The 7805 hasn't "burnt away" paint. It won't get very hot running just those few chips. The original owner repurposed a piece of aluminium as a heatsink which was either anodised or painted. Both anodised aluminium and paint have a high thermal resistance. He understood what he was doing and scraped away the anodised or painted layer so that better thermal contact could be made with the 7805, allowing it to run cooler.
It's been rubbed away on purpose but those 7805 regulators get damn hot with these old systems. I have a Z80 microprofessor from the mid 80s and I had to put a heat sink on it as it was seriously hot. Old chips really suck the power.
When I was a kid I got a book called "How to Design, Build, & Program Your Own Working Computer System" which had all the steps to build your own "SCAMP" based computer complete with hand wired diode matrix bootstrap PROM and teletype interface. I bought a JM Precision MK14 board awhile back and almost have all the parts together to assemble it but haven't gotten around to it just yet... :)
I have that book by Mr Haviland! The JMP one is the first clone I built and is good quality - just watch if you build a separate keypad its connector has a minor difference to the original - you should not need it though as you can fit real buttons to the unit !
I wasn't a kid, I was about 20 but a similar book inspired me too "How to build a Z80 computer" by Steve Ciarca (by Byte books) - learned so much from that, but I never did build a Z80 computer from scratch - because of teh knowledge I acquired from MKL14 I scratch built my own SCAMP based machine using a lot of ideas from Steve's book and knowledge from the SCAMP data book. I think I still have a couple of SCAMP chips in my component draws - and Z80s. Antiques now!
I still have mine. Built as a 16 year old and was the start of a career in hardware and programming. Still working at almost this level of programming writing the operating system code for automotive electronics on all the latest chips.
That's pretty heavy duty buddy! I once heard a car tech (worked at Jaguar, with the injectors side of things) - say that there are very few people who know how car ECUs are programmed, what they're programmed. Apparently.
That sounds great. I always liked playing around with logic gates (without knowing the term, I'd made my own little state machines at home) and assembly programming. Alas, as a child in the late 90s and early 00s that was considered "playing around" and I was pushed to instead try things like C and Java which never clicked with me in the same way. So instead I pursued physics instead of computer science. I did do a bit of electrical engineering in school too, so I did get to continue making circuits with logic tables and stuff in both physics and electrical. But it didn't lead to doing Computer Science.
Back in the 70's here in England, these were the only computers on the market. Due to high import duties and taxes, Apple and Commodore were not available until the early to mid 80's. Which it why Sir Clive was so popular with the MK14 kit and the ZX80 kit. In 1981 he brought out the ZX81 which was his first to be sold in shops fully assembled with PSU, comprehensive instruction book and all the leads to hook it up to a TV and any cassette recorder. (or reel to reel like I did.). And it only cost £100.
@@kaitlyn__L I had a big 4 track reel to reel with 7 inch reels. The tape I used was 120 mins per track, so I bet I could have got about 100+ games per tape. Needless to say, I never filled a tape LOL.
@@kaitlyn__L I'm afraid not. There are over 300 official programs for the ZX81 and over 24,000 releases on the ZX Spectrum. With an average loading time on the ZX81 of 5 mins and an average loading time of 7 mins for the Speccy, that's a lot of tape. LOL.
Fascinating you've been able to show the MK14 off. I'd always heard of it, but never knew how it worked. Thank you! BTW, I think your videos would work without music in the background. Your call of course, that's just my opinion.
When Commodore was selling the C64, they offered a $100 rebate if you bought a C64 and sent them back any computer (which didn't even have to work). At that time, the Sinclair ZX81, introduced at $100, was being marked down to $50 (or sometimes less). I understand from a former Commodore employee that they were getting unopened ZX81's turned in for the $100 rebate, in addition to well used examples of ZX80's, lightly used ZX81's, as well as old Commodore Pets and other vintage machinery. Years later, I attended the auction when Commodore went out of business. There was a Sinclair ZX81 at every door being used as a door stop.
Yup I've seen pictures of Commodore offices with those adorning the doors.. lol. Kinda had low regard for those machines. I did too, until I actually started playing with mine. I'm quite impressed with what they jammed into that thing.
Thank-you for covering this very obscure (by North American standards) system. My very first computing experience was with the TRS-80 Model III in about 1982, so I am largely unfamiliar with anything earlier.
