Sinclair ZX Spectrum User Manual

Chapter 3
19
all later issues the additional RAM was housed directly onboard the main PCB). If a
daughter board is not visible but three thick tracks with about a dozen thinner tracks
beyond them running behind the length of the expansion bus can be seen then the
Spectrum is an issue 1 (all subsequent models have ICs present here instead).
The location to fit the wire link inside an issue 1 Spectrum is shown in the following
photograph:
Luminance wire link position in issue 1 Spectrum
The location to fit the wire link inside an issue 2 Spectrum is shown in the following
photograph:
Luminance wire link position in issue 2 Spectrum
In both cases, the wire link should be fitted between the two holes marked with a
white line and labelled ‘Y’.
Fit wire
link here
Fit wire
link here

Sinclair ZX Spectrum Specifications

General

Processor	Zilog Z80A
Clock Speed	3.5 MHz
RAM	16KB or 48KB
ROM	16KB
Graphics	256 x 192 resolution
Sound	1-channel beeper
Storage	Cassette tape
Input	Keyboard
Power	9V DC
Release Year	1982
Display	TV via RF modulator
Ports	Expansion, RF
Colors	15 (8 colours with two levels of brightness each, plus black)