Replacement:

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Simple steps to replace the keyboard Membrane of the Sinclair ZX Spectrum 128k (heatsink).

• Buy a new Sinclair Spectrum 128k Keyboard membrane.
• Unscrew the eight screws on the bottom.
• Kindly disconnect the keyboard from the connectors on the main pcb.
• Remove the back of the keyboard.
• Unscrew the block that holds the cable.
• Remove the old membrane.
• Clean the keyboard with air-spray and a soft brush.
• Install the new membrane.
• Close the back of the keyboard.
• Very kindly put the block of the flat cable and screw in.
• The keyboard is ready to be connected.
• Very kindly insert the flat cable into the connector.
• Your Sinclair ZX Spectrum 128k is like new.

source: rwapsoftware.co.uk

I thank my dear friend for having found the original power supply of my Sinclair ZX80.

Replacement:

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Simple steps to replace the keyboard Membrane of the Sinclair ZX81. The removal of the old keyboard is not illustrated but it is a very easy job.

• Open the Sinclair ZX81.
• Place the membrane.
• Remove the adhesive protection.
• Place the membrane and press firmly.
• Check the Membrane Connector.
• Gently insert the connectors on the pcb side.
• Close the Sinclair ZX81.
• Enjoy.

source: rwapsoftware.co.uk

Autopsy:

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from Wikipedia:

The Sinclair ZX80 is a home computer brought to market in 1980 by Science of Cambridge Ltd. (later to be better known as Sinclair Research). It is notable for being the first computer (unless one counts the MK14) available in the United Kingdom for less than a hundred pounds (£99.95). It was available in kit form, where purchasers had to assemble and solder it together and as a ready-built version at a slightly higher cost. The ZX80 was very popular straight away, and for some time there was a waiting list of several months for either version of the machine.

Internally, the machine was designed by Jim Westwood around a Z80 central processing unit with a clock speed of 3.25 MHz, and was equipped with 1 kB of static RAM and 4 kB of read-only memory (ROM). The ZX80 was designed around readily available TTL chips; the only proprietary technology was the firmware. While the successor ZX81 used a semi-custom chip (a ULA or Uncommitted Logic Array), this merely combined the functions of the earlier hardware onto a single chip — the hardware and system programs (except the BASIC versions) were very similar, with the only significant difference being the NMI-generator necessary for slow mode in the ZX81. (See ZX81 for technical details.) Both computers can be made by hobbyists using commercially available discrete logic chips or FPGAs.

The ROM contained the Sinclair BASIC programming language, editor, and operating system. BASIC commands were not entered by typing them out but were instead selected somewhat similarly to a scientific calculator – each key had a few different functions selected by both context and modes as well as with the shift key.

The machine was mounted in a tiny white plastic case, with a one-piece blue membrane keyboard on the front; it owed its distinctive appearance to industrial designer Rick Dickinson. There were problems with durability, reliability and overheating (despite appearances, the black stripes visible on the top rear of the case are merely cosmetic, and are not ventilation slots).

source: wikipedia

Autopsy:

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from Wikipedia:

ZX Microdrive

The ZX Microdrive was a magnetic tape data storage system launched in July 1983 by Sinclair Research for its ZX Spectrum home computer. The Microdrive technology was later also used in the Sinclair QL and ICL One Per Desk personal computers.

Microdrives used tiny (44 × 34 × 8 mm including protective cover) cartridges containing a 5-metre (200-inch) endless loop of magnetic tape, 1.9 mm wide, driven at 76 cm/second (30 in/second); thus performing a complete circuit in approximately 8 seconds. The cartridges held a minimum of 85 kB when formatted on a ZX Microdrive (exact capacity depended on the number of “bad” sectors found and the precise speed of the Microdrive motor when formatting). The data retrieval rate was 15 kB/s, i.e., 120 kbit/s. It was possible to “expand” the capacity of a fresh microdrive cartridge by formatting it several times. This caused the tape to stretch slightly, increasing the length of the tape loop so that more sectors can be marked out on it. This procedure was widely documented in the Sinclair community magazines of the 1980s.

ZX Interface 1

A peripheral from Sinclair Research for its ZX Spectrum home computer, the ZX Interface 1 was launched in 1983. Originally intended as a local area network interface for use in school classrooms, it was revised before launch to also act as the controller for up to eight ZX Microdrive high-speed tape-loop cartridge drives. It also included a DE-9 RS-232 interface capable of operating at up to 19.2 kbit/s — a rare instance of Sinclair using an industry-standard connector. At hardware level it was mainly a voltage adapter, the serial protocol being implemented in software by bit-banging. This led to problems when receiving data, but not when transmitting.