Just watched this one, very informative. I still have a scamp processor in a wardrobe (unused), somewhere. My first computer was a ZX81, followed by a Spectrum, then a QL, then a Commodore Amiga, followed by a series of self built PC's
Very cool indeed! These are so rare that I don't think I've ever seen one. I've not seen a working ZX80 either, although there's some in museums here. I have a working ZX81, though. Fascinating to see it working and doing stuff. It's certainly a challenging device to work with!
Around the same time that this came out in the UK, Acorn released their System 1. Similar design to the MK14 in many ways but using a 6502 and it had a better (just) keypad. Same calculator LED display but it did have a built in cassette interface. None of this really matters because being a kid on pocket money I couldn't afford either of them. I use to read the adverts for these computers in the electronics magazine and try to imagine what it would be like to be the proud owner of one. On reflection I've no idea what I would have done with them.
I remember using a fairly similar 6502 based training computer way back in the early 90's. It used a similar single board design to these machines. Did a course learning how to program it using the hexadecimal pad, and one on hardware fault finding and CPU interfacing. There was a date on the board which was something crazy like 1972 or 1975, maybe the year it was first designed.
Acorn's System 1 came out after the MK14 because the same Chris Curry got pissed off with Clive Sinclair and went and set up Acorn with Herman Hauser and the System 1 was their first product.
@@melanierhianna it did but Curry was making and selling Acorn products whilst still working at SoC/Sinclair. MK14 was 78 (officially 77 but no one had one til 78) the System 1 was early 79.
30:20 odd: I remember doing "pair programming" on switches-and-LEDs machines back in the day: One person read out the hex bytes to enter, the other entered them. Then the second person would read back the values from the RAM and the first would verify that the byte matched the listing. Then you both got to see it run! 🙂 Fun times...
Now I have to look for the video concerning the company Chris Curry founded when he left Sinclair, Acorn Computer. I already know you've seen Micro Men! I'm just wishing the BBC make a film regarding wither the history of Commodore or the general life and times of Jack Tramiel! They'd, of course, have to call it _Business Is War!_
There have been a few documentary style videos about Tramiel or Commodore but I've found them to be somewhat lacking in some way.. unfocused or not well produced. It's too bad.. Tramiel had a very interesting life and certainly had some insights in business.
I had one. From there it was upwards and onwards! Finally, Nokia Snr. Specialist/ trainer, with 20-odd countries to my name. Better than being a policeman - my original choice! As a result, I now live in Finland!
As a small aside, the MOS 6502 can operate in a dual CPU SMP configuration with shared ram, this was actively used by Commodore in its IEEE-488 drives, and facilitated by the dual phase bus used by those CPUs. Essentially, the second CPU needs to have its clock shifted 1/2 phase, and you need ram at dual the clock speed of the cpu.
@@paulstubbs7678 the 'half cycle' approach was also used by others for allowing both video hardware and the cpu accessing the same ram. This was a somewhat special time in computing technology, where ram was easily twice as fast as contemporary CPUs required.
Yeah, Sinclair went so cheap that things became unusable. The ZX80 is the same; technically you got a working computer for under a hundred bucks but it was unusable for anything practical.
You need to appreciate that when these were released, disposable income in the UK was around half that of the US, and Sinclair realised there was a huge appetite for affordable computers. Yes, the MK14 and ZX80 were very limited, but the alternative was... well, nothing. The ZX81 was still very primitive but it was considerably easier for a novice to use, and it revolutionised IT in the UK. The Spectrum sent home computing into orbit. Whatever the limitations were, these machines made UK per capita computer ownership the highest in the world for some time, and launched millions of successful IT careers.
Man how far we came in a few decades lol it's hilarious that they made such a terrible keypad they added a port so you can add another one. Ah old school redundancy!
That was typical of all Clive's products from the calculator to the C5 'car'. Spoil the ship for a halfpenny of tar! He had the unshakeable belief that each product had to meet a price point that would undercut all other similar products and so they skimped on quality wherever they could. I started out my career on one of these in my bedroom first by building a cassette interface and external keyboard.
Actual substantiative comment: so what does the reset keypad button do? You’re pressing it in the middle of entering programs so it doesn’t reset memory contents, at least it doesn’t look that way. Does it reset an input/output mode like the term you mention?
Yeah I did a quick dusting as much as I dared but the camera picked up a bunch. Reset always does reset.. I'm not sure what timestamp you're referring to but usually the only time I'd hit reset is if I want to go back to $0000
@@Arivia1 It is the only way to get out of a program loop and back to the monitor - it does no initialisation other than the usual SC/MP clearing of the program counter.
