Commodore DAC-612 from 1969: Inside and Out

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We take a look at a mostly-but-not-completely functional Commodore DAC-612 desktop calculator based upon the Casio 122 first produced in Japan in 1969; this particular unit was likely made in 1970. It uses Elfin display tubes and many components from a family of parts from NEC and Hitachi.
Excellent page from Brent Hilpert about the Commodore DAC-612: madrona.ca/e/eec/calcs/Commodo...
Early Electronic Calculator Technology Reference: madrona.ca/e/eec/index.html
Madrona Grove: madrona.ca/
To support 8-Bit Show And Tell:
Become a patron: / 8bitshowandtell
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1962 Commodore Report: archive.org/details/commodore...
Elfin tube Radio Electronics article: www.decodesystems.com/re-elfin...
Japanese power connectors: www.zimmers.net/commie/docs/cb...
Casio 122 site: casio.ledudu.com/pockets.asp?...
Canonical List of Commodore Products: www.zimmers.net/commie/docs/cb...
Philco SC1772 shift registers: madrona.ca/e/eec/ics/shiftreg....
Adrian's Digital Basement 1970s Towel shown here: • AT&T Unix PC 7300 Mode...
Index:
0:00 Mini Commodore History
1:00 A tour around the DAC-612
2:29 About the AC power connector 163 (not quite)
3:54 Casio 122
4:33 DAC-612: What does it mean? Canonical List of Commodore Products
5:20 Power up: Odd Zeroes
6:30 Doing some calculations: Addition, Subtraction
7:30 Multiplication and Division: No longer working
9:43 Decimals & Rounding
12:10 GT (Grand Total?) and double plus
13:42 1970s Towel: Thanks Richard Pepper
14:04 Undersides
15:11 Inside: first look
16:20 Display board: Elfin tubes
17:17 Keyboard
18:23 Power supply & removing the top logic board
20:03 Examining the boards
21:16 Integrated Circuits in a can & JMOS
23:03 Philco SC1772: 48-bit shift registers
24:25 A few other JMOS ICs - madrona.ca
25:37 Thanks!

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7 авг 2024

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Комментарии : 280

@RetroAdrianBlack 2 года назад

I almost fell out of my chair when you broke out the 70s towel!!! That is so funny and so awesome!! Perfect to use on that wood grain calculator. :-) Welcome to the club!

@gklinger 2 года назад

Begun the 70s towel wars have.

@mal2ksc 2 года назад

I will never complain about your towel again.

@SteveGuidi 2 года назад

My parents still have towels that match this trending style adopted by the RU-vid retro electronics afficionados. Could this is be a Canadian thing? I'll be visiting them next month in Toronto -- maybe I'll sneak one out of the house. I'll have to hide it from my wife though as she'll throw it out on sight!

@gklinger 2 года назад

@@SteveGuidi I've seen your name on Facebook and never realized you were from Toronto. When are you going to be visiting? Maybe you can attend the World of Commodore...

@reppepper 2 года назад

Hey, Robin, are you going to give me my towel back, or will it have permanent role in your videos from now on?

@chrismcovell 2 года назад

The underside of the keypad when you showed it has the numbers "45 5 2" (or similar) stamped in it in white. This is for the Japanese Showa year 45, so that dates the unit to May, 1970.

@8_Bit 2 года назад

Nice catch, thanks!

@antoniomaglione4101 2 года назад

Japan now is in the Reiwa era, begun on 1 May 2019.

@haroldlane4647 2 года назад

Try holding an AM radio next to the DAC-612 while it's operating. You might hear some cool sounds. I first heard (read) in an electronics hobbyist mag (possibly Radio-Electronics) from the 80s (?) that you could use a digital calculator to test your car's AM antenna. Most calcs of the day had LED displays and 9v batteries. My high school TI-30 or 35 made the sweetest calculation sounds when it paused to calculate a trig function. An older general purpose calc made it's own unique noises on this radio: a flashing error display made a good fast-beat klaxon sound and the buzz was louder with each digit that was lit. Would love to see how the DAC-612 sounds

@lucasrem 2 года назад

Are you new to electronics, frequencies and waves, early computers, you can hear what they do!

