More Mailbag!
00:00 - Mailbag Monday time
01:42 - T-88C Analog Multimeter
07:26 - Teardown
12:11 - PCB proto boards from Jon Newcomb
19:02 - 1990 Tandy Catalog from Ant Cross @ANTandTEC
28:04 - Alcatel S12 Line Test Card
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#ElectronicsCreators #Mailbag

Hi Welcome to everyone's favorite segment: Mailbag where people and companies can send in stuff randomly into the mailbag and we take a look at it. If you want to send something in, send it to PO Box 7949 Norwest new SE 2153 Australia not Austria first one from the United States of America thank you very much George Misa from H Florida Hi to all my viewers in Florida Let's uh send let's open this up. It is a um popular item here at the evev blog. so let's check it out and is it? Oh is it new? Is it new? It's it's a cheapy Asian Analog meter.

Check it out. Um, let's have a look. I don't know what brand is it? It's I Got no idea. Nice.

Oh, we have a note. Dave This meter has a nice updated PCB IR Transmit check and off Set uh Range and shunt resistors listed on the dial. thank you very much George Let's let's have a look. Um I I Do like the look of that.

um check it out. Here you go: analog. A lot of people say moldy meter. do I really pronounce it moldy meter I don't think so.

it's moldy meter. It's kind of Novel um and H the front panel stickers all bit how you're doing. but anyway, it's interesting. Yes, you can still buy analog multimeters and you know you can buy decent ones like triplets and stuff like that.

You can still get them. They still make them today, but hands up leave it in the comments down below if you use an analog multimeter. so check it out. It's a rather unusual modern analog multimeter.

and of course it's all in uh Mandarin So I can't read any of it, but you don't really have to to be able to um, operate it. Now this is the T88 C It's also available in the T88, A and B model as well. This C1 is seems to be the top of the range one and a massive 17 Yankee Buck on AliExpress I Think that includes free delivery as well. but uh, interestingly, it's got up to 2500 volts.

Um, as a few analog multimeters do, I've got one that goes up to 5 Kilts So anyway, it looks like they have protective oh yeah, look, look, that's integrated protective cap Ah That's really nice for your uh, current, uh, and your high voltage ranges there. So yeah, it's got a specific uh, 2500 volt input, so you don't use your standard one up to 2500 volts here. Um, because it'll have a big high voltage uh series resistor in there or series resistors. Uh yeah, grown.

We have a transistor tester here. Uh, what is how many k ohms per volt? I hear you ask? Well, 50 microamps down here minimum means that it's going to be 20 kohms uh per volt. even though it doesn't, no, it doesn't doesn't say it down there. It has multiple protection.

Fantastic! IC And apparently it's got an infrared uh receiver as well. So like, hand a battery uh tester. It's got a continuity tester. Um, it's quite feature packed and it's got rubber baby buggy bumpers around the outside.

It's got a big wide tilting Bale Oh geez, that's Schmick isn't it? Uh, doesn't get much better than that. And it's got an integrated uh magnet holder here does that? Oh yeah, yeah, that actually. yeah. so you can actually remove that there you go.
so that just pops out if you don't actually want that if it's causing a uh problem. But I've tried it and it hooks onto my holds on to my uh, metal bench. No problems whatsoever. It just hangs there.

um, nice. and it does have a uh hanger on top. So I like I BL Live for $17 us. Seriously.

as far as the battery compartment, uh, goes here, check this out. Got two spare fuses here and room for another two spare fuses. A couple of AAA batteries here. Interestingly, uh, these are for half amp fuses.

This, this is your 10 amp so and that's marked half amp down in there I'm not sure if you can see that, but yeah, um, so they've replaced that with a uh PTC By the looks of it. Interesting. I'm really actually liking this. Jeez like you know these aren't HRC right? it's not.

You know, it's like not cat r right? Um, it's just not in the same class. but for an analog meter I'm I'm I'm rather impressed and it's got metal threaded insert for the battery holder as well. unfortunately. Um, it.

the screw bounced out and went somewhere deep down on my. uh, the black screw went on my black carpet. So um, yeah, I'm not going to find that right now. All right, let's try this IR receiver here.

That's a handy little function. Look at that. I'm using my You remote control here for the camera and sure enough, it actually works. Look at that? Brilliant.

Let's try the continuity tester that's really good. It's instant, it's latched and it and it moves the needle as well if you really want that. but you know. Wow.

All right. So let's try the OM ski here. So two-step process. we have to zero over here.

