Editing Amstrad CPC 464 Capacitor Replacement Guide (section)

== Diagnostic Procedure ==

# Disconnect the CPC from the monitor (no power).
# Open the system unit, separating the keyboard from the lower case.
# Disconnect the cassette sub-PCB ribbon at CP001 on the main PCB.
# Inspect each electrolytic cap for visible signs of aging: bulged top, leaked electrolyte (brown crust on the PCB around the cap), discoloured plastic sleeve, or cracked seal at the base.
# With a multimeter on resistance / ESR mode, probe each electrolytic in-circuit:
#: '''Good electrolytic''': reads high resistance after a brief charge pulse. ESR within manufacturer spec for the capacitance (e.g. < 1 Ω for 470 µF).
#: '''Bad electrolytic''': reads low resistance (short), or very high ESR (> 3&times; the spec value).
# If any cap reads bad, remove it and confirm out-of-circuit. Other components on the same rail can give false low-resistance readings.

If the system unit appears generally healthy but the audio is degraded, replace the '''AY-3-8912 output stage caps''' (C309, C311, C314, C315) as a set. They are physically clustered on the main PCB and a 4-cap recap takes about 15 minutes.

If the cassette deck does not start the motor, replace C322 first; this single cap accounts for the majority of "cassette motor dead but everything else works" symptoms.