Hi I thought I'd just do one last mailbag item for the year because this one just turned up and it was so big I had to open it and it is Christmas Eve So hey, why not? And it does actually contain one of my favorite items. I Don't know exactly what but one of my favorite categories of items. so thank you very much. Matthew Our Trennis train --is-- for sending this one in.

It costs a lot he's from New York I believe and it costs a lot to send heavy stuff like this. So I really appreciate it. Thank you very much and to everyone who's sitting mailbag this year. So let's find out what's inside this puppy.

It's particularly heavy, but it is certainly big. There's a lot of earrings what air in here so it's uh, here we go. What's the padded stuff? sorry, can't see this. Geez, actually it's probably not that big.

We have a note don't want to spoil it for myself and it comes in the case. Is it on the front? You've probably seen it before me? No, There's no labeling, no labeling. It's just a nondescript case. Let's have a look.

I'm looking on the screen here. I haven't seen it. You probably know more than me. What is it? IBM IBM What? What? It's actually in the case Wow Look at this.

Oh, it took like a floppy disks. What cleaning fluid. It's obviously an IBM disk drive in a box. What? Oh, that's not what was written on the place on the box and the documents that said um, it's a brush Um, it said test equipment Oh and I got a vintage computer.

What? What on earth Wow unload discount we're not in use. Do not touch this. Get when running. It's almost like that this couldn't fit in that what does it dis slot on the top.

What is this thing? Have to read the note hi Dave greetings from Oh Puka see / Kip Poughkeepsie Even yeah suburb somewhere um I've been a long time if you were a big fan and I started watching back in the college days study in India of continued to watch since I graduated five years ago thank you very much Um, he's first job out of college was with IBM in Poke Poke Up see Poke Poke up see no sorry I can't pronounce it I've since quit moved on to better opportunities back then I work for IBM Co-workers made a frequent habit of checking the electronic recycling bins. Our beauty. They are mainframe diagnostic devices. Well, so apparently it's just more than a floppy device.

it's as some sort of mainframe diagnostic device. Um I didn't spoil it for the Tanyard I Don't want to read a spoiler for the teardown. Goodness gracious me. an interesting bit of kid Oh Probably a 5-minute teardown.

Let's go. and. well. this is a bit of test equipment.

I Just foolishly assumed that it would be some sort of, you know familiar bit of bench test gear. Electronics are test gear, but it's not. it's a specific bit of test gear for in this case. IBM Mainframes we believe.

So hey, I shouldn't have assumed such a thing. I Spent many years designing countless production test gear and special purpose test gear. for you know, as some products that only you know. It only made 10 of them, but they needed a spit a special purpose test gear to do it.

Edie, this is very nice. So the thing I mean oh, you know I How many for these IBM mainframes did they sell That's interesting? Is that like a lid? That's a lid? Isn't it? that? could that be a lead character display Wow I Don't know. But anyway, the keypads really interesting. enter yeah, this is a specific bit of kit, so let's take a look at it.

First of all, we've got a whole bunch of instructions under there and setup procedure, disconnect procedure, keyboard key definitions, and it's got yes/no keys for your procedures. All that sort of stuff. Neat. Anyway, we didn't actually get the discs, all we got.

there's a couple of empty pouches. bummer, but not that it's gonna work or do anything useful. Anyway, Now the first interesting thing to note is the floppy drive is on the top here. and obviously the floppy doesn't go all the way into this thing.

because if you have a look here and here's the floppy drive powder to come out to here, it would you know it? Like it. stick out a bit? like there's no motorized thing that takes it in or anything. so it's going to stick out a little bit. but of course the head's going to be in there on the side and that's just fine.

