Hi welcome to everyone's favorite segment: Mailbag where every Monday I open my viewer mail p.o box link down below if you want to send me stuff. so let's open some mail the Aussie way. Let's go! Thank you very much to Robert Alexander from the United States of America now I know what's in here and it's really cool I said I was actually gonna buy one he actually contacted Robert Bob I guess about this and I don't know if I ever paid for it but I think he's dude looks like he's just said me one thank you very much if I give away if I tell you I have to be careful opening this so but it's really cool for those who remember I'm talking the seventies and probably went into the 80s did it? I'm not sure but yes I am cutting towards myself I'm a professional. oh no I think I've got to slice and dice it down the middle I don't want to I'll be very I do have the opener so unlike the proper opener somewhere sorry, but it's I've just moved into the new, barely moved into the new lab and no idea where everything is.

so here we go. Now we're right, no workers, all right. Note: Hi Dave I Hope you enjoy these photographic recreations of Bite Magazine covers. Hands up, if you remember Bite Magazine to recreate: Robert Teenies Computer Engineering I made a printed circuit board that matched in his painting, photographed it, then photographed a Hecho scale trainer and superimposed it on the PCB and for the these are linked them in down below, they're fantastic.

Check it out. Contact a mister. Tinian has given me written permission to sell copies of my Byte Magazine recreations. I am doing so it.

Byte covers comm linked down below. Yeah! I got both. Ah-ah-ah I Love this one. This is the one I wanted.

Ah, fantastic. We're gonna have to get it framed. Check this out. I'll take it out so there's no glare.

That is a thing of beauty is a joy forever. Look at that Bite Magazine cover. that's the I see how did he do the I see one? This is called Chip Building and he D capped a 6809 microprocessor, photographed it, then superimposed the picture of superimposed the picture of himself with the jackhammer. So that's actually Bob with the jackhammer.

Oh like hats off, That is brilliant. And this one superimposed the oh yeah I Can see it's now superimposed the train with the Hecho scale. It's writing like the up with the PCB with the Hecho scale train. Ah, that is fantastic.

I'll link them in down below Byte covers. Calm because these used to be like arm drawings on the front cover or paintings or whatever they were on the front cover of the Byte magazines back in the day. They used to. looks like I've got two copies have I Yep, thank you very much.

Bob These are awesome. Go check them out Byte Covers com. They're available in different sizes and stuff. That finally recommended.

take another random one off the shelf. let's get rid of the big stuff. sorry I should take them in date order but you know, thank you very well. Lots of okay what's the star? sorry um this the Schmidt that family.

thank you very much from Caramel in Indiana I good Indiana Indiana Yes in the U.s. I think so another Yankee one. Thank you very much to the Schmidt family. it's the whole family.

I guess does the whole family whoops. Do they sit down at dinner time and you know instead of watching Jackie Gleason they watch the eevblog? sorry Back to the Future joke I shouldn't I shouldn't have to tell you what they are anyway. the packaging list is a packing list. Thank you very much.

Oh okay. oh I've got some t-shirts twelve. oh it's a it's a I guess they're into one Formula One Formula One Motor Cars I Do play thank you very much Huxley Will love DUPLO Sagen. He's passed the duplo of course but Huxley is only three so thank you very much.

Got another t-shirt Beauty Ozzy See Australian flag twelve soon. that's yet. That's the Australian flags. Got the Southern Cross looks like it? Yeah, another Indy car.

number twelve. Is that an Australian I assume that's an Aussie racer and is that like Webber is that Mark Webber I don't know I've got number twelve Indy car I Haven't followed Mark Webber for a while so I assume it is I got my own personalized to the thermal bag. but I think it's a thermal bag? Be cool. thank you very much.

Is that man. is that my logo and we had you? Think it's not electronics? We do actually have a doodad board. It's some sort of VCC voltage indicator. So let's check that out and more t-shirts galore! Thank you very much and more.