No worries, got a short out probe out now. I've got it on the uh 10K range. so let me, bloody camera's in the way Here we go. Tongue at the right angle? No worries.

Um, it's got a mirrored scale on here of course. Uh, so that you can see that your tongue's at the right angle and you can avoid uh, parallx error on there. Okay, and 10K so let's go. It does show.

Oh, it's pretty close to one there. Now if we turn it to the one K range, it's probably going to be out ski. It should be showing 10K there. but it ain't because our zero is going to be out.

Yeah, look at that. look at that. So let's trim it back. trim it back, trim it back.

There we go, no worries. And ah, Bob's your uncle? Look at that. That's good enough for Australia. No worries.

And of course we put it over to 100 over here. then it should be on, but we probably might have to rezero that as well. A just a smidge. just a smidge.

There you go and put that. of course it's less accurate over here. That's why your Ohm scale is, uh, nonlinear like that. So you want to be like a decent way over your range here to get sort of like the most accuracy.
But yeah, that's all right. now. as for 10 volts, how you doing? I'm reading 9.8 9.8 there. Um yeah, that's not good enough for Australia n not that happy.

but you know what do you want for the price? We got four screws out of this thing, but I cannot see how to get this apart cuz these look like completely molded outside bits and they don't come off. and I don't know. spudger in here perhaps? but I don't know I'll get back to you. Aha no that just the rubber comes off I got medieval on its ass and that got the I Didn't realize that the rubber could actually come off like that.

Okay, that makes sense. Um, it just didn't look like it was coming off before. Yeah, you've really got to. You got to give it a good oh yeah, look, it's got bloody Clips on there.

There you go. So yeah, now this will just come apart so let's have a look now. Oh, look at that. That's nice.

And the Um battery contacts just go straight onto the PCB there. So that's pretty groovy. and uh, single board construction? nice and uh, we? What's what's that? It's busted. Okay, now is this a Tor Band Meter movement Jobby: H Not sure.

There's our little lead board up there for your Um IR uh transmitter, your IR receiver s sorry. got some big ass diodes there for protection so that's pretty groovy it? Um, yeah, it's going to operate like a regular analog multimeter. except everything's surface mount these days. when I was a boy.

Anyway, the uh input Jacks Of course they just stamped, um, things exactly and folded exactly what you'd expect in this, uh, sort of class instrument. But there you go. There's our current shunt resistor down there and just you know, nothing fancy, but jeez, oh, it's all right. It's tidy.

There's your 2.5 kilovolt uh input here, and that's just gone through a bunch of series of surface mount resistors there to increase the voltage cuz they're like, you know, a couple hundred volts a pop. It's a bit how you're doing, but it'll kind of sort of work at a pinch and confirmed nothing else. On the other side of there, there's just our range switch and uh, there it is down there H like when I was a boy, you had a real wafer range switch and none of this PCB rubbish. We got ourselves a Uh 34063 there a boost converter so that's probably used for the Uh transist test I'd be guessing.

Just tried uh 5 milliamps there. it was a little bit low just like it was on Volts but 50 microamps? oh it's bang on. don't know if you can see that. but yeah, win a winner chicken din I do not understand the capacitor mode at all I've got a th000 mic cap in there I've got it on the C * 1 range right? So you'd expect the capacitance which is marked uh 50 Microfarads full scale there.

um yeah n it should be like completely off scale there and that's just yeah n uh, maybe I need to rtfm Well I attempted to read the manual. uh for that. not that there is a manual, but there's like some Chinglish instructions on the Uh ad on the AliExpress ad and well, it says it's really like a go nogo type test then. like why have like a proper scale on here and I yeah yeah.
nice little uh attention to detail which might actually confuse some people is that it actually has the full scale uh, resistant the input resistance value for the different ranges cuz it's 20 K ohms per volt. of course a 50 microamp meter movement. You invert that basically to get you 20 K ohms per volt. and sure enough, your 1vt range is 20K So that's that's nice.

Why haven't all analog meters had that in the past supposed to work it at yourself? So thanks for sending that in. That's the T88 C and I think it's about 17 Yankee bucks like delivered. And for the price, it's actually just like insane. what you can get for the price.

not that like you know it's It's definitely not the best analog meter out there, but it's kind of like passable I guess and it it could be handy I Don't know if you need a throw around analog uh meter? Uh, for something, it might do the business you know, as or with most analog meters. They're not particularly accurate, but hey, what do you expect for the price, right? and I don't know, it's it's kind of cute I guess Anyway, I'll leave a link down below if you're interested in that. That's some people might find it interesting cuz you know the analog meters have their uses. Um, still their Niche uses out there.