@watchmakerful 2 года назад

Half-height zeroes were common in calculators that weren't able to suppress leading zeroes.

@NozomuYume 2 года назад

When you think about it, it's a good idea, as it lets you quickly visually see where your value starts.

@denormative 2 года назад

@@NozomuYume I would imagine it would also help differentiate between 8 and 0 much clearer.

@QuantumScratcher 2 года назад

To this day, some people still write 100 like 1oo.

@lucasrem 2 года назад

we already used the Japanese models, flooding point unit needed, dividing Zero! E.W. Dystra was faster than these machines, that was EPIC!

@CanadianRetroThings 2 года назад

The adding/subtracting is working as an accounting adding machine does, when you put in a number you then hit the key that says wether it is a negative or positive number. This means, rather than adding and subtracting you are totalling a list of negative and positive numbers (it makes more sense when you have a ledger with a list of 40 or 50 numbers to total up)

@csbruce 2 года назад

So, it's a "Negate And Sum" function.

@ropersonline 2 года назад

Would it also work to press 500 [-=] 400 [+=] ?

@CanadianRetroThings 2 года назад

@@ropersonline You would get -100 as the answer, you are making a list of numbers, in your example you are saying 500 is a negative number, 400 is a positive number.

@marknesselhaus4376 2 года назад

Thank you for that info as I was given a old 1970 ish calculator that acts the same way and I had been scratching my head over the results. Now it all makes sense :-)

@CamdenBloke 2 года назад

In the early 2000s I worked at a gas station and for taking inventory of cigarettes (a daily task) there was this funky calculator that had buttons like that and behaved unpredictably when I tried to use it. I was studying mathematics in university at the time and was familiar with both algebraic and RPN inputs. It took me a while to figure out how to use it. A coworker who was about 20 years older than me didn't understand why I was confused by the calculator and said it was "just a regular calculator".

@MicrobyteAlan 2 года назад

Very interesting and well presented. A trip down memory lane, I started as a computer engineer in 1969.

@TheStuffMade 2 года назад

Thanks for taking it apart, nice to have a look inside. No wonder these calculators were very expensive back in the day with the complexity. I can imagine many man hours went into just assembling a single board with all the wires and everything, and probably a large percentage didn't work after assembly and had to be tested and repaired before ending up in a calculator. Cheers, Jake

@lwilton 2 года назад

While there would certainly be a rework area for things that didn't pass QC, the failure rate was probably a lot lower than you are imagining. I'd bet it was around 1% or so, or they would not have been able to afford to make these. The biggest failure area would probably have been with mis-connected jumper wires. But those wires would have all been pre-cut and stripped to length, and the production line would have been arranged so that things were done in a specific order that made it relatively hard to mess up and connect to a wrong via.

@MichaelDoornbos 2 года назад

I have several mid 70s calculators, but nothing this old. So awesome to see this in depth. 5:00 magic smoke can usually be put back in if you let it out I love this calculator stuff, but the song at the end is the best part.

@katho8472 2 года назад

Indeed! Where does the song come from? What did I miss? I mean I can hear it's Robin singing, but except that...

@AureliusR 2 года назад

@@katho8472 it's his band The Bedford Level Experiment!

@domramsey 2 года назад

I have a much earlier Commodore mechanical adding machine and I love it. It's fascinating seeing the mechanism in action when you press keys. None of this new-fangled "electric" stuff.

@DaveF. 2 года назад

That's really interesting - a lot of the odd look and feel of how this behaves - the display of all zero's when turned on; the fixed position of the decimal point once you start using it - all make perfect sense if you're used to a mechanical adding machine.

