Sinclair ZX Spectrum Service Manual

Sinclair ZX Spectrum Service Manual
Spectrum For Everyone https://spectrumforeveryone.com/
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Notes:
• All external RAM ICs must be of the same type (i.e. all -3 or -4 variants)
• LINK 3 on the board (IC26, pin 10) should be fitted if IC15-IC22 are type 4532-3
• LINK 4 should be fitted if IC15-IC22 are type 4532-4
7.3.3 Issue 3 Board
The ICs used on this board are as follows:
IC
Type
IC15-IC22
TI 4532-3 or TI 4532-4 or OKI MSM3732 200ns (or 250ns)
IC23
74LS32
IC24
74LS00
IC25, IC26
74LS157 (NOT National Semiconductors)
Notes:
• All extension RAM ICs must be of the same type.
• Two links must be fitted on the board (grid located between edge connector and mic jack socket)
depending on memory manufacturer and type (high or low enable).

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)