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 +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.
The Spectrum+3 did not sell particularly well in the UK until Currys released this rebranded pack-in box with joystick and six games included.