Archive for the ‘Sinclair family’ Category

Sinclair Microvision MTV1B

April 6th, 2016 No comments

This is a Sinclair Microvision MTV1B. It’s the second attempt of Clive Sinclair’s to make a small portable television.

Released in 1978, it was the smallest television in the world with a CRT tube. A teeny-tiny 2″ D5-100w CRT made by Telefunken. Powered by 4 x AA or via External Powersupply at 6v DC (Negative at the center of the power connector).


Download: Sinclair Microvision MTV1B Schematics (698)

A new donation from Simone B.

September 29th, 2014 No comments

I thank Simone B. for the donation. The donation was made through the Blog.

Donated item:

  • Sinclair Spectrum 128k +2a – Boxed (Black version)
  • Sinclair Spectrum 128k +2  – Boxed (Grey version)

Micro Peripherals Ltd Floppy Disk Interface for Sinclair QL

August 16th, 2014 2 comments


This is a disk interface system made by Micro Peripherals Ltd which was later badged by Sinclair as their “official” disc system.

It used its own software (written by Richard Miller) and did not conform to the QJump “FLP” system used by most companies at the time (it used the name FDK to access the disk drives). The fact that the device name was not “FLP” put a lot of users off. The unit does not support direct sector access.

The interface had an 8K onboard EPROM providing the device driver and toolkit extensions, which included:

  • DGET – Load sector into an array
  • DPUT – Save an array to a sector
  • MSET, FSET – Toggle microdrive emulation mode
  • VSET – Rename the disk device (the interface normally uses the drive name FDK rather than the FLP used by most other QL disk systems)

Plus several other extensions similar to those in other disk interfaces, and some utility programs such as a disk and memory editor were supplied on disk.

The interface was supplied with either one, or a pair of DSDD 720KB drives, the first of which took its power from an external transformer via a 6-way power connector, and the second took its power from the DC output of the first drive via a 5-way connector, plus a ribbon connector from one drive to the other.

The interface had switch-selectable options via a series of jumpers to format single or double sided, and 3ms or 6ms track to track time. Another jumper could be set to make the QL boot from an ‘mdv’ named disk.

Powersupply Pinout:



A new donation from Fabio B. (Frater Sinister)

August 1st, 2014 No comments

I thank Fabio B. (Frater Sinister) for the donation.

Donated item:

  • 1 x Sinclair ZX Spectrum 48k
  • 1 x Sinclair ZX Spectrum + PSU (50% Boxed)
  • 1 x Sinclair Thermal Printer
  • 1 x Sinclair ZX Interface 1
  • 4 x Sinclair Microdrive Boxed
  • 1 x Interface Midi Master for Amiga 500/2000
  • 1 x Vic-20 Cartridge VIC-1941 (Number Nabber / Shape Grabber)
  • 1 x Vic-20 Cartridge VIC-1922 (Cosmic Cruncher)
  • 1 x Harey Alien Invaders Handheld game
  • 4 x IC Motorola 68000
  • 1 x IC MOS 5719 (Amiga Gary)
  • 2 x IC CGS 5719 (Amiga Gary)
  • 3 x IC CGS 8362 (Amiga Super Denise)
  • 1 x IC CGS 8364 (Amiga Paula)
  • 2 x IC MOS 8364 (Amiga Paula)
  • 5 x IC CGS 8520 (Amiga CIA)
  • 1 x IC MOS 8520 (Amiga CIA)
  • 2 x IC Amiga Kickstart ROM v1.3

Z88 Cambridge Computer

June 5th, 2014 No comments
Z88 Cambridge Computer (close-up)

I thank my dear friend that gave me the Z88 Cambridge Computer.


The Cambridge Computer Z88 is an A4-size, lightweight, portable Z80-based computer with a built-in combined word processing/spreadsheet/database application called PipeDream, along with several other applications and utilities, such as a Z80-version of the BBC BASIC programming language.

The Z88 evolved from Sir Clive Sinclair’s Pandora portable computer project which had been under development at Sinclair Research during the mid-1980s. The machine was launched at the Which Computer? Show on 17 February 1987.

The Z88 is a portable computer weighing 0.9 kg, based on a low-power CMOS version of the popular Zilog Z80 microprocessor. It comes with 32 KiB of internal pseudo-static RAM and 128 KiB of ROM containing the operating system (called OZ). The memory can be expanded up to 3.5 MiB of RAM, the contents of which are preserved across sessions. An integrated capacitor prevents the Z88 from losing its data for the limited amount of time it takes to change the batteries.