A wedge-shaped device fitting underneath the ZX Spectrum, ZX Interface 1 contained 8 kB of ROM comprising the control software for the Microdrives, RS-232 port and network interface. This extended the error handler in the Sinclair BASIC to allow extra keywords to be used. As this became an official standard, other developers quickly used this mechanism to create language extensions to Sinclair BASIC.

Download: ZX Microdrive and Interface 1 Manual (PDF) (1098)

source: wikipedia

Autopsy:

from Wikipedia homepage:

The Timex Sinclair 1000 (TS1000) was the first computer produced by Timex Sinclair, a joint-venture between Timex Corporation and Sinclair Research. It was launched in July 1982.

The TS1000 was a slightly-modified Sinclair ZX81 with an NTSC RF modulator instead of a UK PAL (Units sold in Portugal have a PAL RF modulator) device and the onboard RAM doubled to 2K. The TS1000′s casing had slightly more internal shielding but remained the same as Sinclair’s, including the membrane keyboard. It had black-and-white graphics and no sound. It was followed by an improved version, the Timex Sinclair 1500.

Like the Sinclair ZX81, the TS1000 used a form of BASIC as its primary interface and programming language. To make the membrane keyboard less cumbersome for program entry, the TS1000 used a shortcut system of one-letter “keywords” for most commands (e.g. pressing “P” while the cursor was in “keyword mode” would generate the keyword “PRINT”). Some keywords required a short sequence of keystrokes (e.g. SHIFT-ENTER S would generate the keyword “LPRINT”). The TS1000 clued the user in on what to expect by changing the cursor to reflect the current input mode.

The TS1000 sold for $99.95 in the US when it debuted, making it the cheapest home computer to date at the time of its launch (its advertising angle was “the first computer under $100″.) This pricing initiated a price war with Commodore International, who quickly reduced the price of its VIC-20 to match and later announced a trade-in program offering $100 for any competing computer toward the purchase of a Commodore 64. Since the TS1000 was selling for $49 by this time, many customers bought them for the sole purpose of trading it in to Commodore.

source: wikipedia

Autopsy:

The photos of the inside can be found here.

from Wikipedia homepage:

The ZX81, released in a slightly modified form in the United States as the Timex Sinclair 1000, was a home computer produced by Sinclair Research and manufactured in Scotland by Timex Corporation. It was launched in the United Kingdom in March 1981 as the successor to Sinclair’s ZX80 and was designed to be a low-cost introduction to home computing for the general public. It was hugely successful and more than 1.5 million units were sold before it was eventually discontinued.

The ZX81 found commercial success in many other countries, notably the United States, where Timex manufactured and distributed it under licence and enjoyed a substantial but brief boom in sales. Timex later produced its own versions of the ZX81 for the US market – the Timex Sinclair 1000 and Timex Sinclair 1500. Unauthorised clones of the ZX81 were produced in a number of countries.

The ZX81 was designed to be small, simple, and above all cheap, using as few components as possible to keep the cost down. Video output was to a television set rather than a dedicated monitor. Programs and data were loaded and saved onto audio tape cassettes. It had only four silicon chips on board and a mere 1 kB of memory. The machine had no moving parts – not even a power switch – and used a touch-sensitive membrane keyboard for manual input.

The ZX81′s limitations prompted the emergence of a flourishing market in third-party peripherals to improve its capabilities. Such limitations, however, achieved Sinclair’s objective of keeping the cost of the machine as low as possible. Its distinctive design brought its designer, Rick Dickinson, a Design Council award.

The ZX81 could be bought by mail order in kit form or pre-assembled. In what was then a major innovation, it was the first cheap mass-market home computer that could be bought from high street stores, led by W.H. Smith and soon many other retailers. The ZX81 marked the first time that computing in Britain became an activity for the general public, rather than the preserve of businesspeople and electronics hobbyists. It inspired the creation of a huge community of enthusiasts, some of whom founded their own businesses producing software and hardware for the ZX81. Many went on to play a major role in the British computer industry in later years.

The ZX81′s commercial success made Sinclair Research one of Britain’s leading computer manufacturers and earned a fortune and an eventual knighthood for the company’s founder, Sir Clive Sinclair.

source: wikipedia

Today a friend has donated to me some nice things. Thanks Damiano (Manosoft).