Uh so yeah, you know if you need a cheapy, it could do the business. Next up, we've got one from the Old Dart thank you very much John Neukum. Uh so hi to all my viewers in the Old Dart which is uh, the UK England If you don't know, it's called The Old Dart Um let's it's we got to no, Is that just protective stuff? Let's have a look. Is it just paper? No.

I Think there could Pcbs? We have Pcbs. It looks like we have some prototyping boards always extremely handy. so let's go check these up up close and uh I presume John sells them. Yeah, these look like very flexible uh Fpga type breakout boards and stuff.

So yeah, let's get a closer look. Awesome! These are always handy. I've got like a box full of like like adapter Pcbs and the these uh like experimentation Pcbs and stuff like that breakout uh ones where you can you know and you can put some other components around. Great for trying out like new chips that you want to just get and you want to talk to them and you want them to do something stuff like these and especially if they're in a pain in the ass package which you can't put on your regular breadboard then uh, these um experiment of Pcbs are the way to go.

You should have some of these in your kit. Aha this is not John's first sucker. The Sev here since and bought a few years ago. uh, he's added more to the collection.

Enclosed is a version for mounting 32 or 48 pin5 mm pitch, Qfp, Lqfp or Tqfp packages, you know, micros, Fpgas peripherals, anything basically um and uh t ssop uh packages .5 MIM pitch cuz they're always pain in the ass So it's handy to have these little adapter boards here and uh, then you can plug them into your breadboard and uh and play with them. So very handy. While it may not winning awards for EMC performance, the crystals run without issue professionally. He works in firmware, but uh, it's these are a um thing that he sells in his eBay store.
There you go. check out John Yuk's eBay store I will link it in uh down below for easier and cleaner prototyping. Does your design end up looking like a bird's nest? Yes. Always okay.

So what we're going to be looking at here is the Uh T, the uh, Qfp and Tqfp uh version here and uh, we can all 48 microp pins connect to Dedicated pads in the Uh Pro type uh area. Very nice. So they actually pop up on top here so you'll notice that right? How do they get to there? Well, you flip it over flippity. DOA There you go.

Um, that's nice so you can uh Point too. uh wire things. You can break out any pin you want. you can take them out to pin headers here and look, you can actually put Um series resistors in here and they've got other ones on the other side here so it looks like you can have like every pin can have have.

like uh, decoupling. it can have you know, series output resistor. It can have an RC filter or something. Perhaps you could wire that, um in.

It could have like pull up, pull down something like that. So yeah, it looks. Yes, it looks like you can configure that you can break, uh, traces. You can do all sorts of stuff that's really neat, and you can fit your own uh Ldo voltage regulator on here as well for localized regulation.

That's very nice. It's got a debug header as well, you know? So if you want to wire that into your micro for programming and stuff, absolutely fantastic That looks very flexible indeed. it's got some patch uh, strips over here. It's got some just, uh, general purpose uh stuff over here, so that's nice.

I Like how you can just break out every single pin. Yeah, it looks like you can strap the pins either high or low and you can put um, series, uh, termination resistors and all sorts of stuff that's incredibly flexible. Ah, there you go. He's included a handy little uh thing so you can actually uh so you can connect a Z Vols 3.3 and a decoupling cap to a micro pin.

You just short out the pins that you actually need. Uh, so you know this is the ground Loop coming around here. So this particular pin is grounded. uh, for example.

So that's just fantastic. And you can put a little decoupling uh cap in there. Brilliant. You can do that for every pin on your package.

So handy. Ah, here's the ready reckoner chart for it. So yeah, here's the bottom layer area over here. So this is the microcontroller pin.
and then you can either fit or not fit the resistor and that goes over to your prototype uh pad area over here. And then you sold a bridge either high or you sold a bridge low and that can go to A.1 in pin header here as well. That's extremely flexible. Wow.

A lot of thoughts gone into that. There's a more detailed version of that for those playing along at home. He's got eight products in his eBay uh store. Absolutely.

So there you go. It's in pounds that UK stuff. None of that Yankee dollar rubbish. 5 You can get one of these very versatile boards I Highly recommend.

Like, don't wait until you need them. That's the thing with these. Don't wait until you need them, then you have to order them, then they're out of stock or they take time to deliver. No, you should have a whole bunch of these type of uh Proto prototyping and interface boards in your kit just ready to go for whenever you need them.