The machine uses a membrane keyboard, which is almost silent in use; an optional electronic “click” can be turned on to indicate keystrokes. The Z88 is powered by four AA batteries, giving up to 20 hours of use. It has three memory card slots, which accommodate proprietary RAM, ROM or EPROM cards, the third slot being equipped with a built-in EPROM programmer. Card capacities range from 32 KiB to 1 MiB.

The Z88 has a built-in eight-line, “super-twisted” LCD display, which has greater contrast than conventional twisted nematic LCDs.

source: wikipedia

Memory Expansion Spem EXP-MEM 512k for Sinclair QL

April 18th, 2014 8 comments
Spem EXP-MEM 512k for Sinclair QL

I thank my dear friend that gave me the Spem EXP-MEM 512k.


Various companies offered to upgrade your QL with an internal memory upgrade. This was normally 512K, but some companies also offered a 256K version.

The method of upgrade was in two ways:

  • Removal of the existing QL memory chips and replacement to give a total of 512K
  • An internal board, which connects to the 8301 ULA socket, and has a wire to the 68008 processor.

The downside of this method of upgrading the QL’s memory was:

  • The memory access was slower than external memory
  • You could not use some of the later QL expansions, such as the Trump Card which themselves had memory built into the interface.

Internal interfaces were advertised by a range of companies, including CST, MicroPeripherals and Silicon Express.

source: Sinclair QL Computer Wiki

Repaired a Sinclair ZX-80 that has certainly seen better days

December 16th, 2013 1 comment
Sinclair ZX-80 that has certainly seen better days

Gallery of repair and cleaning:

This computer is arrived for a repair from a friend. The defect is the classic Black Screen of Death and also the PCB has certainly seen better days.

Defects found:

  • Short circuits.
  • Tracks interrupted or broken.
  • Tracks partially raised.
  • Jumpers with flying leads.
  • Some components are partially unsoldered and soldered to other components.


  • Rebuild all the tracks interrupted or partially raised.
  • Arrangement of all components removed or partially unsoldered.
  • Removing flying jumpers
  • Replaced CPU Zilog Z80
  • Replaced a RAM 2114
  • Replaced a Multiplexer 74LS157
  • Replaced the ZX-81 Rom with a Eprom 2532 with programmed the ZX-80 Rom.


  • Composite video output (simple version without Transistor). It was made only to make easiest the repair.

Sinclair ZX Spectrum +2A James Bond 007 Action Pack

November 20th, 2013 1 comment
Sinclair ZX Spectrum +2 James Bond 007 Action Pack


The ZX Spectrum +2A was Amstrad’s first Spectrum, coming shortly after their purchase of the Spectrum range and “Sinclair” brand in 1986. The machine featured an all-new grey enclosure featuring a spring-loaded keyboard, dual joystick ports, and a built-in cassette recorder dubbed the “Datacorder” (like the Amstrad CPC 464, but was otherwise identical to the ZX Spectrum 128 in looks. Production costs had been reduced and the retail price dropped to £139–£149
The machine was built in Taiwan (making it the first Sinclair product built outside the UK) and Amstrad’s greater emphasis on quality control made it far more reliable than the first Spectrums.
Amstrad also took a very different line in marketing the ZX Spectrum +2A. Unlike Sinclair, Amstrad did not attempt to market the Spectrum as anything other than a games machine and sold it in packages such as the “James Bond 007 Action Pack” (with bundled games and a light gun). This approach was extremely successful, and the ZX Spectrum +2A sold very well.

The gun connects to the BT style serial ports on the 128K versions of the Sinclair ZX Spectrum, and allows you to point the gun at your TV screen – the programs then interpret the position of the gun on the screen when you press the trigger, giving you the feel and action of using a real gun to hit targets.


Sinclair Spectrum Break – Recovering & Repair *updated*

November 15th, 2013 1 comment
Sinclair Spectrum Break - Recovering & Repair

This gallery shows some stages of the repair of the Sinclair Spectrum 48k.

Defects found on the Sinclair Spectrum #1:

  • Black Screen of Death/Garbage Screen.

Components replaced:

  • 8 x 4116 RAM
  • 1 x Z80 CPU
  • Extra:
    • Composite Video

Defects found on the Sinclair Spectrum #2:

  • There are no colors.

