Hello and welcome back. If you follow the channel, you know that we recently went through a pile of
boxes that had been accumulating while we were so busy with our Apollo comms equipment restoration.
In there were so many treasures. We methodically went through the pile in previous episodes,
and already repaired not one, but two HP 4957 cuties,
got our TI Silent 703 to do its whisper quiet printing job at 1200 bauds, and controlled HP-IB
instruments via a serial teletype using a viewer donated conversion box. But one might argue that
the star of the show was contained in this big box, also a donation from a generous viewer.
Oh, look, it’s crinkled gray, it’s heavy,
and it comes to us from the glorious 1960s, courtesy of IBM.
Holy smokes, lights and buttons galore,
this is the real 1960s’ deal. I present to you the IBM I/O Tester.
[Ken] That looks very nice! [Marc] It's an... Wow!
Yeah, these are the same switches like... [Ken] There is documentation. [Marc] Wow-ph. This one
is broken. So this one is broken. This one is half broken, this is completely broken
[Ken] Look at these schematics. It's got the ALDs. [Marc] It has the ALDs? Yay!
It has electronics in it? From what I understand, there would be an overlay here,
and your lights would have a different meaning, depending on which instrument you hook it up to.
Oh yeah. So you have an overlay here that tells you what the buttons do.
I guess? [Ken] What's the big knob on top? To wind it up? [laughter] [Marc] The pump? Goes through
the bottom. [Ken] Oh that's weird! [Marc] Ejection? [Ken] To latch it onto something else?
[Marc]
And there's some mystery dirty cable down here. Oh! Connector A,
connector B. Is that a Bus and Tag? Doesn't look like it. I have to figure
out what this is. [Ken] I'll study the schematics. [Marc] All right!
So, how are you supposed to use this? This tester dates back to the IBM 360 era, the
famous IBM mainframe series from the 1960’s. You might have spotted my 360 Model 50 control panel
lurking in the background in my videos. We plan to bring it back to life, and I also acquired
several of the peripherals that go with it. I have a card reader, a printer, and several tape drives.
And our IBM tester was used for maintenance of some of these peripherals. You see, these
machines did not have their own control panel. Instead, you would use this portable tester,
plug it in, and use it as a temporary control panel to troubleshoot the peripheral.
And ken is about to verify that. [Ken] This has two plugs: plug A and plug B. These are
weird 104 pin connectors. They're not bus and tag connectors. Basically, just arbitrary signals.
The meaning totally depends on your I/O device. [Marc] But I was wondering, on the 360 side, do
the signals emanate from the controller? We don't know?
[Ken] Yeah, we don't know exactly. [Marc] We need Carl, who is having a good time in Florida.
Ooh, nice! [Ken] And so then, down here, we have I/O tester connector A. [Marc] Oh, it's even
written on it! Yeah, it looks like it. You want to try it? [Ken] Okay, I'm not sure, top - bottom,
how it's keyed. But let's see. Should just plug in here. [Marc] It does! [Ken] It's this
weird T-crank to lock it down. Now we're plugged in. [Marc] Turn it on! [Ken] If either of these
boxes worked, we could check the status lights and and test it out! [Marc] Well, one day!
I need to get done with the Apollo stuff that keeps coming before I have enough
space to bring down the big IBM equipment, but Ken got started working on the tester.
[Ken] So, Eric thinks we should reform the capacitors, but I figured we might as well
measure them before and after to see how sure see how it goes. [Marc] Yeah, sure. Is there
any high voltage in there? Probably not. [Ken] 24 volts. They're 10 volt capacitors. [Marc] You
put you put one of the power supplies at low current, and figure out what happens.
And it has this weird looking schematics. Those are called ALDs, they're typical to IBM,
Automat[ed] Logic Diagrams. And what it is, it's CAD for electronics, but of course they didn't
have graphics printers at that time. So they print boxes. But all the information is in there. So
if you stare at it long enough, you'll find out what it means.
And actually, these IND little boxes, they are just the lamps. And these more complex boxes,
those are IBM SLTs. They're little hybrid circuits, little silver squares which contain
an amplifier. So this is just a little amplifier connected to a lamp. So it's a lamp indicator.
And there are pages and pages of the stuff. So there are 90 lamps altogether. Some more,
some more... And the whole wiring diagram, this is exquisitely documented. Who said they didn't have
CAD in the 1960s? Actually they had it all the way from the 1950s. A little explanation manual.
Tells you right here: the I/O tester is a portable CE (Customer Engineer) tool which may be attached
via either one or two quick disconnect connectors to many of the I/O units of the system 360.
I/O units presently using the I/O tester are the 1016, the 2330-1050 attachment,
1442, 1443, 2501 - I have that one - 2520, 2671, 2701 and the 2821. And they kept adding
more. This thing was kept around all the way to the IBM's 370 era, in the late 70s.
And the only part of electronics we need to check, really, is the power supply. Which is a bit weird.
And I already have made some slight modifications to it, so I can power it on its own. This is
usually powered by the equipment you test it with. Ken, you figured out the machine,
the mystery? [Ken] So I'm powering it through the external I/O connector here,
when I flip on Lamp Test, most of the lamps work. Not all of them,
but most of them. [Marc] And those are three volt lamps? [Ken] Yeah. [Marc] Oh,
I'm not sure I have three volt lamps for that. Can you enter data and switch some lamps?
