The first calculation result was correct, you pressed the M+ twice

I really appreciate that your tear-downs aren’t hack-aparts where a cool old thing ends up broken apart and in a dumpster. Thank you for your care and patience.

Marvellous content and thank you for having the courage to do a partial dismantle and reassemble of 50+ year old electronic artifact - the Japanese certainly show the world how to do it.

The red stamp reads 松田 Matsuda (as in Mazda the car maker who used another spelling); it's a common Japanese family name.

The red stamp is a hanko that reads “Matsuda” A hanko is a personal stamp that’s considered your personal signature in Japan & we’re only now, in 2021 debating fazing out the hanko. The main objection apparently is that signatures can be forged… even though you can pop down to your local Don Quijote & get a hanko with anyone’s name on it, no ID needed for ¥200 (aprox: $2).

Mesh is a RF shield, from when they wanted this to work with an AM radio next to it in the office, along with an unshielded phone. The keyboard also has mechanical 1 key rollover protection, you can only ever have a single numeric key pressed at one time.

Gorgeous! It's a shame the zero had to be lower half.

Wow, this takes me back! I used the little red indicators to mark thousands and thousandths when I was doing calculations, other times to mark thousands and millions, depending on the scale of the numbers I was working with. The decimal point itself was easy to see, but the markers acted like commas to break up long numbers.

Hi Fran, add-to-memory function is all right. You added 256 to memory at 1:58 and a second time at 2:16. Very nice machine, thanks for showing

Boy, the tank level of build brings a tear to one's eye! Interesting how nearly every component lead has the added black 'wrap' on the legs. Makes it appear quite odd when you look at it. Those display tubes are really stylish, dunno that I've seen such before.

Oh, I am _SO_ happy you've discovered these early Sharp calculators! Those early VFD displays are truly a beauty to behold! I have a smaller unit, a QT-8D. Leading zero suppression killed the use of half height zeros, and VFD tubes like this fell out of favor. Many calculators of the era used half height zeroes, even on standard 7 segment displays, because it made viewing numbers easier when leading zeroes are not suppressed.

Hey friend, a place my dad were cleaned out the office probably in the mid 70s. He brought home a couple of calculators just like that, one was a sharp and the other one which looked just like it was a national semiconductor. And you’re right, the displays were awesome never seen anything like it since this video

A thing of beauty! This was a lovely, relaxing video too. I think the mesh layer may be to improve apparent contrast and reduce off-axis reflections.

If you think, those hand drawn pcb traces make a perfect match with the display style. It's the inner beauty inside an obscure office machine!

Traces were likely hand drawn on transparency then a photographic process for mass production Most of that is probably DTL instead of TTL so probably no need for decoupling

20:37 Cute how you feel sorry for that lonely capacitor! 😄

Finally! I’ve been looking for a video covering non-standard segmented display layouts for the better part of this year, I’m really happy you made this!

Due to the little dot for the 4 a 9-segment display for just the digit. That later 7-segment display was a real improvement.

This is very similar to the oddball soviet IV-2 (ИВ-2) tubes, except they don't have the tiny extra segment for 4.

Thanks Fran! You have the best videos! One thing I am NOT sad about is not having to hand draw/tape traces any more! 😃

I almost burst into tears when you opened the case it's so beautiful inside

Nice! This Museum is Not Obsolete just featured a Swedish calculator with the same display tubes last week. Never seen those before. Now there are two videos!

@14:29 I certainly see what you mean, Fran. They really are beautiful numerals. They have a truly unique 'thick-and-thin', calligraphic quality! (BTW: I love the positive and informative comments on this great channel)

The Iseden Itron script is my favorite digital display. The Burroughs (Sharp) C3260 I use at work has these tubes. The zeros are set up to show the way they do as many of these calculators replaced mechanical adding machines and they wanted to duplicate that look instead of blanking the zeros. The Friden 130 calculator and a few others were set up the same way.

Numbers look almost as handwritten and artistic, nice!

