EEVblog #612 - Mailbag - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: May 05, 2014, 10:22:48 pm
content: Mailbag MondayWhat should Dave do with his new lab internet bandwidth?Thermocouple Tutorial:Arduino Tape Shield:http://oceancontrols.com.au/KTA-292.htmlArduino Thermocouple Shield:http://oceancontrols.com.au/KTA-259V3.htmlMAX31855:http://datasheets.maximintegrated.com/en/ds/MAX31855.pdfBoldport PCBmodE Artistic PCB layout program:http://boldport.com/pcbmode.htmlSystem MERA-400 computer schematic:http://mera400.pl/files/mera400-dtr-t4-cz2-mjc400-schematy.pdfElecktronika MK-61 Russian Calculatorhttp://en.wikipedia.org/wiki/Elektronika_MK-61

author: pickle9000
author_rank: Super Contributor
timestamp: May 05, 2014, 10:53:45 pm
content: The Arduino shield is a gut buster. Hope they sell a million.

author: TheAmmoniacal
author_rank: Unknown
timestamp: May 05, 2014, 11:09:29 pm
content: Just to make you a bit jealous for a second, here in Norway I get 30/30 Mbit internet as the basic internet and TV package (only $50 AUD total!).

author: TheGenesis
author_rank: Contributor
timestamp: May 05, 2014, 11:12:12 pm
content: Dave, would you make a video to show how to detect these "dry" caps?Yesterday I have fixed my DSL-Modem by replacing a cap, but I got the hint from a website and before this one I thought caps are dead only if the have popped.Best wishesThomas

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 05, 2014, 11:16:56 pm
content: That looks like a "HV" DC-to-DC converter to drive those VFD digits.What a scandal it would have been if that Polish calculator had NOT used Reverse POLISH notation!

author: Chris_PL
author_rank: Contributor
timestamp: May 05, 2014, 11:18:15 pm
content: Dave, no, we've never used Cyrillic aka Russian alphabet here in PolandThis calculator is a *ekhm, ekhm* state-of-the-art Soviet technology which we were, gently of course (so was the official party line), persuaded to use because of the Cold War and COCOM. And those bad and nasty capitalists from "The West" of course.BTW. The sender is from my city, so "hello to all users/viewers fromWroclaw"

author: Chris_PL
author_rank: Contributor
timestamp: May 05, 2014, 11:23:20 pm
content: Quote from: Richard Crowley on May 05, 2014, 11:16:56 pmGot the joke, but come on, how on earth a polish calculator would have a documentation and button silkscreen all in RussianEven the Yanks know that

author: Gibol
author_rank: Newbie
timestamp: May 06, 2014, 01:07:47 am
content: I've registered to tell you that this is not Polish calculator, but I Chris already did itBTW, I'm also from Wroc?aw so hello viewers from Wroc?aw!Dave, next time, when you visit europe, come to Poland

author: SAI_Peregrinus
author_rank: Contributor
timestamp: May 06, 2014, 01:23:16 am
content: It's a "corDwood" puzzle, not "corKwood." Cordwood is wood cut into 4-foot lengths so it can be sold in cords, a cord is 128 ft^3 (4 ft x 4 ft x 8 ft) of wood.https://en.wikipedia.org/wiki/Cord_%28unit%29

author: MagFlux
author_rank: Contributor
timestamp: May 06, 2014, 01:42:57 am
content: Looking at the letter sent with the calculator it read ( warning, 74XXX porn ahead ) and a look at the schematic indicates those potted chips are of 74XX series. That packaging is something I've never seen before, might be a USSR knockoff? I go back to the late 70's in my electronics experience and have only seen 74XXX chips in plastic or ceramic packaging.

