1. INTRODUCTION
1.1 Test Equipment
Section 4 is intended as a guide to fault diagnosis and repair of the ZX
SPECTRUM. It is assumed that users have a reasonable knowledge of
electronic servicing, theory and standard fault-finding techniques and
have access to the test equipment and tools required to carry out the
task. The table below contains a list of the minimum recommended test
equipment and materials.
EQUIPMENT
Oscilloscope with
Oscilloscope probe (xlO)
Variable power supply unit
Mono
cassette
recorder
Mains extension lead
Multimeter
Colour Television
ZX
Printer
ZXTP
test
tape
Blank tape
Double-sided adhesive tape
SPECIFICATION/MANUFACTURER
Rise Time: 0.02 us/cm
0 to 30V
d.c.
With RECORD and PLAYBACK facilities
'Safebloc' type
General purpose
Open Market
Sinclair
Open Market
12mm and 6mm wide, Tesafix 959
(B.D.F. TESA) or 3M equivalent
Engineers
who are
already
familiar
with
the
Sinclair
ZX81
will
find
some
similarities
in the ZX
SPECTRUM.
The
Spectrum,
however,
is a
more
sophisticated device with colour and sound circuitry.
The ZX
SPECTRUM
is
supplied
with
either
16k or 48k of
on-board
RAM.
The
16k version is wired so that it can be expanded to 48k by the addition
of a
number
of
appropriate
plug-in
ICs.
For
details
of the
memory
upgrade, see sub-section 4 of this section.
See Section 5, Figures 5.1 and 5.2 for the layouts of the Issue 2 and
Issue 3 boards respectively.
4.2
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