@charlesbaldo 2 года назад

The multiplication and division issues makes sense for the challenges at the time for hardware and coding. I remember a class I took in 1978 doing assembly language on an IBM 370 the school had. Our final exam was to write multiplication and division routines, it was all series of adds or subtractions with register shifts. Which is exactly what is happening here.

@JustWasted3HoursHere 2 года назад

Ah, I miss woodgrain on electronic devices like this (and the Atari 2600) back in the day.

@MurderMostFowl 2 года назад

Those traces at 20:42 look like a river flowing. It’s beautiful!

@lwilton 2 года назад

All laid out by hand. Before any software to do PC board layout.

@androo4519 2 года назад

A lovely old calculator. The number of components is incredible. Those half-height zeros are very Casio. They used them on VFD models too until maybe 1975. You see them on the Sperry-Remington calculators that are based on Casio models.

@JustWasted3HoursHere 2 года назад

Within ten years after this calculator came out these things have already been MASSIVELY simplified in their circuitry. Modern calculators have essentially reduced everything to a single tiny chip.

@greatquux 2 года назад

Yeah in fact just yesterday I read it’s the 50th anniversary of the Intel 4004 which was designed for a calculator!

@megatesla 2 года назад

The first single chip calculator was released early in 1971. So about 2 years, not 10 years...

@JustWasted3HoursHere 2 года назад

@@megatesla I said _within_ ten years.

@DaveEtchells 3 месяца назад

This reminds me of a college digital electronics course I took in 1974, where we designed an 8-digit calculator over the course of the lecture series. The prof walked the class through the design step by step, drawing implementation suggestions for the logic from the students and discussing the relative merits before choosing one and proceeding. His TA had an assortment of 7400 TTL logic chips that he used to wire-up the evolving circuitry on a breadboard as we went. The whole thing was built from discreet logic and used a serial ALU and shift registers just as in this Commodore design. By the end of the semester we had an ungodly sprawl across 2-3 square feet of breadboard panels, but it was a working 4-function calculator 👍😁

@8_Bit 3 месяца назад

Sounds like an excellent subject for a course, lots of practical and theory together.

@DaveEtchells 3 месяца назад

@@8_Bit It was very effective, we really got a good feel for how to put together digital circuits to actually do things!

@RonLauzon 2 года назад

When researching some Sperry calculators that I have, the reason for the half height zero is so if there's a segment failure, it will be more noticeable.

@user-bu9nx4ot2u 2 года назад

Thanks for your time and effort in keeping 8-bits alive!

@TomaszWiszkowski 2 года назад

Wow this power cable connector looks like trouble when the cable is plugged on the other end... Beautiful piece of vintage equipment. Thank you for this video!

@westelaudio943 2 года назад

Yes, making things "idiot proof" was not much of a concern back then.

@DrDavesDiversions 2 года назад

Fascinating, Robin - thanks for the tour!

@nickyborrisino 2 года назад

Absolutely gorgeous trace design on the top board.

@video99couk 2 года назад

Makes my 1975 Rockwell pocket calculator look like something from another planet. A lot of progress in a few years. Of course most "newer" calculators don't use a CPU as such, it's just a much more integrated "system on a chip" design.

@Zhixalom 2 года назад

Such gorgeous machines ❤️ The "strange" way the DAC-612 adds and subtracts bears quite a lot of resemblance to book keeping. You know like in the debiting and crediting kind of mindset... so really not that strange anyway.

@dwindeyer 2 года назад

I imagine the primary use for calculators at this time was balancing ledgers so the design choices strike me as completely intentional

@Zhixalom 2 года назад

@@dwindeyer Precisely what I was thinking 😉

@lonewolf31337 2 года назад

I just came across your Instagram and had to come check out the RU-vid channel. I’m glad I did awesome videos

@reiner0609 2 года назад

I wonder if the 7/32 nuts aren't just regular M3 metric as 7/32 is awfully close to the 5.5 Millimeter of a M3 nut.

@8_Bit 2 года назад

I'm curious about this as well. I know Japan has been metric for a very long time but they would still use other units in manufacturing at least in some industries, especially 50+ years ago.