author: 99tito99
author_rank: Regular Contributor
timestamp: May 06, 2014, 03:22:28 am
content: Hi Dave:The postcard from Louisiana is from the Oak Alley Plantation along the Mississippi River west of New Orleans.The trees are Live Oaks; the largest predate the Plantation and were planted by French Settler around 1710, so they say.Cheers,Mark**************

author: Pentium100
author_rank: Frequent Contributor
timestamp: May 06, 2014, 03:36:03 am
content: Yes, it's a 4 phase clock. I have a desktop calculator that also uses 4 phase logic (also made in the USSR).Quote from: TheGenesis on May 05, 2014, 11:12:12 pmThere are three ways of doing this:1. Use an ESR meter to measure the cap.2. Use a scope across the cap to see if there is excessive ripple on the line.3. Temporarily solder a known good cap in parallel with the suspect cap and see if the device starts working better (or at all).

author: TVman
author_rank: Frequent Contributor
timestamp: May 06, 2014, 03:47:55 am
content: I love The Arduino shield!!!!How much does it cost?

author: Bored@Work
author_rank: Super Contributor
timestamp: May 06, 2014, 05:06:32 am
content: That RC generator on the schematic is indeed an RC generator, but with a twist. I happen to know that thing, because we in the West never got a reasonable substitute for that. That thing demonstrated the Eastern communist superiority so well.That thing is - drum rolls - a 555 timer IC with build-in digital binary counter/divider. Yes, you get two IC's for the price of one in Eastern Europe, and we in the West had to bodge it.

author: HP-ILnerd
author_rank: Frequent Contributor
timestamp: May 06, 2014, 06:36:17 am
content: (Edited because the site doesn't seem to like Cyrillic characters (OR high ascii)...I did my best with closest ASCII analog I could muster)I happen to have one of those MK 61's in my collection. Definitely the weirdest thing in it. It's almost alien. Crappy plastic aside, I'd swear those keys are double-shot injection molded which is an unexpectedly swank feature.It has some remarkably clever things, like when you program, itside-scrollsso you can see more than one line at once! And even though you program in hex codes (shudder)some of the hex codes sort of "rhyme" with the operation they represent, so it is oddly readable. The right most digit in the program is the line number.Make sure you use the "run/stop (C/n)" instruction in your program, or it will loop forever. Luckily, the calculator has a completely volatile memory to make starting over very easy.So a program that executes 1/X (yes, it has that on the keyboard, but I wanted this example to be simple)Press the pgr key: Yellow Shift-then nPrENTER //absolutely necessary because there is no assumption that keyboard input has ceased because its starting a program1 //if we did not do the above, this would APPEND 1 on to the input. Interesting.x<->y //this key just looks like <->/STOP // C/nRTN //B/O again, necessary unless you want it to run the null code past the end of the program space. You don't.The program looks like 52 50 13 14 01 0E 06After entering the program, exit the program mode by Yellow Shift-ABT. Makesureyou hit RTN when back in calculator mode (B/O on the cyrillic keyboard), or it won't know to start the program at the beginning.Now you're all set for some loooow speed calculatin'. It's faster than using a pencil, but sometimes you may wonder.

author: k2teknik
author_rank: Regular Contributor
timestamp: May 06, 2014, 09:10:40 am
content: Quote from: TheAmmoniacal on May 05, 2014, 11:09:29 pmJust to add some more jealous for a moment, here in Russia I pay $16 AUD for a 30/30 Mbit internet (real speed is often close to 50/50 on a good day), there should be TV to, but I don't use TV.

author: delmadord
author_rank: Regular Contributor
timestamp: May 06, 2014, 02:42:24 pm
content: I believe it is possible to bend the sides of that shield to replace the tapes, so it is not a one timer...or am I wrong?

author: Unixon
author_rank: Frequent Contributor
timestamp: May 06, 2014, 03:10:33 pm
content: Dave, do you need translation of Cyrillic writing on MK-61 schematic ?