There's some more uh examples there. fantastic s. So there's three. SPI uh Dack For example, he's got those uh, actually connected up there.

oh with bypass caps and uh, series resistors and um, yeah, that's great. Yes, you can have a filter on every pin. Uh, so 0805 or 0603 uh, for decoupling caps, current limiting, series reses, pull up, pull down, series termination, parallel termination, clamping TVs High Pass filters, low pass filters and many others. Um yeah, it's just crazy.

So there's that one for your .5 mm uh. pitch there and you've got a prototype area and you've got similar uh sort of thing. uh, like happening there that you got on the main board over here and then you've got your good old. These are very handy to have I Highly recommend at least these even if you don't have like the prototyping boards.

these adapters because you get a new uh part. you want to use a new part but want to prototype it but only comes in a pain in the ass. surface mount package can't put on your breadboard just to dick around with it and tral it out. Um, so yeah, you put them on these adapter boards and then pin header on there and Bob's your uncle.

You can actually uh, put them straight onto your bread board or you know, sold them into your prototype board or whatever. Uh, you need to do so. yeah, very handy and then it's got some extra uh goodness on the bottom for uh, you know, decoupling and filtering and whatnot. So very handy.

Um, awesome work there. John Um, thumbs up to those so they're go. They're going straight to the pool room here. I've got a specific uh drawer for all of these like adapter and prototyping boards and they're just so handy.

So yeah, I'll link in John's website down below. High recommend you pick some up. These look extremely comprehensive. These are one of the best ones I've seen.

We got another one from the Old Dart thank you very much. Um, ant cross I guess that's your name ant? Fair enough. Uh, ant. and Tech looks like they're on the YouTubes and on the Instagrams as well.
So I'll have to check that out. but once again, it's a documentary type thing. Let's check it out. What do we got? Oh yeah, yeah, you bet.

I like it. Look at this: Tandy catalog Inter 10 UK Limited. There you go. It's on the back Inter 10.

Um, if if you don't know that was the name of I, well I'm not sure that was the name of Tandy here in Australia and I did work experience at the In at the Tandy Intertan uh Factory which was just a bike ride from my place out in the western suburbs. Um, when I was a kid, did work experience there repairing Chandy computers not these ones. Um, it was a bit before that. um I worked on model 3s and uh, stuff like that.

So oh, let's take a look at the old Tandy catalogs. I used to collect Tandy catalogs I had Stacks and stacks I used to collect every monthly flyer like I don't know? Leave it in the comments down below. did Tandy Radio Shack it's Tandy here in Australia none of that yane rubbish. um they used to come out with these monthly flyers and you know you get the specials and everything and and they had like they were really good.

um fantastic and did you have the battery a month club card or multiple ones? HH um and yeah it would. It was great I used to have I collected every Tandy um catalog every well, not just Tandy but all the cataloges from all the you know Dick Smith and electronics and all the rest uh I but in a move one time I don't know I tossed them all out and like oh gosh should never have done that I had collected every monthly Tandy flyer and every Tandy catalog. Wow! Wow! So anyway let's have a Quick Squeeze so A from Liverpool in the UK has sent in the 1980s Tandy catalog. Well this is the 1991 1990 Uh catalog.

so um, you thought it'd be interesting to see followup 10 years on? I've still got that down in my bunker. uh sorry my dungeon down there and I've actually used that as um, it's been in several uh videos actually. um just using as an example down, uh in the dungeon down there anyway um anente Tech has a YouTube channel I'll link it in. um does like vintage uh, repair and stuff and they look really good so it doesn't have many.

Subs Please get him up there. The content looks great so thank you very much. Let's check out 19 Tandy Electronics 1990 W So by 1990 yeah, we're getting into you know, the era of of course, uh, you Ibmr PCS Of course in terms of uh, computers, um and whatnot. but you know we're getting into more.

Still got some 80s happening there. So anyway, uh yeah, Tandy Radio Shack it was Tandy here in Strier of course Radio Shack in the US but uh, yeah, none of that. LCD Rubbish. We've uh, we still got.

um. first Fstc TV with onscreen display. Oh and VHS was still big. Oh look at this high highi oh absolutely fantastic.
That was like state-of-the-art high-fi back then. uh, you know, still like component systems. um were big back then of course, turntables, big graphic equalizers and stuff. Nobody has those anymore.