@@Arivia1 indeed there is no room in its 256 bytes to have any init - Sinclair did optimise the ROM a bit to fit in the Tape Save/Load routines as well...
All about keeping things cheap. Although having experience in calculator manufacturing I feel like he ought to have been able to finagle a better keypad for the MK14 affordably.
From looking at a downloaded manual he was using the 'standard' metal dome 'clickers' used in all calculators back then, it's just that he didn't put plastic buttons on top as per a calculator. These things (and a tin plated circuit board) oxidise over time, so they are now WAY WORSE than when they would have been when new and shiny.
My first computer... still on the shelf but suffering from an inadvertent polarity reversal which has toasted (at least) the proms. One day I shall get around to repairing it.
I have one of those. It didn't come with a power supply, of course, so I bought a transformer, bridge rectifier and large electrolytic capacitor by mail order. (What value capacitor do I need? Hmm... A large one...) Soldered it together, and it worked. I found out a little later that one of the bits in the extra RAM was faulty. 256 bytes basic RAM, 256 bytes extra RAM, 128 bytes of RAM in the I/O chip (the 3 blocks were non-contiguous). I think I managed to burn out one of the segments in the display, though. Oops.
I think you’re only other person in Australia that started on a 2650 ! Same starting timeframe as you… my boss built a a SC/MP and piqued my interest. I bought the KT9500 (2650) development board - then moved on to Z80s… !
@@RoyAntaw Yeah, I skipped the other chips..l broke my interest on 2650, no interest in anything other than Z80… then actually did some work for Zilog ! Juggled between tv industry and DEC for a few years, then fell overseas for a decade, and came back to start a very successful company with my developments, but (old story) my business partner stole the whole thing - leaving me broke. He’s doing very nicely now thank you,
Interesting. I had heard of that microprocessor, but never the MK 14.If I was gonna to spend that kind of money I would probably by a SWTPC 6809 machine. That was one sweet micro from the 80s.
That's not true, since ROM is also memory. The 2600 read a lot of code and other assets directly from the ROM cartridges and therefore needed less RAM. Since the 2600 used 2K cartridges, its memory was significantly more than this MK14.
A while ago a friend of mine designed a version of this that looked period accurate (or *looked* close enough anyway) that fit into a display frame. It could be connected up to work if you so desired but it was more of a show piece for people who wanted a little piece of computing history to display more than anything. I don't know if he ever got anywhere beyond the plans for it, he tends to have a lot of little projects he'll do one or two things with and then move on to a new challenge.
close to 500 bucks (in todays money) the builder has it mounted at a 85 degree or so angle, eye twitches... (not saying the electronics I make at home by hand is dead on but gosh surely he could have used a finger tip to first knuckle as a measuring device lol)
Having played with one of these in my youth, it really brought back happy/frustrating memories. You're right. The keyboard was a total POS. Thanks for the video. Only one minor comment, could you possibly turn down the musac a bit. Xx
As an owner of an original Mk 14, yes, the keyboard is garbage. I got mine from one of my teachers when I was doing electronic engineering in the late 90's, along with a KIM-1, for $20 for both.
Those pre-program addresses were storing data. Machine code (and by extension early assembler) had no proviso for what we now know as "variables." Any time one had data to store and keep track of, a memory address would be used, and the program would read or store to that address when it needed the data. Problems arose when, for instance, you needed more than 8 bits -- the work could double for every additional byte to parse. IIRC, that's one reason why the Y2K "bug" was such a big deal -- the programs written well prior had no reason to account for what century it was. It's also why types of variables (integer, character, long, etc.) were so huge. Storing everything as raw data, assembler will let you do anything, even if it's not what you want to do (like overwriting part of the program). Debugging inappropriately used addresses would have been that much more nightmarish to identify and correct. That kind of bug is probably why the owner crossed out 06 and wrote in 15 for the digital clock program. 👍️
Funny you mention the casio calc watches, i just got one of the reproduction 20 dollar ones casio makes now as a gift for my 22nd birthday. A dual time databank watch is still neat for that cheap at walmart. Ive been loving your channel btw, eventually you run out of well known stuff to watch videos on.
