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ZX Spectrum

Informations common to all ZX Spectrum models and clones.

Hardware failures

when ROM has only 255 values

You will see such picture when ROM is removed, damaged or the chip used as a ROM is empty (filled with bytes of 255). In Timex the picture is stable. On ZX Spectrum the border is usually white and you may notice dinamic snowing, when ROM is not present. The vertical lines can jump by one character cell left or right after repeated reset.

ROM0 of ZX128 cannot switch to ROM1

This picture you can see on ZX Spectrum 128K, when the code in ROM0 tries to switch to ROM1, but fails on that (and continues still on ROM0).


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Files for download

zxsbus6sk.jpg 44.3kB (2006-02-06 13:45)
A picture that shows differences in edge slot in ZX48, ZX128, ZX+2, ZX+2A and ZX+3.
emptyrom.gif 1.9kB (2004-02-05 00:02)
What is seen when the ROM is empty (filled with #FF). Taken from Timex 2048, in ZX Spectrum the border is usually white and flickers apper.
floatspy.zip 2.6kB (2002-09-29 19:39)
Program for testing the ULA timing and properties. TAP format.

See also

Sinclair ZX Spectrum 48kB
Sinclair ZX Spectrum 16kB/48kB.
Sinclair ZX Spectrum+ 128K
Technical notes and simple upgrades for Sinclair ZX Spectrum+ 128K model.
Byte (Bajt)
Byte (Bajt). Russian ZX Spectrum 48kB clone with extended keyboard and 8253 sound generator.
Elwro 800 Junior
Elwro 800 Junior - ZX Spectrum clone produced in Poland. Also works under CP/M 2.2 (CP/J) with access to disk drive via a network.
Orizon-Micro
Russian ZX Spectrum clone.
Sinclair ZX Spectrum +2
Description of Sinclair ZX Spectrum +2 model, equiped with datarecorder.
ZX Spectrum +3
ZX Spectrum +3.
Timex Computer 2048
Timex Computer 2048. Most popular na Portugal and Poland.
Timex Computer 2068
Timex Computer 2068.
Timex Sinclair 2068
Timex Sinclair 2068. Produced in 1983/84 for USA and Canada markets.
ZX Spectrum SE
A virtual ZX Spectrum model, that supports both ZX Spectrum 128K and Timex DOCK/EXROM functionality. Beside, the BASIC is corrected.
Sam Coupé
The Sam Coupé computer by MGT.

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Commodore
Amiga
MSX
SVI 738
Spectrum
16kB/48kB
128kB
+3
Byte
Elwro Junior
Orizon-Micro
Sam Coupé
SE
TC 2048
TC 2068
TC 3256
TS 2068
UK 2086
Timex
FDD 3
FDD 3000
68008
QL
8080
Elwro 500
MK 45
Z80
Amstrad CPC
Bosman 8
Jet 80
MDG-1
ZX Spectrum
ZX81

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© 2009-12-28 21:50 Jarek Adamski, http://8bit.yarek.pl