Hi Welcome to everyone's favorite segment: Mailbag Monday. Yes, I'm inundated with packages. I've got no less than 19 packages. I think this might even be a record so I only get through a few of them today.

So sorry. I'm gonna have to continue to do mailbag every week until they're clear or they may never clear because people keep sending them in. which is fantastic. So thank you very much.

Um, because yes, it is everyone's favorite segment. Uh, it is one of my, if not the most popular segment here on the Eev. Look where I open my mail so I think, uh, these are kind of newish. These are kind of oldish.

so sorry if I, uh, you sent them in first and seen it here in the last couple of mailbags and I haven't opened it. So let's get into it all right. First up, we've got one from Richard Anderson. Double S.

Um, thank you very much. He's from Sweden, so hi to all my Swedish viewers so let's check it out. I knew what's in here. Well, kind of.

uh, this is. I don't think there's any split in the top of this thing, so no, no, I don't think there is. so I'm just going to have to wield the knife all over the shop. There we go.

Slices like butter. Oh fantastic. So let's see what Richard has said. He sent a couple of postcards one from uh, Stockholm excellent and one from Doesn't Say doesn't say oh, that's a lovely house Is that Richard's house? I don't know.

It's got a lovely flag out the front, so what do we got? We've got a note and ta-da vintage. Keithley Beauty Dave. This Keithley multimeter was previously used in our Polymetric Materials testing lab. I work with high voltages and just a small electrical discharge of 30 kilovolts in close proximity to the Dmm.

You guessed it, he killed it. Ah, Unbelievable Richard. what are you doing mate. After a mishap, I measured the rectifying bridge, but failed um in an open state.

therefore changed the diodes. Uh, and so it powers up, but some ranges behave strangely. The last time he tried it, have no need for it since. well, we have new instruments.

Do I take do? Can I fix the thing? Um, yeah. well. might be able to have a crack at it. Not in a mailbag video of course, but uh, hey, let's open up.

Thank you very much Richard. And yes, I do know the difference between Sweden and Switzerland. Yeah, I goofed the Lindstrom side cutters sorry, made in Sweden. I knew that these are beautiful cutters, by the way.

And here it is: the Keithley 177 micro Volt Dmm. It's not a bad, uh, meter at all. You can, uh, generally pick these up are quite cheap on ebay. Yeah, they're ancient, but yeah, they're not too bad at all.

Check out this though. 20 millivolt range and it's got a regular 200 volt range. That's why they call it a micro volt. Uh one? Yeah, it's not like you know, five and a half or six and a half digits or anything, but you know.

Still, quite an accurate meter, and the specs are on the bottom. I love it when meters have specs on the back like this. There you go. It's not too bad.

0.04 percent? Uh, basic Dc volts? 0.03 that's on. The lower ranges are 0.03 percent up, plus one digit, by the way. So yeah, that's pretty good. and unfortunately it doesn't have a high input in impedance.

uh, mode though. But yeah, it's still pretty good. Um, and down in the resistance. You know we're talking 0.04 percent down there, plus one digit.

So yeah, not too shabby. If you can pick one up real cheap, they can be a handy little bench meter. There we go, we pop the lid off, and that's what we get. By the way, the tilting bail on these things is pretty dicky, so you know, not something to write home about there, but this is interesting.

Check it out. The uh. the front panel. uh, terminals, which do look like a Tellurium Copper by the way.

Um, they, you know, spared no expense there. Look, They're just going directly over to one of the protruding pins on the ganged switch mechanism. That's rather fascinating. Um, you know, I haven't seen that before.

Usually they'll terminate into the board and then go over, but some reason they've done that. I don't know the great thing about this. Look at this. calibration instruction sheet and which doubles as a shield in that plate on top.

Followed the number sequences look and it tells you exactly what to do, apply exactly and then using the right tongue angle of course, get in there and tweak everything for your Ac and your Dc modes. Fantastic. So you know, really? Um, well. not going to say really easy, but you know I mean you don't even need to read the manual to calibrate this thing.

Very nice so that just pops out of there. It's not even screwed on, just held in place. Very old school construction look at that. looks like we have a oh yep, Cadec.

Yeah, no surprises. Kadak. They're one of the industry leaders in uh, thick film resistor networks like this. This is the, uh, you know, a high voltage ceramic divider.

uh, network. you know, really very stable. and there's our four-wire current shunt down in there. 0.1 Ohms are 0.1 thank you very much.

That's not too bad at all. And there's you know, a couple of other, uh, precision resistors all around here in very different, uh, shapes and sizes. and uh, Intersil? Yeah, no surprises. Icl.

what? 71 Co3 and you know, 4069? Look at that. Oh goodness. Anyway, um, this does date it to uh, 19th week 1980 by the way. And yep, look at the huge crystal in the thing.

Wow. that thing's a whopping hundred kilohertz. What a Bobby Dazzler And you don't see these packages very often with the extended leads coming out the end of the molding like that. Ah, beautiful.

Oops around. out of room. We need some extra pins, but oh no, let's just use our standard size molding. and presumably that's a Diode bridge mod Richard's talking about.