Indy Car t-shirts I've got no shortage of t-shirts By the way, if you're gonna send t-shirts and I shot these ones out Yes, Small, small or medium adult male thank you very much. No, this large rubbish. I'm not sure if this thing is still for sale or whatnot but it's the high five voltage indicator. And here's the board.

It's just a designed to measure like a five volt rail and give the you a lead indication of like the accuracy Green of course is in the middle. There you go, you can get the what the values are whether or not how close your rail is to five volts and this is what's called an expanded scale volt meter and these were a common project back in the 70s and stuff like that. and yep, uses a good ol' LM three Nine one, four bar display driver of course. little TLC Twenty Two Sixty four.

Is that just a that's just a quad up amp and a reference job II over there. What's that? A ref? Forty-three Neat. and that's all she wrote. but it is a like Ninety Eight design.

The documentation is actually a very comprehensive. It's designed to it like integrate into an existing product or you know something like that. don't know if it's open source and I've just got life theory of Operation and all sorts of things. I Like going to the details, there you go.

you can screen capture that and read the theory of operation for yourself. There's not much to it, of course. expanded scale Volt meters aren't rocket science, but we've got our sauce. The schematic: There you go.

For those playing along at home, it's not much to it, just a Op amp and a reference. And then it's just doing some expanded scale stuff to drive the LM and then to translate that expanded scale into the range required for the LM three nine, one four dot bar display driver. So there you go. Neat.

Got a bill of materials errata and an application guide Wow Ego. Terrific stuff, but there's no website or anything. Hmm, oh, the psychology of centre green. We have chosen the lid, color assignments, and correspondingly VCC levels to help an auntie user easily maintain a suitable operating voltage.

is quick and intuitive to tell the user that VCC is in the green and preferably centered, even if a Digital Reader of the VCC level is available. Yes, I Have been like many production things over the years where it's always easier to give like a red, green no-go indicator to an operator rather than give them a voltmeter and say it needs to be 5.0 You know, 5.0 + 0 0 + - you know, point O 5 or something like that within a range. It's just much easier for people doing. You know you're more unskilled people, especially, you know, doing daily tasks and stuff like that.

You don't. You can make the mistakes, you get drowsy, bored, do whatever your minds wondering, and you just don't read indicators properly. So yeah, definitely indicators are the way to go. Here we go.

Hooked it up for the calibrator. Sure enough, we've got our pretty good. Well, it's pretty close to center. there is none.

There is no one. that's actually because there's not an even number. so there's you know there's not an odd number, so there's no center. But we go up.

Come on. what? Oh there we go. And there we go. Point Oh five.

So I probably should. That took a while. There we go and you can see it. That's the expanding.

or can we get all right on the edge? Leave that without. Both of them got both right on the edge and red. 5.25 There you go. Soon as you reach precisely 5.25 Well, there abouts.

and if you get to down to four point, seven is at four Point Seven Five which is the nominal five volt, not four point Eight five. Actually, yes it is four point Eight five is the low. So according to the table, so that's bang on sweet. This article was received in Australia in this condition and has been rewrapped by: Australia Post What looks in pretty good Nick I don't know what maybe is it? is it the inside did the units fall out and Australia Post repacked it so don't know why they gave it that sticker.

me and I've seen stuff like that before that's like literally falling apart in the post. but ya know that's all good. Ah, we have a calculator. It's Russian Mark 51.

we'll check that out. it's from Belarus Apparently I'm the I Gor has moved for a mother. yes, sorry Michael is moved from to Belarus and both of them work. Not sure about the batteries though.

Oh yeah, the FML IO one you know 1980s side button. You know if Luke copy multimeter the old the old buttons on the side I lusted after one of these. you know, like back in the day Oh Check that out. The Mark 51 anyone read Russian let's chew up.

Whoa. Whoa. blinky, blink, blink. Well I think I think we have a dodgy button there Wow works like a bought one.

What on earth is all that? I've got no idea. like what? I don't What is that? Bueller Bueller What is the point of all that? Got the clear keys up here? Can we do our 69 factorial? This looks like our function key. Our Shift key. It just puts a dot that night.