Um, does anyone still have like a giant ass graphic equalizer like it was just like an 80s fad? Pretty much wasn't it? Um, the jewel? Jew T Decks of course. Uh oh. look at those speakers. Beautiful, beautiful front ported.

They almost look like Studio model. Oh yeah, they've got the Genexa uh brand that was one of their house. Brands wasn't it? Uh, back then? So yep. Speakers, lots of audio, keyboards, Keyboards were huge Back then.

they probably rebed casos like they rebadged. Uh, the Casio calculators. Of course. We no doubt see the calculators? in here.

so let's just you know. Parts and parts. and Aviation headsets. Oh Walkman's Of course you got to have Walkman's and uh, yep, you got to have the old little ghetto blaster there bedside clock radios of course.

Um, yep, yeah. Scanners of course. Had that one had that exact one. My old man had that.

uh, he would. Yeah, I listen to that a lot. The 200 he upgraded from the H what was it the 50 channel to the 200 channel or something like that. And yeah, back then you could I actually listen to mobile phone calls back when they were analog phones and they're boring as bat poo? Uh yeah.

really, you don't want to listen to people's phone on me home for dinner? Dear? um yeah. no antennas, home security stuff. Uh, no. complete complete index.

Why is the index here? I Don't get it. like why is it not at the back? That's weird. Um, the phones cordless phones Ru All the Rage car stereos of course have they got a removable one? Oh, you've got to watch movie recommendation of the day MC Gruber MC Gruber Watch Mcgruber I'm serious. go and watch Mcgyver series of course and then watch M Grber.

Anyway, Oh, I lusted after that at the time. The portable bench top multimeter that came out in the 80s looks like they were still selling it I Still have that analog Fet Vom look at that. Ah beautiful. It's got dual fets 10 mega oh input impedance.

oh absolutely winner winner chicken. Then another 20K per volt. Rubbish. You could buy a triple five timer for 99p.

I Still have my Mrcon digital logic probe it's in the old uh lab back in the garage. Nice. Still selling the 16 in1. There you go.

Fantastic! They got the analog multimeter here. There you go, but they sell it as part of the kids remote control cars. or Battleship let's drop some lead on those computer chest. Computer chest was a huge thing back then I had computer chest I was into chest for a while.

Um and yeah. the battery. Aandy battery a month club? There you go. The battery A month club hands up.

If you had it or multiple you have to multiple ones. nudge nudge wink wink Um yep. and you get your free battery every month. and you always went for the 9vt jobby.
you always went for that. Really? you know, maybe a Dell or something perhaps? Oh look at these calculator watches. fantastic but unfortunately no scientific uh stuff at all. And the LCD talking Vox watch? um I can't remember what the battery life on that is but gez anyway.

uh, talking watch kit anyone? And before the new shoe phone? uh r um yeah, the roller decks and the and the digital Diaries and digital assistance and stuff anyway I've got both of those I believe uh that was one of my very early ones. um that I used uh in my courses way back in the day. So anyway, uh, didn't know. They sold the Atari 520 and the Commodore 64 and the Spectrum Really? really? Oh anyway, the Wp2 word processor the Tandy 111 1100 FD had one of those.

um, unfortunately I sold it. This was way before the blog. Um, but yeah, that's nice little machine that um I've still got my uh Tandy 200 here. it's here.

it is. It's actually within reaching distance. sorry can't see it there. But there you go.

Oh look here you go. look look Tandy 200. Look at this like a bought one. Bobby Desler Works Treat I Don't think I've done a tear down on it though.

I' have to rectify that dot matrix printer. Fantastic! And then 386 the Tandy 4000 of course I had the Tandy 1000 designed and published a turbo board for it, done a old video back in the day. uh on that and what else have we got? Yeah they they they still selling the Tandy 1000 SL2 and the Tl2 that was the 286 jobby. this was the only only the 8086 Is this the one with uh Doss in ROM yes, MS DOS and Des Mate 3 software built into ROM This is the world I'm going to make make the claim correct me down below in the comments but this is the world's fastest boo in MSDS computer.

It is the fastest boot in MS DOS computer. Um, yeah, it's like less than a split second or something. Anyway, Unbelievable. That's it.

That's that's the 10 years later that is 1990 Tandy catalog. Thank you very much Aunt for sending that in trip down memory lane. Please correct me if I'm wrong, but that's pretty thin on the ground I Mean by 1990, the tand is sort of starting to dwindle a little bit. I don't I think it was past its prime.

