AREA SYMPTOM ACTION
Colour faults Intermittent 1. Change TC2 (Issue 1 and
(cont'd) colour. Issue 2 boards).
2. Change IC14.
Red, Blue or Change IC1.
Green 'Sinclair'
logo.
Washed-out Check TR2.
colours.
Keyboard faults. KB1 fault. 1. Check for short on 2 or
more of the 5 tracks.
2. Change membrane.
KB2 fault. 1. Check for short on 2 or
more of the 8 tracks.
2. Change membrane.
Dead keyboard. Change IC1.
Wrong keyboard Change IC1.
response.
Keyboard response Change IC1.
too fast.
Regulator
coil.
Coil excessively
Change
coil.
noise.
Speaker. No speaker output. 1. Check load input wave-
forms
.
NOTE: Figure 4.2 2. Check TR7.
shows typical 3. Check D9.
waveforms in the 4. Change speaker.
speaker circuit
Test program. 'Tape Loading Error' Reload program.
output.
Paper area edges Change IC1.
distort.
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