If there we go. Factorial: it's taking a while gets it? Alright, let's crack this open and Tada oh that beautiful circular encapsulated package with the and and cutout in the board with it sunk down in there. Standard Lithium coin cell suite. You know it's got a real PCB You know this membrane.

rubbish. Got a couple of resistors in Qatar It's up here. have we? what's doing there? Anyway, let's get this board out. so can I So can I come out.

It's not gonna come out without a fight Oh Another screw. Oh alright, here we go. OOP Falling apart is our back is there I'm silver bucking on there. You can see the segments on the LCD and that's you know.

It's pretty pretty standard construction. There's not much how you're doing about this at all. I Like it. What's that? Is that a crystal? Is that like a little? Is it? I Do I Don't know or is it a cap? It's kind of strange.

Wow Oh quite. Show me we've got an SMD cap there. So I Must I'm presuming that that's that's the little. Like a little watch crystal or something.

but it's tiny. It's absolutely tiny. But anyway, that's not too shabby at all. Hands up.

if you had one of these, if you're still using one, oh, look at this. Bobby Dazzler Oh I Just love the look at the clicky wow. This solid as that's absolutely incredible. The four millimeter banana jacks they go.

Jeez, they barely look four millimeters I Don't know. but anyway, can anyone read it right? Anyway, he's got a tilting Bay Oh, look at that. Terrific. and oh hello that's conformally coated.

You can see the shine on that. Wow Anyway, let's wow. That's that's brilliant. Look at that, the fuse in the battery holder and then it's like wiring loom with the little toys on it.

Oh wow. Attention to detail. Fantastic. Let's see if that does that work.

Oh, it works. It works. Let's plug it up to the cow Raela I'm feeding in 1.9 milliamps and from the calibrator that's not too. that's not too shabby.

19 milliamps. it's not too far off. Wow and that's one volt. Not too bad.

that's a hundred millivolts. Jeez, it's hanging in there and that's ten volts. It still works. a treat.

Oh look at this. Got flat head? No, no that. Philips rubbish. It's gonna come open, come parties, or a clip somewhere.

Oh, it's all through-hole hello. She's not sure what the deal is though. Okay, it's the buttons. I Think we've got to push all the buttons in before we can get out.

Well there you go. Look at that. Oh, isn't that beautiful. All the gang switches, of course.

Fantastic and like classic, you know, through-hole vertical resistors and stuff like that. Lots of little trimmers everywhere in there, which is kind of what you'd expect in these old-school designs. So and of course we've got ourselves genuine chips as well. They'd be you know, equivalent to Western jobs.

And do we have a ICL display driver under there or the you know, the Soviet equivalent? Well that's pretty how you doing Lee lat. that is the wiring for the LCD bugger. Like having a zebra strip or anything like that or any sort of like pin header. Nope.

Do they even go in order? Yes, they go in order. Look. oh no, no said the odd ones. No yeah I think they go in order.

Wow Why would you What they obviously like, they don't physically line up so like we've got the road like the connections are here. but they're sort of like way down on the inside of that so that I had physically line up. so to get the form factor, they had to individually wire each one. They couldn't be bothered doing a ribbon and that's terrible.

Muriel Ali of that and they've just budged. Look there just budged on this. like tin copper wire right along. It's a it's barely that, they're almost touching.

Wow, that's incredible. and that's how chip down in there anyone recognize it? Ninety. We talking ninety one? really? The fourth week, ninety-one Do they still have the same take hoes I'm going to assume. but was this thing really it was done in 91 Wow 887 These are 12th week 87 on them.

Okay, so they're using some old stock if this one is 91. Wow, that's that's amazing I Love it. Thanks for sending that in. That is classic.

Wait, you ain't seen nothing yet. Are these the probes that came with it? Really? That is hilarious. Oh wow, oh wow. they're ridiculously sharp.

Wow but they are the most how you doing probes I've ever seen. That is amazing. Wow The point on that thing. Even better.

Look at this we have is this: got the schematic. We've got the board overlay. that's fantastic. and if we got the schematic on the other side, please, yes, we have the schematic.