author: SeanB
author_rank: Super Contributor
timestamp: May 06, 2014, 05:40:44 pm
content: Cordwood construction, fun to repair. Even more fun is it was potted in silicone as well. First carefully trim off all the silicone from the top and bottom of the board, then locate the faulty component, using the very helpful diagrams of which component goes where on the puzzle, then when you definitely have it then carefully dig it loose and cut the legs and remove it. Test and then replace it. Then pull out the big tube of silicone and the PTFE sheet to remake the potting again. Then cure and finally test. That could take a week, and the recommended procedure from the manual was " replace module xx", not "repair module xx", but as they were no longer available from the original manufacturer, and in any case would take a few months to get in any case it was repair. Reason for the potting was high voltage isolation, and while I did have a 5kV insulation tester, it was not much use except to find gross faults, as operating voltage was 12kV. At least that tester was better than the old wind up Megger.

author: faust1002
author_rank: Contributor
timestamp: May 06, 2014, 06:52:01 pm
content: Because of Cold Warm all normal ICs weren't available in USSR. Soviet engineers had to be really "creative". So they designed so funny things like MK-61 or MERA400. But they got job done!Dave, please come to Poland. I'm also from Wroclaw. You have lot of fans here. I guess you haven't been to Wroclaw yet, I promise you will have great time.

author: Unixon
author_rank: Frequent Contributor
timestamp: May 06, 2014, 08:39:13 pm
content: Enjoy this stuff to the very depth of you heart:http://www.155la3.ru/. You may also try Google for online translation.

author: poorchava
author_rank: Super Contributor
timestamp: May 06, 2014, 09:11:23 pm
content: Wroc?aw has a strong representation on this forum(born and raised here). One of the most if not the most high-tech cities in Poland thanks to very good communication with neighbouring countries.

author: OrangeJacketGuy
author_rank: Contributor
timestamp: May 06, 2014, 10:09:11 pm
content: ????.

author: OrangeJacketGuy
author_rank: Contributor
timestamp: May 06, 2014, 10:24:51 pm
content: why does this forum hate unicode?