@lwilton 2 года назад

@@8_Bit I'm betting that it was 5.5mm, but you are right, they did use SAE parts on things for the American market in those days. However, by the 1960s (really by WW II, when "national standard" parts sizes came into existence) the odd 32nds nut and bar stock sizes that had been common in the first half of the century had been largely dropped in almost everything except automotive ignition parts. That makes it much more likely that this is really metric.

@lwilton 2 года назад

@Electronic Adventures Well, you are almost correct _today_. In the 1960s you would have been quite incorrect, and that is when this was built. Thus the size was a legitimate question.

@ByWire-yk8eh 2 года назад

Today, there are only three countries that don't use the metric system: Miramar, Liberia, and the USA. Now, that's Making America Great Again!

@westelaudio943 2 года назад

@@ByWire-yk8eh That's not strictly true. Many countries still use imperial or other pre-metric units for many things, even though they mainly use metric. Thread sizes, wheel diameters, etc. And it's just not worth making truck loads of tools, parts and machinery obsolete just because some people don't like fractions. The metric train for the US has departed... 100 years ago.

@scality4309 2 года назад

Your channel is a gem! ❤️✌️

@ag3ntorange164 2 года назад

Beautiful. I want!! Thank you for letting us peer inside. Great video!

@Bubu567 2 года назад

DAC = Desktop Adding Calculator. That is a name used by casio. Is this a rebadge? Pretty sure the half height 0 was simply a simplification of the routing and reduced the number of components, but I could be wrong.

@naderhumood1199 2 года назад

Thank you v much Sir, Great video. Lovely machine, and lovely past.

@kemi242 2 года назад

Clint of LGR would approve the brown plastic/woodgrain design. :)

@benanderson89 2 года назад

My complete wild guess on the multiplication bug is that some kind of memory switching circuit similar to what an LS series chip in an 8-bit does. A line or lines is being held high or low, and the multiplication button must send the equivalent of a rotate command to the display memory and when the value falls off the end of the display, whatever handles that must finally pull the rouge lines high or low along with the working ones to finally let the logic circuit perform the calculation. Multiplication on a fundamental level is also a multiplication to a computer, so it's no surprise it also affects division.

@brightquark 2 года назад

First thing that jumped out at me was those pins on that power cable appear to be flush with the external plastic so possible to brush against a live conductor when not plugged in to the calculator. Id be very careful when handling that cable. It just goes to show the many silent safety features in modern plugs we just take for granted now

@Breakfast_of_Champions 2 года назад

Yes! The 1960s towel! Grandpa Calc rarely felt so good in his life🤩

@greendryerlint 2 года назад

You can really tell the age too by the cylindrical can germanium transistors on the board. And the can ICs of course. Back from the days when building PCBs of this complexity was a labor-intensive art. I'm sure these were hand-assembled.

@moconnell663 2 года назад

They were hand-stuffed, but wave- or selective-soldered.

@tookitogo 2 года назад

@@moconnell663 Automatic insertion was actually already available by 1970, when this thing was likely assembled (since the oldest component date found was at the very end of 1969) so it’s possible that most of the components were placed by machine. The wiring and connectors would definitely have been placed by hand though.

@moconnell663 2 года назад

@@tookitogo that's interesting! I thought the squeezing of IC legs to get them to fit in the PCB locations would have required human hands. My work just discontinued our very last all thru-hole assembly (one of those products that people just refuse to stop buying). I'll have to check with our assembly house to see how they've been doing it.

@merykjenkins3274 2 года назад

I wonder if the leading zeros are to keep the display warm? I certainly hope that the calculator can be repaired and restored, what a great piece! I wonder if I can get to-5 package ic's for my c64? That would look awesome inside! Thanks again Robin!

@DaveF. 2 года назад

It's also exactly how a mechanical calculator would display it's output - I wouldn't be surprised if that was also a factor is setting it up that way.