What a beautiful, artistic display! These are little poetic Japanese brushstrokes, not straight and stodgy western segments! I have a Sharp Compet sold as a Facit 1131J. Same layout, but it appears to be from later as it has 3 or 4 LSI ICs in it, and it’s all Nixie tubes! I would have thought that the Nixie version would have predated the VFD one. Maybe Facit had to swap the artful display for a more traditional one for the Western market?

I counted 11 segments. The digit 4 adds a short bar. Add the dot and the apostrophe at the top end.

the samp is probaly 松四, which is a family name, so its a inspector name

what a treat to find this video!! thank you for this wonderful investigation on this lovely calculator!

Whole Lotta Love to Fran for this great content.

Way down inside 🎸🎶 (9:54) - "Whole Lotta Love" reference 🤣🤣🤣 Good one, Fran !! 👍😂

God those figures are gorgeous. How delightful. I'm very envious :)

At first I thought it was a 6 segment display, but using extra segments to make the the numbers more readable is pretty awesome. I counted 9 segments though, there's an extra stroke on the 4.

A thing of beauty and joy for ever, lovey work Fran..

The most beautiful display for shure! And a very well done machine. Wonderfull video, as always, Fran! Thank you very much.

This reminds me of a Scott FM stereo tuner once owned by a friend that used Nixie tubes for the display and punch cards to select the station frequency!

wow, what they called compact, or portable, sure has changed from then to now. I love looking at these older devices, so beautifully built. Thanks for sharing, Fran !

The mesh is probably RF shielding, if it's connected to gnd somewhere. Back in the day they took avoiding interference a lot more seriously.

That was awesome Fran, I also thought to myself how well you control the camera. All the projects are very very interesting. Thank you Fran

A beautiful piece of electronics. Thanks Fran!

I love this type of show and tell of old technology. Thanks.

I had a few of the tube display calculators with colorful keys, loved them.

Whole Lotta Love, same era as the calculator. Thanks for the time machine Fran.

Wow, a tiny segment just for the "4" alone, just because it's more beautiful... I love it!

The bulbs come forward out of the rubber leaving the wire lose through the grommet/shield. (try pushing it from behind with a little crab fork) Cut both off in the mid-length of its wire, measure the resistance of the working bulb, and the voltage the machine puts on the wires, then you'll have your bulb spec. Splice pigtails back together, add sockets and connectors if ya like. :) A gorgeous machine thank you for showing it off, and all the others too!

Fran I really love the vintage stuff thanks for the video also at 17:28 tracks far right the third one in looks blown

22:26 (pause here) It looks like the date code is printed on the label containing the letters FEC... just below that is 691107J, which may mean it was assembled November 7, 1969 (YYMMDD) or it could be July 11, 1969 (YYDDMM). I don't exactly know what the J means other than perhaps it was assembled in Japan.

A true work of art there Fran!

The red stamps says 松田, "Matsuda", which is a Japanese surname. Most likely an inspector's surname.

Still have my Casio FX-10 calculator from about 1974, Nixie tube digit display very similar to what you're showing. Last time I checked it a few years ago, it still worked.

Those tubes are gorgeous!

The red stamp looks like a name stamp. Likely used as an approval seal for QI. In Japan they have stamps that are used for signature. The characters are in line with that, being both correct for a family name.

Thank you Fran!

Fran, you are a great researcher, thank you for all your teaching. Steely Dan "Aja" T.V. Commercial (1978) Steve Gadd

If I'm not mistaken that was built on 12-2-1973. Older devices like that had the date code on the PCB.

Interesting teardown, I worked on similar gear in the late 70's and the schematics were mind blowing! The keys look to be reed switches which unfortunately can fail, c.f. IBM token ring hubs, and often had a spring delay line for debounce which was often in a rectangular can under the main PCB.

You are so right, I have never seen such a beautiful cursive-style display, so much nicer than traditional.

That is a very well made calculator with an unusual display. Amazing circuitboard with a lot of quality components as well as Germanium cat whisker diodes. Thanks for sharing.

Thanks for taking this beautiful calculator apart. Very brave. The mask in the display reminded me of my early 1970s Busicom that uses a mask around the very square segments of its gas discharge display to make them look a bit more conventional and to make the actually square decimal point look round. I collect calculators so always like it when you have them on. You still have the delights of the dynamic scattering mode LCD to explore, which, if you can find a working one, is intriguing enough even for somebody who isn't normally impressed by liquid crystal! I love mine but I'm told it will die in a few years because they all do in the end.