author: richfiles
author_rank: Regular Contributor
timestamp: May 07, 2014, 02:31:50 am
content: I get a smile on my face every time someone sends you a classic calculator!You see, I collect calculators!http://richfiles.solarbotics.net/calc/CalculatorShelf.jpghttp://richfiles.solarbotics.net/calc/DisplayCabinet.jpgI have over 100 calculators myself, including a 1965 Smith Corona Marchant (SCM) Cogito 240SR thatalmostworks (and by almost, I mean that it did work, but after moving, the keyboard register won't load into the working register anymore when you hit an operator key). That calculator is built up of discrete components, using resistor diode logic, and the absolute minimum number of transistors that RDL let them get away with. It uses a magnetostrictive delay line memory, a CRT display that outputs 4 LINES of numbers, and a solenoid locks the keyboard while it is in operation, because it's slow enough that stray keypresses would screw with it!I have a Casio 121-A that does not yet work. It's a small scale integration based nixie calc, with a medium scale shift register memory. There is also my Friden EC-132... It is OLD... I think it too is around 1965. It's not quite in as working order as the Cogito. It uses a voltage doubler circuit to achieve the CRT voltages, and the indications are that that circuit is failing. The magnetostrictive delay line is also bordering on untuned. It SOMETIMES can perform a SMALL addition operation, but subtraction, division and multiplication tend to result in garbage. Larger numbers, most division operations, and EVERY attempt to perform a square root freezes the unit.Still, there are many models I have that do work...I've got a Remington 1259S. It's a small desktop scientific calculator that outputs using Nixie tubes... And the best part... It does NOT blank the display while calculating! Watching a cube root is a thing of BEAUTY! It's a regular neon numerical dance! It worksperfectlytoo! I also have a Canon Canola F-11 scientific calculator that also works, even if its not quite a cool as the old Remington!I've also got a Monroe 344 Statistician, which looks like they re appropriated an early 70s cassette tape player housing (at least the dimensions) to build a "portable" programable statistics calculator!Aside from the hoards of working machines, and the collection of non working ones I have as well, I've managed to successfully restore a couple calculators too. I restored a pair of Commodore N-60 Navigation calculators. Sold one to a pilot from Australia, and the other is sitting a foot from my hand, on my desk! A foot further down my desk is the Commodore S-61 I restored. I actually use these calculators regularly, and I love the huge "pocket sized" beasts! I've also got an HP-41CX that I did some VERY MINOR repairs to. I love the fact that HP included a piezo buzzer in this calculator! It's such a silly little thing, but it's simply not enough for it to be an AMAZING calculator. I mean, HP's engineers thought, we have this utterly amazing, programmable, expandable calculator... lets throw in a buzzer too just because! I guess so it can tell you audibly when it completes a program, or give you an audio cue for input, etc! Just thinking outside the box! Cool calc, HP!I've also got an AMAZING HP 9825. This thing is called a calculator... It's full blown computer. 16 bit, 10 MHz CPU in 1976! Single line LED dot matrix display, a full QWERTY computer style keyboard, tape printer and tape drive, and expansion ports and cartridge slots EVERYWHERE!Speaking of HP, now if ONLY I could find my dream machine, the HP 9100 (A or B)...Why are you so impossible to find, 9100... And expensive!I also can't find an early ANITA. They were nixie calculators with a full manual keyboard and neon filled thyratron tubes as switching elements. They used a dekatron or two for things like keyboard polling and such, and were the first electronic calc available to the public. I have 6 of the nixie decade counter pc boards and plan to build a custom calculator using telephone dials as inputs. Even finding those parts was a pain!I also have fully restored a Sony SOBAX ICC-600W, by scavenging parts from a very ruined ICC-500W. These were nixie tube calculators, that had hybrid modules instead of integrated circuits. Hybrid modules were an interim between discrete components and chips, to any that are unfamiliar with them. generally, they were usually a ceramic plate with capacitors, diodes, transistors, etc bonded to a conductive trace on the plate. I think resistors were often carbon films right on the ceramic. They would then have leads attached to one end and were then potted. These were more common in the era when chips existed, but the military and aerospace industry was gobbling up anything they could get their hands on, and they were ridiculously expensive still. The finished SOBAX is BEAUTIFUL, works flawlessly, and since I had spare parts, I made a nixie tube clock to go in my 1939 Philco radio cabinet PC case!http://richfiles.solarbotics.net/eb/NixieDetail.jpghttp://richfiles.solarbotics.net/eb/PhilcoNixie.jpgAside from the Sony calculators, I also have an electronic organ that is PACKED with hybrid modules! I've wanted to take it apart, but I can't justify it... it's too amazing... The organ is packed with hybrid modules, has 18 plunger switches with 8 positions each. These are wired into a rats nest of enameled wires that lead off to a bank of boards that run the width of the entire dual manual (two keyboards) organ. Crazy amazing craftsmanship!Finally, speaking of craftmanship, and rounding back to the topic of calculators, and more specifically, Russian calculators, I have an Elektronika MK 61. I can vouch for the cheapness of that plastic. OH MY!!! It HUUURTS my ears, and it feels WRONG!!! The cheapness! LOLIn all seriousness though, I love those old USSR models. The later stuff tends to universally feel cheap, like the death throws of the old USSR cut into their manufacturing ability or something. The earlier days had some amazing craftsmanship though! Furthermore, the technology, for better lack of a word, feelsalien. It took me a few minutes to realize a part inside one of my favorite Russian models was actually a FUSE HOLDER! I thought it was a pot!The Soviets were truly cut off from the world because of the cold war. Their technological path diverges from the eastern and western paths. Often times, they flat out stole a western or eastern design. A LOT of their products were ripoffs of Japanese, European, and American tech, sometimes even going so far as to copy ROM content, board layouts, etc! Other times, they genuinely did their own engineering, but as a result of their isolation from the remainder of the world, their paths often diverged from our own... Familiar things... aren't! There is an almost anachronistic dichotomy between what they considered new vs what we considered old. I have a 1989 Elektronika MKy that has a case that draws it's styling from angular 1980's era design influences, uses asingle long VFD for it's display, not in a modern flat glass package, but a long "valve" style tube, with radial leads on one end, and the vacuum seal nipple on the other. It's primary chip was a staggered pin DIP, and it had an 8 pin DIP that wasnotscaled to match our pin spacing... It was oversized. It also had a metal can IC. The case on that one actually felt rather solid, yet the keypad felt as cheap and as flimsy as the 1976 4-71b keypad! Heck! My Mky was shipped to me from the Ukraine in an ENVELOPE and survived!http://richfiles.solarbotics.net/calc/Elektronika4_71b.jpgSince I mentioned it, I have an Elektronika 4-71b (or as best as an English keyboard can replicate Cyrillic text). Despite not being my best or most featured Soviet calc, it's my underdog favorite! This calculator looks like it went to war and came back... barely! It is MISSING parts of the case! It uses wonderful 9 segment displays and produces a lovely 1, 3, and 7 using said display! It's a simple 4 banger from 1976, nothing more. Inside are 4 staggered pin DIPs, and an EXQUISITE degree of workmanship! I suppose it should be expected from the land of the "worker". In Soviet Russia, all wire is hand lace by you! Seriously, the laced wire bundles are just...pretty! I have to admit that I'd love to learn that hand laced wire bundle technique. It really adds something special to any project, and it's a PURE JOY anytime I encounter the technique in any vintage electronic device!Now if only I could track the problem in my Cogito down! Sadly, I have no schematics for it... So no idea where to start.