Fantastic. Sorry. I can't show all this in one shot, but that's fantastic that you actually get the schematic with your meter, which it was not uncommon back in the day for those who want to screen capture the whole thing. Here we go.

Thank you very much! Paul Lennon Dola From Buffalo in New York Hi to all my viewers in New York Let's have a quick squeeze. it's too easy. Ah, Calculator Casio Datta Khel 50 It's not a it's like data, calendar, telephone, secret, all that sort of jazz $0.79 But again, the Casio Data Cow 50. Hands up if you had one of these bad boys.

nothing scientific, calculator, rubbish and it's yeah, it's like it. It's got telephone and secret. no no entries. Ah, back when you know you actually I used to carry like not a one of these but I used to carry like a Casio diary thing back in the day where you can't believe your phone numbers and things in this is the days before you know, phones and everything else you'd carry around.

you'd like little diary, calendars, scheduler thingamabob whenever they were cord. Anyway, classic. all this stuff's made in Japan Yeah, 2 Milli Watts. and are we going to get PCB or membrane? My money's on membrane.

yet it's Sofia and flexible. and yep, membrane. Of course there's nothing on the other side there that's just the the carbonyl. that's interesting I Don't think I've seen I don't think I've seen that before.

they've actually got the back in on these. the implement the carbons impregnated on the back of the molded plastic like that. That's so that's the conductive button is on the backside so it's like a reverse keyboard. That's really fascinating because normally the buttons you know the conductive pattern is on your button, but in this particular case, nope, that just pushes it down and your conduction is on the back against the back of your plastic.

Wow Pretty sure I haven't seen that before. It doesn't ring a bell so I wonder how many Cassio's actually had that and how many and why you don't see it in him. I don't think you see it anymore. Please correct me if I'm wrong.

There you go. I Got our wah chip on Flex and it's just a single chip solution. There's no other passier. Yeah, we've got our reservoir electro.

they're usually you don't know. You might have a diet if it's dual power. you know, solar and battery. This one's not solar so this one can't be from the Don McKenzie Surely no can't be because it comes from Mary Lands in New South Wales Don McKenzie If you don't know, just retire it anyway.

thank you very much. D McKenzie I Don't know, it's obviously not V Don McKenzie Don Don Tronics go look up Don Tronics He just he just retired after he went. Payoneer basically pioneered online electronics component retail. I received this accidentally with an order from China off ebay.

Rather than throw it out, I figured you might use it in your mailbag videos and tell me what it is, if and what it's used for. Um, okay. let's take a look. We have a rant sealed for our protection so it's just a random board.

Just take a squiz, try and figure it out. Well what is our mystery item? We've got a max to our tera PLD and what else we got here? we're going. It's just like a whole bunch of pads. So uh huh.

Blue, Green, Red The ground ship Select. Aha Well that's a Ths 73, 74 and I Originally thought, well this has got to be some. say you know. Red Green Blue right? Then Chip Select: I Thought: maybe you know some sort of RGB driver or something like that.

No, Turns out that this is like a video amplifier chip. So it's like an RGB and composite video amplified. So it's um, does some sort of video processing. So obviously the Altaira Max 2 is outputting video stuff.

Is this an R to R deck? So it's generating? You know, some crude video and they're using the 73-74 here. So someone out there has know what this thing does. some sort of custom video. you know, processor? are these going off to some you know, zebra strip or some other connector system? They've got like a data bus kind of thing and a clock mate is an external clock coming in.

Probably, you know we've got what's that? D is something in clock for external external connections I like 3.3 volts and ground. How does it physically connect in with whatever device or product it's designed to integrate into your design by TW in 2016. So maybe I could Google that part number there and we might find out if I cannot add it in. But anyway, the Eevblog audience is large enough.

Someone must recognize this. Surely it's know in the comments. By the way, I do like the layout and how they got everything onto the one side. By the looks of it, let's take that off.

Be disappointed if there's a track underneath breaking out. great. Now look at that. Ah - oh fails.

