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Sinclair ZX Spectrum
128K Plus 2A/B

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The ZX Spectrum 128K +2A was a 128K +3 but the disk drive was replaced by a +2 datacorder and the disk drive controller was taken off. This was made to use the +3 components (the +2 sell more than the +3). A external disk controller (the Amstrad SI-1) can be connected to the +2A expansion port and use the Amstrad external disk drive (the Amstrad FD-1). When this disk controller is plugged in, the "+2A" sign in the start menu is replaced by a "+3". As the +3, +2A can use Centronics printers, use 48K and 128K programs (since they don't use the 128K/+2 RAMdrive). With this model the ZX Interface 1 can't be used. All the peripherals used in the early models must be tested to see if they work with +2A The +2A edge connector is incompatible with 48K edge connector, but a fix board can be made to change it.

A later version as been launched as +2B. The boards havenīt been modified. In the test program (builted in ROM) of the +2B the ROM version shows 4.1 and the menu shows +2A. In the +3 test program the ROM version showed is 4.0 (the +2 didn't have this test program, only the test screen).

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Processor:
-Zilog Z80A running at 3.5Mhz
RAM:

-128K. Paged in 16K chunks.
Storage:

-Cassete tapes at 1200 baud.
-RAM disk
-Amstrad Disk Drive 3"
Firmware:

-16K ZX colour BASIC
-32K +3 Basic
-16K +3 DOS
Screen:

-Text 32x22 16 colors
-Graphics 256x192. Color resolution is 32x22x16
Sound:
-3 channels AY-3-8912 chip
-Beeper
Other:

-Expansion connector
-TV Modulator
-Reset button
-MIDI/RS232
-RGB/peritel monitor
-AUX
-Sound
-Parallel port
-Joysticks SJS1

This page was updated at 03-03-2003