Editing Amstrad CPC 464 Maintenance Guide (section)

== Connector Care ==

* '''J101''' (6-pin DIN female): RGB, sync, luminance, ground. Bent pins are a common DIN-socket failure mode. Inspect before reseating the monitor cable.
* '''J102''' (DB-9 male): joystick. Compatible with Atari-pin joysticks; the CPC adds Fire 3 on pin 5 (undocumented) and Joystick 2 ground on pin 9.
* '''J103''' (3.5 mm stereo jack): line-level audio output. Not strong enough to drive headphones directly &mdash; pass through an amplifier or low-impedance amplified speakers.
* '''J104''' (2.1 mm DC socket, centre positive): 5 V power input.
* '''Printer port''' (PCB edge connector, 34-pin): Centronics-compatible parallel printer port. The CPC has '''only 7 data bits''' (D7 is pulled to ground); some printers reject this and require a third-party 8-bit converter cable. Outputs are TTL-compatible.
* '''Expansion port''' (PCB edge connector, 50-pin): general-purpose system bus &mdash; the connector for the DDI-1 external floppy interface, the silicon disc, the multiface 2, ROM-boxes and aftermarket interfaces. Pin 1 carries the AY-3-8912 SOUND output, pins 27/49 carry +5 V and GND.

When reseating PCB edge connectors, clean the gold-plated fingers on the PCB and the contacts in the mating connector with a soft eraser or a deoxidising contact cleaner. Edge-connector contacts oxidise faster on the CPC 464 than on most contemporaries because the PCB-edge fingers are exposed at the rear of the case.