author: TonP
author_rank: Newbie
timestamp: May 07, 2014, 12:37:24 pm
content: So.. I have 200Mb download, 20Mb upload

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 07, 2014, 03:04:24 pm
content: You guys are making me sick with your internet speeds. I am a pilot-tester of WiMax (developed by my own employer, although I didn't work in the wireless group) and I am using the commercial WiMax service by Clearwire (now bought out by Sprint). Because I live between two rather widely-spaced cell towers, I get maybe 1.2M down on a good day and upload is artificially throttled at 0.5M!But, fortunately my neighborhood was "wired" with optical fibre a couple years ago, and I will probably switch to that when Sprint turns off WiMax (replaced by "4G LTE") But the one thing I liked about WiMax is that I can get unlimited high-speed service anywhere in the wide metro area. "Mobile" service is typically better than at home and download speeds can go well over 5M).

author: reagle
author_rank: Unknown
timestamp: May 08, 2014, 01:01:02 am
content: Hey Dave,the gunk in the screw hole of MK61 was a typical warranty seal. You'd have one of these on one of the screws or inside a little metal stamped washer like thingy. They'd usually press in a stamp with some letters/numbers to seal it. When you disrupt it you void warranty.Small plug-in board has a bunch of silicon transistors (yellow cases), red "flags" are caps

author: reagle
author_rank: Unknown
timestamp: May 08, 2014, 02:02:21 am
content: Awesome site- brings back many memories and fills in many gaps-thanks!Quote from: Unixon on May 06, 2014, 08:39:13 pm

author: miguelvp
author_rank: Super Contributor
timestamp: May 08, 2014, 05:25:35 am
content: Quote from: Richard Crowley on May 07, 2014, 03:04:24 pmI did use Clear for a while because the only thing I could get was ADSL and I was dropping packets like crazy, Clear as a little bit better but no dice, incredible that in a big city like chicago you can't get good internet unless you live in the suburbs.Now I have cable and it's not great either (used to have Verizon Fios when I lived in TX) but WiMax is really not a good tech. Specially in dense areas like Chicago is.I recall moving the orientation of the 4G modem to see if I could get the "right" bounce out of buildings to get a better signal.

author: XpsikotiX
author_rank: Regular Contributor
timestamp: May 08, 2014, 06:18:03 am
content: Quote from: k2teknik on May 06, 2014, 09:10:40 amYou should be all jealous on the internet connection in Romania - 1000 Mbit (1 Gbps) download and 100 Mbit upload for like $20 AUD ....Dave with your connection you could mount some webcams in your lab and stream live when you are there, so we can peek at what you are up to (if you think its not creepy)