@DenizTurkmen 2 года назад

I think so. Also if it's blank we wouldn't know if it's out or really blank.

@mjh5437 2 года назад

@@DenizTurkmen Good point!

@antoniomaglione4101 2 года назад

Incredible. The board with all that wires should have been a four layers type. The keyboard is made to last forever. The shift registers, multiple gates and half adders are used instead of a CPU and contains all transit memory. The 4004 for the Busicom was still to be invented in 1969. I don't know the uPD serialization used by NEC, but at that time we used RTL logic, which preceeded DTL and TTL. In those years the americans invented the 2N3866 transistor, able to produce few watts at UHF frequencies in a TO39 case, and powered the radar in the lunar lander. Eroic times for technology. Thanks for the video, I enjoyed the jump in the past...

@kins749 2 года назад

Absolutely fascinating!

@tiikoni8742 2 года назад

6:10 Since it is filling leading digits with zeros also, could reason for half size zero be just to make it easier to see from where actual number begins.

@1337Shockwav3 2 года назад

Half size zeros were actually quite common back then. I can't recall the exact model but I've seen calculators with VFD displays showing the same behaviour. I _think_ it was from Sharp and had slightly more natural looking numbers. EDIT: Google turned up "Facit 1128" with a very similar display to the one I've encountered. Half size zeros there.

@markboulton954 2 года назад

@@1337Shockwav3 Also many books (especially financial ones) of that era were printed in what was called "ranging" type. A zero was a small circle like a lower-case 'o', a number 1 was like a small 'I' with serifs, the number 2 was also half-height, numbers 3, 4 and 5 descended below the baseline, 6 ascended, 7 descended, 8 ascended and 9 descended. There must have been legibility reasons for this, but it fell out of style in the early 70s and was replaced by "non-ranging type" in which all digits were full height with no ascenders or descenders. See: upload.wikimedia.org/wikipedia/commons/2/20/Poliphilus_468.png

@markboulton954 2 года назад

@@ButterfatFarms I think it derives from the Arabic way of writing numerals which is where our number system comes from. Most numerals ended in a downward stroke of some kind where the pen nib is lifted from the page leaving a trail of ink.

@lordanthrax2417 2 года назад

The tracing! Man! Mindblowing! Would love to see the process of building everything from start to finish

@lucasrem 2 года назад

why you need that, the blue prints you need? making PCB's your hobby? Post it here, wee if it is anything people need to see here!

@lordanthrax2417 2 года назад

@@lucasrem i maybe did not express myself correctly cause english is not my native language,sorry. my point is that i am realy impressed of the handmade work that went into this. it feels like a lost art to me to build something like that and i get a weird satisfaction whenever i need to resolder stuff on my gaming consoles or fix a broken cables. i wont call myself someone with great soldering skill so this gets a massive respect from me. thanks

@lordanthrax2417 2 года назад

@@lucasrem i just want to see it cause i love it. its like watching someone making art.

@jamesbennettmusic 2 года назад

The NEC can said week 2 of 1970 so it must be right on the turn of the decade!

@diegoprat3709 2 года назад

Great video!!

@MontieMongoose 2 года назад

Wow that towel is very 70s.

@Dedicatedtolivinginthepast 2 года назад

Its fascinating seeing really complicated electronics from over 50 years ago!

@fischX 2 года назад

DAC Digital analog calculator - a Casio thing back in the day. Probably also the reason why the thing freaks out a little - it uses discrete components for calculation that give out a voltage that then gets converted to digital. It's cheap it's fast, it gives you a result that is correctish

@ByWire-yk8eh 2 года назад

I have a 1969 Friden Singer EC1113 calculator. It has 12 Nixie Tubes (Hitachi CD-71), and the logic technology is 108 Small-Scale PMOS IC's, Hitachi HD7xx-Series. It works fine, and I thougt it had a bug in the reset function. Reading up on it, I found out that the reset problem was a 'feature' and not a bug; They all worked that way.