Just couldn't do it. Oh, you'd be bitterly disappointed if you were the PCB layout person for that. If you're designing that and you had to lousy, is it those two there? it's at those two bastards there. Oh, you just couldn't do it.

Couldn't get it all on the one side. Oh I Feel your pain. This one just comes from Greg good on your Greg for the Sunshine Coast in Queensland So it's got no return postcode so yeah, I'm sure it would have got back to Greg Everyone knows Greg in on the Sunshine Coast so know why can't you know I'm generally if you just send stuff to anyone in Australia Australia is a small place so they just send it to. you know Bob send it to your uncle Bob care of our whoop-dee-doo and it'll get there.

You know, know why? cus we've got. there's a couple of random little things. What is it? Can't find any Google on it? My guess. maybe some sort of crystal? Nope.

I betcha this is a delay line. I've done a couple of videos on delay lines which are pretty interesting so we'll do a it's barely a two minute teardown because I've already done in to extensive videos on delay lines and some other little prototype board. Cool! he is Greg's letter and this is the doodad here and you can tell it's a delay line because it's got 63 Point Nine, four, three microseconds on there and the number of terminals and just the form factor and everything else. Classic delay line.

If you've ever pulled apart any sort of older video you know, like a camcorder or anything else back in the day, very common. I Won't go into our details again. Suffice it to say I'll crack it open of course, and it will definitely be. Oh yeah, there we go.

Can we get in there? It'll definitely be a classic delay line collage. Delay line. Oh, I might pop open. There we go.

Yep, Classic delay line. So as I said, I've done two videos on how these delay lines at. Laughs. Pretty sure I've done at least two on how these delay lines work.

So their analog delay lines your feed your signal in and it comes out precisely sixty. Three Point Nine Four, three microseconds later and you can actually use them as storage elements. A lot of older computers. In fact, I think I might have one down in the bunker for a retro teardown.

They used to use delay line memory, but this is are designed for because you know it would take. You can store stuff in there because it takes so long you keep feeding in data and then either analog, digital, whatever you know, kind of whatever you want to do, feed it in and it acts as one big shift register buffer. you shifted in. If it comes out, of course you lose it once it comes out.

so you have to like keep recirculating and stuff like that. But but quick Summary: These are the transducers on the side here. so you get an acoustic wave which emits out it. Let's say, this is the transmitter here and emits out here.

It bounces off here, goes up here. bounces off there, bounces off there. bound down here like this goes around here. bounces off this surface here.

goes up there. bounces off. That one goes down here, bounces off there, bounces off there. It goes back here and out the receiver here.

and that's how you get. and based on the geometry of all that, and the sound propagation, the acoustic propagation of the material, that they're actually of, the quartz, that they're actually, well, the material that they're actually using in their get you your exact delay like that. Terrific. Love analog delay lines.

Well, this thing is bloody handy. Look at this. It's a little. There's four of them here.

you chop it off, break them off, and you put them in your double-a or triple-a battery holders. Allows you to measure current in line. Brilliant. Thank you very much because yeah, usually you've got to have the battery half hanging out with your tongue at the right angle, standing on one foot as the moons in alignment.

and then you might be able to probe with your third hand. get the battery current, but that's that's great. You just stick it in there and it's that's not point. eight millimeters, stick it in the back and you can just and of course the two points.

there's one connects to one side, one connects to the other, and bingo, you've got your inline current measurement. Fantastic! I Love that so much that's gone straight to the poolroom. I Hope you enjoyed mailbag. Monday If you did, please give it a big thumbs up because that always helps a lot and you can subscribe by clicking down here.

Make sure you also click on the bell notification icon so that YouTube actually notifies you of new videos. Speaking of which, videos you can watch over here and over here. just random ones. Maybe another mailbag? Who knows? it's a lucky dip.

As always, you can leave comments down below or on the Eevee blog forum, which is much better place discussing. I Try and read and respond to comments where possible, particularly in the hours after I release a video and as always, you can now support me down below on Patreon, Paypal donations, Crypto, merch products, all that sort of crap. I'm chilling, you know, whatever. Hope you enjoyed it.

Catch you next time.