Things that have been donated:

• Sinclair ZX Spectrum +2 Boxed.
• Commodore CD32 Joypad Brand new.
• VIC-20 Expansion Cartridge.
• Commodore C2N old model.
• Joystick Microswitch – The Bug from Cheetah.

Autopsy:

This is the program QL Toolkit for the Sinclair QL home computer written by Tony Tebby (the author of the QDOS and SMSQ/e operating systems) and published by Sinclair on their Silver Label.

QL Toolkit offered a lot of facilities which Tony had originally devised for the original QL QDOS operating system, but which were never released.  It included commands to control jobs, improvements to SAVE and COPY commands, wildcard file handling, and much more.

It also contains a host of example SuperBASIC programs on the microdrive cartridges. It was later to become Toolkit II (or Super Toolkit) which was recognised as the standard toolkit upgrade to the Sinclair QL Home Computer.

Working Sinclair ZX Spectrum 16k for Spare parts.

Autopsy:

source: rwapsoftware.co.uk

Replacement the Sinclair QL membrane and reassemble the Keyboard.

source: rwapsoftware.co.uk

Autopsy:

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from Wikipedia:

The Sinclair QL (for Quantum Leap), was a personal computer launched by Sinclair Research in 1984, as the successor to the Sinclair ZX Spectrum. The QL was aimed at the hobbyist and small business markets, but failed to achieve commercial success.

The QL was originally conceived in 1981 under the code-name ZX83, as a portable computer for business users, with a built-in ultra-thin flat-screen CRT display (similar to the later TV80 pocket TV), printer and modem. As development progressed, and ZX83 became ZX84, it eventually became clear that the portability features were over-ambitious and the specification was reduced to a conventional desktop configuration.

Based on a Motorola 68008 processor clocked at 7.5 MHz, the QL included 128 KB of RAM (officially expandable to 640 KB) and could be connected to a monitor or TV for display. Two built-in Microdrive tape-loop cartridge drives (first seen as a peripheral for the Sinclair ZX Spectrum) provided mass storage, in place of the more expensive floppy disk drives found on similar systems of the era.

Interfaces included an expansion slot, ROM cartridge socket, dual RS-232 ports, proprietary QLAN local area network ports, dual joystick ports and an external Microdrive bus. Two video modes were available, 256×256 pixels with 8 RGB colours and per-pixel flashing, or 512×256 pixels with four colours (black, red, green and white). Both screen modes used a 32 KB framebuffer in main memory.

The hardware was capable of switching between two different areas of memory for the framebuffer, thus allowing double buffering. However, this would have used 64 KB of the standard machine’s 128 KB of RAM and there is no support for this feature in the QL’s original firmware. The alternative and much improved operating system Minerva does provide full support for the second framebuffer.

source: wikipedia

Autopsy:

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from Wikipedia:

Planning of the ZX Spectrum+ started in June 1984, and the machine was released in October the same year. This 48 KB Spectrum introduced a new QL-style case with an injection-moulded keyboard and a reset button.

Electronically, it was identical to the previous 48 KB model. It retailed for £179.95. A DIY conversion-kit for older machines was also available. Early on, the machine outsold the rubber-key model 2:1; however, some retailers reported a failure rate of up to 30%, compared with a more usual 5-6%.

source: wikipedia

Autopsy:

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from Wikipedia:

Sinclair developed the ZX Spectrum 128 (code-named Derby) in conjunction with their Spanish distributor Investrónica. Investrónica had helped adapt the ZX Spectrum+ to the Spanish market after the Spanish government introduced a special tax on all computers with 64 KB RAM or less which did not support the Spanish alphabet (such as ñ) and show messages in Spanish.

New features included 128 KB RAM, three-channel audio via the AY-3-8912 chip, MIDI compatibility, an RS-232 serial port, an RGB monitor port, 32 KB of ROM including an improved BASIC editor, and an external keypad.

The machine was simultaneously presented for the first time and launched in September 1985 at the SIMO ’85 trade show in Spain, with a price of 44,250 pesetas. Because of the large amount of unsold Spectrum+ models, Sinclair decided not to start selling in the UK until January 1986 at a price of £179.95. No external keypad was available for the UK release, although the ROM routines to use it and the port itself, which was hastily renamed “AUX”, remained.

source: wikipedia