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Sinclair ZX Spectrum +3

The ZX Spectrum +3 looked similar to the +2 but featured a built-in 3-inch floppy disk drive (like the Amstrad CPC 6128) instead of the tape drive, and was in a black case. It was launched in 1987, initially retailed for £249 and then later £199 and was the only Spectrum capable of running the CP/M operating system without additional hardware.

The machine was a fairly big redesign over the +2, with new ports added, or changed. Probably the biggest difference was to the rear of the machine, which now sported an all new interface port for a printer and also for the allowance of a second disk drive.

Gone was the keypad port, Amstrad had never supported this with the +2, and even Sinclair had only released this officially in Spain, it was replaced by an auxiliary port, which was used by such things as the Cheetah light gun.

The RS232 socket was retained, and because the machine now required more power, and different voltage lines, a larger PSU, and a DIN socket on the machine were needed, this larger plug did prevent some peripherals from being attached. In addition to the handling the music and FX out of the machine, the sound socket now also allowed a cassette deck to connect, to load games from tape. The RF socket remained unchanged.

The left side of the machine also remained the same and contained the two Sinclair joystick ports and the reset button.

The disk drive uses 3.0 disks, not the industry standard 3.5, these disks and drive loaded quickly, and were reasonably reliable. In recent years, the drive belts perished, leaving a sticky residue on the capstans, this needed to be removed carefully, and a new belt fitted, great care must be taken not to lose the drive pin, if this happens the drive is left permanently in write mode.

The +3 saw the addition of two more 16 KB ROMs, now physically implemented as two 32 KB chips. One was home to the second part of the reorganised 128 ROM and the other hosted the +3's disk operating system. This was a modified version of Amstrad's AMDOS, called +3DOS. To facilitate the new ROMs and CP/M, the bank-switching was further improved, allowing the ROM to be paged out for another 16 KB of RAM.

Almost all +3 machines have a sound fault, due to a component being left off the board, which means the sound is distorted and clips.

The only models not to have the problem contain the 270835 motherboard, and only seem to appear in Spain.

Unfortunately for Amstrad, the machine's high cost, and games costing on average five pounds more on disk, sales of the computer and software were low, those who did buy the machine were happy enough to load cassette games in through the sound socket.

Manufacturer: Sinclair
Date: 1st June 1987



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Sinclair ZX Spectrum +3 Manuals:

Item Manufacturer Date
A Course in BASIC Programming - ZX80 Operating Manual Science of Cambridge 1980
Disk Interface Manual (Technology Research) Technology Research 1984
Sinclair - ZX Spectrum Servicing Manual Sinclair Jan 1984
Sinclair ZX Spectrum +2 Manual Sinclair 1986
Spectral Manual (East German ZX Spectrum Clone) Hübner Elektronik 1988

Sinclair ZX Spectrum +3 Articles:

Item Manufacturer Date
Memories - The Tatung Einstein (1) Unknown
Memories - My History of Computing - From a School Teacher Feb 2009

Other Systems Related To Sinclair ZX Spectrum +3:

Item Manufacturer Date
Prototype of MK14 Sinclair 1977
Science of Cambridge MK 14 + Original Keyboard Sinclair 1977
Science of Cambridge MK 14 - Original Kit Sinclair 1977
Science of Cambridge MK14 + Memory Expansion in wooden case Sinclair 1977
Science of Cambridge MK14 Sinclair 1977
Sinclair ZX80 8K Basic Sinclair 1980
Sinclair ZX81 with Basic EPROM Sinclair 1980
Sinclair ZX80 Prototype PDZ 4732 Basic ROM - Nine Tiles Sinclair 1980
Sinclair ZX80 Updated to ZX81 Sinclair 1980
Sinclair ZX80 Sinclair 1st June 1980
Sinclair ZX81 Kit Sinclair 1981
Sinclair ZX Spectrum Prototype Sinclair 1981
Sinclair ZX81 Issue One Sinclair 1981
Sinclair ZX81 - Signed by Rick Dickinson Sinclair 5th March 1981
Sinclair ZX81 with Custom Case/Keyboard Sinclair 5th March 1981
Argentinian Sinclair Spectrum Sinclair 1982
Sinclair Spectrum with Homemade Keyboard Sinclair 1982
White Replica ZX Spectrum (Millionth Edition) Sinclair 1982
Early Sinclair ZX Spectrum Computer Sinclair 1982
Timex Sinclair 1000 Sinclair 1982
Sinclair ZX Spectrum Console Sinclair 1982
Sinclair ZX Spectrum Console Sinclair 1982
ZX Spectrum Issue 2 With ULA Modification Sinclair 1982
Timex Sinclair 1500 Sinclair 1982
Sinclair ZX Spectrum Case (Signed) Sinclair 1st March 1982
Sinclair ZX Spectrum 48k Sinclair 1st March 1982
Sinclair ZX Spectrum 16K Sinclair 1st March 1982
Sinclair ZX Spectrum Computer - Early Issue Sinclair 23rd April 1982
Sinclair QL + SchÖn Keyboard Sinclair 1984
Investronica Sinclair Spectrum Sinclair 1984
Sinclair QL (German) Sinclair 1984
Sinclair QL (Signed) Sinclair 1984
Sinclair QL (US) Sinclair 1984
Sinclair QL (Property of Sinclair) Sinclair 1984
Sinclair QL Sinclair 1984
Sinclair ZX Spectrum+ Sinclair 1st June 1984
Sinclair ZX Spectrum +2 Sinclair 1986
Sinclair ZX Spectrum 128 Sinclair January 1986
Cambridge Z88 All In One Pack Sinclair 1987
Cambridge Z88 Sinclair 1987
Sinclair ZX Spectrum +3 (Currys Box) Sinclair 1st June 1987
Sinclair PC200 Sinclair 1988
Cambridge Z88 With PC Link Kit Sinclair 1988

This exhibit has a reference ID of CH509. Please quote this reference ID in any communication with the Centre for Computing History.

 

Sinclair ZX Spectrum +3

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