@Loenne555 2 года назад

Love those classic mainboards with their handdrawn traces. Piece of art.

@neilloughran4437 2 года назад

Beautiful!

@cpt_nordbart 2 года назад

Curious Marc could probably safe this. They recently repaired an PS/2 main board with some interesting errors. They also did an interesting series about Apollo Computers like from the Space Program.

@ryballs4569 2 года назад

Thanks Robin for the interesting video and cool song at the end, where can we find the full version?

@thorro3 2 года назад

Very cool. I remember my parents using a mechanical adding machine with a paper "display" even in early 80s.

@TheTarrMan 2 года назад

When multiplication was working at 7:38 I noticed the "Sigma switch" was in the other position. I don't know if that's relevant to the issue.

@CallousCoder 2 года назад

Lol yesterday I fixed an East German chess computer (video on my channel) and after I’d put it back together, I also saw a warning to unplug the device before opening it. Now obviously you always do it. But I found it funny that I’d not seen it until I had it fixed :)

@rubusroo68 2 года назад

beautiful

@Soulintent95 2 года назад

Ive never seen an early calculator. Never really thought about it either. I always assumed calculators came after the computer and unless they were for business use and included a printer they were relatively small.

@nathanwoodruff9422 2 года назад

Your multiplication is off because when you originally multiplied the switch was in the 5/4 cut position and now when you are multiplying the switch is in the OFF position.

@lariveePhoto 2 года назад

The keys sound really great

@jpcompton 2 года назад

8:08 Why did you cut the video just before we saw the overflow?!

@nicholastotoro7721 2 года назад

Kill screen coming… 🤣

@SergiuszRoszczyk 2 года назад

Thanks! Given the fact that YT filled advert blocks with music digital audio converters I know it has no clue about video contents itself 😀

@Gazdatronik 2 года назад

My 1985 Panasonic does the same thing with the plus before minus subtraction. I used it daily for production tabulation and came to prefer it.

@OtaconEmmerich 2 года назад

I just noticed the NEC logo is stylized...I'm use to the more plain NEC font logo from the 80's and 90's.

@Vallee152 2 года назад

I would like to see some of TI's old programmable calculators, those ones with cards you can store programs on

@ninefingerdeathgrip 2 года назад

18:30 Nothing weird about it tho, it's just rated for 250VAC and 7.5A. It's easiest for manufacturers to use as much parts that will work anywhere in the world than have specific ones for each market. Only difference between markets is transformer, just stick in one with 230V primary and it's good to go in Europe, 100V primary and it works in Japan and so on.

@tookitogo 2 года назад

Exactly. Practically every AC connector has its voltage and current rating printed on it.

@southerncharity7928 9 месяцев назад

If anything it should be admired for being so overbuilt. 250v x 7.5amps connector in a calculator! Lol

@berndeckenfels 2 года назад

Fran would love those display tubes

@april7_ 2 года назад

Slightly amused 14:40 when you guide not to open wrong screws! How many of these have survived? I got only 2 models from 70's and one Texas Instruments model. Thanks for sharing these! That must have been an expensive one late 60's!

@richpickings2845 2 года назад

LGR has to be drooling over this beautiful wood grain beauty.

@ChaseMC215 2 года назад

And The 8-Bit Guy is drooling over the Commodore brand

@martinhaub2602 2 года назад

I love this kind of thing. This old technology is just fascinating! My old Singer/Friden desktop calculator with a CRT display and based on ECL logic still works, but I need someone more technologically literate to explain how it works.

@lucasrem 2 года назад

All you need a a display, or read the Pascal wheels! They all do the same thing!

@logiciananimal 2 года назад

Out of curiosity - how does this handle overflow (and divide by zero)?

