Editing ZX Spectrum (section)

== Amstrad models ==

=== ZX Spectrum +2 {{anchor|plus2}}===
[[file:ZX Spectrum Plus2 (retouched).jpg|thumb|ZX Spectrum +2]]

The ''ZX Spectrum +2'' marked Amstrad's entry into the Spectrum market shortly after their [[Sinclair Research Ltd#Amstrad acquisition|acquisition of the Spectrum range and "Sinclair" brand]] in 1986. This machine featured a brand-new grey case with a spring-loaded keyboard, dual joystick ports, and an integrated cassette recorder known as the "Datacorder," akin to the [[Amstrad CPC 464]]. The ROM was updated so that the screen on boot-up showed an Amstrad copyright message (''© 1986 Amstrad'' in place of the previous ''© 1982 Sinclair Research Ltd''). However, it was largely identical to the ZX Spectrum 128 in most technical aspects. The machine retailed for £149.{{sfn|Phillips|1986|p=47}}

The new keyboard did not feature the BASIC keyword markings seen on earlier Spectrums, except for the keywords <code>LOAD</code>'','' <code>CODE</code>'','' and <code>RUN</code>'','' which were useful for loading software. Instead, the +2 introduced a menu system, almost identical to that of the ZX Spectrum 128, allowing users to switch between 48K BASIC programming with keywords and 128K BASIC programming, where all words, both keywords and others, needed to be typed out in full (though keywords were still stored internally as one character each). Despite these changes, the layout remained identical to that of the 128.<ref name="Goodwin-145" />

=== ZX Spectrum +3 {{anchor|plus3}}===
[[file:ZX Spectrum Plus3.jpeg|thumb|ZX Spectrum +3]]
The ''ZX Spectrum +3'', which was launched in 1987, bore a resemblance to its predecessor but introduced a built-in 3-inch [[floppy disk]] drive instead of the cassette drive. Initially priced at £249,<ref name="South">{{Cite journal |last= South |first= Phil |date= July 1987 |title= It's here... the Spectrum +3 |journal= [[Your Sinclair]] |issue= 17 |pages= 22–23 |url= http://www.worldofspectrum.org/showmag.cgi?mag=YourSinclair/Issue19/Pages/YourSinclair1900022.jpg |access-date= 5 August 2008 |archive-date= 9 August 2012 |archive-url= https://web.archive.org/web/20120809145932/http://www.worldofspectrum.org/showmag.cgi?mag=YourSinclair/Issue19/Pages/YourSinclair1900022.jpg |url-status= live }}</ref> it later retailed for £199.<ref name="sincuser-68">{{Cite journal |author= Amstrad |date= November 1987 |title= The new Sinclair has one big disk advantage |journal= [[Sinclair User]] |issue= 68 |pages= 2–3 |url= http://www.worldofspectrum.org/showmag.cgi?mag=SinclairUser/Issue068/Pages/SinclairUser06800002.jpg |access-date= 5 August 2008 |author-link= Amstrad |archive-date= 25 August 2012 |archive-url= https://web.archive.org/web/20120825201005/http://www.worldofspectrum.org/showmag.cgi?mag=SinclairUser/Issue068/Pages/SinclairUser06800002.jpg |url-status= live }}</ref> It was the only Spectrum model capable of running the [[CP/M]] operating system without additional hardware. Unlike its predecessors, the ZX Spectrum +3 power supply utilised a DIN connector and featured "Sinclair +3" branding on the case.<ref>{{cite web|url=http://www.yorkdistribution.co.uk/acatalog/Power-supply-for-Spectrum-128---2A---3-PS_SPE3.html|title=Power supply for Spectrum 128, +2A, +3|publisher=York Distribution Limited|access-date=21 December 2012|url-status=dead|archive-url=https://web.archive.org/web/20160829065203/http://www.yorkdistribution.co.uk/acatalog/Power-supply-for-Spectrum-128---2A---3-PS_SPE3.html|archive-date=29 August 2016}}</ref>

Significant alterations caused a series of incompatibilities, such as the removal of several lines on the expansion bus edge connector. This resulted in complications for various peripherals. Additionally, changes in memory timing led to certain RAM banks being contended, causing failures in high-speed colour-changing effects. The keypad scanning routines from the ROM were also eliminated, rendering some older 48K and 128K games incompatible with the machine. The ZX Interface 1 was also rendered incompatible due to disparities in ROM and expansion connectors, making it impossible to connect and use the Microdrive units.<ref name="Goodwin-145">{{Cite magazine| last= Goodwin |first= Simon |date=December 1987 |title= Tech Tips – +3 Faults |magazine= [[Crash (magazine)|Crash]] |issue= 48 |page= 145 |url=https://archive.org/details/Crash_Magazine_048b/page/144|access-date=24 April 2024}}</ref>