Hi to all my fellow Aussie viewers. Um, this one comes from the Mal uh malver uh post office. but apart from that it's got no name I've got no idea what's in it. Um, so yeah.

let's go anyway. there's the address if you want to send it in. remember Australia not Austria Let's go have no idea what this is. Okay, it's got some cardboard on top.

protective. What are they trying to protect? It's a P Ofb. Oh P Ofb of some description. We have a note I won't read it yet.

Let's have a look who this is A that's no, that's not the pink ESD stuff. Um, oh nice big Analog Devices parted on there and that's that's got to be some sort of Telecom Z type card. Well I have a closer look at that but uh yeah, there's nothing on the back. There's no bodgers at all.
but uh yep I looks sort of like Telecom You know it's got like Transformers and you know stuff like that. So and relays and things like that. So aha, it's an Alcatel S12 line test card. It was used to test the subscriber copper line for foreign potential AC or DC between A and B or with uh, ground leakage resistance, capacitance Loop resistance, right? So it's a test card.

so at the uh, you know, at the phone exchange or whatever or whatever you would actually you know plug this in. Uh, so would you replace the card or would they have a specific test slot or would there be a test jig and this plugs into the test jig and then you've got the card on top. I Don't know how it works, but uh yeah, it looks like it. Yeah, it's it's a line test so would actively check the subscriber copper lines.

Okay, and then you plug this in and it can test the uh copper lines for for leakage. You know, after the pits full of water or something like that. um this would this would find out. Neat.

So yeah. I really like specific bits of Industry test kit like this and this was a good part of my uh career is actually designing specific bits of uh, production. mostly uh, test gear for you know, testing, um, your products in situ, or testing them at the production floor or whatever. and um, yeah, it's it's a fun thing.

test engineering anyway. I Do recommend Test engineering. Um, as a career path, you can end up like me. So this: Alcatel S12 Line Test card.

Oh, it's upside down. All the electrons are going to fall out. Look at that. Um, so nice.

Analog Devices Jobby down here I think I've seen one of these before or it's ilk. it's a complete module in there. um and oh little little heat sink on there on the Uh to220 Jobby bur Browns uh, that looks like an optical isolator or something. or it's an ISO 100.

Is it a Transformer isolator? I don't know. I'd have to look that up. Uh, looks like we've got a ceramic hybrid here for the line interface. so that would all be well.

no, that's all on this. That's all right on this side of the board, whereas the connections are over here where it connects to the line. So why is all the isolation stuff over here? I Don't don't really get it. Another hybrid there? Look at that.

Um, they got a dip package on there and they've just gunked it. They've just gunked that whole board there. Another Bur BR Look at it. Programable Gain Instrumentation Amp 3606 Look at that.

Oh, that's a special snowflake is it not? Wow I'll see if I can pull up a data sheet for that. That's a Bobby Desler. But anyway, tons of relay switching on here, another uh ceramic hybrid, and a whole bunch of uh, standoff uh, load resistors here. We've got 820 ohms this is that.
I don't know part of the standard thing. and then they got uh, some cap you know, big ass, um high voltage caps here and just a whole bunch of relay arrays and 74 series logic. um, a good lot of it anyway. and I don't oh 91? yeah know we have a date code uh, 991 vintage here a Mech I don't know what's a Mech um Dptc some customized jobby I don't know what that is at all.

Leave it in the comments down below if you ever use one of these I'd be surprised if someone hasn't actually, uh, used one of these bad boys. As I said, there you go. There's no uh, bodgers on this thing which is, uh, really quite nice and you can see, uh, the basically the four layer rou in. you can see that of course we've got uh Power planes, power and ground planes uh in there, but all the tracers running on this this side just so that they can you know running in this direction and all the ones on the top are going to be running in this direction like that for your uh, typical 2/ 4 layer routing like that.

So oh no, it makes sense. Um, you've got your line signals, come in your connector over here, then they go through all this switching Matrix and you switch in the loads and test loads and whatnot. Um, and then yeah, it basically flows through here like this and then over here you've got an instrument, a amp, and then you've got your all of your uh line interface hybrid uh stuff here. and then it eventually goes down here through and this is looks like the final Opdo isolator here and then that uh converter over here.

and then it does. Its whatever it needs to do. It's got analogy stuff around here. um to actually measure it.

although might be an analog to digital converter somewhere. but I don't really see any processing on there to do it. So yeah, that's that's interesting and this program will gain instrumentation app up here that must be like, uh, floating on the like, the line side of uh, this and then you've got your isolation Transformer there, of course. but yeah, yeah, that makes sense.