@gshingles 2 года назад

The "C" in the part number might be for "Ceramic". I don't know if DIP came out of the gate as plastic, or when PDIP was introduced; I couldn't find any info on that (there's a reference in wikipedia to a 1979 study comparing the cost of the two). I tried scratching the screen to see what they felt and sounded like, but that didn't tell me anything,

@lwilton 2 года назад

DIPs were originally ceramic, but those were made of an upper and lower ceramic plate with hermetic sealing frit in between, like a sandwich. They were hermetically sealed, like the metal cans with the gold-plated leads. Plastic DIPs of the early era suffered from not being as well sealed, allowing some moisture ingress along the leads, which could lead to eventual chip failure. They also had problems with some of the plastic chemicals eventually breaking down the passivation layer on the die inside, corroding it or the leads, again killing the chip. The C in this case is separating the plastic DIP parts from the original parts, which were probably the metal can TO-5 (I think, at least TO-something) military grade parts. In TTL the letter N was often used for plastic parts.

@tookitogo 2 года назад

Most of those DIPs don’t look like ceramic, though. (The Hitachi chips are definitely ceramic, for reference.) I can’t be entirely sure without touching the chips, but the shapes and mold lines on the NEC chips look like plastic DIP.

@cmuller1441 2 года назад

With the small zeros, it's easier for your brain to ignore the leading zeros. Watching the video, it's obvious that this trick works well ...

@ericcarabetta1161 2 года назад

19:36 These ancient circuit traces on the brown circuit board look like worm tracks on a piece of wood and all the giant ICs are like pill bugs.

@dru1432 2 года назад

The way this machine handles subtractions is... interesting. :)

@eekmeout 2 года назад

It's beautiful to me

@awilliams1701 2 года назад

yeah -24v is really unusual so it's pretty hard to replace. It's too bad it's not TTL if it was it would be easy to fix.

@alpaykasal2902 2 года назад

JMOS :) Those traces are crazy looking!

@alpaykasal2902 2 года назад

I'd love to hear stories about the process from the old timers designing and producing these boards

@atkelar 2 года назад

I still think that half height zeros might be a design choice to make it visually easier to see zero from eight. As somebody mentioned, the leading zero suppression might have been a reason, but for financial stuff with commonly computed in thousand or million values it also might have added simplicity; I'm not aware of any specific meaning, but the "C" suffix on chips would be a good hint to the "ceramic" case as opposed to the "metal" one. I'm looking at a data sheet for a MC1496 now that also came in both versions and early chips seemed to have re-used the metal cans from transistors and gradually transitioned to the DIP packages we know. Sadly I might need an adapter for that old chip, cause I clearly suspect it to be broken in my device.

@zigsym 2 года назад

Hahhaa! It looks like it came as the matching free gift when Chevy Chase bought the "Family Truckster". Seriously though, great video of a beautiful vintage machine. Thank you.

@jakubkrcma Год назад

😱The complexity! 😯

@WDCallahan 2 года назад

Maybe digital automatic calculator?

@MD_il_microcanale 2 года назад

you brought extremely erotic Commodore themed content! I love the Commodore DAC-612!

@ossianhaufe4671 2 года назад

A really interesting device. It isn’t high integrated, is it? But nevertheless sophisticated more than I expected. I’m really impressed how you figured the issues out by trying some calculations. Could you fix it?

@gaeshows1938 2 года назад

nice!

@iCQ_www.SPCL.tk_ 2 года назад

what a beauty... and a monster at the same time :-)

@rjhelms 2 года назад

I wonder if "C" in the part numbers on the chips means "ceramic" - from a time when the most relevant distinction would be ceramic DIP vs metal can.

@AB-Prince 2 года назад

my guess is that dac stands for desktop automatic calculator, due to replacing mechanical calculators which were a bit more manual

@youreperfectstudio4789 2 года назад

Where do I hear the rest of that awesome song at the end?

@ikke1981 2 года назад

That song over the end credits is really funny

@retrotechandelectronics 2 года назад

The power cable looks like that of the connector of my old HP harmonic distortion analyser.