Well, crude, but effective. Not one Meg thank you very much, but 1.005 Meg 0.5 percent. Thank you very much for the size of that beast, Houston. We have a problem.

Well, that resistor that's had the absolute ass blown out of it is, uh, right on the output terminals. Because yeah, there we go. You can actually, uh, get the output for this thing. So yeah, that's just cactus.

so it's not like it blew up on the input. So yeah, go figure. Anyway, that may or may not be related to the actual uh problem, but good place to start. Check out those multi-tuned trimmers.

Aren't they beautiful? Look at that. So thank you very much Richard. We can certainly have a crack at that because we can get the schematic. uh, someone on the Euv blog forum has actually, uh, redrawn a crappy one from uh, Keithley.

So yeah, we have got the schematics. Annoying that you don't have the reference designated silkscreen printed on here. Um, you know it's one of the disadvantages, but still should be easily repairable. Access is fantastic and stuff like that pretty much, uh, you know, commonly available uh components.

So yeah, we'll have a crack at that in a future video. Next up, we have Portugal. Yes, I don't want my Portuguese viewers from Samuel Ferreira Marquez Lorenco absolutely pronouncing that incorrectly. My apologies, uh, probably don't even.

Yeah, I do need the knife a little bit so everyone likes the knife. no, sorry, I don't have a spoon. and let's uh, crack this sucker open and see what Samuel has sent. Uh, we have some C code, El Grey, Algarve, Algarve greetings from Portugal, and yet another postcard thank you very much and something in some ziploc bags.

Let's take a look and it turns out Samuels had a second sucker, the Sav. He's the one who sent in the Pixel into the mailbag some time ago. This is a new one called the Pictory. Uh, it's a peak development board based on the 16 F 690 mid-range pick with 18 Io uh, one assembled and one pre-programmed the other unassembled.

So check it out if you want to. uh, get the picture. I'll include the link in down below and I should receive the solder paste stencil I did. There it is and this is from Osh Stencils.

There you go. And yes, um, just like a mylar sheet here. So you know really cheap and easy people are giving away stencils these days and included a solder paste spreader as well which is just a credit card. And yes, you can just use any credit or other plastic card.

Makes a great solder paste spreader like that. You whack the solder paste on and whoosh straight across. And there's a stencil. So even for doing tiny pitch work like this, hey, it's easily achievable by anyone when you've got one of these solder paste stencils there it is.

There's not much to it at all. just the in-circuit serial programming header on here and some headers to plug it into a breadboard too easy. And of course that would hook up to the Pick Guitar Three or any other pick programmer you care to mention. So thank you very much.

Samuel Link is down below if you want to check it out. Next up. Yes, Yankee Land, you guessed it. Uh, Max Scott from Cookville in Tn, Tennessee I think.

Anyway, let's check it out. I don't need the knife for this one. I don't think because it could contain that. uh, horrible stuff.

Yeah, I think it does. Yeah, don't want that. So here we go. Oh yeah, oh, I hate that crap.

I really do. Oh man, what do we got? What's Max sent in? It is a Commodore calculator beauty. Whoa. Look at this.

I've never seen a well, I've heard of, but I've never, uh, physically had a Commodore brand. Yes, Commodore Computers. They made calculators as well. Ga Gl 987r model.

look at that uses a rechargeable electronic calculator. Um, unfortunately Max says that he picked it up at a local second-hand store. so thank you very much. Serial number: 15 025 So yeah, that could actually be You know, the 15 000 unit made in the Us of a beauty.

I'm going to have to get a date code on this sucker, but he doesn't know if it works so we can power it up. Oh yeah, Four Function. Of course it's a Four banger. You know it's not scientific, but hey, it's a Commodore.

So yes, before Commodore made famously made computers, they were in the calculator business. The calculator wars of the 70s. Of course everyone was involved in that. from Mitz to Sinclair Tandy.

All the uh, all of those, and uh, Commodore were one of them. and uh, they all branched into uh computers of course because it was a natural extension. Oh, it's gotta. I'm gonna have to break it apart.

it's got a clip somewhere. Oh yeah, look at that crusty batteries. yet? no wonder it doesn't work. Those rechargeables.

have seen better days. Um, ah, you cannot beat the laws of chemistry, Captain. There's a front panel keypad and as to be expected, Ta-da look at the circuitry. Yes, a big single chip custom Lsi there.

Of course those batteries are horrible, but hey, check out that vacuum fluorescent display. There isn't that lovely. I mean, there's nothing else in here. There is a main Lsi chip which is the driver as well.

And there's a vacuum fluorescent display. Wow, that's actually really something. Look at that. I don't think I've seen one of those before.

I mean, you know, eight digit vacuum fluorescent display like that? Look at all the all the wiring coming out of it at one end. of course, sealed. At the other end. there's the uh, there's the vacuum sealer where they uh, sealed it off and uh, um, sucked out all the air out of the sucker and uh, well, that is.

That is a thing of beauty. Might have already used the term in this video already, but that is a Bobby Dazzler. Folks, it really is. I love it.

Gotta power this thing up. It's alive. Yes. Pair it with that.