You know, do not touch the disc when running because then you can cause friction inside the thing and yet, no, it upsets the apple cart and I have no idea what our loop s loop POA parallel I/o IPL reset whatever that is I Got no idea what this thing actually does, but hey, it's a specialized better kiss and Teske unless you had the full instructions for it or you are familiar with that, using these things, you wouldn't have a clue, but there would have been some you know design team of engineers that actually designed and built this thing. They've put a lot of work into it. It's going to have software and everything else in it because it is basically a little computer. a diagnostic type computer that plugs in and does whatever tests it needs to do into whatever mainframe e type thing it plugs into.

so oh um, disconnect all this. It's obviously designed to go into this up portable carry case designed for you know, fueled service techs or something like that to go into the field and repair IBM mainframe stuff I'll take it all out and we'll have a squeeze inside actually. I'm gonna violate my rule I'm gonna power it up because I don't want to take it all apart, haven't got time to take it all apart, then put it back together today. it's Christmas Eve I've got to get out of here.

So I'll power it up are first and see if it does anything. Kits: 110 volts. So there we go. Fingers crossed.

there's a fan. You can hear the drive doing something. We've got some leads. Hello Enter: Nope.

Love House got yes. no buttons went backwards. return forward. No.

so powers up. No magic smokes escaping. But yeah, nothing was that a big no. I thought that was a heatsink.

Yeah, that could be it. Yeah, that's a big heat sink on the back of that I think but nothing on the display here, so that's a bit of a bummer. Oh well, for those playing along at home, it's the 901. X Is it? He's our first peek inside this puppy.

We can see the floppy drive mechanism here and so that's the entire top half. Oops. Looks like the belt has seen better day. Well, no, the belts actually intact.

it's just it's just come off. Huge big flywheel there for it, but nice. neat cabling all tied up. Somebody's taken pride in that.

Definitely even tagged all the individual wires. Beautiful! So here's the entire floppy mechanism we've got out. The board's really interesting I'll show you that in a second. Absolutely fascinating, but that's oh.

there we go, Is that a head? Well, that's that would be the motor. Drive the power stuff there. Yep, there's our motor motor soldered directly onto the board. Is it interesting? up here? It looks like we've got some track sensors there and of course we've got the motor in here that drives the head back and forth.

We've got our worm drive in there and there is our head. There we go. It's not a single or double sided job E And there's the other side. so double sided head for this puppy.

Check out the PCB and yes, it is a piece of B It looks like a matrix our board with the square pads on there at first glance. But look, you can actually see all the etched traces in there. So this must have been like a an internal IBM thing of how they did. you know, and maybe prototypes or short run boards or something like that they just did as a matrix layout.

I Mean half those pads aren't connected yet. They've left them in there. It's like bizarre did they have some rapid and prototyping system that allowed them to make boards like this easily. Otherwise, you know, if you're gonna itch a board and do it, you know, why not just get your proper board? Why use a system like this so they know they wouldn't have placed them down afterwards, Would they Know It's it's weird.

I Ah, maybe I might have seen this somewhere once, but I can't duh. It's kind of rings a bell. but I can't remember if anyone knows if this particular technique has a name. If it was specific to IBM or what not, then please let us know.

But that's that's very, very unusual. Anyway, we have some date codes in here. 87th. Nope.

87 Eight to 80 Second week: 87. That doesn't sound right. Hmm. Anyway, look at these cans metal cans.

IBM specific part numbers. Are they some custom silicon? hang on and there's the back pattern on that look. Completely fascinating. Wow Look at all the right angles.

All the electrons are going to fly off the bends there. We've got ourselves a little mud wire down in there. But yeah, that's really interesting that they've used that technique. Wow I Mean the annoying part about you're not using a technique like this is you got bugger-all routing space.

Yeah, you can get, you know, two traces down between pads there. But oh geez, there's a PCB layout engineer I wouldn't want to have with that limitation. Horrible. that looks like a real date code.

There you go. National Semiconductor our second week 85. So you know these. This would have been for mainframes designed in the 70s.

