Sinclair ZX Spectrum Service Manual
Spectrum For Everyone https://spectrumforeveryone.com/
29
4.2.4 Symptomatic Faults
As with any complex digital equipment the possible permutations are vast, thus the following table is
not intended to be an exhaustive list of the faults that might occur on the Spectrum. It is intended as a
guide only to possible courses of action to follow when faults show up in particular areas of the circuit.
These areas are listed in the table with sub-headings, in no particular order of priority. It is envisaged
that the ZXTP test tape has been loaded, or an attempt has been made to load the tape, in order to
check for a faulty condition.
Authors Note: Table details to follow when production and in-service history is known.
4.3 REPAIR
Renewal of components should be carried out using recognised desoldering/heatsinking techniques to
prevent damage to the component or to the printed circuit board. Other points to be noted are:
a) When replacing a keyboard matrix, take care that the ribbon connectors are fully inserted into
the board connectors, and are not kinked during insertion.
b) Make sure there is a good contact made between the voltage regulator body and the associated
heatsink in order to ensure adequate heat conduction.
c) When the regulator is being replaced it is recommended that a suitable proprietary thermal
grease is applied to the rear surface of the component body.
d) The modulator should be replaced as a complete unit.
e) When replacing plug-in IC’s, it is advisable to use the correct removal and insertion tools. Avoid
contaminating the connection pins by handling.
f) When handling IC’s take normal anti-static precautions. It is recommended that only a suitably
earthed, low power soldering iron be used.
g) After any component has been renewed the circuit board should be examined carefully, to
ensure that there are no solder 'splatters' which may cause short circuits between tracks and
connector pins.
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