Have you tried? [Ken] No. [Marc] Well I don't want to put you under pressure in front of the camera.
We'll come back. [Ken] No, I function best under pressure!
[Marc] And so now you can take control of the machine?
Yeah! There you go. There's one over there, one over there. Yeah, so, it's
basically the earliest form of logic analysis you can do.
And then the data switches is the same, it gives you three volts or whatever? [Ken] Um, no, the
switches are just dry contacts. [Marc] Oh, they're just available to you as contacts? [Ken] Yeah.
[Marc] So the only thing that there is in this box is is a driver? [Ken] Right. [Marc] Oh, wow.
So it turns out, a lot of the switches didn't work. So I started to
take them all out. There is a little bit of disorder here. And one was completely broken.
The switches, they are riveted, but I drilled the rivets out, and i put screws instead.So,
I'll take this one out. So here's our little switch. This is the actuator. It's just a ball
that's pressed. And, what happened, is that here, it's not supposed to be round like this.
It's supposed to be a slot. So that's the problem. Actually, I have a piece of similar material,
same thickness, also an insulator. So maybe I can just hand mill it quickly.
So I think I Clickspring'ed my way out of trouble. And that will do fine.
There, new old switch, and it's not wobbly anymore. So when you get the switches,
a lot of them don't work. So it should be on: it's not. But as we have seen, it's simply constructed,
and there's a whole right over the contact. So if I infiltrate Deoxit...
Ah? That will be the first one that doesn't repair. Oh.
There we go!
It comes back. So it just takes a little bit of time for the Deoxit to fall down. And that's the
driver for the lamps. This is a typical IBM 360 construction, with these little modules that go
in in the back plane, where everything is drilled. And you have locations marked. And you can make
modifications on this side, those are wire wrap pins. And you can plug in stuff on this side.
And these are all the paddles for the lamps, I think.
And it's all marked. This is B3. This is mark B, and this is marked on top of it:
one, two, three. So this one goes there.
Okay. And then the power supply. That's the only one that's
not very well terminated.There is no way to detach it cleanly. And then you can tell, there's a there
has been a rework. There's been a wire, here, a yellow wire that goes to one of the switches. So
probably a wire that broke inside the whole thing, and they had to redo it. And here we have actually
an SMS card. So that's a format that dates back to the IBM 1401 on the first cards with transistors.
And you can see it has an 086 and an 026. So those are the first transistors, probably Germanium.
All right. So we're almost good. I need to replace some of the bulbs.
To take them out, it's very easy. Off they go. You were not meant to replace the bulbs, you were
meant to buy the assembly. And it's really a pain to change. The
two won't separate at all. So I eventually found what bulb it is inside. It's a 2158,
3.3 volt bulb. And it doesn't matter how hard you pull, they won't come apart. They knew somebody
was going to try not to pay for them. The best way I have found that allows me to open them up,
is to use the miracle tool: the Dremel. And to Dremel the little nib a little bit.
Enough that will open, but not enough that it won't lock anymore.
There you go.
Tada!
All repaired! So we have been playing some more with the IBM I/O tester, and we got some... Yeah,
it all it all lights up! But we got from Al Kossow, we got some gifts here.
[Ken] So the problem is: how do you know what these lights mean and what these switches mean?
The solution is: you get a card for each I/O device, you slide the card in.
And now all your all your lights are labeled! [Marc] so this one is? [Ken] The 2314, that's the
disk drive, I believe. [Marc] The big disk drive system, the giant disk drive system. [Ken] Yeah,
the wall of disk drives. And so TROS is the transformer read-only storage. That's
similar to the Apollo guidance computer's core rope, except it's implemented with mylar sheets
that put the wires through, or around the transformers.
And then here we have the 1403 printer. That's the same type of printer that's hooked up to the IBM
1401, but I think this might only work with the N1 version which we don't have. [Marc] That's too
bad. [Ken] With this you have a bunch of switches, you can set the address, you can um you can do
scan load print. You can do a check reset, it shows you the contents of your data register,
the character it's decoding to print, as it steps through the 132 columns.
You can see all the internal state of the printer, and what's going on.
So, it's all fixed. I worked a little bit more on it, reprinted the bottom
card. All the lamps do work. And I was looking for a way to display it. So,
first problem was to find the connectors, those humongous connectors. Took me four connectors
to make two,. Fortunately I got the extractor tool, and I just painfully got every contact,
removed it, put it over there, and wired it up to an Arduino Mega. So let's plug in our Arduino
contraption to our tester, let's have the tester test the Arduino contraption. So here we go.
You guess what it's going to be.
Oh man, those connectors are industrial strength and size!
All right! So, yes, it's a clock, and it's actually
22:39 in military hours or in European hours. I have three modes: I have this which is a clock,
I have a chronometer, and I have a really fast one. This is the second chronometer with the
hundredths of a second. Stop will actually stop it, and the start button will actually start it.
That's going to be the use for that panel:
it's going to be a clock or a chronometer while it's not attached to an IBM instrument.
And you have the grape of wrath one. [Ken] So that one, that one is the 2314
card. And there's this warning on the back: do not remove from J & J unless you consult H. L. Porter.
You can risk the wrath! [Marc] Yeah, because, basically, the machine
is unusable without the front panel, right? If you don't have the overlay,
you're kind of dead. [Ken] So we may be haunted by H. L. Porter.
H. L. Porter, if you if you watch this video, don't be mad at us. [Ken] No wrath please!