Components replaced:

  • 5 x Electrolytic Capacitors 22uf / 16v
  • 1 x SN94459 (LM 1889) Tv video Modulator IC with Chroma Reference Signal (Color)

Defects found on the Sinclair Spectrum #3:

  • Jaundice problems.


  • Calibration of Trimmer (VR2)

Defects found on the Sinclair Spectrum #4:

  • Black Screen of Death.

Components replaced:

  • 1 x RAM TMS4532
  • 1 x Transistor ZTX650
  • Extra:
    • Composite Video
    • Conversion from Spectrum (Issue 2) To Spectrum +

Defects found on the Sinclair Spectrum #5:

  • Garbage Screen and high absorption on the 12v line and 0v (ground) with explosion of the transistors ZTX-650 (651) and ZTX-213

Components replaced:

  • 1 x Zener 5v1
  • 12 x Electrolytic capacitors
  • 3 x 4116 RAM (two of these in total short circuit between pin 8 and 16)
  • 8 x OKI 3732 RAM
  • 1 x Sinclair ROM
  • 1 x 74HCT(LS)32
  • 1 x Transistor ZTX-213
  • 1 x Transistor ZTX-650
  • Extra:
    • Composite Video
  • Info:
    • About the explosion of the transistors i have isolated the problem, are the ram (LOW).

      The bad way used some years ago was cut the pin 8 of the all 4116 ram to isolate the bad one, in this case, i didn’t cut the pins of the ram, but i have cut the track of 12v which is part of all the 4116 ram, doing so, the transistor ZTX650(651) doesn’t explode.

      At this point there is a short in one or more RAM between +12 and 0v. I have measured the absorption where i have cut the track and it absorbs too much.

      I just have to unsolder the pin 8 of the 4116 ram and trying to isolate it for find which ram is short-circuited.

  • …it was not over:
    • When the repair is finished and i have replaced all OKI 3732 RAM with a new one, another IC has decided to die, a 74HC(LS)32. I have no words.

Defects found on the Sinclair Spectrum #6:

  • Faulty / AutoLoad.

Components replaced:

  • 1 x TMS 4532 RAM
  • Extra:
    • Composite Video

Sinclair Spectrum Faulty / AutoLoad Video:

Small and Convenient retro-keychain

November 5th, 2013 No comments
Small and Convenient retro-keychain

Small and Convenient retro-keychain.

Sinclair FTV1/B Boxed Mint Condition

October 26th, 2013 2 comments
Sinclair FTV1/B (front side)


You can use any power supply with 6v / 1.5 amp with the polarity described below:

Polarity is positive + on the outside or barrel and negative - on the inside or tip

from Wikipedia and The National Valve Museum homepage:

The Sinclair TV80, also known as the Flat Screen Pocket TV or FTV1, was a pocket television launched by Sinclair Research in 1984. Unlike Sinclair’s earlier attempts at a portable television, the TV80 used a flat CRT with a side-mounted electron gun instead of a conventional CRT; the picture was made to appear larger than it was by the use of a Fresnel lens.

The set has a 2 in. screen, measures 5= x 3= x 1< in. and weighs 9= oz. A special Polaroid flat battery that provides 15 hours’ operation has been produced to power it — there’s also a mains adaptor. The set itself goes on sale at #79.95, with the 6V Polaroid lithium batteries in packs of three at #9.95 per pack and the adaptor at #7.95, all prices inclusive of VAT, postage and packing. Normal retail and export sales are expected to start during the first half of 1984. Sir Clive Sinclair predicts sales rising to a million or more a year worldwide, and speaks of the set ‘achieving for television what the transistor radio did for wireless, creating a new one-per-person product’.

The set has some interesting technical features. It is for example a multi-standard receiver with automatic switching between most UHF standards worldwide except for France. Most of the circuitry is contained within a single ic that uses innovative digital techniques to monitor the vision and sound signals and adjust the circuitry automatically to suit the transmission standard. The ic was jointly developed by Ferranti and Sinclair Research and is being produced by Ferranti. Manufacture of the flat-screen tube (the gun is mounted to one side and the phosphor is deposited on the rear section of the viewing part) has been subcontracted to Timex in Dundee, using Sinclair designed and owned automatic plant. Assembly of the sets has been subcontracted to Thorn.

Apart from the tube and the ic, the main electronic items consist of the video output transistor, line and field output stages, the tube power supply generator and the tuner. The latter measures just 31 x 23 x 11 mm and uses hybrid microminiature components with advanced surface mounting. It’s output is at 230 MHz, which has been chosen to avoid image frequency problems in the UHF band.