2.4 volts. No problems whatsoever. That is a beauty. Let's see if all the segments work.

They certainly do. Ah, terrific. Well, you know you'd expect it to still work, although the display might have faded with time or something like that, but it still looks pretty darn good. It's drawing um, 114 milliamps at 2.4 volts.

And just for kicks, I probe one of the lines on the vacuum fluoro display and bingo, That's what we get there. We go. We're at 5 volts per division. So yeah, it's pretty huge.

5 10, 15, 20, 25. you know, around about 28 volts or something like that at 287 Hertz. And there we go. You probe some of the other lines and uh, you play around with the uh keys and you can see, uh, see things all changing around.

As we put, I'm pressing the keys there, putting more on the display. Let's clear the display. There we go and I'll put up all eights. here.

We go there we go. Bingo. Terrific stuff. And the really great thing is is that they're doing that all in the one Lsi chip.

They're doing the uh, the vacuum Fluro driver. The high voltage are driving everything in that one chip. Fantastic. So thank you very much Max.

That is just awesome. I love that. Yes, Commodore Calculators. Ah, who had one? Hands up.

Come on, did you have a four Banger Or do you have the scientific one? By the way, that is the 49th Week 1974. Jeez. Next up. Jordan Ross from West Hills in California and time sensitive.

Oops. Sorry, I'm not sure if I missed in the last video. uh, postmarked August 11th. so it's August 30th today.

So yeah, it's not that bad I guess. But geez, yeah, sorry, I'll use the knife. Here we go. What's in it? What's in it? That's difficult.

I should have just sliced it right open, time sensitive. We're going to note and we've got some little metal things. Oops. Unfortunately, I missed the deadline.

Sorry Jordan. Um, and well. yeah, maybe it would have helped because she didn't uh, unfortunately. uh.

Jordan didn't meet his uh. kickstarter um, goal. So bummer. Sorry about that.

Oops. Um, yeah, it's a sharpie holder. At first I thought, huh, what's this and it rotates? I thought, the hell's going on here? What is this? Huh? what does this do And then no. It's obvious this actually breaks apart.

And yes, I do use Sharpies here in the lab. This is a mini and yeah, it just holds you sharpie and they're designed to just a magnetic like an adhesive uh, metal back. So yes, I can actually use that here in the lab. I can.

just there you go. Whack that up there like that and whack my sharpie in. That's actually quite handy. Thanks Jordan.

Sorry, I didn't get to you in time and we've got another one here. This is from an Aussie and it is from James from uh. Denniston here in New South Wales. It's just a stone's throw from here today.

James and uh, let's oh, this looks like it's been repaired by Australia Post. It's got the sticker on it. the uh ah yeah. horrid hate these things.

Uh yeah. I should have done the zip and pull. I'm an idiot. Zip and pull.

There we go. Let's clean up the lab again. Goodness. All right, let's have a look at what James has sent.

Oh, it's big. It's electronic. It's got buttons. It's another calculator.

Check this one out. Compuc Compucop Micro computer. It's Mo. It's a micro computer.

It's not just a calculator Beauty. Never heard of it. never seen it before. Oh hi Dave, I very much enjoy your channel.

And when I saw this in the Skip at Sydney Uni, oh tragic. I thought you might like to add it to your collection of old calculators. I do, thank you very much. It's a Compucop 322g programmable scientific calculator from the early 70s.

Tried to power it up, but it drew the right current. Unfortunately, that's all I could do. A interesting vintage teardown. Thanks for the vids, No worries.

Thanks James for sending in. Oh this is just beautiful. Look at that. A programmable scientific calculator.

Oh, look at the keypad on this thing. It's just. it just oozes quality. It really does got indents on the keys and I look at the Pi symbol there that the feel is uh, awful.

Um, but look, run, load three to do Scientist Three Two two G scientist, high degrees, radians, exchange, key, exponent key. oh goodness. and on the back here we have ourselves some how to use instructions. There you go.

Serial number for those playing along at home requires 7 volts at 1.3 amps, but usage instructions and then we've got power on off on the top. Here there's the uh, yep, there's the Dc Jack. and yeah, Compucorp Computer Design Corporation, Los Angeles, California, Who can remember them And check out this flip up stand here? Wow, that just oozes quality. The spring in that? geez, it'll take your finger off.

Unbelievable. Anyway, our Compucorp Micro, um or Copy Corp Computer Design Corporation. They made a whole bunch of stuff. Hang on, We got an engraving.

There we go. Sydney University Physics Department. Love it. Um, they made a whole range of calculators.

banking, calculators, Bond trading calculators, ender and programmable scientifics like this beauty here. Oh, and it gets even better. Watch this. Look at that.

There's your battery compartment. Beautiful. And yes, it does run on rechargeable batteries. Gorgeous.

And just like James. I tried to power this up and it was drawing about 2.4 amps at 7 volts. so I'm not sure if it's supposed to do that. that's with no battery pack in there.

So anyway, I think this is going to be a rather interesting teardown, so I'm not going to spoil this on the mailbag. I'm going to keep it for a teardown Tuesday. Thanks James! Awesome! You.