Anyway, customized test card isn't that really groovy? It's going to have some specialized devices on that. Maybe that this Analog Devices is more generic. It's not designed specifically for this application. We just got a lead on the front panel I Thought you might have been able to plug something in the front like that, but no, it must all come through the Uh card.

Edge connectors over here. but yeah, um, so some sort of switching Matrix load, uh, array there and some miscellaneous stuff and it does some. Oh, we got another uh Analog Devices Jobby down there a 57. what's that an ad 571 I think there and um yeah, interesting huh? thanks for sending that in.

It's a these special purpose cards I mean you know some engineer or Engineers went to a lot of trouble to actually uh, design, build and test this specific card and they probably only made well I don't know. there's lots of texts out there at the time working on the line when the transmission lines, but they would have only made like hundreds of these at most I would have thought um, but if you have any other info, leave it in the comments cuz this is just a test card. um I don't know if they tested them periodically so I don't know if these were like permanently in the back and then like periodically you just like call up a test and then it would switch in the loads and the test signals and read them back and measure the line leakage and do all sorts of uh stuff like that. Oh I just noticed nice little cap there that will be that there is a poly polyp.
the kettle on special uh, polystyrene? uh Jobby I believe and that would be a high stability uh cap there. Then we got some metal cans. not sure what's doing there I can barely read them. Oh, they're just transistores, are they 2N something or other? Anyway, that's an absolutely fascinating look at a line test card.

So yeah, leave it in the comments down below. If you knew how this, uh work, would they just come along and plug it in and test like actually replace a card And what happened to those lines? did they go down or does it as I said, like permanently in the rack and then they could like switch it in in parallel and they could disconnect the line temporarily And they can just the line test that way. But so that's a fascinating bit of a specific industry test kit. I Just love looking at uh, stuff like this and uh, you know, lot of engineering efforts gone into that I'm absolutely sure.

and uh, like, how did they get the D Did it just like flash? did it just like there's only one lead on here. like does it did it report data back out? I mean I don't see a microcontroller on here I mean I don't know what that's doing, but it doesn't look microcontroller. Um, and so how did they sort of like, how do they know? How do they? How did it report back the test results? If you know, leave it in the comments down below.

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24 thoughts on “Eevblog 1580 – macgruber mailbag”
  1. Avataaar/Circle Created with python_avatars Universe is under no obligation to make sense says:

    If I don't need high precision ill use an analog meter, never have to worry about dead batteries.

  2. Avataaar/Circle Created with python_avatars mreducto2 says:

    I had a golden arrow, and a wild pony – I loved those things.

  3. Avataaar/Circle Created with python_avatars Karl Langeveld says:

    Nice review. I wish these analog meters would skip the resistance and capacity ranges all together and add some volt / amp ranges instead. It would eliminate the leaky batteries and free up the top scale. Nobody measures ohms on an analog meter anymore, when you can get a digital meter for even less. Just my opinion.

  4. Avataaar/Circle Created with python_avatars Christian Ivarsson says:

    We all know the fav part is male bags!

  5. Avataaar/Circle Created with python_avatars Brett Gilsinger says:

    The Alcatel S12 is a type of telephone switch. Many of the old POTS telephone switches had cards like these that handled testing the lines either in an automated way or on demand. The card stays in the switch and gets accessed through commands that tell it which line to test and what series of tests to run. Back when I was in telecom, and actually had copper lines, we had an automated test line that we could call up and enter a line number to test. It would take about 30 seconds and then an automated voice would read off the test results. Being able to test a line on demand was a real time saver. This testing equipment was also used to automatically close out trouble tickets as resolved when line conditions improved. For example, after a rain instead of actually fixing the problem, the system would just keep testing the link until it dried out and then report the problem as fixed guaranteeing another trouble ticket the next time it rained.

  6. Avataaar/Circle Created with python_avatars ANT&TEC says:

    Yes the 1990 catalogue was starting to get thinner.
    UK Tandy had disappeared by year 2000 so you'll not be getting another one 10 years on!

  7. Avataaar/Circle Created with python_avatars Thomas Moore says:

    That last board: I'm guessing one connector mates with an IBM Main Frame and the other mates with an outbound wire trunk, and that is how you get the data.

  8. Avataaar/Circle Created with python_avatars Poorboy Man says:

    Now that's a KNIFE!