@jaredloveless 2 года назад

9:10 I've played with some old calculators and a lot of times they have unintentional features that are just bugs with how they coded these things

@jms019 2 года назад

Nice towel !

@SabretoothBarnacle 2 года назад

$125! Quite a gamble for an 'untested' purchase!

@8_Bit 2 года назад

Pound for pound, component for component, woodgrain for... woodgrain (?) it was a bargain! In today's market I was surprised it didn't go for a lot more.

@SabretoothBarnacle 2 года назад

@@8_Bit I hope you can find someone who is willing to spend the time getting it running for you! Hopefully, after it is fixed you can demonstrate it again in all its glory?

@LilMalygos 2 года назад

Great towel

@MurderMostFowl 2 года назад

“ I can’t decide if this is Hideous or beautiful” … my thoughts exactly. How wonderfully strange looking. Dignified yet ugly

@asayake1 2 года назад

bibliologies

@rodoherty1 2 года назад

Surprised that you're the only person to have commented on this. I was expecting every second comment to point that out. Nice one!

@georgemaragos2378 2 года назад

Hi - Early calculators added up a bit funny, but it was not quite reverse polish notation For example today calculators ( and mid 80's onwards ) you perform the addinf by the way you talk eg 1 + 2 = we get 3 the older machines were 1 + 2 + = we get 3 This was enter first number and then what do you do with it, enter second number then what to do eg add or subtract in a few companies i was given or had some of these calculators and i actually fond it frustrating and used my own - they were know as Plus Equals machines, they were fine if you learnt on it and never used the other style, but i was to young for that. Also later you had the sign change where you enter say 1 + 3 sign change to make it a negative 3 so the answer would be -2 The 5/4 is the rounding so it would round up on 5 and down on 4 sort of like converting to integer maths They way to think of it is like scamming interest payed 1.49 become 1 so you work out interest on $1 not $2 in this example you save 1/2 your payment - but bot very practical if you had say 123.44cents , it will become 123 - then you do the extra maths however - think of that 80's superman 2 movie and think of the input is all as cents, you cannot collect or pay a portion of a cent so it disappears These days the round is normal set to "floating" or do not round - same as excel where you showplay or show 2 decimals or whatever it takes Oh, the machine also had to perform less cycles to display the answer as it was not processing multiple calculations to show say 8 decimal places

@robertinobongiorno5148 2 года назад

Nice calculator

@freddylq67 2 года назад

I like that towel!

@markboulton954 2 года назад

22:48 -- "you could Pikachu between many manufacturers..."?!?!?!

@VladoT 2 года назад

It seems that those NEC chips are similar to the later TTL 74xxx family of logic chips.

@csbruce 2 года назад

0:50 That's not exactly what the adjective "8-bit" means… Cf. the VIC-20 isn't an 8-bit computer - it's a 45,104-bit computer! (If you're counting RAM and processor registers.) 1:31 Are they only available around Christmas? 2:27 Did they even have three-prong wall sockets in the 1960s? 5:59 The "lowercase" zeroes are really ugly! 8:06 What happens when it overflows? 16:49 I guess there's no room to move the decimal point farther to the right. 18:30 That seems like the maximum the plug itself is rated for. 18:42 Why "minus"? Isn't that just plugging in the power lines in backwards? 19:56 I can see why Intel wanted to replace all that crap with one chip to rule them all. 22:00 I guess chips with DIP was a new thing back then. 23:53 SAM - Sequential Access Memory. I remember that term being used in a parody ad for the Comma-Door 264.

@6581punk 2 года назад

Typically 8-bit refers to data bus width.

@WhatALoadOfTosca 2 года назад

Hi Robin. What's the story with the Commodore Security badge?

@8_Bit 2 года назад

Hi! It's a reproduction of what the actual security guards at the Commodore plant in Pennsylvania had on their uniforms, made by my friend DLH who runs the excellent bombjack dot org website.

@WhatALoadOfTosca 2 года назад

@@8_Bit thanks Robin. I thought maybe you worked as security for them. Thank you.