Computers I’ve owned – Sinclair ZX Spectrum

Well it’s been 35 years since the original Sinclair ZX Spectrum was launched so i think it’s only fair to pair homage to it with my latest addition to the Computers i’ve owned section.

I’ve actually owned a few of these, albeit in there original Sinclair incarnation pre Amstrad buy out of the company in 1986 & later the +3 model.  Many people may not know this but now the Amstrad brand is now owned by Sky TV & with it they inherit all the rights to the Sinclair product line. Viglen of course absorbed the computer side of Amstrad as well, although this is it’s PC & Word processor division but i believe the Sinclair name is now still property of Sky itself as they bought out Amstrad mainly to continue development of the TV receiver boxes.

The ZX Spectrum 8-bit (Z80A) computer was released in 1982 by Sinclair Research Ltd. Originally released in 16K and also a 48K version which was the one to have.  The Spectrum evolved through a variety of versions including the Spectrum+ which added a better Sinclair QL style keyboard to the original board following criticism about the rubber key dead flesh feeling keyboard. The + model also featured a reset switch was just a push button which shorted out the circuit board to reset the machine.. basic but it did the job. Also, the 16k model wasn’t transferred with the upgraded keyboard to the Spectrum+ & killed off.  The higher spec (& now rarer) Spectrum 128 (128K RAM), the +2 with fitted tape drive), and +3 which was essentailly identical to the +2 model but came with a 3 inch Amstrad floppy drive instead. Notably, the latter two systems we created by Amstrad & not Sinclair.
The Spectrum is based on a Zilog Z80 A CPU running at 3.5 MHz. The original model had 16 KB (16×1024 bytes) of ROM and either 16 KB or 48 KB of RAM depending on which model you bought although why would you buy the 16k version?   Video is done through a built in RF Modulator – no extenal modulator to use the computer on a TV by converting a monitor output like on similar computers of the era such as the VIC20 etc.  Sound on the original Spectrum was not produced through the TV however, instead the sound was done through an internal bleeper which was basically a small mono headphone type speaker fixed to the main board although if you had the right leads & a TV with an external audio in, you could use the “Ear” port on the unit to send sound to a TV or amplifier, but would you really want to?   The “ear” port can drive headphones as we say but it’s main function was to send save files to a tape recorder and the other port for connecting a domestic tape recorder so you could load from cassette tape.

I bought my 1st spectrum when i was about 16 years old, I bought it from an old college friend for a bargain 2nd hand price of (if i remember correctly) about £35 which at the time was a weeks income to me.  It was an original 48k model with everything included, tape recorder, leads, loads & loads of games on cassette & some original Sinclair software.  I also learned a lot about computer repair from the Spectrum as i was training in electronics at the time & having took the lid off i wanted to know what each part of the computer board was doing.

Later, i then acquired an old 16k model which i upgraded to 48k by installing the additional memory chips Although as time went on the keyboard was not functional, i’d replaced the membrane (which was the common problem) but it seemed to be the plastic casing had warped not allowing for good key contact. As luck would have it i managed to pick up a Spectrum+ 48 which had a good keyboard however the main board was on it’s last legs so i transferred the upgraded 16k board into the 48k keyboard.  The last unit i acquired was an Amstrad variation.  the Spectrum +3 with working disk drive – many of the drives on +3 models were rumoured to fail quite often & it’s sometimes said because Amstrad used the better models for the CPC range or the PCW machines, alhough personally i can’t see any difference & think many of the failures were down to abuse rather than mechanical or electrical gizmo’s failing because the machines were still seen more as a toy than the other Amstrad machines.

There was also the original 128k version which i never owned, mainly as i was put off because the keyboard had a huge heatsink down the side which used to give off lots of heat.. health & safety today probably wouldn’t allow such a thing, however i bet it was nice in winter & saved on the heating bills in those cold 1980’s winters in many schoolboy’s bedrooms.

The +3 was a good machine, however i was a bit limited as i couldn’t find a lead to connect a cassette recorder so i was restricted to the disks i got with the machine & hand programming as the majoity of games etc were still on cassette & usually sold in many high street newsagents & petrol stations for just £1.99 or £2.99 by then. but with a decent keyboard & real computer feel compared to it’s predecessor, programming by hand wasn’t a problem.  Both the Spectrum +2, & +3 had two BASIC modes, the 48k BASIC to remain compatible with the original rubber keyed model & the 128k mode from the 128k with the heatsink.  The +3 however was a close cousin of the CPC464 / CPC664 & CPCP6128 especially in the way it loaded from the disk drive as the spectrum after all was designed to be only used with cassette tapes.

I later discovered that original Spectrum games could be downloaded & played on the Amstrad emailer although these days i mostly use emulation or remakes.

I really could go on for ages talking about the Spectrum & how i cut my teeth in computer repair with it, but i’ll save that for further updates.  I will howeer urge anyone into 8 bit machines to watch the Docudrama “Micro Men” which you can view here.  I will however leave you with a clip above of the programme click which sir Clive tells us how the British computer industry boomed before the market got gobbled up in the consumer world of Microsoft & the likes.

 

 

Leave a Reply

Your email address will not be published. Required fields are marked *