Editing Amstrad CPC 464 Capacitor Replacement Guide (section)

== Failure Mode and Symptoms ==

* '''C322 (470 µF/10 V)''' &mdash; supplies the cassette motor relay. Most likely to dry out and develop high ESR. Symptom: '''cassette motor will not start, or starts then stops''', and the system may print "Read Error a" repeatedly.
* '''C309, C311, C314 (1 µF/50 V)''' &mdash; AY-3-8912 DC-blocking on the three sound output channels. Aged caps cause distorted audio or one of the three channels going silent. Symptom: '''one or more sound channels distorted or dead'''.
* '''C315 (100 µF/16 V)''' &mdash; audio output coupling. Aged cap causes weak speaker output. Symptom: '''quiet speaker, audio jack J103 also affected'''.
* '''C301, C304 (100 µF/10 V, cassette sub-PCB)''' &mdash; LA4140 audio amp supply rail. Aged caps cause hum, ripple-on-output, or instability. Symptom: '''mains hum or oscillation on speaker output'''.
* '''C302 (0.068 µF polystyrene)''' &mdash; reset RC. Failure is rare but produces erratic power-on behaviour. Symptom: '''random failures to start, requires multiple power cycles'''.