It was a commercial failure, and did not recoup the £4m it cost to develop; only 15,000 units were sold. New Scientist warned that the technology used by the device would be short-lived, in view of the liquid crystal display technology being developed by Casio.

Download: Service Manual Sinclair FTV1 & FTV2 (1104)


source: wikipedia

Restoration and Repair of a Sinclair Spectrum 128k +2A Arabic Version

August 11th, 2013 4 comments
Sinclair Spectrum 128k +2A (Black) Arabic Version


This is the translation of the Arabic boot screen:

© 1987, 1988 Sinclair of Egypt
presented by Matsico Corp, an authorized dealer of Sinclair & Amstrad in Egypt
prepared by Dr. Nabil Nazmi
(Version 3)

The computer is arrived in pitiful condition. The inside of the computer and the keyboard were are full of sand and dirt.

Restoration and repairs that have been made:

  • Replaced the top case with a new one.
  • Replaced the bottom case with a new one, then replaced again with the old one to keep the original appearance. (the hole for the switch is standard in the Arabic version)
  • Replaced the tape recorder.
  • Replaced the motherboard with a issue #2 instead of issue #1 (was not convenient the repair)
  • Cleaned all keys and membrane.
  • Replaced all rusty springs of the keyboard.
  • General cleaning.
  • Moved the ROM/EPROM mod on the new motherboard.
  • Replaced the original switch with a new one, then replaced again with the old one to keep the original appearance.

from Wikipedia:

The ZX Spectrum +2 was Amstrad’s first Spectrum, coming shortly after their purchase of the Spectrum range and “Sinclair” brand in 1986. The machine featured an all-new grey case featuring a spring-loaded keyboard, dual joystick ports, and a built-in cassette recorder dubbed the “Datacorder” (like the Amstrad CPC 464), but was in most respects identical to the ZX Spectrum 128. The main menu screen lacked the Spectrum 128′s “Tape Test” option, and the ROM was altered to account for a new 1986 Amstrad copyright message. These changes resulted in minor incompatibility problems with software that accessed ROM routines at certain addresses. Production costs had been reduced and the retail price dropped to £139–£149.

The new keyboard did not include the BASIC keyword markings that were found on earlier Spectrums, except for the keywords LOAD, CODE and RUN which were useful for loading software. This was not a major issue however, as the +2 boasted a menu system, almost identical to the ZX Spectrum 128, where one could switch between 48k BASIC programming with the keywords, and 128k BASIC programming in which all words (keywords and otherwise) must be typed out in full (although the keywords are still stored internally as one character each). Despite these changes, the layout remained identical to that of the 128. The ZX Spectrum +2 power supply was a grey version of the ZX Spectrum+ and 128 power supply.

The ZX Spectrum +2A was a variant of the Spectrum +3 housed a black version of the Spectrum +2 case mouldings. The Spectrum +2A/+3 motherboard (AMSTRAD part number Z70830) was designed such that it could be assembled without the floppy disk controller or associated logic and a +2 style “datacorder” connected. Originally, Amstrad planned to introduce an additional disk interface for the +2A/+2B called the AMSTRAD SI-1, however this never appeared. If an external disk drive was added, the “+2A” on the system OS menu would change to a +3.

The power supply of the ZX Spectrum +2A used the same pinout as the +3. However, the power supply purchased with the +2A/B had “Sinclair +2″ written on the case.

source: wikipedia

Some spare parts from a Friend

July 21st, 2013 No comments

I have received from a friend a couple of components that can be used as spare parts for the repairs. Thanks Andrea.

Close-up description:

  • 1 x Commodore CBM 4040 Dual Floppy Disk Drive PCB
  • 1 x Commodore CBM 8050/8250 Dual Floppy Disk Drive PCB
  • 2 x Texas Instruments TI-99/4A PCB
  • 1 x Main powersupply of Commodore CBM 4040/8050/8250 Dual Floppy Disk Drive.
  • 1 x Sinclair ZX Spectrum+
  • 1 x Sony HB-10P MSX

Sinclair ZX81 Reverse mod Fix and a working Composite Mod

May 12th, 2013 No comments

I have disabled the mod to make the screen in reverse (white chars on black background), i have also made the composite mod with the right resistor value for the best quality video output.

Replace Sinclair ZX Spectrum 128k (heatsink) Keyboard membrane

May 11th, 2013 2 comments
Buy a new Sinclair Spectrum 128k new Keyboard membrane


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.