EEVblog #557 - Retro Sinclair ZX Spectrum Computer Teardown

Inside the classic retro Sinclair ZX Spectrum computer from the 1980's
Was supposed to be part of the previous Mailbag video, but Dave is an SEO keyword whore, so it gets it's own video.

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[CoolDudeClem]

Memories of my childhood have come flooding back (along with memories of waiting several minutes for games to load and dreading the "R tape loading error"!)

[flapjackboy]

Don't sell yourself short, Dave. You are certainly a celebrity to all us geeks who watch your show.

[rbtx]

The bottom side has solder mask because it needed to go through wave soldering. There is really no need for top side solder mask, but yes it does look a lot better with it.

[obiwanjacobi]

Went thru the keyboard membrame in a couple of years typing. Learned digital electronics with it, built shadow ROM, DAC/ADC, a PWM on the NMI to slow down hard to play games and even built an interface for a XT-PC keyboard using an eprom to map key codes. Learned Z80 assembly on it as well. Also had the joystick interface, and Interface 1 for the printer and micro-drives. Build my first adventure game with those...  Ah, it was a good friend. 

[DaithiDublin]

I had a Commodore, but my best friend had a Spectrum back in the day. He also had ZX81, the first computer on our street! Loved _all_ of these old comps. Another friend had an Amstrad with a tape deck built in. It wasn't like everyone wanted the same thing back then and we were actually happier to each have different computers. Great days! Have you seen the recent BBC film based on Sinclair those early days, called Micro Men? Well worth a look.

[nickclark]

I was sending emails with my spectrum back in1983. How? Well with the aid of cb radio, mic and ear connected up to spectrum ear and mic at each end ! My group of friends were "connected". We also sent games to each other to load. A couple of lads were intercepting our data and. Messages so I had to devise a basic encryption program ! The spectrum taught a lot of kids SO much about electronics and programming. A lost art amongst children ( and adults ) these days who seem to be just phone morons now !..

[paullangton-rogers]

If you want to see the full story/drama of how Sir Clive almost by accident ended up in the computer industry as the main player, watch "Micro Men" a BBC documentary-drama which tells the story of his rise and fall.

There's a funny scene on it, which shows how obsessive and hands-on Sinclair was with every aspect of his product development and design...one of his engineers brings 3 keyboards to his desk for the new XZ Spectrum and sets them out in line, one a proper tactile resistance keyboard, one another version of the ZX80/81 flat, and the rubber keys..he tried them all and tapped the rubber one signaling his choice.

The spectrum was initially the fastest and biggest selling home computer in the UK (and even in some overseas markets, in the US even it was licensed as Timex Spectrum but didn't make as much impact there), and it came down to 2 factors unrelated to the machine itself really or its capability (there were faaar better and more powerful machines, like the Acorn, Commodore, and BBC Micro). The Spectrum was a) very cheap and attractively priced b) first to market as a "games ready" computer with colour graphics and sound c) but the real clincher was, Sinclair had already established his name in the home computer market and so there were hundreds, if not thousands of programmers writing games for the ZX81 which soon began writing for the Spectrum. Pretty soon you had 1, 000s upon 1, 000s of games for the Spectrum and people exchanging games on cassette tapes lol. So having a Spectrum was a must-have, if you wanted the best games and/or access to good games free off your mates. You only had to walk into a shop that sold home computers and you could see row after row of Spectrum games, and just 1 bottom shelf for "other" computers.

It's ironic that Sir Clive was totally against going into the computer industry AT ALL and he was very dismissive of computers (still is today!) and even dismissive of the games industry..he just failed to appreciate the value in software or the huge business potential which would eventually overshadow the hardware industry (something Microsoft DID realise).

Now we have come full circle...Sir Clive has launched (indirectly, someone else is doing it, but he has lent his name and has a stake in the venture) to a crowfunded product called "Vega" which is like a modernised retro speccy..the original design proposal (done on a 3D printer looked very much like an original ZX Spectrum except it has only 4 rubber buttons and a joystick lol. They've now done a much more modern looking design.

The Vega is claimed to have 14, 000 speccy games (and more you can download freely) it plugs into modern TV's (oddly via composite tho, not HDMI, probably due to the limitations of spectrum graphics in those games) and is like a games console and is retailing for £100.