Hi Fran. What an amazing piece of "elder tech". Thank you for sharing. Did you hear all the "NO's" when you mentioned disassembling it? Glad you did though.

You had me at "SHARP". I owned many lovely SHARP devices back in the 80s.

17:00 : It *is* tape. In the 70s I used the very same stuff to make layouts. It came in various thicknesses in dispensers like Tipp-Ex. Nice and quick to work with on simple, analog boards. With the advent of more digital stuff and bus structures people did not use that anymore. Guess I still have some (very much aged and dried out) rolls of the tape in my old drawing stuff. Thanks for showing ! I like these VFDs also quite a lot, even though I am more "the Nixies guy" ... 🙂

9:52 I love the Led Zeppelin rift.

Absolutely amazing!

The mesh is probably to stop glare. I seen the same thing on an apple 2 computer, but they used fabric (it got damaged quite easily).

The VFD's are actually 9-segment if you include the small horizontal tab for the number 4 on the right. :) All discrete transistor logic so this is vintage 1967-1971 time period. Integrated circuit manufacturers (Mostek, National Semiconductor, Toshiba, TI) started producing calculator processor integrated circuits in the early 70's which resulted in a significant reduction in volume, weight, and especially power consumption. Fran, your assessment of the different subsystems is right on. The area were there are tons of diodes (especially near the banks of transistors) is likely the arithmetic logic section; every transistor-diode pair is likely an inverter OR a flop. A flip-flop will of course hold one binary digit of data. As always, excellent video quality and brilliant work. Really appreciate have the camera held in fixed position (with presumably a good tripod). Great video!

Amazing! I'd assume the mesh was to cast a slight shadow inside the display so that the meager wattage of the tubes would't be overwhelmed by the ambient light, like when you're outdoors and the sun is too bright to see your phone so you put your hand over it to shade it. Its also possible that LimaVictor down there is correct, that it's for RF shielding, or maybe its both.

Wow!! those are really unusual tubes! I have an old Bell and Howell desktop multimeter that uses nixie tubes, which is pretty cool, but the font on these VFD tubes is just fantastic

My dad had the same one growing up! Thx for the memory’s

Breathtaking, I tell you there's nothing better for me than viewing a VFR. It's like Eye Candy. Awesome video!

I have never seen that type of display and your right, it is so pleasing to the Eye. What is really cool, it makes the digits 1 - 9 appear as if they are standing up lol.

If that rubber boot is still flexible enough, you can replace those bulbs; the round flange on the back side of the boot can be compressed with a diy 'split tube' tool and pushed out of the metal bracket toward the front, then you can gently work diy split straws, "shims" between each side of the shrink-tubed wires and the boot gland to push the bulb and loom out of the front of the boot... I wish I could mess with it with you, I've done similar extractions with very good results... My best advice? tend toward compressing actions to complete the task and avoid stretching at all if possible. Don't 'pull' rubber parts out of rigid supports, compress them and push them out. Thin slivers of straw and scrap plastic packaging are your friends, you can release stuck rubber from mounting holes by gently shimming around the contact area after compressing the flange with a split tube... Microscopically, new and old rubber are like an asphalt road and a cobblestone road respectively, The new rubber (asphalt road) can endure stretching, expansion and compression without much damage; the old rubber (cobblestone road) can endure compression, but expansion or stretching will cause 'stones' to shift out of place and "rip" gaps into the structural pattern...

My dad had a handheld calculator that had floresent display tubes. It had 4 functions plus memory. It was battery powered. i think it was a Sharp also from the early 70s.

Really enjoy the "handmade feel" of the tubes, each is its own length.

Great video! Nice to see the old equipment and how beefy it was designed. I'm not as jazzed about the display as you are, especially the lower case "o" - but it is pretty.

