Editing Amstrad CPC 464 Maintenance Guide (section)

== Cassette Deck Maintenance ==

The integrated cassette deck is a single-motor design driven by a rubber main belt (part 170204). The belt drives the flywheel (part 809156), which drives the capstan; a separate idler (part 809155) drives the take-up reel during play and rewind. Maintenance points:

* '''Main belt (170204)''': replaces about every 10&ndash;20 years; 35-year-old original belts are almost universally either liquefied (turned into a sticky black residue on the pulleys) or stretched. Symptom: tape will not load, motor runs but capstan does not turn. Replace the belt with a 67&times;1.2&nbsp;mm square-section drive belt of equal length.
* '''Pinch roller (809162)''': hardens with age. Symptom: tape speed drifts under load, or tape edge curls because the pinch roller is no longer compressing evenly. Replace with a modern silicone-rubber pinch-roller of matching diameter.
* '''Capstan and head cleaning''': clean every 50 tapes or annually, whichever comes first. IPA on a foam swab. Do not over-saturate &mdash; IPA running down the capstan can wash old lubricant out of the bearing.
* '''Speed adjustment''': the cassette motor (part 170208) has no service-adjustable speed pot; speed is set by the motor governor and the belt tension. A speed error of &plusmn;4% will not affect software loading per the official service manual; greater errors require pinch-roller and belt replacement before suspecting the motor.
* '''Azimuth''': adjusted by the screw on the R/P head. Insert a test tape recorded at 6 kHz constant tone, set volume to maximum, and adjust the azimuth screw to read 330&ndash;520 mV at pin 7 of IC302 (LA6324). This is per the official service-manual procedure.

The cassette sub-PCB carries two electrolytic capacitors that age (C322 470µF/10V on the motor relay, C315 100µF/16V on the audio output). See [[Amstrad CPC 464 Capacitor Replacement Guide]].