Mechanical computers ARE A THING !
    Did you spot that A to D converter in the Juke Box ? Yeah, that's the one that measures the amount of record played and convert it ti a digital signal via a microswitch to lift the tone arm off the record once it's been played – and miraculously, it compensates for the length of the record whether 4 minutes or 3:59.

    Of course you may love your microswitches and relays – but these are not core components of analogue computers. And for those that understand digital maths, 1+1=1 innit.
    People have, and have had cars containing analogue computers. They are generally used to calculate transmission ratio between engine and wheels. You are experienced with red buttons and green buttons. But I am aware that in the RED corner there is an analogue computer and in the green corner, there is another analogue computer.
    They (don't) work together. 1 analogue computer + 1 analogue computer = 1 analogue computer. One could argue that in the case of transmissions, it's more correct to say 1 analogue computer – 1 analogue computer = 1 analogue computer.
    The 'green' analogue computer near the engine is saying "I am spinning too fast and I need a higher transmission ratio". Meanwhile the 'red' analogue computer near the differential is saying "I am handling too much torque and I need a lower transmission ratio." And so between these two analogue computers is a fixed length of drive belt that they fight over – a balance of speed on one side and torque on the other and between them, they fight it out and always come up with the correct answer: 42 in all cases.

  69. S1m0ne says:

    "This beautifully dark orange beast hails from the year 1970."

  70. TGGeko says:

    1:12 You can tell it came from 1970 because the letters W, X, Y, or Z hadn't been invented yet.

  71. Gundam Serpent says:

    What song was that green disk?
    Sounded rather nice…

  72. Hunter Kiotori says:

    THIS. THIS right here is one a perfect example of why I subscribed to you and am still subscribed to you. Please don't change course. Keep teaching old tech and how it works

  73. Shalom Korf says:

    I love your channel. Thanks so much for what you do.

  74. Joey Mormann says:

    Y'all know James Burke? You ever see his BBC series Connections? Tell me if you have so I will stop asking you.

  75. EraYaN says:

    For all you electromechanical aficionado's you might like this: (a teletype restoration series) and the rest of that series. It's like this jukebox but a lot more components and a lot more fiddly. The series also shows how many ways you can tune these and how narrow the band for "working as intended" is.

  76. Ancurio says:

    Just today I looked up what an RS latch in Minecraft redstone looks like, and soon after I'm recommended this video. Either the tags of the videos are similar, or YouTube's algorithm has become scarily smart.

  77. Kristján Kjartansson says:

    I'm guessing this is a first; a youtube retro tech video ending on a cliffhanger! Can't wait for part 2, hope it's released soon.

  78. Aaron W says:

    Anyone else disappointed that the green record wasn’t ’Never gonna give you up’?

  79. True River says:

    3:30 a rats nest of wires and a staggering number of switches. That's what goes into a microprocessor surely? OK we call the wires tracks, but it is just the same only smaller.

    The reason you prefer electromechanical to electronic switched logic is that the stuff happens visibly (and audibly).

    And if you say that another difference is the presence of code, let me remind you of the Babbage engine that was an electromechanical programmable device.

  80. DrunkCat says:

    That it uses SR latches makes it a computer doodad.

  81. True River says:

    The Russians sent a robot to the moon that collected some rock and brought it back to Earth before Apollo had used a human to collect a sample. All done electromechanically. No computer. You'd have loved it

  82. cutest panda! says:

    literally just minecraft redstone

  83. Hans Isbrücker says:

    Neat! 😁

  84. David Strohl says:

    I’m having flashbacks from my electromechanical logic classes in the 80s. How we ever got through them is a mystery to me still to this day. Excellent video.

  85. Atrixium says:

    The timing of this video could not have been more perfect, it just so happens I have a jukebox to repair, though one that's much more modern than this one, but still a devilishly complex, electro-mechanical wonder!

  86. Moon Moon says:

    This is why I’ve always found lifts (or elevators for that one weird part of the world) fascinating. The logic control ones do interest me, but there’s something satisfying and almost ASMR-like (groan) about this:

  87. SteevyTable says:

    You should see the mess that an air logic circuit can be.

  88. Josu Gambee says:

    Okay, you have got to go to the phone museum in Seattle now! If you think a jukebox is complicated, check out the panel switching system:

  89. Dr. Dank says:

    “As an outspoken fan of the color brown“ I think you mean color orange

  90. Parallel Disney says:

    Nice tribute to the electric umbrella closure.

  91. AvilerED says:

    I'm guessing there is also a mechanism (some mechanisms?) for knowing a slot is empty.

  92. maxis2k says:

    You should do a video describing how early Pinball machines worked. Some of those are so complex with so many switches, they make Swiss watches look tame.

  93. William Maclin says:

    I love electromechanical machines. Back in the 70s I was poised with a question, "could I put 6000 wraps on a guitar pickup using number 40 wire?" I thought about it and after a week I decided that I didn't want to hand spin that much wire into anything by hand, I would instead build a machine to do it for me. After about 3 months of trial and error, I had my machine. It would not only count the turns of wire but it would lay each wire (wire about the size of a human hair) neatly next to the wire on the pickup. Once it reached the end of the 6000 turns, it would automatically shut itself off. This was all done with electric motors, switches and gears.

  94. Audey says:

    Episodes about electromechanical wizardry like this one and the toaster video are some of my absolute favorites. Very excited for the next one!

  95. Doggerel says:

    “You’ll find some other switches that do some other groovy things”
    That pun spun my head round baby right round, like…. um …. don’t needle me about it, I’ll remember!

  96. CommanderTaco says:

    Tbh, these have always been more interesting than computer automation. But you cannot deny that it is cool what can be done with small form factor computer, cramming as much power as possible into a small case is just wild imo

  97. Gergely Feldhoffer says:

    Listening the narrative for this video reminds me when we bought a new laptop 10 years ago, and there was a "Switch release hatch" named something in the description. We wondered why should we release a switch with a hatch, as a laptop is not a jukebox. Turned out Dell came out an interchangeable lid called "Switch", and that hatch was supposed to actuate to release the lid 🙂

  98. biaroca says:

    I didn't understand a thing of this whole video, but it was very cool nonetheless

  99. BioJutsu says:

    Oh boi, even the Endgame's cliffhanger wasn't that unbearable

  100. Eric Freeze 19 says:

    So many darn micro switches.

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