I Don't know, but they could have been manufacturing these still. I Mean they would have only manufactured these probably in the dozens. or you know, hundreds. How many these things and service techs do? They go out there have fixing? These are mainframes so it wouldn't be I wouldn't suspect it'd be in the thousands.

and you know I had to decap that big baby. There it is. Um, it looks like we've got like a maybe a ceramic, but it's It's not a hybrid because there's no other like you know, hybrid, you know, laser Department laser trim resistors or any other components on there. So it's just a basically a mounting board for this little tiny chip they've got in the middle there.

look at that. The pitch on that. it's tiny. Is that like an early BGA thing? I Don't know.

I'm not not sure if we can even get under there to have a look, but yeah, that is. that is cute in it. Well, I've gone to a lot of trouble. This is obviously the part of the floppy drive our control a bit.

You know, just the engineers that worked on this module alone, let alone the the test gear that we've got here. This customized a test gear which wouldn't have been, you know, not a consumer Idol or whatever whole team's worked on this sort of stuff. testing. I'll tell you what is this, A multi-layer board? They got a big fat ground plane running through the center of that.

Wow And yep, they were really fond of this. All right. It extends right through the main border though. this one here is different.

doesn't have that ground plane in the middle. You can see the difference between the dark and the light side of the force there. But yeah, that's like they're obsessed with this. I've got to find out more info.

What is it? So I asked on Twitter if I anyone knew what this was and Brouhaha says I don't know the name but IBM used it a lot. Yep and Mark Morin says it's LGA stands for linear grid array I actually checked and it's a I believe it could be land grid array so that's the name for that sort of technique. Langer iterate There you go. I Guess we can google that one and here we go.

I've got some more custom IBM goodness in there. Surely they have not designed all this custom silicon just for this test jig so they're probably repurposing them. maybe from the mainframes themselves. Who knows the logic from those? I don't know the processor I don't know.

Um, let's hey hello hello we've got ourselves a real in quote marks PCB Look at that. once again fond of right angles. Oh all this order out of stuff and you can tell it's Auto router rubbish because look at this. the trace comes here right angle up to the middle of that pin and then in the middle of the line of those and then over.

No peace and be designer in their right mind would do that like even a beginner would not do that You would know, you know. just look. even if you're doing right angles, go all the way over here and then this straight in. like it.

It's just yeah, it's dumb. this thing's Auto around. Oh wow and it's interesting that this just pops off like that. I Mean there was no nothing holding that.

the only thing holding it in was the screws and the force. Ah Star Wars Again and yeah, these just did not. Well can I Just yep. I Can just whip em out.

Do that. There's a mine is that? Oh no, we got lots of them. I don't know where or what the processor is is a combination of a whole bunch of stuff. but anyway I assume extremely similar under oh, that one's high.

Oh, it's a double. it's got a piggyback. Do that. Oh Advanced technology and all the chips on here.

Look, you know they made by Motorola National Semiconductor but they've got almost certainly our IBM part numbers. There we go 19th week 82. But yeah, these are all be our custom IBM part numbers. they're They would have their own extensive bill a material system so the designers of this would have gone well.

We have to use these. I bet they would have looked up the IBM catalog of parts and you can probably only use the pre-authorized catalog of IBM parts at each have the individual part number and they'd have their own internal documents which map the IBM part number against the actual I Mean this could be a, you know, a 7, 4, LS, 2, 4, 5 or something like that. You know, bus, transceiver, or some other thing. You know it could just be regular jelly bean logic.

but hey, the IBM are something so big, that and so bureaucratic. They have their own part numbering system and they get them. You know they'd buy you know, a hundred thousand chips at a time or something and get them all silkscreen with their own custom numbers on them. And these are obviously a resistor pull-up packs here.

But mmm, what's that puppy? I Don't know. does anyone play along at home? There's one thing you don't see on here is bypass capacitors. Where are they? Well, maybe that's what some of these puppies are. Some would be pull up some, it'd be maybe bypass capacitors in a Sip single inline package perhaps.

Hmm. I Broke a couple of these off. see if we can probe that. I'm getting something.