  9. Avataaar/Circle Created with python_avatars Lemming says:

    Dave I worked for Telstra in the early 2000's and we had access to a system called "OATS" which afaik interfaced with cards similar to those. The system allowed us to punch in various different identifiers for a line and then would switch this card into the circuit with the line, perform a number of tests and combine that with database information on what was on the line to show us how it should be performing and would flag any dangerous conditions on the line.

    The worst one I ever saw was a line with 450V of foreign voltage on it and that triggered all sorts of safety processes we had to jump through to report it and get it checked out.

  10. Avataaar/Circle Created with python_avatars Soren Kuula says:

    I got rid of my Hioki Kit Tester, an analog multimeter, after a couple of decades of use. The movement got stuck, and I think I ruined the spring trying to fix it. Maybe it's time for an analog meter again.

  11. Avataaar/Circle Created with python_avatars popraw a says:

    On analog meter they 250V for current measurement, as it is provided with 250V fuse on 10A :>
    On second range PTC is probably 60V and will blow up for sure at mains :>

  12. Avataaar/Circle Created with python_avatars Hugo Bloemers says:

    About the Mietec chip on the Alcatel test board: Mietec was a single fab 4" semiconductor manufacturer in the 80's in Oudenaarde Belgium. Around the early 90's they where bought by Alcatel and it bcame Mietec Alcatel. They added a 6" sub micron fab to their 4" line. A few years later the name was changed to Alcatel Mietec. At some point the 4" line got closed and eventually somewhere after the 2000's Alcatel sold the remaining 6" line to ON-Semi. A few years ago, ON-Semi spun the fab off because it was too small to be of strategic importance to them (In Europe, they are focusing on their Czech fab, formally Motorola, formally Tesla). Fortunately there was a management buy out and the site is now called BelGaN. This company is converting the fab to 8" and they are qualifying GaN FETs. What the chip does, no idea, but I suspect some early ASICS around the 1.5 micron node. It would have been build in the 4" line.
    I used to work there for an equipment vendor in the early 90's and still visit them occasionally as contractor.

  13. Avataaar/Circle Created with python_avatars Bogdan Serban says:

    Hey Dave, can you make a video about LDO noise and PSRR and ultra low noise LDOs like LT3042?

  14. Avataaar/Circle Created with python_avatars George N. says:

    You can get New Old Stock Chinese analogue meters for peanuts if you know where to look.

  15. Avataaar/Circle Created with python_avatars Simon Paul says:

    Didn’t John Newcombe play tennis for Australia

  16. Avataaar/Circle Created with python_avatars Shaun Tremayne says:

    Tandy might have been the first consumer machine booting MS-DOS from ROM but loads of industrial systems did as HD with spinning rust unreliable due to vibration.
    In pre flash days it was a CMOS battery back loaded from your laptop. Power spikes caused mostly by motor drive failure caused mem corruption.
    Toshiba & HP had MS-DOS on rom machines as well

  17. Avataaar/Circle Created with python_avatars GuidoK says:

    Ah, the analog muldimedah 🤣😂

  18. Avataaar/Circle Created with python_avatars Shaun Tremayne says:

    Radio Shack had to use the name Tandy as UK, Europe & Australia markets had Radio Spares so to close!
    RS components (Radio Spares) are still going. In the last company I worked for I drove everyone nuts by calling RS Radio Spares which they at first thought I had found a new supplier until penny dropped?

  19. Avataaar/Circle Created with python_avatars randy greenwood says:

    Those battery of the month batteries were very leaky.

  20. Avataaar/Circle Created with python_avatars Bert Blankenstein says:

    Still have my Tandy chess computer, works a treat, certified (approved whatever it is) by Gary Kasparov.

  21. Avataaar/Circle Created with python_avatars Panthony says:

    Back in the 80s here in the Uk there was a Tandy store in Grimsby, and the batteries etc were branded Radioshack, and I use to have one of their 75 in 1 electronics kits. None of that Australian rubbish, thank you very much 😉

  22. Avataaar/Circle Created with python_avatars Thomas W says:

    Still use the old BBC MAH2 often as it's passive and can be left on forever when monitoring long time battery stuff or alike.

  23. Avataaar/Circle Created with python_avatars Bob Sacamano says:

    Who remembers the car tape decks with graphic equalizers? Now that was 80's cool right there.

  24. Avataaar/Circle Created with python_avatars Coke Sandwich says:

    AliExpress tells me that the T-88C is now $43 USD. But allowing for inflation that's way cheaper than the Radio Shack model I bought 50 years ago.

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