The mesh shielding in front of the tubes are probably to protect the tubes from getting activated by the static charge that can build up on the front glass. Since there is no grid in the tubes the electrons can go in the wrong direction. I have some single tube VFD's and if you wave your hand in front of them they will flicker because of the static field.

It is very beautiful Fran.

Great video Fran. Very interesting stuff... well, to me at least! Thank you.

Hey Fran, did you notice that the key switches use perminant magnets and reed switches?

Digits in those fluorescent tubes look like they were drawn with kanji brush, nice ✨

For the tabulation--it does make sense, because for whole numbers, for example $10.00, you can just type "10" and it will add the .00 for you. Easier for mostly whole numbers, you only have to manually add the cents for odd amounts. If it was the other way around, you would have to type 2 extra 0's for every single whole number.

That is gorgeous!

Thank you very much for your videos, I really like your channel, this is my first time and I feel at home.

I absolutely love your content!

Very artful display tubes! I have a Burroughs C3155 desk calculator that also contains these tubes. It actually showed up in the mail the very same day this video came out! The Burroughs C3155 is a rebranded Sharp QT-8D "micro Compet", which is notable for being one of the first calculators to use large scale integrated circuits.

Back in the late 60s and early 70s I used to be a calculator repair guy. I used to repair calculators made by the Japanese company Buisicom. The main product was a basic 4 function unit with no memory. It had around 50+ plug-in PCBs and you got a hernia lugging around the repair kit. You would swap out the faulty card and at the end of the day repair the faulty ones back at base. Each card had a few logic gates built using standard discreet components. I remember the first hand held calculators that chewed through batteries and cost almost a year's wages (for me anyway). My first miniature calculator cost me over a month's wages and I still have it (somewhere).

The electronics are stunning, all hand made and beautiful l layout

BigClive would have a field day with this. Boy they did not want this machine shorting out

That is amazing, not just the beautiful display but the general quality of construction - sleeving on all the component leads for example. Thanks Fran :) Incidentally I tried in vain to find any info on those NEC chips but I did find a doc on their IC-making history that says "...three DTL-family products were announced in mid-1964, and total of eight products including RS flip-flop circuits, half-shift resistors, and half-adders went into production..."

Truly beautiful… a thing of beauty is a wonder to behold. Almost wish it could be in a pure transparent case so one could enjoy the sheer workmanship🎉

The first electronic calculator I saw was a Texas Instrument one about the same size as that. This was in 1971 and it cost $4,000! It was purchased by the owner of a company that manufactured precision gears for Pratt & Whitney Aircraft. Adding machines had been around for a long time, but the advantage of the calculator was its ability to multiply and divide and it’s memory functions.

Incredibly beautiful.

Looks like the little tails on the 4s bring it up to a 9-segment, which seems extravagant.

that calculator is a throwback at a a documentary i re-watch from time to time, called "A video history of Japan's electronic industry", a 4-parter documentary you can find on youtube. It talks about the story from the beginning (just after WW2 with the birth of the transistor) to the time the documentary was probably shot (calculator wars, IC's, and technology surrounding VLSI's).

Cool, I love vintage like this

I have a Toshiba desk calculator from the same era. It has about 250 transistors, no integrated circuits, and several thousand diodes. Its storage is dynamic RAM made out of a capacitor and two switching diodes per memory bit. It uses Nixie tubes for display. It is assembled on six PCBs all using almost identical PCB technology - hand drawn tracks and sleeved component leads. The overflow and negative lamps are also neons rather than filament bulbs.

What an interesting package for an IC.

This is a really cool device! It reminds me of the Toko Mini-8 calculator which had a single tube blue-green fluorescent display like this. When you switched it on and off, the display tube would make a noticeable _deenk-dink-dink_ noise as parts inside warmed and cooled.

Fran: The display of this Sharp is very similar to my father's old university calculator which he gave to me. It still works. It's a Commodore 64 scientific with 110 functions (considered a lot in the late 1970's) with glow red Light Emitting Diode display powered by a rechargeable nickel cadmium battery...and it's "Made in England." The original manual is still intact and it comes with a soft vinyl case. Love your program...watch every episode. ❤ Diane, Vancouver, Canada. MnAU16/21 12:43 pm

All hand made amazing