Editing Amstrad CPC 664 Capacitor Replacement Guide (section)

== Floppy Drive Logic Board Capacitors ==

The Hitachi 3-inch drive carries its own small PCB on top of the mechanism with the head amplifier, the FDC interface buffers and the motor driver. Capacitors on this logic board age along with everything else and are a known source of intermittent read/write failures.

Typical positions and values (vary by drive manufacturer date):
* '''47 µF / 16 V''' on the head pre-amp supply &mdash; one or two caps. Aged caps cause weak read signal and CRC errors.
* '''10 µF / 16 V''' on the motor driver. Aged caps cause unstable motor speed.
* '''0.1 µF ceramic''' per logic IC supply pair. These rarely fail.

Inspect the drive logic board for leaked electrolytes (a brown crust around the cap base or a wet appearance on the PCB) before any work. If electrolyte has leaked, clean the board thoroughly with IPA, neutralise with a baking-soda paste sparingly, and inspect for trace corrosion.