I think I saw keypads like this in electronics shops at that time, with interchangeable paper overlays, so I don't think its designed by science of Cambridge, but just bought on the open market, and adapter for it. Other computer experimentation units like this didn't even had keypads and seven segment display, just switches and LED's. one of the first that did have a hex pad and seven segment display was the KIM-1, and that one cost four times as much. I think the reason for the rarity of an MK14 now is just that previous owners just threw theirs in the trash heap after a few years, and not many survived that destiny.
You're way off on the exchange rate around 11:15. The current exchange rate is about $1.3=£1, so £250 is about $325. The exchange rate hasn't been $2=£1 for decades.
I think the INS 8060, better known as the SC/MP was used as the in-car computer and seatbelt alarm on some US cars during the 1970's as the chip only needed +5v and was cheap compared to all the other 5volt alternatives (MC6800 and MOS 650x family)
I'm a collector of Sinclair (Spectrum) computers and was wondering if I should try to get a MK14 into my collection. Thank you for demonstrating it - now I know that it is too "remote" from all my other computers, that I don't really have to hunt one down.
That's really cool. If I was a rich little kid I would have had tons of fun with one of these for sure. Paul Robson and Doug Rice have emulators you can play with (Doug's runs in a web page). I would post a link but this site bans everything these days.
After trying out some programs, about the first serious thing I did with mine was adding an external keyboard to replace that achingly awful membrane keyboard.
Sinclair was as much as disaster as he was a genius. He had what we'd called questionable quality assurance, but at the same time often undercutting his competitors by half, making these things available to the average person. Take the Spectrum, for playing games it was not really any worse than a C64(there were advantages and disadvantages, for instance lack of hardware sprites, but you'd get double frame rate for 3D rendering in flight sims etc.) but sold for the price of a VIC 20. It didn't matter if you lived in a council estate with your single mother, you could afford and have a ZX Spectrum, and to top it off, games started at 99 pence each. The keyboard felt like dead flesh and they were notorious for breaking down, but at the same time you'd get a free replacement... eventually. Just an all round interesting guy. From 2" battery powered TVs in 1970(MTV-1) to the disastrous "car" that eventually broke him.
@@Louis2282I've come to realise he was just living in a very different world to most people - he was so visionary that most people couldn't keep up with his ideas.
Actually I think I know what I did. I did the inflation conversion and then converted from pounds to USD using exchange rates at the time. I failed to adjust for the change in rates in effect today.
@@TechTimeTraveller Ah OK. Either way it was cheap for the time. My first computer was the ZX81 - great little machine that even allowed programming in machine code.
I'm not sure TBH. I would assume not.. 5vdc is 5vdc.. maybe a more experienced electronics engineer could answer that. I actually watched the timing of the seconds passing against my watch and it seemed pretty on target.
No, it's a rectified DC input and it has a separate oscillator for the clock. The 50 hz frequency *was* the reason the PAL standard chose a 50 hz field display rate for the video output, and the clock speed of most commonwealth countries were designed to be an integer ratio of the desired pixel clock rate of a PAL line.l, which is 14.75 MHz for 767 square pixels, and slightly less for slightly stretched pixels on Sinclair designs.
Fantastic little drama with great acting in it. The designer of the ARM architecture and the BBC Micro Sophie Wilson, which is everywhere now is a barmaid in it!
According to Chris Curry in an interview also on RU-vid, they sold 90,000 of the MK14 kits: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KrTmvqwpZF8.htmlsi=UcCqKHFrOXFq8NpC&t=1495
Why call it Clive Sinclair's wonder? It wasn't even his own design! Just a re-implementation of national Semiconductors reference design. The National Semicomputer intro kit
Well it's sort of riffing off the way Clive marketed things. I suppose I could have put it in quotes but I opted to be generous to the late Mr. Sinclair.
@@TechTimeTraveller don't mistake me, I'm a great admirer of sir clive, I even designed a replica of his ZX-81.(the ZX81+38) It is just that if you call something "his wonder" it should be his, not simply a company reference design. but i did not say it to belittle the MK14, its a great little device and I wished I had one at the time, instead I had a KIM-1.
National Semicondutors SC/MP - wassat. Out in the real world (well, the small amount of it we computer nuts could see from our bedroom workbenches) we just called it the 'Scrumpy'.
Back then, the word got around that there was an 'affordable' computer. There were some adverts and there were articles in electronics magazines. The only thing that was not mentioned was for what it could be used. It wasn't much but it surely was magic.