Production of the +3 was discontinued in December 1990, reportedly in response to Amstrad's relaunch of their CPC range, with an estimated 15% of ZX Spectrums sold being +3 models at the time. The +2B model, the only other model still in production at this point, continued to be manufactured, as it was believed not to be in direct competition with other computers in Amstrad's product range.<ref>{{cite news|title=Amstrad Kills Plus 3|url=https://archive.org/stream/crash-magazine-82/Crash_82_Nov_1990#page/n19/mode/2up|access-date=6 March 2018|work=Crash|issue=82|publisher=Newsfield|date=November 1990}}</ref><ref>{{cite news|title=Death Of The +3|url=https://archive.org/stream/your-sinclair-60/YourSinclair_60_Dec_1990#page/n9/mode/2up|access-date=6 March 2018|work=Your Sinclair|issue=60|publisher=Future Publishing|date=December 1990|url-status=live|archive-url=https://web.archive.org/web/20160610135431/http://archive.org/stream/your-sinclair-60/YourSinclair_60_Dec_1990#page/n9/mode/2up|archive-date=10 June 2016}}</ref>

=== ZX Spectrum +2A, +2B and +3B ===
[[file:Spectrum 128-2 (retouched).jpg|thumb|ZX Spectrum +2A]]

The ZX Spectrum +2A was a new version of the Spectrum +2<ref name='crashfeb89'>{{cite magazine|title=Dishy New Spectrum in Sex Scandal|magazine=Crash|issue=26|publisher=Newsfield|date=26 January 1989|page=9|url=https://spectrumcomputing.co.uk/page.php?issue_id=1028&page=7|access-date=26 November 2022}}{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> using the same circuit board as the Spectrum +3.<ref name='crashfeb89' /><ref name='nce101288'>{{cite magazine|title=Amstrad again|magazine=New Computer Express|issue=5|publisher=Future Publishing|date=10 December 1988|page=55|url=https://spectrumcomputing.co.uk/page.php?issue_id=4777&page=55|access-date=26 November 2022|archive-date=8 August 2020|archive-url=https://web.archive.org/web/20200808064929/https://spectrumcomputing.co.uk/page.php?issue_id=4777&page=55|url-status=dead}}</ref> It was sold from late 1988 and unlike the original grey +2 was housed inside a black case.<ref name='crashfeb89' /><ref name='nce101288' /> The Spectrum +2A/+3 motherboard (AMSTRAD part number Z70830) was designed so that it could be assembled with a +2 style "datacorder" connected instead of the [[floppy disk controller]].<ref name="+3-Manual-18">''Spectrum +3 Service Manual''. AMSTRAD. p.18.</ref> The power supply of the ZX Spectrum +2A used the same [[pinout]] as the +3 and has "Sinclair +2" written on the case.<ref name="Fuente+2A">{{cite web|url=http://hardware.speccy.org/hardware/Fuente+2A/imagenes/vista_superior.jpg|title=Image of Spectrum +2A power supply|access-date=21 December 2012|url-status=live|archive-url=https://web.archive.org/web/20130430080452/http://hardware.speccy.org/hardware/Fuente+2A/imagenes/vista_superior.jpg|archive-date=30 April 2013}}</ref>

1989 saw the release of the ZX Spectrum +2B and ZX Spectrum +3B. They are functionally similar in design to the Spectrum +2A and +3,<ref>''Spectrum +2B/+3B Service Manual''. AMSTRAD.</ref> though changes to the generation of the audio output signal were made to resolve problems with [[Clipping (audio)|clipping]].<ref name='nce090989'>{{cite magazine|title=Spex – Sounding Out|magazine=New Computer Express|issue=44|publisher=Future Publishing|date=9 September 1989|page=54|url=https://spectrumcomputing.co.uk/page.php?issue_id=4816&page=54|access-date=26 November 2022}}{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> The +2B board has no provision for floppy disk controller circuitry, while the +3B motherboard has no provision for connecting an internal tape drive. Production of all Amstrad Spectrum models ended in 1992.<ref name="bbclegacy" />