[StevetSDBP]

Love this tear-down, though the vid under-estimates the impact of the Spectrum in the UK. It was huge (rather than quite popular) and for its day it did a lot more than the bare basics. I still have and use one. :) Love it! and thanks for this vid.

[paullangton-rogers]

Get to see a speccy. It's just sooo iconic of the 80's and brings back memories. I remember seeing them on sale new in WHSmiths for £49.99 the year they came out. It didn't seem like a lot of money for a computer which could play 1, 000s of games and had colour graphics..yet to a 10 year old, it may as well have been £5, 000.

My brother got one for xmas some years after they came out, and I was well miffed!! I sooo badly wanted one and was sure we'd both get one. My mother didn't realise you could actually program them and thought it was purely for playing games on, and my brother wouldn't let me it to play games even, let alone program on it! I ended up with a Tandy TRS-80 (a horrible computer, but also running BASIC). Years and years later, I bought a speccy for sentimental value and it's in my vintage computer collection now which has grown considerably large!

[mrezniable]

When i was 7 year old I got ZX81. 5 years later I got Zx Spectrum. This computers, retyping listings and learning basic decieded my profession. Becouse this I choised technical education, digital electronic, and now 30 year later of my first Zx81 I am professional programmer. Sir Sinclaire was changed the World!

[AntonyTCurtis]

The regulator isn't floating - there is a missing piece of bent aluminium sheet heatsink.

[rjday]

Nice to see one again. I owned one back in it early 80's and used to repair them as part of my job. Good machine for the era.

[pev_]

I did like the rubber keyboard along with some other Speccy-using friends of mine. It was quite fast to type basic when you memorized the keyword placings. The only bad part was the membrane key contacts. After a few years of hard use some keys would go bad. Somehow the white contact material would corrode on one or two of the most used keys (at least one friend had the same problem). I remember I did a DIY repair on the symbol shift key in my Speccy by inserting a copper wire in place of the top membrane and surprisingly it worked for a long time. Then I actually made a full replacement with a PCB with soldered separate momentary switches for each key, and the rubber mat would go on top of that. I still have it.

[riklowe]

Love it. I have a working Spectrum and Commodore 64 at home - learnt to program on them and have been in IT all my life

[snoballuk]

A very detailed book about the Spectrum is 'The ZX Spectrum ULA: How To Design A Microcomputer' by Chris Smith.

[mrmattandmrchay]

This is the machine where I first learned the BASIC programming language when I was about 11 or 12.  We had a few of those keyboard membranes and those cassette tape connectors at the back were always dodgy - kept having to weigh down the connectors so that they would bend at an angle to make contact inside the connector!  Memories!  Oh yes, and Daley Thompson's super test used to take 12 minutes to load then "R TAPE LOADING ERROR" at the end hehe (oh, that was on the 128k version not the rubber keyed 48k)

[ForViewingOnly]

Nice one Dave. I LOVE vintage computers from the 70's and 80's, and from what I've seen in the comments on past videos I'm not the only one! Any teardowns of classic computers are always much appreciated, but if I ever see the words 'Acorn BBC Micro' in the title of an EEVblog video I will literally wet myself with joy :)

[CubeCyclone]

I converted mine to the Spectrum+ keyboard which was ok but you still couldn't type quickly. It was a bit like go faster stripes on slow car.
Very versatile and far exceeded the limitiations it was originally designed for. There was a lot you could squeeze out of that 48k of memory !

[pstonbroke]

The reason the solder mask is wrinkled is not that it was applied over wrinkled solder, but rather that it was applied over solder, and then subjected to wave soldering to solder all the through hole components. The solder itself would have been a tin lead plated layer that was used as an initial etch mask, and then IR, or hot oil reflowed. The reason that there is no solder mask at the the top is that there was no soldering done at the top, so it was deemed as not necessary. A cost saving measure, but one that leaves the upper surface of the board at risk from shorts caused by any loose conductive particulate matter.
I remember my own spectrum with some fondness, I applied the 128 upgrade which added not only more memory, but also a grown up sized keyboard, and an all important reset switch. My first attempt at soldering :)

[IanScottJohnston]

Modified my Spectrums back in the day with 27128 eproms to replace the ROM and via a home built eprom programmer / serial-parallel interface. I didn't mind the rubber keys.