Yeah. 3k. There you go is a resistor array and this puppy. Here, it's most likely capacitor array.

Is it? No, no, no, that's 170 Ohms. Thank you. 89 Ohms Wow Okay, that's interesting. So where's all the bypass caps on here? Um, low enough.

they didn't need it. So anyway, these are our three boards. Board number two. It's just mostly big chippies.

This one's a little bit more discreet. II There you go. So I'm not sure what's going on there, but then three boards that have to have that's part of it. That's the processor system.

Hmm, they couldn't even wrap this properly. Look, they could be going up between the pins and then right angle. What the what? Unbelievable. And here's inside the keyboard.

Wow They've got some sponge on here and some tactile dough and the keys all sat on top of there. So the little tactile domes. We've got our matrix type board construction. Again, we've got a big foam pad under there, so we've got all the circuitry for that.

but look at that and he's six on a stick. Wow Got the display. Wow. This looks like some sort of weird alien technology that crashed at Roswell and like brilliant.

Wow These are presumably our character based displays I Need to get a macro lens on these Wow Look at this in a dip package. These are for character displays. We've got one, two, three, and four and they're seven high by five digits. Well, obviously look so you can see the bond wires going between these.

So obviously we've got individual column drivers like that and then this would be a row driver. I See here. Remarkable. And there's some serious heat dissipation going on there.

Look at that monster heatsink. I've done some maths random poking around with the Diode test. ahirat I Can't get anything to light up. so yeah, not sure what the deal is, but hold on to your hat using a super-secret multimeter that has a 15 volt diode test range.

Oh II Don't need the 15 volts. It's actually a 1.8 voltar drop, but it gives us more current capability. You're a measuring 1.8 5 volts drop. Bingo I Can light those puppies up.

it's a little. LED display isn't that cute Wow LED Dot-matrix display Brilliant! So thank you very much Matthew for sending this puppy in. This was incredibly interesting. like all this custom.

IBM chip tech, the matrix layout PCBs the old 8 inch floppy and Wow these beautiful little LED dot matrix displays. If anyone's got any data on these things, I'm easy to find the pin out. Now you just hook it up and you know, fairly trivial and you could drive I Could you know use this as a display drive? That'll be a cool project if I've got time to actually hook up and drive this thing. Multiplex star obviously.

but wouldn't that be awesome to get that puppy up and running? Oh yeah, an awful lot of engineering that just goes into. you know, sort of a low volume, probably in the hundreds or something like that at best. I'd be guessing a custom bit of artistic. it might be for testing a floppy drives in the field or something.

not entirely sure, but there's something to do with IBM mainframe. so the service techs are take these into the field and you know, fiddle a few things and repair your mainframe for you. But you know there's a lot of engineering that goes into this. all the custom firmware, the process in everything else.

So you know a team worked on laying out all these boards. as I said, they probably didn't roll custom silicon for this I'd be surprised if they did. You know it probably wouldn't been worth it. but hey, IBM being IBM who knows.

But if anyone's got any info, detailed info at all on these things they worked at IBM They know what this thing is. Somebody out there's got to know. Please leave it in the comments. so thank you very much.

Matthew That was awesome! If you like that video, please give it a big thumbs up because that helps a lot these days with the engagement and all that YouTube crap going on and stuff like that and it's I'm off to a Christmas party. it's Christmas Eve here I Just got an hour or two to drop by the lab. So I hope you like this video and by the way, I have bad arises batteries. Our update: if you haven't been following the eevblog forum they did deliver.

it is is somebody sent them. Somebody sent my ones. haven't been delivered yet, but somebody sent them to me. they are on adhe old truck but I probably won't get those until after.

Well, I obviously won't get them until after Christmas Hopefully and we can run some tests, but it's looking pretty. Go check out the Eevblog the 300-page eevblog forum. It's absolutely fascinating on that. Everyone's a few people have got them and there are tests in them and yeah told you so.

Catch you next time you.