8-bit Personal Computer - Dismantled for reference and curiosity
Released in 1982 the Sinclair ZX Spectrum (pronounced zed-x) was the second home computer released from the mind of British inventor and entrepreneur the late Sir Clive Sinclair who founded 'Sinclair Radionics' then later 'Sinclair Research Ltd'. The predecessor of the ZX Spectrum is the Sinclair ZX80 and that was arguably the first affordable home computer released in the United Kingdom.
The ZX Spectrum was extremely popular with both consumers and developers and competed aggressively with the BBC Microcomputer, Commodore 64 and eventually with the Amstrad CPC. The Spectrum was so successful that it's widely accepted to have kicked off the IT industry in the UK and Sir Clive Sinclair was knighted for his contribution to Britain. Interestingly Sir Clive is not a big computer user himself and while his inventions and commitment kicked off a nation's technological revolution, he preferred the more pedestrian approaches and personal forms of communication.
The ZX Spectrum was originally sold in two models, a 16kB and a 48kB version. Consumers who'd purchased the 16kB version could upgrade their Spectrum to the full 48kB or mail their unit back to the manufacturer to have the upgrade done for them.
Of the 16kB versions there are a further two models or 'Issues'; Issue 1 and Issue 2. They are distinguishable by the Issue 1 having light grey keys while the Issue 2's keys are blue grey. If you're unsure the Issue version it's clearly printed on the mainboard; see image five below. The main difference practically is Issue 1 boards could be upgraded to 48kb with the addition of a daughter board while Issue 2 units required eight dynamic RAM chips and a number of transistor–transistor logic (TTL) chips; probably (low voltage) LVTTL however I'll need to confirm that.
One of the endearing features of the Spectrum is its tiny size. At approximately 23×14×3 cm it's one of the smallest yet fully functional home computers to sell well. A key to its size is the lack of joystick ports. These can be added by connecting the ZX Interface 2.
There were a number of official hardware add-ons for the computer, the ZX Printer, ZX Interface 1, ZX Interface 2 and the ZX Microdrive but as is often the case, the third party and unlicensed add-ons offered extra and more useful features than the manufacturer. A good example is the ZX Interface 2 compared to the third party 'RAM Turbo'. The RAM Turbo looks much the same as the ZX Interface 2 however where the latter was not compatible with the 'Kempston interface' the RAM Turbo supported the Kempston and Protek standards and joysticks conforming to the Atari 2600 swtich to wire standard. Both units have a pass-through interface as they occupied the expansion port on the computer and where the Interface 2 only supported use of the ZX Printer, the RAM Turbo's pass-through was fully functional; see separate page in this section for details on the RAM Turbo.
The Sinclair ZX Spectrum is a great little workhorse that rightly deserves the respect it's gained. For a system with limited sound, no native joystick support and a graphics system designed around text rather than images, it's supported with over 1700 software titles and new software is still be created for it today; as of 2011. The system's limitations themselves are challenge enough to encourage enthusiastic developers to push more and more out of an aging yet still extremely reliable system.